A practical guide for assessing and managing cardiovascular risk during androgen-deprivation therapy in patients with prostate cancer

Prostate cancer is the most common malignancy among men worldwide, and androgen-deprivation therapy (ADT) is a mainstay of treatment. There are observational data demonstrating an increased risk of cardiovascular events in patients who receive ADT, particularly those who have an elevated baseline cardiovascular risk. Because, for most patients with prostate cancer, death is predominantly from noncancer-related causes, cardiovascular disease and its risk factors should be optimized during cancer treatment. This review provides an overview of the landscape of ADT treatment and serves as a guide for appropriate cardiovascular screening and risk-mitigation strategies. The authors emphasize the importance of shared communication between the multidisciplinary cancer team and primary care to improve baseline cardiovascular screening and treatment of modifiable risk factors within this higher risk population.

Noninferiority of Hypofractionated vs Conventional Postprostatectomy Radiotherapy for Genitourinary and Gastrointestinal Symptoms: The NRG-GU003 Phase 3 Randomized Clinical Trial

Importance

No prior trial has compared hypofractionated postprostatectomy radiotherapy (HYPORT) to conventionally fractionated postprostatectomy (COPORT) in patients primarily treated with prostatectomy.

Objective

To determine if HYPORT is noninferior to COPORT for patient-reported genitourinary (GU) and gastrointestinal (GI) symptoms at 2 years.

Design, Setting, and Participants

In this phase 3 randomized clinical trial, patients with a detectable prostate-specific antigen (PSA; ≥0.1 ng/mL) postprostatectomy with pT2/3pNX/0 disease or an undetectable PSA (<0.1 ng/mL) with either pT3 disease or pT2 disease with a positive surgical margin were recruited from 93 academic, community-based, and tertiary medical sites in the US and Canada. Between June 2017 and July 2018, a total of 296 patients were randomized. Data were analyzed in December 2020, with additional analyses occurring after as needed.

Intervention

Patients were randomized to receive 62.5 Gy in 25 fractions (HYPORT) or 66.6 Gy in 37 fractions (COPORT).

Main Outcomes and Measures

The coprimary end points were the 2-year change in score from baseline for the bowel and urinary domains of the Expanded Prostate Cancer Composite Index questionnaire. Secondary objectives were to compare between arms freedom from biochemical failure, time to progression, local failure, regional failure, salvage therapy, distant metastasis, prostate cancer-specific survival, overall survival, and adverse events.

Results

Of the 296 patients randomized (median [range] age, 65 [44-81] years; 100% male), 144 received HYPORT and 152 received COPORT. At the end of RT, the mean GU change scores among those in the HYPORT and COPORT arms were neither clinically significant nor different in statistical significance and remained so at 6 and 12 months. The mean (SD) GI change scores for HYPORT and COPORT were both clinically significant and different in statistical significance at the end of RT (-15.52 [18.43] and -7.06 [12.78], respectively; P < .001). However, the clinically and statistically significant differences in HYPORT and COPORT mean GI change scores were resolved at 6 and 12 months. The 24-month differences in mean GU and GI change scores for HYPORT were noninferior to COPORT using noninferiority margins of -5 and -6, respectively, rejecting the null hypothesis of inferiority (mean [SD] GU score: HYPORT, -5.01 [15.10] and COPORT, -4.07 [14.67]; P = .005; mean [SD] GI score: HYPORT, -4.17 [10.97] and COPORT, -1.41 [8.32]; P = .02). With a median follow-up for censored patients of 2.1 years, there was no difference between HYPORT vs COPORT for biochemical failure, defined as a PSA of 0.4 ng/mL or higher and rising (2-year rate, 12% vs 8%; P = .28).

Conclusions and Relevance

In this randomized clinical trial, HYPORT was associated with greater patient-reported GI toxic effects compared with COPORT at the completion of RT, but both groups recovered to baseline levels within 6 months. At 2 years, HYPORT was noninferior to COPORT in terms of patient-reported GU or GI toxic effects. HYPORT is a new acceptable practice standard for patients receiving postprostatectomy radiotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT03274687.

Long-term Outcomes of Chemoradiation for Muscle-invasive Bladder Cancer in Noncystectomy Candidates. Final Results of NRG Oncology RTOG 0524-A Phase 1/2 Trial of Paclitaxel + Trastuzumab with Daily Radiation or Paclitaxel Alone with Daily Irradiation

BACKGROUND

Chemo-radiation is a well-established alternative to radical cystectomy in patients with muscle-invasive bladder cancer. Many patients due to age or medical comorbidity are unfit for either radical cystectomy, or standard cisplatin- or 5-fluorouracil-based chemoradiation, and do not receive appropriate treatment with curative intent. We treated patients with a less aggressive protocol employing seven weekly doses of paclitaxel and daily irradiation. In those whose tumors showed overexpression of her2/neu, seven weekly doses of trastuzumab were also administered.

OBJECTIVE

To report the long-term survival outcomes and toxicity results of the of NRG Oncology RTOG 0524 study.

DESIGN, SETTING, AND PARTICIPANTS

Seventy patients were enrolled and 65 (median age: 76 yr) were deemed eligible. Patients were assigned to daily radiation and weekly paclitaxel + trastuzumab (group 1, 20 patients) or to daily radiation plus weekly paclitaxel (group 2, 45 patients) based on tumor her2/neu overexpression. Radiation was delivered in 1.8 Gy fractions to a total dose of 64.8 Gy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was unresolved treatment-related toxicity. The secondary endpoints were complete response rate, protocol completion rate, and disease-free and overall survival.

RESULTS AND LIMITATIONS

Protocol therapy was completed by 60% (group 1) and 76% (group 2); complete response rates at 12 wk were 62% in each group. Acute treatment-related adverse events (AEs) of grade ≥3 were observed in 80% in group 1 and 58% in group 2. There was one treatment-related grade 5 AE in group 1. Unresolved acute treatment-related toxicity was 35% in group 1 and 31% in group 2. The median follow-up was 2.3 yr in all patients and 7.2 yr in surviving patients. Overall survival at 5 yr was 25.0% in group 1 and 37.8% in group 2 (33.8% overall). At 5 yr, disease-free survival was 15.0% in group 1 and 31.1% in group 2.

CONCLUSIONS

In a cohort of patients with muscle-invasive bladder cancer who are not candidates for cystectomy or cisplatin chemotherapy, chemoradiation therapy offers a treatment with a significant response rate and 34% 5-yr overall survival. While there were many AEs in this medically fragile group, there were few grade 4 events and one grade 5 event attributable to therapy.

PATIENT SUMMARY

Patients with invasive bladder cancer who cannot tolerate surgery were treated with radiation and systemic therapy without surgically removing their bladders. Most patients tolerated the treatment, were able to keep their bladders, and showed a significant treatment response rate.

Cardiovascular Mortality and Duration of Androgen Deprivation in Locally Advanced Prostate Cancer: Long-term Update of NRG/RTOG 9202

BACKGROUND

Androgen deprivation therapy (ADT) has been associated with coronary heart disease and myocardial infarction (MI) in prostate cancer patients, but controversy persists regarding its effects on cardiovascular mortality (CVM).

OBJECTIVE

We assessed the long-term relationship between ADT and CVM in a prostate cancer randomized trial (NRG Oncology/Radiation Therapy Oncology Group 9202).

DESIGN, SETTING, AND PARTICIPANTS

From 1992 to 1995, 1554 men with locally advanced prostate cancer (T2c-T4, prostate-specific antigen <150 ng/ml) received radiotherapy with 4 mo (short-term [STADT]) versus 28 mo (longer-term [LTADT]) of ADT.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Using the Fine-Gray and Cox regression models, the relationship between ADT and mortality was evaluated.

RESULTS AND LIMITATIONS

With a median follow-up of 19.6 yr, LTADT was associated with improved overall survival (OS) versus STADT (adjusted hazard ratio [HR] 0.88; p = 0.03) and prostate cancer survival (subdistribution HR [sHR] 0.70, p = 0.003). Comparing LTADT with STADT, prostate cancer mortality improved by 6.0% (15.6% [95% confidence interval 13.0-18.3%] vs 21.6% [18.6-24.7%]) at 15 yr, while CVM increased by 2.2% (14.9% [12.4-17.6%] vs 12.7% [10.4-15.3%]). In multivariable analyses, LTADT was not associated with increased CVM versus STADT (sHR 1.22 [0.93-1.59]; p = 0.15). An association between LTADT and MI death was detected (sHR 1.58 [1.00-2.50]; p = 0.05), particularly in patients with prevalent cardiovascular disease (CVD; sHR 2.54 [1.16-5.58]; p = 0.02).

CONCLUSIONS

With 19.6 yr of follow-up, LTADT was not significantly associated with increased CVM in men with locally advanced prostate cancer. Patients may have increased MI mortality with LTADT, particularly those with baseline CVD. Overall, there remained a prostate cancer mortality benefit and no OS detriment with LTADT.

PATIENT SUMMARY

In a long-term analysis of a large randomized prostate cancer trial, radiation with 28 mo of hormone therapy did not increase the risk of cardiovascular death significantly versus 4 mo of hormone therapy. Future studies are needed for patients with pre-existing heart disease, who may have an increased risk of myocardial infarction death with longer hormone use.

External Validation of a Digital Pathology-based Multimodal Artificial Intelligence Architecture in the NRG/RTOG 9902 Phase 3 Trial

BACKGROUND

Accurate risk stratification is critical to guide management decisions in localized prostate cancer (PCa). Previously, we had developed and validated a multimodal artificial intelligence (MMAI) model generated from digital histopathology and clinical features. Here, we externally validate this model on men with high-risk or locally advanced PCa treated and followed as part of a phase 3 randomized control trial.

OBJECTIVE

To externally validate the MMAI model on men with high-risk or locally advanced PCa treated and followed as part of a phase 3 randomized control trial.

DESIGN, SETTING, AND PARTICIPANTS

Our validation cohort included 318 localized high-risk PCa patients from NRG/RTOG 9902 with available histopathology (337 [85%] of the 397 patients enrolled into the trial had available slides, of which 19 [5.6%] failed due to poor image quality).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Two previously locked prognostic MMAI models were validated for their intended endpoint: distant metastasis (DM) and PCa-specific mortality (PCSM). Individual clinical factors and the number of National Comprehensive Cancer Network (NCCN) high-risk features served as comparators. Subdistribution hazard ratio (sHR) was reported per standard deviation increase of the score with corresponding 95% confidence interval (CI) using Fine-Gray or Cox proportional hazards models.

RESULTS AND LIMITATIONS

The DM and PCSM MMAI algorithms were significantly and independently associated with the risk of DM (sHR [95% CI] = 2.33 [1.60-3.38], p < 0.001) and PCSM, respectively (sHR [95% CI] = 3.54 [2.38-5.28], p < 0.001) when compared against other prognostic clinical factors and NCCN high-risk features. The lower 75% of patients by DM MMAI had estimated 5- and 10-yr DM rates of 4% and 7%, and the highest quartile had average 5- and 10-yr DM rates of 19% and 32%, respectively (p < 0.001). Similar results were observed for the PCSM MMAI algorithm.

CONCLUSIONS

We externally validated the prognostic ability of MMAI models previously developed among men with localized high-risk disease. MMAI prognostic models further risk stratify beyond the clinical and pathological variables for DM and PCSM in a population of men already at a high risk for disease progression. This study provides evidence for consistent validation of our deep learning MMAI models to improve prognostication and enable more informed decision-making for patient care.

PATIENT SUMMARY

This paper presents a novel approach using images from pathology slides along with clinical variables to validate artificial intelligence (computer-generated) prognostic models. When implemented, clinicians can offer a more personalized and tailored prognostic discussion for men with localized prostate cancer.

Mortality Risk for Docetaxel-Treated, High-Grade Prostate Cancer With Low PSA Levels: A Meta-Analysis

Importance

Patients with high-grade prostate cancer with low levels of prostate-specific antigen (PSA; <4 ng/mL) are at high risk of mortality, necessitating an improved treatment paradigm.

Objective

To assess for these patients whether adding docetaxel to standard of care (SOC) treatment is associated with decreased prostate cancer-specific mortality (PCSM) and all-cause mortality (ACM).

Data Sources

PubMed search from 2000 to 2022.

Study Selection

Five prospective randomized clinical trials (RCTs) performed in the US, France, and the United Kingdom evaluating SOC treatment with radiotherapy and androgen deprivation therapy (ADT) or with radical prostatectomy vs SOC plus docetaxel.

Data Extraction and Synthesis

Individual data were included from patients with nonmetastatic prostate cancer, a PSA level of less than 4 ng/mL, and a Gleason score of 8 to 10. Patients initiated treatment between February 21, 2006, and December 31, 2015 (median follow-up, 7.1 [IQR, 5.4-9.9] years). Data were analyzed on December 16, 2022.

Main Outcomes and Measures

Hazard ratio (HR) of ACM and subdistribution HR (sHR) of PCSM adjusted for performance status (1 vs 0 or good health), Gleason score (9 or 10 vs 8), tumor category (T3-T4 vs T1-T2 or TX), and duration of ADT (2 years vs 4-6 months).

Results

From a cohort of 2184 patients, 145 patients (6.6%) in 4 RCTs were eligible (median age, 63 [IQR, 46-67] years). Thirty-one patients died, and of these deaths, 22 were due to prostate cancer. Performance status was 0 for 139 patients (95.9%) and 1 for 6 patients (4.1%). A reduced but nonsignificant risk of ACM (HR, 0.51 [95% CI, 0.24-1.09]) and PCSM (sHR, 0.42 [95% CI, 0.17-1.02]) was associated with patients randomized to SOC plus docetaxel compared with SOC. The risk reduction in ACM (HR, 0.46 [95% CI, 0.21-1.02]) was more pronounced among patients with a performance status of 0 and was significant for PCSM (sHR, 0.30 [95% CI, 0.11-0.86]).

Conclusions and Relevance

Adding docetaxel to SOC treatment for patients who are in otherwise good health with a PSA level of less than 4 ng/mL and a Gleason score of 8 to 10 was associated with a significant reduction in PCSM and therefore has the potential to improve prognosis.

Long-Term Outcomes of NRG/RTOG 0126, a Randomized Trial of High Dose (79.2 Gy) vs. Standard Dose (70.2 Gy) Radiation Therapy (RT) for Men with Localized Prostate Cancer

PURPOSE/OBJECTIVE(S)

NRG/RTOG 0126, a phase III trial for men with localized prostate cancer testing whether dose escalation to 79.2 Gy with 3DCRT/IMRT improved overall survival (OS). Long-term results of this trial are presented.

MATERIALS/METHODS

Patients with clinical stage T1b-T2b and either Gleason Score (GS) 2-6 and 10 ≤ PSA < 20 or GS 7 and PSA < 15 were eligible and randomized to receive 79.2 Gy or 70.2 Gy. No previous or concurrent androgen withdrawal therapy was administered. Treatment was delivered with 3DCRT/IMRT to a dose of 79.2 Gy in 44 fractions or 70.2 Gy in 39 fractions to the PTV encompassing the prostate and seminal vesicles. Image guidance was not required. ASTRO and Phoenix definitions were used for biochemical failure (ABF and PBF, respectively). OS was estimated by the Kaplan-Meier method and arms compared with the log-rank test. ABF, PBF, local progression (LP), distant metastases (DM) and time to late GI/GU toxicities were estimated by the cumulative incidence method and arms compared with Gray's test.

RESULTS

One thousand five hundred thirty-two men were randomized, 763 to 79.2 Gy and 769 to 70.2 Gy. 1499 were eligible, 748 and 751 in the 79.2 Gy and 70.2 Gy arms respectively. Median age was 71, 70% had PSA < 10 ng/ml, 84% with GS 7, 57% had T1 disease, and 66% treated with 3D-CRT. Outcomes are shown in the TABLE: . With a median follow up of 12 years, there was no significant difference in OS. There was a statistically significant decrease in the cumulative incidence of ABF, PBF, DM, LP, and salvage therapies in the 79.2 Gy arm. There were significantly higher rates of grade 2+ GI and GU toxicity in the 79.2 Gy arm. There were no statistically significant differences in the rates of grade 3+ GU or GI toxicity between either arm.

CONCLUSION

Long term follow up confirms no improvement in OS with dose escalation in this study population. However, there are significant improvements in ABF, PBF, DM, LP, and need for salvage therapy. Despite the use of more salvage therapy in the low dose arm, dose escalated RT resulted in lower rates of DM, a clinically relevant endpoint. Patients receiving dose escalation do experience a higher rate of grade 2+ GU and GI toxicity but no worse grade 3+ toxicities.

Genomic Classifier Performance in Intermediate-Risk Prostate Cancer: Results From NRG Oncology/RTOG 0126 Randomized Phase 3 Trial

PURPOSE

Intermediate-risk prostate cancer is a heterogeneous disease state with diverse treatment options. The 22-gene Decipher genomic classifier (GC) retrospectively has shown to improve risk stratification in these patients. We assessed the performance of the GC in men with intermediate-risk disease enrolled in NRG Oncology/RTOG 01-26 with updated follow-up.

METHODS AND MATERIALS

After National Cancer Institute approval, biopsy slides were collected from NRG Oncology/RTOG 01-26, a randomized phase 3 trial of men with intermediate-risk prostate cancer randomized to 70.2 Gy versus 79.2 Gy of radiation therapy without androgen deprivation therapy. RNA was extracted from the highest-grade tumor foci to generate the locked 22-gene GC model. The primary endpoint for this ancillary project was disease progression (composite of biochemical failure, local failure, distant metastasis, prostate cancer-specific mortality, and use of salvage therapy). Individual endpoints were also assessed. Fine-Gray or cause-specific Cox multivariable models were constructed adjusting for randomization arm and trial stratification factors.

RESULTS

Two-hundred fifteen patient samples passed quality control for analysis. The median follow-up was 12.8 years (range, 2.4-17.7). On multivariable analysis, the 22-gene GC (per 0.1 unit) was independently prognostic for disease progression (subdistribution hazard ratio [sHR], 1.12; 95% confidence interval [CI], 1.00-1.26; P = .04), biochemical failure (sHR, 1.22; 95% CI, 1.10-1.37; P < .001), distant metastasis (sHR, 1.28; 95% CI, 1.06-1.55; P = .01), and prostate cancer-specific mortality (sHR, 1.45; 95% CI, 1.20-1.76; P < .001). Ten-year distant metastasis in GC low-risk patients was 4% compared with 16% for GC high-risk patients. In patients with lower GC scores, the 10-year difference in metastasis-free survival rate between arms was -7%, compared with 21% for higher GC patients (P-interaction = .04).

CONCLUSIONS

This study represents the first validation of a biopsy-based gene expression classifier, assessing both its prognostic and predictive value, using data from a randomized phase 3 trial of intermediate-risk prostate cancer. Decipher improves risk stratification and can aid in treatment decision-making in men with intermediate-risk disease.

Validation of a Genomic Classifier in the NRG Oncology/RTOG 0521 Phase III Trial of Docetaxel with Androgen Suppression and Radiotherapy for Localized High-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

Decipher is a prognostic genomic classifier (GC) validated in several prospective NRG Oncology Phase III trials. Herein, we validate the GC in pre-treatment biopsy samples for risk stratification in a cohort of high-risk men treated with definitive radiotherapy and androgen suppression with or without docetaxel chemotherapy.

MATERIALS/METHODS

As per a pre-specified and approved NCI analysis plan (Navigator #1061), we obtained available formalin-fixed paraffin-embedded tissue from biopsy specimens from the NRG biobank from patients enrolled on the NRG/RTOG 0521 randomized phase III trial. After central review, the highest-grade tumors were profiled on clinical-grade whole-transcriptome arrays (Veracyte, San Diego, CA) and GC scores were obtained. Pre-specified categorical GC scores, adjusted for archival tissue analysis, were used to define higher (>0.46) and lower (≤0.46) risk groups. The primary objective was to validate the independent prognostic ability of GC for metastasis-free survival (MFS) with Cox multivariable analyses (MVA).

RESULTS

Samples were obtained from 283 consented, evaluable patients with tissue (50% of trial) yielding 183 (65%) GC scores that passed quality metrics, 91 from control and 92 from the interventional arm. Median age was 66 years, median PSA was 19.3 ng/uL (IQR: 8.1-41.4), 81% had clinical stage ≥T2 and 80% had Gleason score ≥8 (47% ≥9). Median GC score was 0.55 (IQR: 0.38-0.78) and overall the arms were balanced for key covariates. With a median follow-up of 9.9 years (IQR: 9.3, 10.7), 67 MFS events including 34 distant metastases (DM) were observed. On MVA, only the GC (per 0.1 unit) was independently associated with MFS (HR 1.12, 95% CI 1.01-1.25) as well as DM (sHR 1.22, 95% CI 1.06-1.41), whereas the 4 pre-defined trial risk groups used for stratification (based on Gleason score, T-stage and PSA), randomization and patient age were not. For categorical GC, on MVA, higher-risk GC patients (65%) had worse DM (sHR 2.82, 95% CI 1.1-7.3) compared to those with lower GC. Cumulative incidence of DM at 10-years was 27% for higher GC vs 9% (95% CI 7-18%) for lower GC. No biomarker-by-treatment interaction with GC and the addition of docetaxel was detected.

CONCLUSION

In pre-treatment biopsy samples from a randomized Phase 3 trial cohort, GC demonstrated its ability to further risk stratify clinically high-risk men demonstrating an independent association of GC score with DM and MFS. High-risk prostate cancer is a heterogeneous disease state and GC can improve risk stratification to help personalize shared decision-making. NRG-GU009/PREDICT-RT (NCT04513717) aims to determine the optimal therapy based on GC score for high-risk prostate cancer.

Individual Patient Data Analysis of 17 Randomized Trials vs. Real-World Data for Men with Localized Prostate Cancer Receiving Radiotherapy

PURPOSE/OBJECTIVE(S)

Prior work has demonstrated poor correlation between the results of randomized controlled trials (RCTs) and real-world evidence (RWD). However, patients enrolled in RCTs are often considered to poorly represent the real-world population. Herein, we utilize multiple large data repositories to determine differences in baseline characteristics and long-term outcomes between patients enrolled in RCTs and RWD that received radiotherapy for localized prostate cancer.

MATERIALS/METHODS

Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) Consortium was leveraged, and 17 phase III randomized trials were included. RWD were accessed through the Staging Collaboration for Cancer of the Prostate (STAR-CAP) cohort, a cohort that is comprised of >60 centers across the United States and Europe. Additionally, RWD was assessed via the Surveillance, Epidemiology, and End Results (SEER) database. MARCAP and STAR-CAP both contain outcomes for distant metastasis (DM), metastasis-free survival (MFS), prostate cancer-specific mortality (PCSM), and overall survival (OS). SEER only contains PCSM and OS. Wilcoxon signed-rank test and chi-square test were used to compare continuous and categorical variables, respectively. Inverse probability of treatment weighting (IPTW) analysis was conducted, balancing for age, PSA, Gleason score, T stage, and treatment year in the three cohorts. Cox and Fine-Gray regression models were used to compare disease outcomes between RCTs vs. RWD.

RESULTS

Data from 10,666 patients from RCTs, 6,530 patients in STAR-CAP, and 117,586 patients in SEER were included. SEER patients were slightly younger (p<0.001, median age 68 (IQR 62-73) than those in RCTs (70, IQR 65-74) and in STAR-CAP (70, IQR 64-74). 10-year OS in RCTs was 65.4%, STAR-CAP 70.2%, SEER 64.1%. OS was superior in STAR-CAP (RCTs as reference; HR 0.91, 95% CI 0.85-0.96, p<0.0001), but there was no significant difference between SEER and RCTs (HR 0.96, 95% CI 0.91-1.02, p = 0.22). 10-year PCSM cumulative incidence was 7.4% in RCTs, 8.1% in STAR-CAP, and 11.0% in SEER. There was no significant difference in PCSM between STAR-CAP RWD and RCTs (HR 0.88, 95% CI 0.78-1.01, p = 0.08), whereas PCSM was worse in SEER than RCTs (HR 1.37, 95% CI 1.21-1.55, p<0.0001). There was no significant difference in DM between STAR-CAP RWD and RCTs (HR 0.93, 95% CI 0.83-1.04, p = 0.2).

CONCLUSION

While baseline differences exist in patients enrolled on localized prostate cancer RCTs and real-world datasets, there were small if any significant relative differences in oncologic outcomes. This provides reassurance that RCT results are generally applicable to patients in routine practice.

Long-Term Follow-Up Analysis of NRG Oncology RTOG 0415: A Randomized Phase III Non-Inferiority Study Comparing Two Fractionation Schedules in Patients with Favorable-Risk Prostate Cancer

PURPOSE/OBJECTIVE(S)

To assess whether the efficacy of a hypofractionated (H) schedule is no worse than a conventional (C) schedule in men with low-risk prostate cancer.

MATERIALS/METHODS

Accrual began April 2006 and ended in December 2009. 1115 men with favorable-risk prostate cancer were randomly assigned 1:1 to a conventional (C) schedule (73.8 Gy in 41 fractions over 8.2 weeks) or to a hypofractionated (H) schedule (70 Gy in 28 fractions over 5.6 weeks). The trial was designed to establish with 90% power and alpha = 0.05 that (H) results in 5-year disease-free survival (DFS) that is not lower than (C) by more than 7% (hazard ratio (HR) < 1.52). Protocol specified secondary endpoints evaluated for noninferiority include: biochemical recurrence (BR), local progression, disease-specific survival, and overall survival.

RESULTS

One thousand ninety-two protocol eligible men were analyzed: 542 to C and 550 to H. Median follow-up is 12.75 years. Baseline characteristics were not different according to treatment arm. The estimated 12-year DFS is 56.1% (95% CI 51.5, 60.5) in the C arm and 61.8% (57.2, 66.0) in the H arm. The DFS hazard ratio (H/C) is 0.85 (0.71-1.03), confirming non-inferiority (p<0.001). Twelve-year cumulative incidence of biochemical recurrence (BR) was 17.0% (CI 13.8, 20.5) in the C-RT and 9.9% (CI 7.5, 12.6) in the H-RT arm; (HR = 0.56, (0.40-0.78) suggesting improved efficacy with H. Additional pre-specified secondary endpoints were non-inferior Late Grade ≥ 3 GI toxicity is 3.2% (C) vs. 4.4% (H), Relative risk (RR) for H vs. C 1.39 (CI 0.75, 2.55) Late Grade ≥ 3 GU toxicity is 3.4% (C) vs. 4.2% (H), RR = 1.26 (CI 0.69, 2.30).

CONCLUSION

In men with favorable-risk prostate cancer, long-term disease-free survival is non-inferior with 70 Gy in 28 fractions compared to 73.8 Gy in 41 fractions. The risk of BR is reduced with moderate hypofractionation. No differences in late Grade ≥3 GI/GU toxicity were observed between the arms. (ClinicalTrials.gov identifier: NCT00331773).

Non-Redundant Mechanisms of Immune Resistance to Radiotherapy Converge on Innate Immunity

PURPOSE/OBJECTIVE(S)

Despite evidence of preclinical synergy between radiotherapy (RT) and immune checkpoint blockade (ICB), randomized trials of RT/ICB have demonstrated limited benefit in solid tumors. We performed single-cell RNA sequencing (scRNA-seq) and CITE-seq (cellular indexing of transcriptomes and epitopes) to address the discordance between preclinical and clinical data. We hypothesized that multiple orthogonal inhibitory immune pathways restrain the local and systemic efficacy of RT beyond T-cell oriented immune checkpoints.

MATERIALS/METHODS

We used the EO771 syngeneic murine model of breast cancer to characterize the immune tumor microenvironment following RT with or without ICB. RT (16 Gy x 1) was delivered using the X-RAD SmART platform with CT image guidance. Neutralizing antibodies (anti-PD-1/Ly6G/Gr-1/CD47) were delivered by intraperitoneal injections. scRNA-seq analysis were performed by Seurat and BBrowser (BioTuring).

RESULTS

We found that adaptive ICB (anti-PD-1) reprogrammed the immune response to RT by promoting an M1-like interferon-primed state (ISG15, CXCL10) in tumor associated macrophages (TAMs) and by increasing the late recruitment of intratumoral neutrophils. Given that neutrophils may drive resistance to RT in other models, we evaluated the effect of intratumoral neutrophil depletion using anti-Ly6G or anti-Gr-1 on the antitumor efficacy of RT/ICB. Both neutrophil depletion strategies led to enhanced tumor control and improved survival in advanced EO771 tumors compared to RT/ICB alone (P<0.001). In parallel to this approach, we found that TAMs upregulated several innate immune checkpoints including SIRPα in response to RT. Disruption of the SIRPα-CD47 interaction by anti-CD47 antibodies similarly enhanced the antitumor efficacy of RT/ICB by improving tumor control and survival (P<0.001). Using scRNA-seq and unbiased clustering, we found that anti-CD47 eliminated an entire cluster of chronically inflamed TAMs, characterized by pro-inflammatory markers (IL1A, NOS2) and chemokines (CCL3, CXCL1/2/3). Anti-CD47 also reduced intratumoral neutrophils by eliminating a cluster of pathologically activated neutrophils, termed myeloid-derived suppressor cells (PMN-MDSCs) that expressed several markers of ferroptosis (TFRC, PTGS2, SLC3A2). Consistent with the potent immunosuppressive capacity of PMN-MDSCs, we found that anti-CD47 increased tumor-infiltrating lymphocytes including central memory TCF7+ T cells and CD19+ B cells. Lastly, by inference and analysis of cell-cell communication (CellChat), we found that anti-CD47 strengthened the interactions between TAMs and CD8+ T cells compared to RT/ICB alone.

CONCLUSION

Our data collectively indicate that resistance to RT/ICB in the EO771 model Is driven by innate immune cells including neutrophils and chronically inflamed TAMs. Targeted disruption of the CD47-SIRPα axis is a promising approach to overcoming immune resistance by reprogramming TAMs and eliminating PMN-MDSCs.

Quality of Life Results of Addition of Androgen Deprivation Therapy and Pelvic Lymph Node Treatment to Prostate Bed Salvage Radiotherapy: NRG Oncology/RTOG 0534 SPPORT

PURPOSE/OBJECTIVE(S)

Report the quality of life (QOL) analysis of the SPPORT trial of men with a detectable prostate specific antigen (PSA) after prostatectomy for prostate cancer randomized to (Arm 1) salvage prostate bed radiotherapy (PBRT), (Arm 2) 4-6 months of short-term androgen deprivation therapy (STADT) + PBRT, and (Arm 3) pelvic lymph node radiotherapy (PLNRT) + STADT + PBRT. Primary analysis established a benefit of adding PLNRT and STADT to PBRT. There was higher short term but no statistically significant difference in long term adverse events with the exception of blood or bone marrow events.

MATERIALS/METHODS

QOL endpoints were assessed at baseline, 6 weeks after RT start, 1 and 5 years, including Expanded Prostate Cancer Index Composite (EPIC) (bowel, urinary, sexual, and hormonal domains), Hopkins Symptom Checklist (HSCL-25) (depressive symptoms), and the EuroQol (EQ-5D) (health state weights used in quality adjusted life years (QALYs). In addition to statistical significance, differences in scores were assessed using 0.5 standard deviation (SD) as the criterion for clinical importance. Difference among arms was assessed using pairwise t-tests, Fisher's exact test, and mixed effects regression modeling. To control for multiplicity, the p-value required for statistical significance is p<0.025.

RESULTS

Six hundred forty-four patients consented to QOL, about 210 on each arm. Baseline characteristics were not significantly different among arms: 81% were white and 54% <65 years. For EPIC, bowel domain scores decreased at 6 weeks post-RT then increased by years 1 and 5, although not to baseline levels. One clinically significant difference in bowel scores was Arm 3 vs. Arm 1 at 6 weeks. For the urinary domain, scores decreased at 6 weeks post-RT and remained below baseline at 1 and 5 years, but there were no significant differences among arms. For the sexual domain, there were statistically significant differences between arms at 6 weeks and 1 year with patients receiving STADT exhibiting poorer sexual QOL scores. By year 5 the differences were no longer significant. A similar pattern was seen for the hormonal domain. For HSCL-25, differences at 6 weeks were statistically but not clinically significant, and there were no significant differences at the later time points. Comparisons of QALYs for overall survival over an 8-year horizon showed no significant group differences, with a mean of about 7.8 in each arm. Regarding freedom from progression, QALY means were 5.7, 6.5, and 7.4 years for Arms 1, 2, and 3, respectively, with a significant difference between Arms 3 and 1 (p = <.001) favoring the more intensive treatment.

CONCLUSION

While QOL generally declined among all arms at 6 weeks post RT, there were no clinically significant differences in QOL among arms at 5 years. QALYs for freedom from progression favored STADT + PLNRT + PBRT for salvage treatment of prostate cancer.

Effect of Brachytherapy With External Beam Radiation Therapy Versus Brachytherapy Alone for Intermediate-Risk Prostate Cancer: NRG Oncology RTOG 0232 Randomized Clinical Trial

PURPOSE

To determine whether addition of external beam radiation therapy (EBRT) to brachytherapy (BT) (COMBO) compared with BT alone would improve 5-year freedom from progression (FFP) in intermediate-risk prostate cancer.

METHODS

Men with prostate cancer stage cT1c-T2bN0M0, Gleason Score (GS) 2-6 and prostate-specific antigen (PSA) 10-20 or GS 7, and PSA < 10 were eligible. The COMBO arm was EBRT (45 Gy in 25 fractions) to prostate and seminal vesicles followed by BT prostate boost (110 Gy if 125-Iodine, 100 Gy if 103-Pd). BT arm was delivered to prostate only (145 Gy if 125-Iodine, 125 Gy if 103-Pd). The primary end point was FFP: PSA failure (American Society for Therapeutic Radiology and Oncology [ASTRO] or Phoenix definitions), local failure, distant failure, or death.

RESULTS

Five hundred eighty-eight men were randomly assigned; 579 were eligible: 287 and 292 in COMBO and BT arms, respectively. The median age was 67 years; 89.1% had PSA < 10 ng/mL, 89.1% had GS 7, and 66.7% had T1 disease. There were no differences in FFP. The 5-year FFP-ASTRO was 85.6% (95% CI, 81.4 to 89.7) with COMBO compared with 82.7% (95% CI, 78.3 to 87.1) with BT (odds ratio [OR], 0.80; 95% CI, 0.51 to 1.26; Greenwood T P = .18). The 5-year FFP-Phoenix was 88.0% (95% CI, 84.2 to 91.9) with COMBO compared with 85.5% (95% CI, 81.3 to 89.6) with BT (OR, 0.80; 95% CI, 0.49 to 1.30; Greenwood T P = .19). There were no differences in the rates of genitourinary (GU) or GI acute toxicities. The 5-year cumulative incidence for late GU/GI grade 2+ toxicity is 42.8% (95% CI, 37.0 to 48.6) for COMBO compared with 25.8% (95% CI, 20.9 to 31.0) for BT (P < .0001). The 5-year cumulative incidence for late GU/GI grade 3+ toxicity is 8.2% (95% CI, 5.4 to 11.8) compared with 3.8% (95% CI, 2.0 to 6.5; P = .006).

CONCLUSION

Compared with BT, COMBO did not improve FFP for prostate cancer but caused greater toxicity. BT alone can be considered as a standard treatment for men with intermediate-risk prostate cancer.

Artificial Intelligence Predictive Model for Hormone Therapy Use in Prostate Cancer

Predictive Model for Hormone Therapy in Prostate CancerDigital pathology images and clinical data from pretreatment prostate tissue were used to generate a predictive model to determine patients who would benefit from androgen deprivation therapy (ADT). In model-positive patients, ADT significantly reduced the risk of distant metastasis compared with radiotherapy alone.

Androgen Deprivation and Radiotherapy with or Without Docetaxel for Localized High-risk Prostate Cancer: Long-term Follow-up from the Randomized NRG Oncology RTOG 0521 Trial

BACKGROUND

Intensification of therapy may improve outcomes for patients with high-risk localized prostate cancer.

OBJECTIVE

To provide long-term follow-up data from phase III RTOG 0521, which compared a combination of androgen deprivation therapy (ADT) + external beam radiation therapy (EBRT) + docetaxel with ADT + EBRT.

DESIGN, SETTING, AND PARTICIPANTS

High-risk localized prostate cancer patients (>50% of patients had Gleason 9-10 disease) were prospectively randomized to 2 yr of ADT + EBRT or ADT + EBRT + six cycles of docetaxel. A total of 612 patients were accrued, and 563 were eligible and included in the modified intent-to-treat analysis.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was overall survival (OS). Analyses with Cox proportional hazards were performed as prespecified in the protocol; however, there was evidence of nonproportional hazards. Thus, a post hoc analysis was performed using the restricted mean survival time (RMST). The secondary endpoints included biochemical failure, distant metastasis (DM) as detected by conventional imaging, and disease-free survival (DFS).

RESULTS AND LIMITATIONS

After 10.4 yr of median follow-up among survivors, the hazard ratio (HR) for OS was 0.89 (90% confidence interval [CI] 0.70-1.14; one-sided log-rank p = 0.22). Survival at 10 yr was 64% for ADT + EBRT and 69% for ADT + EBRT + docetaxel. The RMST at 12 yr was 0.45 yr and not statistically significant (one-sided p = 0.053). No differences were detected in the incidence of DFS (HR = 0.92, 95% CI 0.73-1.14), DM (HR = 0.84, 95% CI 0.73-1.14), or prostate-specific antigen recurrence risk (HR = 0.97, 95% CI 0.74-1.29). Two patients had grade 5 toxicity in the chemotherapy arm and zero patients in the control arm.

CONCLUSIONS

After a median follow-up of 10.4 yr among surviving patients, no significant differences are observed in clinical outcomes between the experimental and control arms. These data suggest that docetaxel should not be used for high-risk localized prostate cancer. Additional research may be warranted using novel predictive biomarkers.

PATIENT SUMMARY

No significant differences in survival were noted after long-term follow-up for high-risk localized prostate cancer patients in a large prospective trial where patients were treated with androgen deprivation therapy + radiation to the prostate ± docetaxel.

Five-Year Patient-Reported Outcomes in NRG Oncology RTOG 0938, Evaluating Two Ultrahypofractionated Regimens for Prostate Cancer

PURPOSE

There is considerable interest in very short (ultrahypofractionated) radiation therapy regimens to treat prostate cancer based on potential radiobiological advantages, patient convenience, and resource allocation benefits. Our objective is to demonstrate that detectable changes in health-related quality of life measured by the bowel and urinary domains of the Expanded Prostate Cancer Index Composite (EPIC-50) were not substantially worse than baseline scores.

METHODS AND MATERIALS

NRG Oncology's RTOG 0938 is a nonblinded randomized phase 2 study of National Comprehensive Cancer Network low-risk prostate cancer in which each arm is compared with a historical control. Patients were randomized to 5 fractions (7.25 Gy in 2 week and a day [twice a week]) or 12 fractions (4.3Gy in 2.5 weeks [5 times a week]). Secondary objectives assessed patient-reported toxicity at 5 years using the EPIC. Chi-square tests were used to assess the proportion of patients with a deterioration from baseline of >5 points for bowel, >2 points for urinary, and >11 points for sexual score.

RESULTS

The study enrolled 127 patients to 5 fractions (121 eligible) and 128 patients to 12 fractions (125 eligible). The median follow-up for all patients at the time of analysis was 5.38 years. The 5-year frequency for >5 point change in bowel score were 38.4% (P = .27) and 23.4% (P = 0.98) for 5 and 12 fractions, respectively. The 5-year frequencies for >2 point change in urinary score were 46.6% (P = .15) and 36.4% (P = .70) for 5 and 12 fractions, respectively. For 5 fractions, 49.3% (P = .007) of patients had a drop in 5-year EPIC-50 sexual score of ≥11 points; for 12 fractions, 54% (P < .001) of patients had a drop in 5-year EPIC-50 sexual score of ≥11 points. Disease-free survival at 5 years is 89.6% (95% CI: 84.0-95.2) in the 5-fraction arm and 92.3% (95% CI: 87.4-97.1) in the 12-fraction arm. There was no late grade 4 or 5 treatment-related urinary or bowel toxicity.

CONCLUSIONS

This study confirms that, based on long-term changes in bowel and urinary domains and toxicity, the 5- and 12-fraction regimens are well tolerated. These ultrahypofractionated approaches need to be compared with current standard radiation therapy regimens.

Analysis of a Biopsy-Based Genomic Classifier in High-Risk Prostate Cancer: Meta-Analysis of the NRG Oncology/Radiation Therapy Oncology Group 9202, 9413, and 9902 Phase 3 Randomized Trials

PURPOSE

Decipher is a genomic classifier (GC) prospectively validated postprostatectomy. We validated the performance of the GC in pretreatment biopsy samples within the context of 3 randomized phase 3 high-risk definitive radiation therapy trials.

METHODS AND MATERIALS

A prespecified analysis plan (NRG-GU-TS006) was approved to obtain formalin-fixed paraffin-embedded tissue from biopsy specimens from the NRG biobank from patients enrolled in the NRG/Radiation Therapy Oncology Group (RTOG) 9202, 9413, and 9902 phase 3 randomized trials. After central review, the highest-grade tumors were profiled on clinical-grade whole-transcriptome arrays and GC scores were obtained. The primary objective was to validate the independent prognostic ability for the GC for distant metastases (DM), and secondary for prostate cancer-specific mortality (PCSM) and overall survival (OS) with Cox univariable and multivariable analyses.

RESULTS

GC scores were obtained on 385 samples, of which 265 passed microarray quality control (69%) and had a median follow-up of 11 years (interquartile range, 9-13). In the pooled cohort, on univariable analysis, the GC was shown to be a prognostic factor for DM (per 0.1 unit; subdistribution hazard ratio [sHR], 1.29; 95% confidence interval [CI], 1.18-1.41; P < .001), PCSM (sHR, 1.28; 95% CI, 1.16-1.41; P < .001), and OS (hazard ratio [HR], 1.16; 95% CI, 1.08-1.22; P < .001). On multivariable analyses, the GC (per 0.1 unit) was independently associated with DM (sHR, 1.22; 95% CI, 1.09-1.36), PCSM (sHR, 1.23; 95% CI, 1.09-1.39), and OS (HR, 1.12; 95% CI, 1.05-1.20) after adjusting for age, Prostate Specific Antigen, Gleason score, cT stage, trial, and randomized treatment arm. GC had similar prognostic ability in patients receiving short-term or long-term androgen-deprivation therapy, but the absolute improvement in outcome varied by GC risk.

CONCLUSIONS

This is the first validation of a gene expression biomarker on pretreatment prostate cancer biopsy samples from prospective randomized trials and demonstrates an independent association of GC score with DM, PCSM, and OS. High-risk prostate cancer is a heterogeneous disease state, and GC can improve risk stratification to help personalize shared decision making.

Dose-Escalated Radiotherapy Alone or in Combination With Short-Term Androgen Deprivation for Intermediate-Risk Prostate Cancer: Results of a Phase III Multi-Institutional Trial

PURPOSE

It remains unknown whether or not short-term androgen deprivation (STAD) improves survival among men with intermediate-risk prostate cancer (IRPC) treated with dose-escalated radiotherapy (RT).

METHODS

The NRG Oncology/Radiation Therapy Oncology Group 0815 study randomly assigned 1,492 patients with stage T2b-T2c, Gleason score 7, or prostate-specific antigen (PSA) value >10 and ≤20 ng/mL to dose-escalated RT alone (arm 1) or with STAD (arm 2). STAD was 6 months of luteinizing hormone-releasing hormone agonist/antagonist therapy plus antiandrogen. RT modalities were external-beam RT alone to 79.2 Gy or external beam (45 Gy) with brachytherapy boost. The primary end point was overall survival (OS). Secondary end points included prostate cancer-specific mortality (PCSM), non-PCSM, distant metastases (DMs), PSA failure, and rates of salvage therapy.

RESULTS

Median follow-up was 6.3 years. Two hundred nineteen deaths occurred, 119 in arm 1 and 100 in arm 2. Five-year OS estimates were 90% versus 91%, respectively (hazard ratio [HR], 0.85; 95% CI, 0.65 to 1.11]; P = .22). STAD resulted in reduced PSA failure (HR, 0.52; P <.001), DM (HR, 0.25; P <.001), PCSM (HR, 0.10; P = .007), and salvage therapy use (HR, 0.62; P = .025). Other-cause deaths were not significantly different (P = .56). Acute grade ≥3 adverse events (AEs) occurred in 2% of patients in arm 1 and in 12% for arm 2 (P <.001). Cumulative incidence of late grade ≥3 AEs was 14% in arm 1 and 15% in arm 2 (P = .29).

CONCLUSION

STAD did not improve OS rates for men with IRPC treated with dose-escalated RT. Improvements in metastases rates, prostate cancer deaths, and PSA failures should be weighed against the risk of adverse events and the impact of STAD on quality of life.

Neighborhood Deprivation and Rurality Associated With Patient-Reported Outcomes and Survival in Men With Prostate Cancer in NRG Oncology RTOG 0415

PURPOSE

Rurality and neighborhood deprivation can contribute to poor patient-reported outcomes, which have not been systematically evaluated in patients with specific cancers in national trials. Our objective was to examine the effect of rurality and neighborhood socioeconomic and environmental deprivation on patient-reported outcomes and survival in men with prostate cancer in NRG Oncology RTOG 0415.

METHODS AND MATERIALS

Data from men with prostate cancer in trial NRG Oncology RTOG 0415 were analyzed; 1,092 men were randomized to receive conventional radiation therapy or hypofractionated radiation therapy. Rurality was categorized as urban or rural. Neighborhood deprivation was assessed using the area deprivation index and air pollution indicators (nitrogen dioxide and particulate matter with a diameter less than 2.5 micrometers) via patient ZIP codes. Expanded Prostate Cancer Index Composite measured cancer-specific quality of life. The Hopkins symptom checklist measured anxiety and depression. EuroQoL-5 Dimension assessed general health.

RESULTS

We analyzed 751 patients in trial NRG Oncology RTOG 0415. At baseline, patients from the most deprived neighborhoods had worse bowel (P = .011), worse sexual (P = .042), and worse hormonal (P = .015) scores; patients from the most deprived areas had worse self-care (P = .04) and more pain (P = .047); and patients from rural areas had worse urinary (P = .03) and sexual (P = .003) scores versus patients from urban areas. Longitudinal analyses showed that the 25% most deprived areas (P = .004) and rural areas (P = .002) were associated with worse EuroQoL-5 Dimension visual analog scale score. Patients from urban areas (hazard ratio, 1.81; P = .033) and the 75% less-deprived neighborhoods (hazard ratio, 0.68; P = .053) showed relative decrease in risk of recurrence or death (disease-free survival).

CONCLUSIONS

Patients with prostate cancer from the most deprived neighborhoods and rural areas had low quality of life at baseline, poor general health longitudinally, and worse disease-free survival. Interventions should screen populations from deprived neighborhoods and rural areas to improve patient access to supportive care services.

Dose-Escalated Radiation Alone or in Combination With Short-Term Total Androgen Suppression for Intermediate-Risk Prostate Cancer: Patient-Reported Outcomes From NRG/Radiation Therapy Oncology Group 0815 Randomized Trial

PURPOSE

To report patient-reported outcomes (PROs) of a phase III trial evaluating total androgen suppression (TAS) combined with dose-escalated radiation therapy (RT) for patients with intermediate-risk prostate cancer.

METHODS

Patients with intermediate-risk prostate cancer were randomly assigned to dose-escalated RT alone (arm 1) or RT plus TAS (arm 2) consisting of luteinizing hormone-releasing hormone agonist/antagonist with oral antiandrogen for 6 months. The primary PRO was the validated Expanded Prostate Cancer Index Composite (EPIC-50). Secondary PROs included Patient-Reported Outcome Measurement Information System (PROMIS)-fatigue and EuroQOL five-dimensions scale questionnaire (EQ-5D). PRO change scores, calculated for each patient as the follow-up score minus baseline score (at the end of RT and at 6, 12, and 60 months), were compared between treatment arms using a two-sample t test. An effect size of 0.50 standard deviation was considered clinically meaningful.

RESULTS

For the primary PRO instrument (EPIC), the completion rates were ≥86% through the first year of follow-up and 70%-75% at 5 years. For the EPIC hormonal and sexual domains, there were clinically meaningful (P < .0001) deficits in the RT + TAS arm. However, there were no clinically meaningful differences by 1 year between arms. There were also no clinically meaningful differences at any time points between arms for PROMIS-fatigue, EQ-5D, and EPIC bowel/urinary scores.

CONCLUSION

Compared with dose-escalated RT alone, adding TAS demonstrated clinically meaningful declines only in EPIC hormonal and sexual domains. However, even these PRO differences were transient, and there were no clinically meaningful differences between arms by 1 year.

Artificial Intelligence Predictive Model for Hormone Therapy Use in Prostate Cancer

Background

Androgen deprivation therapy (ADT) with radiotherapy can benefit patients with localized prostate cancer. However, ADT can negatively impact quality of life and there remain no validated predictive models to guide its use.

Methods

Digital pathology image and clinical data from pre-treatment prostate tissue from 5,727 patients enrolled on five phase III randomized trials treated with radiotherapy +/- ADT were used to develop and validate an artificial intelligence (AI)-derived predictive model to assess ADT benefit with the primary endpoint of distant metastasis. After the model was locked, validation was performed on NRG/RTOG 9408 (n = 1,594) that randomized men to radiotherapy +/- 4 months of ADT. Fine-Gray regression and restricted mean survival times were used to assess the interaction between treatment and predictive model and within predictive model positive and negative subgroup treatment effects.

Results

In the NRG/RTOG 9408 validation cohort (14.9 years of median follow-up), ADT significantly improved time to distant metastasis (subdistribution hazard ratio [sHR] = 0.64, 95%CI [0.45-0.90], p = 0.01). The predictive model-treatment interaction was significant (p-interaction = 0.01). In predictive model positive patients (n = 543, 34%), ADT significantly reduced the risk of distant metastasis compared to radiotherapy alone (sHR = 0.34, 95%CI [0.19-0.63], p < 0.001). There were no significant differences between treatment arms in the predictive model negative subgroup (n = 1,051, 66%; sHR = 0.92, 95%CI [0.59-1.43], p = 0.71).

Conclusions

Our data, derived and validated from completed randomized phase III trials, show that an AI-based predictive model was able to identify prostate cancer patients, with predominately intermediate-risk disease, who are likely to benefit from short-term ADT.

Abstract 6409: Non-redundant mechanisms of immune resistance to radiotherapy converge on innate immunity

Multiple studies have demonstrated synergy between immune checkpoint blockade (ICB) and radiotherapy (RT) in preclinical murine models; however, randomized trials of RT/ICB have been inconsistent in patients with solid tumors. To better understand this discordance, we hypothesized that there are non-redundant inhibitory immune pathways that restrain the efficacy of RT beyond T-cell oriented immune checkpoints. To this end, we performed scRNA-seq and CITE-seq analysis of the EO771 syngeneic murine model of breast cancer to characterize the immune landscape following RT±ICB. We found that ICB reprograms the immune response to RT by shifting tumor-associated macrophages (TAMs) from a lipid-associated phenotype (APOE, FABP5) to an M1-like interferon-stimulated state (CXCL10, ISG15). However, ICB also promoted the late recruitment of intratumoral neutrophils, which drive resistance to RT in other contexts. To evaluate whether neutrophils may be limiting antitumor immunity to RT/ICB, we depleted intratumoral neutrophils using two separate antibodies, anti-Ly6G and anti-Gr-1. Compared to RT/ICB alone, both neutrophil depletion strategies enhanced tumor control and prolonged survival in advanced EO771 tumors (P&lt;0.001). Given that indiscriminate neutrophil depletion is not a viable therapeutic strategy, we tested alternative immune targeting approaches to alter the TAM response to RT/ICB. By scRNA-seq, we found that RT strongly upregulated several innate immune checkpoints on TAMs (e.g., SIRPα, SLAMF3/7, LRP1). Accordingly, we disrupted the SIRPα-CD47 interaction with anti-CD47 antibodies and characterized the impact on response to RT/ICB. Anti-CD47 significantly improved tumor regression and survival when combined with RT/ICB (P&lt;0.001). We then used scRNA-seq and CITE-seq to understand why disruption of SIRPα-CD47 improved antitumor responses to RT/ICB. We found that anti-CD47 depleted an entire cluster of chronically inflamed TAMs, expressing pro-inflammatory markers (IL1A, NOS2) and chemokines (CCL3, CXCL1/2/3). Furthermore, anti-CD47 reduced the recruitment of intratumoral neutrophils and depleted a cluster of pathologically activated neutrophils (PMNs), termed myeloid-derived suppressor cells (PMN-MDSCs), expressing WFDC17, PTGS2, S100A8/9. Lastly, anti-CD47 enhanced the recruitment of tumor-infiltrating lymphocytes including central memory TCF7+ T cells and CD19+ B cells. By inference and analysis of cell-cell communication (CellChat), we found that anti-CD47 strengthened the interactions between myeloid cells and T cells compared to RT/ICB alone. Collectively, our data indicate that innate immune cells, in particular neutrophils and chronically inflamed TAMs, promote resistance to RT/ICB in the EO771 model. These data suggest that inhibition of CD47-SIRPα is a promising therapeutic strategy to overcoming immune resistance through the elimination of PMN-MDSCs.

Citation Format: Anthony T. Nguyen, Tahir B. Dar, Jolene Viramontes, Satchel Stevens, Julie K. Jang, Emily Y. Ko, Diana J. Lu, Eric M. Chung, Samuel C. Zhang, Katelyn M. Atkins, Mitchell Kamrava, Howard M. Sandler, Jlenia Guarnerio, Simon Knott, Zachary S. Zumsteg, David M. Underhill, Stephen L. Shiao. Non-redundant mechanisms of immune resistance to radiotherapy converge on innate immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6409.

Body composition and mortality in men receiving prostate radiotherapy: A pooled analysis of NRG/RTOG 9406 and NRG/RTOG 0126

PURPOSE

To validate the association between body composition and mortality in men treated with radiation for localized prostate cancer (PCa). Secondarily, to integrate body composition as a factor to classify patients by risk of all-cause mortality.

MATERIALS AND METHODS

Participants of NRG/Radiation Therapy Oncology Group (RTOG) 9406 and NRG/RTOG 0126 with archived computed tomography were included. Muscle mass and muscle density were estimated by measuring the area and attenuation of the psoas muscles on a single slice at L4-L5. Bone density was estimated by measuring the attenuation of the vertebral body at mid-L5. Survival analyses, including Cox proportional hazards models, assessed the relationship between body composition and mortality. Recursive partitioning analysis (RPA) was used to create a classification tree to classify participants by risk of death.

RESULTS

Data from 2066 men were included in this study. In the final multivariable model, psoas area, comorbidity score, baseline prostate serum antigen, and age were significantly associated with survival. The RPA yielded a classification tree with four prognostic groups determined by age, comorbidity, and psoas area. Notably, the classification among older (≥70 years) men into prognostic groups was determined by psoas area.

CONCLUSIONS

This study strongly supports that body composition is related to mortality in men with localized PCa. The inclusion of psoas area in the RPA classification tree suggests that body composition provides additive information to age and comorbidity status for mortality prediction, particularly among older men. More research is needed to determine the clinical impact of body composition on prognostic models in men with PCa.

Contemporary use of wearable activity monitors in prostate cancer survivors: A scoping review

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Background: Remote monitoring of daily activity using wearable activity monitors (“wearables”) (e.g., Fitbits) provides an unintrusive method to obtain continuous, objective physical activity (PA) and sleep data outside the clinical setting. Despite their potential for improving PA assessment for cancer survivors, there is currently limited information on how wearables are being used in PCa survivors. Thus, we reviewed the literature to understand how wearables are being integrated into research and interventional studies conducted in PCa survivors. Methods: We searched PubMed, CENTRAL, and Clinicaltrials.gov for randomized controlled trials (RCTs) and observational studies that involve commercially available wearables in PCa survivors, published between 2012 and 2022. Upon screening and full-text review by two independent reviewers, data were extracted from eligible studies, including study and patient characteristics, details on study interventions and outcomes, and purpose of device use. Baseline PA data were abstracted from articles with available quantitative data, including step counts, time spent in moderate-to-vigorous physical activity (MVPA), and sleep duration, and included in a quantitative analysis. Results: Eighty studies were screened and 17 studies met eligibility criteria and were included in this review (8 RCTs; 9 observational), with a total sample size of 1,148 PCa survivors (median age 66 years, range 39-84). Wearables used included: Fitbit: (47%), pedometer (18%), smartphone (6%), Jawbone (6%), and heart rate monitor (6%). Most studies (71%) involved individual or group-based exercise interventions that were either gym-based supervised by an exercise physiologist or home-based (online web-based delivery or written recommendations), as well as remotely delivered behavioral interventions. One study compared objective (actigraphy) and subjective sleep quality measures and one was a validation study comparing Fitbit to the ActiGraph accelerometer. Study durations ranged from 1-48 weeks with median reported adherence to wearing the device of 79.5% (range 63-100%). PA data, as measured with wearables, were available in 13 studies and summarized. Conclusions: Wearables are increasingly being used to assess daily activity and monitor adherence to exercise interventions in PCa survivors. Findings suggest wearables are feasible for use in this population with high levels of adherence. Wearables can provide added value to PA and functional assessment, although more research is needed to understand how wearables can be integrated into routine patient care or used as means to track or deliver tailored interventions for PCa survivors. [Table: see text]

Patient-level data meta-analysis of a multi-modal artificial intelligence (MMAI) prognostic biomarker in high-risk prostate cancer: Results from six NRG/RTOG phase III randomized trials

299

Background: Recently, an MMAI prognostic biomarker, ArteraAI Prostate, was trained and validated in localized prostate cancer to more accurately risk stratify patients for multiple endpoints compared to NCCN risk groups (Esteva et al., 2022). Prognostication within an NCCN risk group remains clinically important given the multiple treatment decisions required within each risk group (e.g., radiotherapy dose or hormone therapy use). Herein, we validated the MMAI biomarker in high-risk prostate cancer where an increasing number of therapeutic decisions is required. Methods: This study leveraged histopathology image and clinical data from patients with at least one high-risk feature (HRF; cT3-cT4, Gleason 8-10, PSA > 20 ng/mL, primary Gleason pattern 5) from six NRG/RTOG phase III randomized trials (n=1,088). Patients from two trials not part of the initial MMAI biomarker training/validation (RTOG 0521 [n=344] and 9902 [n=318]) and the MMAI validation cohort (RTOG 9202, 9408, 9413, and 9910 [n=426]) were included. Fine-Gray, cumulative incidence, and time dependent area under the curve (tdAUC) analyses were performed for time to distant metastasis (DM) and prostate cancer-specific mortality (PCSM) for standard clinicopathologic variables (age, PSA, Gleason score, T-stage, number of HRFs) and the MMAI model, as a continuous score (per standard deviation increase) and categorically by quartile. Death from other causes were treated as competing risks. Results: The analyzed cohort had a median follow-up of 10.4 years. Median PSA was 21 ng/mL, 60% had Gleason 8-10 disease, 37% had cT3-T4 disease, and 20% were African American. On univariable analysis, the MMAI model was significantly associated with DM (subdistribution hazard ratio [sHR] 2.05, 95% CI 1.74-2.43, p<0.001) and PCSM (sHR 2.04, 95% CI 1.73-2.42, <0.001). On multivariable analysis, the MMAI model, adjusting for either age, PSA, Gleason score, T-stage, or number of HRFs, was the only variable significantly associated with DM. TdAUC was highest for the MMAI biomarker for both 5-year DM (0.71), compared to PSA (0.56), Gleason score (0.61), T-stage (0.63), or number of HRFs (0.64), and for 5-year PCSM (0.75), compared to clinicopathologic variables (range 0.53-0.63). The estimated 10-year DM and 15-year PCSM rates for MMAI quartile 1 vs 4 were 8% vs 31% and 8% vs 34%, respectively. Conclusions: Our novel MMAI prognostic biomarker was successfully validated across six phase III randomized trials with long-term follow-up to be independently prognostic over standard clinical and pathologic variables for men with high-risk prostate cancer. Despite all patients having high-risk disease, the MMAI biomarker identified those with highly variable risks for DM and PCSM. This tool can help enable personalized, shared decision making for patients and providers.

Prostate cancer extracellular vesicle digital scoring assay - a rapid noninvasive approach for quantification of disease-relevant mRNAs

Optimizing outcomes in prostate cancer (PCa) requires precision in characterization of disease status. This effort was directed at developing a PCa extracellular vesicle (EV) Digital Scoring Assay (DSA) for detecting metastasis and monitoring progression of PCa. PCa EV DSA is comprised of an EV purification device (i.e., EV Click Chip) and reverse-transcription droplet digital PCR that quantifies 11 PCa-relevant mRNA in purified PCa-derived EVs. A Met score was computed for each plasma sample based on the expression of the 11-gene panel using the weighted Z score method. Under optimized conditions, the EV Click Chips outperformed the ultracentrifugation or precipitation method of purifying PCa-derived EVs from artificial plasma samples. Using PCa EV DSA, the Met score distinguished metastatic (n = 20) from localized PCa (n = 20) with an area under the receiver operating characteristic curve of 0.88 (95% CI:0.78-0.98). Furthermore, longitudinal analysis of three PCa patients showed the dynamics of the Met scores reflected clinical behavior even when disease was undetectable by imaging. Overall, a sensitive PCa EV DSA was developed to identify metastatic PCa and reveal dynamic disease states noninvasively. This assay may complement current imaging tools and blood-based tests for timely detection of metastatic progression that can improve care for PCa patients.

Sequencing of Androgen-Deprivation Therapy of Short Duration With Radiotherapy for Nonmetastatic Prostate Cancer (SANDSTORM): A Pooled Analysis of 12 Randomized Trials

PURPOSE

The sequencing of androgen-deprivation therapy (ADT) with radiotherapy (RT) may affect outcomes for prostate cancer in an RT-field size-dependent manner. Herein, we investigate the impact of ADT sequencing for men receiving ADT with prostate-only RT (PORT) or whole-pelvis RT (WPRT).

MATERIALS AND METHODS

Individual patient data from 12 randomized trials that included patients receiving neoadjuvant/concurrent or concurrent/adjuvant short-term ADT (4-6 months) with RT for localized disease were obtained from the Meta-Analysis of Randomized trials in Cancer of the Prostate consortium. Inverse probability of treatment weighting (IPTW) was performed with propensity scores derived from age, initial prostate-specific antigen, Gleason score, T stage, RT dose, and mid-trial enrollment year. Metastasis-free survival (primary end point) and overall survival (OS) were assessed by IPTW-adjusted Cox regression models, analyzed independently for men receiving PORT versus WPRT. IPTW-adjusted Fine and Gray competing risk models were built to evaluate distant metastasis (DM) and prostate cancer-specific mortality.

RESULTS

Overall, 7,409 patients were included (6,325 neoadjuvant/concurrent and 1,084 concurrent/adjuvant) with a median follow-up of 10.2 years (interquartile range, 7.2-14.9 years). A significant interaction between ADT sequencing and RT field size was observed for all end points (P interaction < .02 for all) except OS. With PORT (n = 4,355), compared with neoadjuvant/concurrent ADT, concurrent/adjuvant ADT was associated with improved metastasis-free survival (10-year benefit 8.0%, hazard ratio [HR], 0.65; 95% CI, 0.54 to 0.79; P < .0001), DM (subdistribution HR, 0.52; 95% CI, 0.33 to 0.82; P = .0046), prostate cancer-specific mortality (subdistribution HR, 0.30; 95% CI, 0.16 to 0.54; P < .0001), and OS (HR, 0.69; 95% CI, 0.57 to 0.83; P = .0001). However, in patients receiving WPRT (n = 3,049), no significant difference in any end point was observed in regard to ADT sequencing except for worse DM (HR, 1.57; 95% CI, 1.20 to 2.05; P = .0009) with concurrent/adjuvant ADT.

CONCLUSION

ADT sequencing exhibits a significant impact on clinical outcomes with a significant interaction with field size. Concurrent/adjuvant ADT should be the standard of care where short-term ADT is indicated in combination with PORT.

Recent Trends in Medicare Payments for Outpatient Cancer Care at the End of Life

PURPOSE

Outpatient care for cancer patients compromises 60 - 70% of healthcare costs over the last 6 months of life. Recent approvals for expensive biologics and growing support for lower-cost hypofractionated radiotherapy in the palliative management of advanced cancer have introduced offsetting spending effects on end-of-life care that may shift overall expenditures for this patient cohort.

METHODS AND MATERIALS

In this descriptive retrospective cohort study, end-of-life care is defined as the aggregate of medical services and supplies, including drugs, furnished to cancer patients in the outpatient setting over the last 6 months of life. 84,744 Medicare beneficiaries with a cancer diagnosis were identified as having died between Jan 1 2016 and Dec 31 2019. Beneficiaries with Medicare Advantage are not included in this study. Medicare Standard Analytic Files were abstracted for all paid claims for these beneficiaries over the last 6 months of life, and provider payments were summed according to service/supply category and year of death. Comparisons of service and supply utilization and costs between patient groups were performed using Pearson's chi square test.

RESULTS

Average total Medicare Part B payments per treated beneficiary over the last 6 month of life increased by 12.0% between 2016 - 2019 (from $14,487 to $16,227) with the greatest absolute cost increase observed for the Medical Oncology category (from $7,030 to $9,436 [+34.2%]). Within the Medical Oncology category, drug utilization shifted away from less costly chemotherapy and hormone therapy agents and toward more expensive immunotherapy agents. The increase in immunotherapy utilization and drug costs alone accounted for 84% of the increase in total Part B payments for all categories during the period.

CONCLUSION

While costs related to end-of-life care for nearly all cost categories have remained relatively stable, oncology drug costs overall and immunotherapy costs specifically have accelerated and account almost entirely for the observed overall increase in outpatient cost burden for Medicare.

Feasibility and acceptability of ChatGPT generated radiology report summaries for cancer patients

Objective

Patients now have direct access to their radiology reports, which can include complex terminology and be difficult to understand. We assessed ChatGPT's ability to generate summarized MRI reports for patients with prostate cancer and evaluated physician satisfaction with the artificial intelligence (AI)-summarized report.

Methods

We used ChatGPT to summarize five full MRI reports for patients with prostate cancer performed at a single institution from 2021 to 2022. Three summarized reports were generated for each full MRI report. Full MRI and summarized reports were assessed for readability using Flesch-Kincaid Grade Level (FK) score. Radiation oncologists were asked to evaluate the AI-summarized reports via an anonymous questionnaire. Qualitative responses were given on a 1-5 Likert-type scale. Fifty newly diagnosed prostate cancer patient MRIs performed at a single institution were additionally assessed for physician online portal response rates.

Results

Fifteen summarized reports were generated from five full MRI reports using ChatGPT. The median FK score for the full MRI reports and summarized reports was 9.6 vs. 5.0, (p < 0.05), respectively. Twelve radiation oncologists responded to our questionnaire. The mean [SD] ratings for summarized reports were factual correctness (4.0 [0.6], understanding 4.0 [0.7]), completeness (4.1 [0.5]), potential for harm (3.5 [0.9]), overall quality (3.4 [0.9]), and likelihood to send to patient (3.1 [1.1]). Current physician online portal response rates were 14/50 (28%) at our institution.

Conclusions

We demonstrate a novel application of ChatGPT to summarize MRI reports at a reading level appropriate for patients. Physicians were likely to be satisfied with the summarized reports with respect to factual correctness, ease of understanding, and completeness. Physicians were less likely to be satisfied with respect to potential for harm, overall quality, and likelihood to send to patients. Further research is needed to optimize ChatGPT's ability to summarize radiology reports and understand what factors influence physician trust in AI-summarized reports.

The Influence of the Pretreatment Immune State on Response to Radiation Therapy in High-Risk Prostate Cancer: A Validation Study From NRG/RTOG 0521

PURPOSE

The immunoinflammatory state has been shown to be associated with poor outcomes after radiation therapy (RT). We conducted an a priori designed validation study using serum specimens from Radiation Therapy Oncology Group (RTOG) 0521. It was hypothesized the pretreatment inflammatory state would correlate with clinical outcomes.

METHODS AND MATERIALS

Patients on RTOG 0521 had serum banked for biomarker validation. This study was designed to validate previous findings showing an association between elevations in C-reactive protein (CRP) and shorter biochemical disease free survival (bDFS). CRP levels were measured in pretreatment samples. An exploratory panel of related cytokines was also measured including: monocyte chemotactic protein-1, granulocyte-macrophage colony-stimulating factor, interferon-γ, interleukin (IL)-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-17A, IL-23, and tumor necrosis factor. The primary endpoint examined was bDFS. Additional exploratory endpoints included overall survival, distant metastases, and toxicity events attributed to RT.

RESULTS

Two hundred and two patients in RTOG/NRG 0521 had serum samples available. Median age was 66 years (48-83), and 90% of patients were White. There was not an association between CRP and bDFS (adjusted hazard ratio [HR], 1.07 per 1 log increase in CRP; 95% confidence interval, 0.83-1.38; P = .60). In the exploratory, unplanned analysis, pretreatment IL-10 was significantly associated with worse bDFS (adjusted HR, 1.61 per log increase; P = .0027) and distant metastases (HR, 1.55 per log increase; P = .028). The association of IL-10 with bDFS was maintained on a multiplicity adjustment. The exploratory analyses of pretreatment levels of interferon-γ, IL-1b, IL-2, IL-13, IL-23 were negatively associated with grade 2 or higher pollakiuria (adjusted odds ratio, 0.64, 0.65, 0.71, 0.72, and 0.74, respectively, all P < .05), and IL-6 was negatively associated with grade 2 or higher erectile dysfunction (odds ratio, 0.62; P = .027).

CONCLUSIONS

Pretreatment CRP was not associated with a poorer bDFS after RT. In a hypothesis- generating analysis, higher baseline levels of IL-10 were associated with lower rates of bDFS. These findings require additional prospective evaluation.

Biochemical Failure Is Not a Surrogate End Point for Overall Survival in Recurrent Prostate Cancer: Analysis of NRG Oncology/RTOG 9601

PURPOSE

Metastasis-free survival (MFS), but not event-free survival, is a validated surrogate end point for overall survival (OS) in men treated for localized prostate cancer. It remains unknown if this holds true in biochemically recurrent disease after radical prostatectomy. Leveraging NRG/RTOG 9601, we aimed to determine the performance of intermediate clinical end points (ICEs) as surrogate end points for OS in recurrent prostate cancer.

MATERIALS AND METHODS

NRG/RTOG 9601 randomly assigned 760 men with recurrence after prostatectomy to salvage radiation therapy with 2 years of placebo versus bicalutamide 150 mg daily. ICEs assessed were biochemical failure (BF) per NRG/RTOG 9601 (prostate-specific antigen nadir + 0.3-0.5 ng/mL or initiation of salvage hormone therapy; [BF1]) and NRG/RTOG 0534 (prostate-specific antigen nadir+2 ng/mL; [BF2]), distant metastasis (DM), and MFS (DM or death). Surrogacy was assessed by the Prentice criteria and a two-stage meta-analytic approach (condition one assessed at the patient level with Kendall's τ and condition two assessed by randomly dividing the entire trial cohort into 10 pseudo trial centers and calculating the average R2 between treatment hazard ratios for ICE and OS).

RESULTS

BF1, BF2, DM, and MFS satisfied the four Prentice criteria. However, with the two-condition meta-analytic approach, there was strong correlation between MFS and OS (τ = 0.86), moderate correlation between DM and OS (τ = 0.66), and weaker correlation between BF1 (τ = 0.25) or BF2 (τ = 0.40) and OS. Similarly, for condition two, the treatment effect of antiandrogen therapy on MFS and OS were correlated (R2 = 0.67), but this was not true for BF1 (R2 = 0.09), BF2 (R2 = 0.12), or DM (R2 = 0.18) and OS.

CONCLUSION

MFS is also a strong surrogate for OS in men receiving salvage radiation therapy for recurrence after prostatectomy. Caution should be used when inferring survival benefit from effects on BF in biochemically recurrent prostate cancer. Lack of comorbidity data did not allow us to assess whether BF in men with no/minimal comorbidity could serve as a surrogate for OS.

Quantitative Nodal Burden and Mortality Across Solid Cancers

BACKGROUND

Nodal staging systems vary substantially across solid tumors, implying heterogeneity in the behavior of nodal variables in various contexts. We hypothesized, in contradiction to this, that metastatic lymph node (LN) number is a universal and dominant predictor of outcome across solid tumors.

METHODS

We performed a retrospective cohort analysis of 1 304 498 patients in the National Cancer Database undergoing surgery between 2004 and 2015 across 16 solid cancer sites. Multivariable Cox regression analyses were constructed using restricted cubic splines to model the association between nodal number and mortality. Recursive partitioning analysis (RPA) was used to derive nodal classification systems for each solid cancer based on metastatic LN count. The reproducibility of these findings was assessed in 1 969 727 patients from the Surveillance, Epidemiology, and End Results registry. Two-sided tests were used for all statistical analyses.

RESULTS

Consistently across disease sites, mortality risk increased continuously with increasing number of metastatic LNs (P < .001 for all spline segments). Each RPA-derived nodal classification system produced multiple prognostic groups spanning a wide spectrum of mortality risk (P < .001). Multivariable models using these RPA-derived nodal classifications demonstrated improved concordance with mortality compared with models using American Joint Committee on Cancer staging in sites where nodal classification is not based on metastatic LN count. Each RPA-derived nodal classification system was reproducible in a large validation cohort for all-cause and cause-specific mortality (P < .001). High quantitative nodal burden was the single strongest tumor-intrinsic variable associated with mortality in 12 of 16 disease sites.

CONCLUSIONS

Quantitative metastatic LN burden is a fundamental driver of mortality across solid cancers and should serve as a foundation for pathologic nodal staging across solid tumors.

High-dose Radiotherapy or Androgen Deprivation Therapy (HEAT) as Treatment Intensification for Localized Prostate Cancer: An Individual Patient-data Network Meta-analysis from the MARCAP Consortium

BACKGROUND

The relative benefits of radiotherapy (RT) dose escalation and the addition of short-term or long-term androgen deprivation therapy (STADT or LTADT) in the treatment of prostate cancer are unknown.

OBJECTIVE

To perform a network meta-analysis (NMA) of relevant randomized trials to compare the relative benefits of RT dose escalation ± STADT or LTADT.

DESIGN, SETTING, AND PARTICIPANTS

An NMA of individual patient data from 13 multicenter randomized trials was carried out for a total of 11862 patients. Patients received one of the six permutations of low-dose RT (64 to <74 Gy) ± STADT or LTADT, high-dose RT (≥74 Gy), or high-dose RT ± STADT or LTADT.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

Metastasis-free survival (MFS) was the primary endpoint. Frequentist and Bayesian NMAs were performed to rank the various treatment strategies by MFS and biochemical recurrence-free survival (BCRFS).

RESULTS AND LIMITATIONS

Median follow-up was 8.8 yr (interquartile range 5.7-11.5). The greatest relative improvement in outcomes was seen for addition of LTADT, irrespective of RT dose, followed by addition of STADT, irrespective of RT dose. RT dose escalation did not improve MFS either in the absence of ADT (hazard ratio [HR] 0.97, 95% confidence interval [CI] 0.80-1.18) or with STADT (HR 0.99, 95% CI 0.8-1.23) or LTADT (HR 0.94, 95% CI 0.65-1.37). According to P-score ranking and rankogram analysis, high-dose RT + LTADT was the optimal treatment strategy for both BCRFS and longer-term outcomes.

CONCLUSIONS

Conventionally escalated RT up to 79.2 Gy, alone or in the presence of ADT, does not improve MFS, while addition of STADT or LTADT to RT alone, regardless of RT dose, consistently improves MFS. RT dose escalation does provide a high probability of improving BCRFS and, provided it can be delivered without compromising quality of life, may represent the optimal treatment strategy when used in conjunction with ADT.

PATIENT SUMMARY

Using a higher radiotherapy dose when treating prostate cancer does not reduce the chance of developing metastases or death, but it does reduce the chance of having a rise in prostate-specific antigen (PSA) signifying recurrence of cancer. Androgen deprivation therapy improves all outcomes. A safe increase in radiotherapy dose in conjunction with androgen deprivation therapy may be the optimal treatment.

Prostate cancer therapy personalization via multi-modal deep learning on randomized phase III clinical trials

Prostate cancer is the most frequent cancer in men and a leading cause of cancer death. Determining a patient's optimal therapy is a challenge, where oncologists must select a therapy with the highest likelihood of success and the lowest likelihood of toxicity. International standards for prognostication rely on non-specific and semi-quantitative tools, commonly leading to over- and under-treatment. Tissue-based molecular biomarkers have attempted to address this, but most have limited validation in prospective randomized trials and expensive processing costs, posing substantial barriers to widespread adoption. There remains a significant need for accurate and scalable tools to support therapy personalization. Here we demonstrate prostate cancer therapy personalization by predicting long-term, clinically relevant outcomes using a multimodal deep learning architecture and train models using clinical data and digital histopathology from prostate biopsies. We train and validate models using five phase III randomized trials conducted across hundreds of clinical centers. Histopathological data was available for 5654 of 7764 randomized patients (71%) with a median follow-up of 11.4 years. Compared to the most common risk-stratification tool-risk groups developed by the National Cancer Center Network (NCCN)-our models have superior discriminatory performance across all endpoints, ranging from 9.2% to 14.6% relative improvement in a held-out validation set. This artificial intelligence-based tool improves prognostication over standard tools and allows oncologists to computationally predict the likeliest outcomes of specific patients to determine optimal treatment. Outfitted with digital scanners and internet access, any clinic could offer such capabilities, enabling global access to therapy personalization.

Patient (pt) population and radiation therapy (RT) type in the long-term phase 3 double-blind, placebo (PBO)-controlled ATLAS study of apalutamide (APA) added to androgen deprivation therapy (ADT) in high-risk localized or locally advanced prostate cancer (HRLPC)

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Background: Current management of HRLPC includes long-term ADT with primary RT. Despite definitive primary treatment, these pts have a high risk of metastasis and death. The phase 3 ATLAS study (NCT02531516) is investigating whether treatment intensification with the addition of APA to neoadjuvant and adjuvant treatment with gonadotropin-releasing hormone agonist (GnRHa) and external beam radiation therapy (EBRT) will improve metastasis-free survival (MFS) in high-risk pts. Here we describe (1) the distribution of baseline characteristics in this high-risk pt population and (2) the application of different RT regimens reflecting recent international guidelines and clinical practice changes for pts with HRLPC. Methods: Eligible HRLPC pts (Gleason score [GS] ≥ 8 or 7 and prostate-specific antigen [PSA] ≥ 20 ng/mL and stage ≥ cT2c), with ECOG PS 0/1 and Charlson Comorbidity Index (CCI) ≤ 3 are stratified by GS, pelvic nodal status, use of brachytherapy boost, and region; pts are randomized 1:1 to APA or PBO plus GnRHa for 30 (28-d) treatment cycles. Study treatment is applied neoadjuvant/concurrent to RT with APA 240 mg/d vs bicalutamide 50 mg/d for 4 cycles; another 26 cycles are completed adjuvantly after RT with APA 240 mg/d vs PBO. Primary end point is MFS (time from randomization to first distant metastasis on CT/MRI/bone scan by independent central review blinded to treatment or death from any cause). Imaging is conducted at baseline and q6m from biochemical failure until MFS. The protocol has been amended to include PET imaging (PSMA, fluciclovine, or choline). Results: Pts (N = 1503) were randomized at 266 sites in 24 countries in North America, Latin America, Europe, and Asia. The study is fully enrolled, but ongoing. Baseline characteristics for the total population: median age, 67 yrs; ECOG PS 0/1; 89%/11%; tumor classification at study entry: high-risk, 66%/very high–risk, 34%; median PSA, 6.3 ng/mL; cT2, 44%/cT3, 50%; cN1, 13%. In 90% of ATLAS pts, RT used was standard EBRT to prostate/pelvis over 6-8 weeks (cumulative 78-81 Gy); in 10%, recent hypofractionation schedules (per CHHiP or NRG/RTOG 0415) were applied (20x3 Gy/d or 28x2.5 Gy/d). 5.6% of pts had EBRT combined with brachytherapy (per ASCENDE-RT). Conclusions: Baseline characteristics of the ATLAS study population are reflective of pts with high- and very high–risk features and pelvic nodal involvement undergoing primary RT in clinical practice. The RT schedules applied reflect recent evidence and guideline changes for the use of hypofractionation in this pt population. ATLAS is an example of how RT can be included in phase 3 trials of HRLPC, in combination with next-generation androgen receptor inhibitors (eg, APA). Clinical trial information: NCT02531516.

Prostate cancer risk in African American men evaluated via digital histopathology multi-modal deep learning models developed on NRG Oncology phase III clinical trials

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Background: Artificial intelligence (AI) tools can display racial bias as a result of existing systemic health inequities and biased datasets. We have previously developed multi-modal AI (MMAI) prognostic models based on digital pathology images from five phase III randomized radiotherapy prostate cancer trials that outperform NCCN risk groups for prediction of distant metastasis (DM), biochemical failure (BF), prostate cancer-specific mortality (PCSM) and all-cause mortality (OS). In this study, we assessed the algorithmic fairness of the locked MMAI models between African American (AA) and non-AA populations in the five randomized trials. Methods: Patients enrolled in NRG/RTOG 9202, 9408, 9413, 9910, and 0126 with digitized biopsy histopathology slides were included in this study. The locked MMAI models were applied, and subgroup analyses were conducted by comparing distributions of clinical variables and MMAI scores (medians for continuous variables and proportions for categorical variables reported), and evaluating MMAI models’ prognostic ability among AA and non-AA men. The performance of the models were compared using DM as the primary endpoint and secondary endpoints of BF, PCSM, OS (death without an event as a competing risk) with Fine-Gray or Cox Proportional Hazards models. Either Kaplan Meier or cumulative incidence estimates were computed and compared using log-rank or Gray’s test. Results: This study included 5,624 men: 932 (17%) AA, 4503 (80%) white, and 189 (3%) other races. AA had younger median age (69 vs 71 year [yr]), higher median baseline PSA (12 vs 10 ng/mL), more T1-T2a (62% vs 57%), more Gleason < 7 (42% vs 36%) and 8-10 (15% vs 12%), and more NCCN low and high risk (12% vs 10% and 41% vs 33%). AA and non-AA had estimated 5-yr BF rates 27% and 27%, 5-yr DM rates 5% and 5%, 10-yr PCSM 5% and 7%, and 10-yr OS 58% and 60%, respectively. The median (interquartile range) score of the model optimizing for 5-yr DM (5-yr DM MMAI) was 0.044 (0.037–0.059) in AA and 0.043 (0.036–0.057) in non-AA. Similarly, all other MMAI models had differences in the medians between AA and non-AA ranging from 0.001 to 0.02. For all endpoints, the 5-yr DM MMAI model showed strong prognostic signal (hazard ratio [HR] per one standard deviation increase: 1.6 for DM, 1.4 for BF, 1.6 for PCSM and 1.3 for OS, all p-values < 0.001) and had comparable trends within AA vs. non-AA in the entire cohort (e.g., HR for DM 1.4 vs 1.6). Similar results were observed for the MMAI model optimizing for 10-yr PCSM. Conclusions: To our knowledge, this represents the first comparative analyses of a digital pathology AI prognostic model in AA vs. non-AA prostate cancer patients. The prognostic performance of the AI models was found to be comparable between subgroups. Our data supports the use of these models across racial groups, though further validation in AA cohorts is ongoing.

Methodological Comparison of Mapping the Expanded Prostate Cancer Index Composite to EuroQoL-5D-3L Using Cross-Sectional and Longitudinal Data: Secondary Analysis of NRG/RTOG 0415

PURPOSE

To compare the predictive ability of mapping algorithms derived using cross-sectional and longitudinal data.

METHODS

This methodological assessment used data from a randomized controlled noninferiority trial of patients with low-risk prostate cancer, conducted by NRG Oncology (ClinicalTrials.gov identifier: NCT00331773), which examined the efficacy of conventional schedule versus hypofractionated radiation therapy (three-dimensional conformal external beam radiation therapy/IMRT). Health-related quality-of-life data were collected using the Expanded Prostate Cancer Index Composite (EPIC), and health utilities were obtained using EuroQOL-5D-3L (EQ-5D) at baseline and 6, 12, 24, and 60 months postintervention. Mapping algorithms were estimated using ordinary least squares regression models through five-fold cross-validation in baseline cross-sectional data and combined longitudinal data from all assessment periods; random effects specifications were also estimated in longitudinal data. Predictive performance was compared using root mean square error. Longitudinal predictive ability of models obtained using baseline data was examined using mean absolute differences in the reported and predicted utilities.

RESULTS

A total of 267 (and 199) patients in the estimation sample had complete EQ-5D and EPIC domain (and subdomain) data at baseline and at all subsequent assessments. Ordinary least squares models using combined data showed better predictive ability (lowest root mean square error) in the validation phase for algorithms with EPIC domain/subdomain data alone, whereas models using baseline data outperformed other specifications in the validation phase when patient covariates were also modeled. The mean absolute differences were lower for models using EPIC subdomain data compared with EPIC domain data and generally decreased as the time of assessment increased.

CONCLUSION

Overall, mapping algorithms obtained using baseline cross-sectional data showed the best predictive performance. Furthermore, these models demonstrated satisfactory longitudinal predictive ability.

The addition of androgen deprivation therapy and pelvic lymph node treatment to prostate bed salvage radiotherapy (NRG Oncology/RTOG 0534 SPPORT): an international, multicentre, randomised phase 3 trial

BACKGROUND

In men with a detectable prostate-specific antigen (PSA) level after prostatectomy for prostate cancer, salvage prostate bed radiotherapy (PBRT) results in about 70% of patients being free of progression at 5 years. A three-group randomised trial was designed to determine whether incremental gains in patient outcomes can be achieved by adding either 4-6 months of short-term androgen deprivation therapy (ADT) to PBRT, or both short-term ADT and pelvic lymph node radiotherapy (PLNRT) to PBRT.

METHODS

The international, multicentre, randomised, controlled SPPORT trial was done at 283 radiation oncology cancer treatment centres in the USA, Canada, and Israel. Eligible patients (aged ≥18 years) were those who after prostatectomy for adenocarcinoma of the prostate had a persistently detectable or an initially undetectable and rising PSA of between 0·1 and 2·0 ng/mL. Patients with and without lymphadenectomy (N0/Nx) were eligible if there was no clinical or pathological evidence of lymph node involvement. Other eligibility criteria included pT2 or pT3 disease, prostatectomy Gleason score of 9 or less, and a Zubrod performance status of 0-1. Eligible patients were randomly assigned to receive PBRT alone at a dose of 64·8-70·2 Gy at 1·8 Gy per fraction daily (group 1), PBRT plus short-term ADT (group 2), or PLNRT (45 Gy at 1·8 Gy per fraction, and then a volume reduction made to the planning target volume for the remaining 19·8-25 ·2 Gy) plus PBRT plus short-term ADT (group 3). The primary endpoint was freedom from progression, in which progression was defined as biochemical failure according to the Phoenix definition (PSA ≥2 ng/mL over the nadir PSA), clinical failure (local, regional, or distant), or death from any cause. A planned interim analysis of 1191 patents with minimum potential follow-up time of 5 years applied a Haybittle-Peto boundary of p<0·001 (one sided) for comparison of 5-year freedom from progression rates between the treatment groups. This trial is registered with ClinicalTrials.gov, NCT00567580. The primary objectives of the trial have been completed, although long-term follow-up is continuing.

FINDINGS

Between March 31, 2008, and March 30, 2015, 1792 eligible patients were enrolled and randomly assigned to the three treatment groups (592 to group 1 [PBRT alone], 602 to group 2 [PBRT plus short-term ADT], and 598 to group 3 [PLNRT plus PBRT plus short-term ADT]). 76 patients subsequently found to be ineligible were excluded from the analyses; thus, the evaluable patient population comprised 1716 patients. At the interim analysis (n=1191 patients; data cutoff May 23, 2018), the Haybittle-Peto boundary for 5-year freedom from progression was exceeded when group 1 was compared with group 3 (difference 17·9%, SE 2·9%; p<0·0001). The difference between groups 2 and 3 did not exceed the boundary (p=0·0063). With additional follow-up beyond the interim analysis (the final planned analysis; data cutoff May 26, 2021), at a median follow-up among survivors of 8·2 years (IQR 6·6-9·4), the 5-year freedom from progression rates in all 1716 eligible patients were 70·9% (95% CI 67·0-74·9) in group 1, 81·3% (78·0-84·6) in group 2, and 87·4% (84·7-90·2) in group 3. Per protocol criteria, freedom from progression in group 3 was superior to groups 1 and 2. Acute (≤3 months after radiotherapy) grade 2 or worse adverse events were significantly more common in group 3 (246 [44%] of 563 patients) than in group 2 (201 [36%] of 563; p=0·0034), which, in turn, were more common than in group 1 (98 [18%] of 547; p<0·0001). Similar findings were observed for grade 3 or worse adverse events. However, late toxicity (>3 months after radiotherapy) did not differ significantly between the groups, apart from more late grade 2 or worse blood or bone marrow events in group 3 versus group 2 (one-sided p=0·0060) attributable to the addition of PLNRT in this group.

INTERPRETATION

The results of this randomised trial establish the benefit of adding short-term ADT to PBRT to prevent progression in prostate cancer. To our knowledge, these are the first such findings to show that extending salvage radiotherapy to treat the pelvic lymph nodes when combined with short-term ADT results in meaningful reductions in progression after prostatectomy in patients with prostate cancer.

FUNDING

National Cancer Institute.

Development and validation of a prognostic AI biomarker using multi-modal deep learning with digital histopathology in localized prostate cancer on NRG Oncology phase III clinical trials

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Background: Prognostication in localized prostate cancer is reliant on non-specific tools, an issue that leads to the over- and under-treatment of patients. Various tissue-based molecular biomarkers have attempted to fill this unmet need, but most lack prospective randomized trial validation. Herein, we train and validate prognostic biomarkers in localized prostate cancer using five phase III randomized trials, by leveraging multi-modal deep learning on digital histopathology. Methods: Histopathology image data was generated from pre-treatment biopsy slides in five NRG Oncology phase III randomized radiotherapy prostate cancer trials (RTOG 9202, 9408, 9413, 9910, and 0126). The trials were randomly split into training (80%) and validation (20%) cohorts. A multi-modal artificial intelligence (MMAI) architecture was developed to take clinicopathologic and image-based (histopathology) data as input and predict binary outcomes. Using this architecture, various models were trained to predict relevant clinical endpoints: biochemical recurrence (BCR), distant metastasis (DM), prostate cancer-specific survival (PCaSS), and overall survival (OS). These models were then validated for measures of prognostic discrimination using the time-based area under the curve (AUC) method. Results: Clinicopathologic and histopathology image data was available for 5,654 of 7,957 eligible patients (71.1%), yielding 16.1 TB of data from 16,204 histopathology slides of pretreatment biopsy samples. After training the models, locking them, and evaluating them on the validation cohort, we found that the MMAI prognostic model had superior discrimination compared to the NCCN model (PSA, T-stage, and Gleason score) for 5-year DM (AUC of 0.84 vs 0.73), 5-year BCR (AUC of 0.69 vs 0.58), 10-year PCaSS (AUC of 0.79 vs 0.66), and 10-year OS (AUC of 0.65 vs 0.58). Within each of the individual trials in the validation cohort, the MMAI-model had superior performance compared to NCCN risk groups for all clinical endpoints. Conclusions: This represents the first ever development and validation of prognostic biomarkers in localized prostate cancer using multiple large phase III clinical trials. We have successfully validated that our MMAI-prognostic biomarkers are superior to standard clinical and pathologic variables in identifying future BCR, DM, PCaSS, and OS. This massively scalable technology is feasible and can help personalize the management of prostate cancer patients. Funding: This project was supported by grants U10CA180868 (NRG Oncology Operations), U10CA180822 (NRG Oncology SDMC), UG1CA189867 (NCORP), U24CA196067 (NRG Specimen Bank) from the National Cancer Institute (NCI).

Local failure, distant metastasis, and survival after definitive radiotherapy for intermediate- and high-risk prostate cancer: An individual patient-level meta-analysis of 18 randomized trials

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Background: The prognostic importance of local failure (LF) after definitive radiotherapy (RT) in patients with NCCN intermediate- (IRPCa) and high-risk prostate cancer (HRPCa) remains unclear, particularly given the likelihood that occult distant metastases (DMs) at presentation may be the true driver of natural history. Here, we leverage individual patient data (IPD) from 18 randomized control trials (RCTs) to evaluate the prognostic impact of LF and the kinetics of DM after RT. Methods: IPD for 18 RCTs were obtained from the Meta-Analysis of Randomized trials in Cancer of the Prostate (MARCAP) Consortium, comprising a total of 12533 patients (6288 HRPCa & 6245 IRPCa). Multivariable Cox proportional hazards (PH) models were developed to evaluate the relationship between overall survival (OS), PCa-specific survival (PCSS), DM-free survival (DMFS) & LF as a time-dependent covariate, adjusted for clinicodemographic parameters. Markov PH models, defined via transitions between 4 states, were developed to evaluate the aforementioned relationship. Proportional hazards assumption was imposed and examined for both models. Time is from randomization. Results: Median follow-up was 9.1 years. There were 795 (13%) LF & 1288 (21%) DM events for patients with HRPCa; these numbers were 449 (7%) & 451 (7%) for IRPCa. For HRPCa & IRPCa, 81% and 81% of DMs developed from a clinically relapse-free state (cRFS), with a median time of 46 and 60 months, respectively (p < 0.0001). 39% & 13% of DM events occurred within 2 years after RT for HRPCa & IRPCa, respectively. At later time points, DM events were more likely to emerge after an LF event for both HRPCa (9% vs. 34% between 0-2 vs. 8-10 years post-RT, p = 0.001) and IRPCa (10% vs. 34% between 0-2 vs. 8-10 years post-RT, p = 0.008). LF was significantly associated with OS (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.06–1.30), PCSS (HR 2.02, 95% CI 1.75-2.33) & DMFS (HR 1.94, 95% CI 1.75–2.15) (p < 0.01 for all) in patients with HRPCa. LF was also significantly associated with DMFS (HR 1.57, 95% CI 1.36–1.81) but not OS in patients with IRPCa. Patients who had not transitioned to the LF state had a significantly lower HR of transitioning to a PCa-specific death state than those who transitioned to the LF state (HR 0.32, 95% CI 0.21–0.50, p < 0.001). Conclusions: LF is an independent prognosticator of OS, PCSS & DMFS in HRPCa and of DMFS in IRPCa. The predominant mode of DM development is from the cRFS state, underscoring the importance of accurate upfront staging & systemic therapy. However, particularly at late time points, an increasing proportion of DM events originated after diagnosis of a LF, constituting a “second wave” of DM events. This suggests that optimizing local control is also important, though the majority of DM events appear prior to a clinically-detected LF.

Impact of lymph node yield at prostatectomy on outcomes in NRG/RTOG 9601

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Background: A recent study ( Fossati et al, 2018) found that higher lymph node count at radical prostatectomy was associated with improved outcomes in patients treated with salvage radiation for elevated prostate-specific antigen (PSA) after surgery. We sought to validate these results in NRG/RTOG 9601, a randomized controlled trial of men with pT2/T3 disease who underwent either radiation (RT) alone or RT+antiandrogen (bicalutamide) therapy for PSA elevation following radical prostatectomy from 1998-2003. Methods: We reviewed available pathology reports for all patients in NRG/RTOG 9601 to determine the nodal count at radical prostatectomy. Clinical data was as of 11/5/2015, same as the primary endpoint for the trial. Cox proportional hazards models were used to assess the effect of number of positive lymph nodes, treatment arm (RT alone or RT+bicalutamide), Gleason score, positive margins, and seminal vesicle invasion on the following endpoints: times to local and distant failure and overall and disease specific survival. Results: Out of the 760 patients originally eligible in the trial, 552 (73%, 276 in each arm) had complete data available. Median node count in the entire cohort was 6 (range 0-33, Q1-Q3 3-9). There were no significant differences between treatment arms in terms of patient demographic or clinical characteristics, including total lymph nodes removed in either arm (RT alone vs RT+bicalutamide median 5 vs 6, p = 0.11). There was no significant association between total lymph nodes and overall survival with both arms combined (HR = 1.00, 95% CI:0.97-1.03, p = 0.87) or in the individual arms alone (RT+Casodex: HR = 1.01, 95% CI:0.97-1.05, p = 0.65; RT+Placebo: HR = 0.98, 95% CI: 0.94-1.03, p = 0.45). There was also no significant association between total lymph nodes and disease-specific survival with both arms combined (HR = 1.00, 95% CI:0.95-1.04, p = 0.84) and in the arms alone (RT+Casodex: HR = 1.00, 95% CI:0.95-1.05, p = 0.92; RT+Placebo: HR = 0.99, 95% CI: 0.92-1.07, p = 0.86). In multivariable analysis performed on the two arms, Gleason score was the only feature associated with worse overall and disease-specific survival, seen only in the RT alone arm. Similar findings were seen when evaluating times to local and distant failure. Conclusions: Lymph node yield in NRG/RTOG 9601 did not show any association with adverse outcomes in the entire cohort, or in either treatment arm alone. The therapeutic benefit of an extensive lymph node dissection in this population remains uncertain. Clinical trial information: NCT00002874.

Adding Short-Term Androgen Deprivation Therapy to Radiation Therapy in Men With Localized Prostate Cancer: Long-Term Update of the NRG/RTOG 9408 Randomized Clinical Trial

PURPOSE

For men with localized prostate cancer, NRG Oncology/Radiation Therapy Oncology Group (RTOG) 9408 demonstrated that adding short-term androgen deprivation therapy (ADT) to radiation therapy (RT) improved the primary endpoint of overall survival (OS) and improved disease-specific mortality (DSM), biochemical failure (BF), local progression, and freedom from distant metastases (DM). This study was performed to determine whether the short-term ADT continued to improve OS, DSM, BF, and freedom from DM with longer follow-up.

METHODS AND MATERIALS

From 1994 to 2001, NRG/RTOG 9408 randomized 2028 men from 212 North American institutions with T1b-T2b, N0 prostate adenocarcinoma and prostate-specific antigen (PSA) ≤20ng/mL to RT alone or RT plus short-term ADT. Patients were stratified by PSA, tumor grade, and surgical versus clinical nodal staging. ADT was flutamide with either goserelin or leuprolide for 4 months. Prostate RT (66.6 Gy) was started after 2 months. OS was calculated at the date of death from any cause or at last follow-up. Secondary endpoints were DSM, BF, local progression, and DM. Acute and late toxic effects were assessed using RTOG toxicity scales.

RESULTS

Median follow-up in surviving patients was 14.8 years (range, 0.16-21.98). The 10-year and 18-year OS was 56% and 23%, respectively, with RT alone versus 63% and 23% with combined therapy (HR 0.94; 95% confidence interval [CI], 0.85-1.05; P = .94). The hazards were not proportional (P = .003). Estimated restricted mean survival time at 18 years was 11.8 years (95% CI, 11.4-12.1) with combined therapy versus 11.3 years with RT alone (95% CI, 10.9-11.6; P = .05). The 10-year and 18-year DSM was 7% and 14%, respectively, with RT alone versus 3% and 8% with combined therapy (HR 0.56; 95% CI, 0.41-0.75; P < .01). DM and BF favored combined therapy at 18 years. Rates of late grade ≥3 hepatic, gastrointestinal, and genitourinary toxicity were ≤1%, 3%, and 8%, respectively, with combined therapy versus ≤1%, 2%, and 5% with RT alone.

CONCLUSIONS

Further follow-up demonstrates that OS converges at approximately 15 years, by which point the administration of 4 months of ADT had conferred an estimated additional 6 months of life.

Quality of Life Implications of Dose-Escalated External Beam Radiation for Localized Prostate Cancer: Results of a Prospective Randomized Phase 3 Clinical Trial, NRG/RTOG 0126

PURPOSE

External beam radiation therapy (EBRT) dose escalation has been tested in multiple prospective trials. However, the impact on patient reported outcomes (PROs) associated with higher doses of EBRT remain poorly understood. We sought to assess the differences in PROs between men treated with a dose of 70.2 Gy versus 79.2 Gy of EBRT for prostate cancer.

METHODS AND MATERIALS

The phase 3 clinical trial RTOG 0126 randomized 1532 patients with prostate cancer between March 2002 and August 2008 to 79.2 Gy over 44 fractions versus 70.2 Gy over 39 fractions. Eligible patients participated in the PRO data collection. PROs completed included the International Index of Erectile Function Questionnaire (IIEF), Functional Alterations due to Changes in Elimination (FACE), and the Spitzer Quality of Life Index (SQLI). The timepoints for the IIEF were collected pre-entry and at 6, 12, and 24 months. The FACE and SQLI were collected pre-entry and at 3, 6, 12, 18, and 24 months. The impact of EBRT dose to normal structures (penile bulb, rectum, and bladder) on PROs was also examined. Mixed effects models were used to analyze trends across time.

RESULTS

In total, 1144 patients completed baseline IIEF forms and of these, 56%, 64%, and 61% completed the IIEF at 6, 12, and 24 months, respectively; 1123 patients completed the FACE score at baseline and 50%, 61%, 73%, 61%, and 65% completed all 15 items for the FACE metric at timepoints of 3, 6, 12, 18, and 24 months, respectively. Erectile dysfunction at 12 months based on the single question was not significantly different between arms (38.1% for the standard dose radiation therapy arm vs 49.7% for the dose escalated radiation therapy arm; P = .051). Treatment arm (70.2 vs 79.2) had no significant impact on any PRO metrics measured across all collected domains. Comprehensive dosimetric analyses are presented and reveal multiple significant differences to regional organs at risk.

CONCLUSIONS

Compliance with PRO data collection was lower than anticipated in this phase 3 trial. Examining the available data, dose escalated EBRT did not appear to be associated with any detriment to PROs across numerous prospectively collected domains. These data, notwithstanding limitations, add to our understanding of the implications of EBRT dose escalation in prostate cancer. Furthermore, these results illustrate challenges associated with PRO data collection.

Comparison of Response to Definitive Radiotherapy for Localized Prostate Cancer in Black and White Men: A Meta-analysis

IMPORTANCE

Black men have a 2-fold increased risk of dying from prostate cancer compared with White men. However, race-specific differences in response to initial treatment remain unknown.

OBJECTIVE

To compare overall and treatment-specific outcomes of Black and White men with localized prostate cancer receiving definitive radiotherapy (RT).

DATA SOURCES

A systematic search was performed of relevant published randomized clinical trials conducted by the NRG Oncology/Radiation Therapy Oncology Group between January 1, 1990, and December 31, 2010. This meta-analysis was performed from July 1, 2019, to July 1, 2021.

STUDY SELECTION

Randomized clinical trials of definitive RT for patients with localized prostate cancer comprising a substantial number of Black men (self-identified race) enrolled that reported on treatment-specific and overall outcomes.

DATA EXTRACTION AND SYNTHESIS

Individual patient data were obtained from 7 NRG Oncology/Radiation Therapy Oncology Group randomized clinical trials evaluating definitive RT with or without short- or long-term androgen deprivation therapy. Unadjusted Fine-Gray competing risk models, with death as a competing risk, were developed to evaluate the cumulative incidences of end points. Cox proportional hazards models were used to evaluate differences in all-cause mortality and the composite outcome of distant metastasis (DM) or death. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline was followed.

MAIN OUTCOMES AND MEASURES

Subdistribution hazard ratios (sHRs) of biochemical recurrence (BCR), DM, and prostate cancer-specific mortality (PCSM).

RESULTS

A total of 8814 patients (1630 [18.5%] Black and 7184 [81.5%] White) were included; mean (SD) age was 69.1 (6.8) years. Median follow-up was 10.6 (IQR, 8.0-17.8) years for surviving patients. At enrollment, Black men were more likely to have high-risk disease features. However, even without adjustment, Black men were less likely to experience BCR (sHR, 0.88; 95% CI, 0.58-0.91), DM (sHR, 0.72; 95% CI, 0.58-0.91), or PCSM (sHR, 0.72; 95% CI, 0.54-0.97). No significant differences in all-cause mortality were identified (HR, 0.99; 95% CI, 0.92-1.07). Upon adjustment, Black race remained significantly associated with improved BCR (adjusted sHR, 0.79; 95% CI, 0.72-0.88; P < .001), DM (adjusted sHR, 0.69; 95% CI, 0.55-0.87; P = .002), and PCSM (adjusted sHR, 0.68; 95% CI, 0.50-0.93; P = .01).

CONCLUSIONS AND RELEVANCE

The findings of this meta-analysis suggest that Black men enrolled in randomized clinical trials present with more aggressive disease but have better BCR, DM, and PCSM with definitive RT compared with White men, suggesting that other determinants of outcome, such as access to care, are important factors of achieving racial equity.

Paid Parental Leave Policies Among U.S. News & World Report 2020-2021 Best Hospitals and Best Hospitals for Cancer

This cross-sectional study examines paid parental leave policies for faculty and staff physicians at leading US hospitals and cancer centers.

Mapping expanded prostate cancer index composite to EQ5D utilities to inform economic evaluations in prostate cancer: Secondary analysis of NRG/RTOG 0415

PURPOSE

The Expanded Prostate Cancer Index Composite (EPIC) is the most commonly used patient reported outcome (PRO) tool in prostate cancer (PC) clinical trials, but health utilities associated with the different health states assessed with this tool are unknown, limiting our ability to perform cost-utility analyses. This study aimed to map EPIC tool to EuroQoL-5D-3L (EQ5D) to generate EQ5D health utilities.

METHODS AND MATERIALS

This is a secondary analysis of a prospective, randomized non-inferiority clinical trial, conducted between 04/2006 and 12/2009 at cancer centers across the United States, Canada, and Switzerland. Eligible patients included men >18 years with a known diagnosis of low-risk PC. Patient HRQoL data were collected using EPIC and health utilities were obtained using EQ5D. Data were divided into an estimation sample (n = 765, 70%) and a validation sample (n = 327, 30%). The mapping algorithms that capture the relationship between the instruments were estimated using ordinary least squares (OLS), Tobit, and two-part models. Five-fold cross-validation (in-sample) was used to compare the predictive performance of the estimated models. Final models were selected based on root mean square error (RMSE).

RESULTS

A total of 565 patients in the estimation sample had complete information on both EPIC and EQ5D questionnaires at baseline. Mean observed EQ5D utility was 0.90±0.13 (range: 0.28-1) with 55% of patients in full health. OLS models outperformed their counterpart Tobit and two-part models for all pre-determined model specifications. The best model fit was: "EQ5D utility = 0.248541 + 0.000748*(Urinary Function) + 0.001134*(Urinary Bother) + 0.000968*(Hormonal Function) + 0.004404*(Hormonal Bother)- 0.376487*(Zubrod) + 0.003562*(Urinary Function*Zubrod)"; RMSE was 0.10462.

CONCLUSIONS

This is the first study to identify a comprehensive set of mapping algorithms to generate EQ5D utilities from EPIC domain/ sub-domain scores. The study results will help estimate quality-adjusted life-years in PC economic evaluations.

Validation of a 22-Gene Genomic Classifier in Patients With Recurrent Prostate Cancer: An Ancillary Study of the NRG/RTOG 9601 Randomized Clinical Trial

Question

Can a genomic biomarker estimate the risk of prostate cancer clinical end points in men who received salvage radiation for rising prostate-specific antigen levels after surgery?

Findings

In this ancillary study of 352 men randomized to placebo or hormone therapy in the NRG/RTOG 9601 clinical trial of salvage radiation, the Decipher genomic classifier was independently associated with the risk of metastasis, prostate cancer–specific mortality, and overall survival.

Meaning

These findings suggest that the Decipher genomic classifier is a promising biomarker to risk stratify men to better enable hormone therapy treatment decisions for biochemical recurrence of their prostate cancer after surgery.

Importance

Decipher (Decipher Biosciences Inc) is a genomic classifier (GC) developed to estimate the risk of distant metastasis (DM) after radical prostatectomy (RP) in patients with prostate cancer.

Objective

To validate the GC in the context of a randomized phase 3 trial.

Design, Setting, and Participants

This ancillary study used RP specimens from the phase 3 placebo-controlled NRG/RTOG 9601 randomized clinical trial conducted from March 1998 to March 2003. The specimens were centrally reviewed, and RNA was extracted from the highest-grade tumor available in 2019 with a median follow-up of 13 years. Clinical-grade whole transcriptomes from samples passing quality control were assigned GC scores (scale, 0-1). A National Clinical Trials Network–approved prespecified statistical plan included the primary objective of validating the independent prognostic ability of GC for DM, with secondary end points of prostate cancer–specific mortality (PCSM) and overall survival (OS). Data were analyzed from September 2019 to December 2019.

Intervention

Salvage radiotherapy (sRT) with or without 2 years of bicalutamide.

Main Outcomes and Measures

The preplanned primary end point of this study was the independent association of the GC with the development of DM.

Results

In this ancillary study of specimens from a phase 3 randomized clinical trial, GC scores were generated from 486 of 760 randomized patients with a median follow-up of 13 years; samples from a total of 352 men (median [interquartile range] age, 64.5 (60-70) years; 314 White [89.2%] participants) passed microarray quality control and comprised the final cohort for analysis. On multivariable analysis, the GC (continuous variable, per 0.1 unit) was independently associated with DM (hazard ratio [HR], 1.17; 95% CI, 1.05-1.32; P = .006), PCSM (HR, 1.39; 95% CI, 1.20-1.63; P < .001), and OS (HR, 1.17; 95% CI, 1.06-1.29; P = .002) after adjusting for age, race/ethnicity, Gleason score, T stage, margin status, entry prostate-specific antigen, and treatment arm. Although the original planned analysis was not powered to detect a treatment effect interaction by GC score, the estimated absolute effect of bicalutamide on 12-year OS was less when comparing patients with lower vs higher GC scores (2.4% vs 8.9%), which was further demonstrated in men receiving early sRT at a prostate-specific antigen level lower than 0.7 ng/mL (−7.8% vs 4.6%).

Conclusions and Relevance

This ancillary validation study of the Decipher GC in a randomized trial cohort demonstrated association of the GC with DM, PCSM, and OS independent of standard clinicopathologic variables. These results suggest that not all men with biochemically recurrent prostate cancer after surgery benefit equally from the addition of hormone therapy to sRT.

Trial Registration

ClinicalTrials.gov identifier: NCT00002874