Time Interval to Biochemical Failure as a Surrogate End Point in Locally Advanced Prostate Cancer: Analysis of Randomized Trial NRG/RTOG 9202

Challenges and Opportunities in Establishing Appropriate Intermediate Endpoints Reflecting Patient Benefit: A Roadmap for Research and Clinical Application in Nonmetastatic Prostate Cancer

Defining meaningful endpoints for research of early-stage high-risk prostate cancer is challenging, with established measures such as overall survival and metastasis-free survival facing limitations related to feasibility and adequate reflection of patient relevance. Developing endpoints must cater to diverse perspectives across scientific, clinical, regulatory, and patient viewpoints. Endpoints such as pathological complete response, no evidence of disease, and prevention of prostate-specific antigen relapse may reflect patient benefit by accounting for diagnostic and treatment burdens.

Novel hormone therapy and coordination of care in high-risk biochemically recurrent prostate cancer

Biochemical recurrence (BCR) occurs in 20-50% of patients with prostate cancer (PCa) undergoing primary definitive treatment. Patients with high-risk BCR have an increased risk of metastatic progression and subsequent PCa-specific mortality, and thus could benefit from treatment intensification. Given the increasing complexity of diagnostic and therapeutic modalities, multidisciplinary care (MDC) can play a crucial role in the individualized management of this patient population. This review explores the role for MDC when evaluating the clinical evidence for the evolving definition of high-risk BCR and the emerging therapeutic strategies, especially with novel hormone therapies (NHTs), for patients with either high-risk BCR or oligometastatic PCa. Clinical studies have used different characteristics to define high-risk BCR and there is no consensus regarding the definition of high-risk BCR nor for management strategies. Next-generation imaging and multigene panels offer potential enhanced patient identification and precision-based decision-making, respectively. Treatment intensification with NHTs, either alone or combined with radiotherapy or metastasis-directed therapy, has been promising in clinical trials in patients with high-risk BCR or oligometastases. As novel risk-stratification and treatment options as well as evidence-based literature evolve, it is important to involve a multidisciplinary team to identify patients with high-risk features at an earlier stage, and make informed decisions on the treatments that could optimize their care and long-term outcomes. Nevertheless, MDC data are scarce in the BCR or oligometastatic setting. Efforts to integrate MDC into the standard management of this patient population are needed, and will likely improve outcomes across this heterogeneous PCa patient population.

Association of PSA kinetics after testosterone recovery with subsequent recurrence: secondary analysis of a phase III randomized controlled trial

PURPOSE

After cessation of androgen deprivation therapy (ADT), testosterone gradually recovers to supracastrate levels (> 50 ng/dL). After this, rises in prostate-specific antigen (PSA) are often seen. However, it remains unknown whether early PSA kinetics after testosterone recovery are associated with subsequent biochemical recurrence (BCR).

METHODS

We performed a secondary analysis of a phase III randomized controlled trial in which newly diagnosed localized prostate cancer patients were randomly allocated to ADT for 6 months starting 4 months prior to or simultaneously with prostate RT. We calculated the PSA doubling time (PSADT) based on PSA values up to 18 months after supracastrate testosterone recovery. Competing risk regression was used to evaluate the association of PSADT with relative incidence of BCR, considering deaths as competing events.

RESULTS

Overall, 313 patients were eligible. Median PSADT was 8 months. Cumulative incidence of BCR at 10 years from supracastrate testosterone recovery was 19% and 11% in patients with PSADT < 8 months and ≥ 8 months (p = 0.03). Compared to patients with PSADT of < 4 months, patients with higher PSADT (sHR for PSADT 4 to < 8 months: 0.36 [95% CI 0.16-0.82]; 8 to < 12 months: 0.26 [0.08-0.91]; ≥ 12 months: 0.20 [0.07-0.56]) had lower risk of relative incidence of BCR.

CONCLUSIONS

Early PSA kinetics, within 18 months of recovery of testosterone to a supracastrate level, can predict for subsequent BCR. Taking account of early changes in PSA after testosterone recovery may allow for recognition of potential failures earlier in the disease course and thereby permit superior personalization of treatment.

Biochemical Recurrence Surrogacy for Clinical Outcomes After Radiotherapy for Adenocarcinoma of the Prostate

PURPOSE

The surrogacy of biochemical recurrence (BCR) for overall survival (OS) in localized prostate cancer remains controversial. Herein, we evaluate the surrogacy of BCR using different surrogacy analytic methods.

MATERIALS AND METHODS

Individual patient data from 11 trials evaluating radiotherapy dose escalation, androgen deprivation therapy (ADT) use, and ADT prolongation were obtained. Surrogate candidacy was assessed using the Prentice criteria (including landmark analyses) and the two-stage meta-analytic approach (estimating Kendall's tau and the R2). Biochemical recurrence-free survival (BCRFS, time from random assignment to BCR or any death) and time to BCR (TTBCR, time from random assignment to BCR or cancer-specific deaths censoring for noncancer-related deaths) were assessed.

RESULTS

Overall, 10,741 patients were included. Dose escalation, addition of short-term ADT, and prolongation of ADT duration significantly improved BCR (hazard ratio [HR], 0.71 [95% CI, 0.63 to 0.79]; HR, 0.53 [95% CI, 0.48 to 0.59]; and HR, 0.54 [95% CI, 0.48 to 0.61], respectively). Adding short-term ADT (HR, 0.91 [95% CI, 0.84 to 0.99]) and prolonging ADT (HR, 0.86 [95% CI, 0.78 to 0.94]) significantly improved OS, whereas dose escalation did not (HR, 0.98 [95% CI, 0.87 to 1.11]). BCR at 48 months was associated with inferior OS in all three groups (HR, 2.46 [95% CI, 2.08 to 2.92]; HR, 1.51 [95% CI, 1.35 to 1.70]; and HR, 2.31 [95% CI, 2.04 to 2.61], respectively). However, after adjusting for BCR at 48 months, there was no significant treatment effect on OS (HR, 1.10 [95% CI, 0.96 to 1.27]; HR, 0.96 [95% CI, 0.87 to 1.06] and 1.00 [95% CI, 0.90 to 1.12], respectively). The patient-level correlation (Kendall's tau) for BCRFS and OS ranged between 0.59 and 0.69, and that for TTBCR and OS ranged between 0.23 and 0.41. The R2 values for trial-level correlation of the treatment effect on BCRFS and TTBCR with that on OS were 0.563 and 0.160, respectively.

CONCLUSION

BCRFS and TTBCR are prognostic but failed to satisfy all surrogacy criteria. Strength of correlation was greater when noncancer-related deaths were considered events.

Managing postoperative biochemical relapse in prostate cancer, from the perspective of the Francophone group of Urological radiotherapy (GFRU)

Up to 50% of patients treated with radical surgery for localized prostate cancer may experience biochemical recurrence that requires appropriate management. Definitions of biochemical relapse may vary, but, in all cases, consist of an increase in a PSA without clinical or radiological signs of disease. Molecular imaging through to positron emission tomography has taken a preponderant place in relapse diagnosis, progressively replacing bone scan and CT-scan. Prostate bed radiotherapy is currently a key treatment, the action of which should be potentiated by androgen deprivation therapy. Nowadays perspectives consist in determining the best combination therapies, particularly thanks to next-generation hormone therapies, but not exclusively. Several trials are ongoing and should address these issues. We present here a literature review aiming to discuss the current management of biochemical relapse in prostate cancer after radical surgery, in lights of recent findings, as well as future perspectives.

Risk of Short-Term Prostate-Specific Antigen Recurrence and Failure in Patients With Prostate Cancer: A Secondary Analysis of a Randomized Clinical Trial

Importance

A shorter time interval to prostate-specific antigen (PSA) failure is associated with worse clinical outcomes; however, specific factors defining this state remain unknown.

Objective

To evaluate the factors of a short time interval to PSA failure in order to identify patients for treatment escalation randomized clinical trials.

Design, Setting, and Participants

This secondary analysis of a randomized clinical trial was a secondary analysis of the Dana-Farber Cancer Institute 05-043 trial and included 350 patients with nonmetastatic unfavorable risk prostate cancer (PC).

Interventions

Patients were randomized 1:1 to receive androgen deprivation therapy (ADT) and radiation therapy (RT) plus docetaxel vs ADT and RT.

Main Outcomes and Measures

Cumulative incidence rates curves of PSA failure, defined as PSA nadir plus 2 ng/mL or initiation of salvage therapies, and the Fine and Gray competing risks regression was used to assess the prognostic association between these factors and time to PSA failure.

Results

The study included 350 males who primarily had a good performance status (330 [94.3%] with Eastern Cooperative Oncology Group score of 0), median (range) age of 66 (43-86) years, with 167 (46.6%) having Gleason scores of 8 to 10, and 195 (55.2%) presenting with a baseline PSA of more than 10 ng/mL. After a median (IQR) follow-up of 10.2 (8.0-11.4) years, having a PSA level of 10 ng/mL to 20 ng/mL (subdistribution hazard ratio [sHR], 1.98; 95% CI, 1.28-3.07; P = .002) and a Gleason score of 8 to 10 (sHR, 2.55; 95% CI, 1.63-3.99; P < .001) were associated with a shorter time to PSA failure, and older age (sHR, 0.82; 95% CI, 0.72-0.93; P = .002) was associated with reduced risk for PSA failure after adjusting for other baseline clinical factors. The high-risk category, defined by these 3 factors, was associated with a shorter time to PSA failure (sHR, 2.69; 95% CI, 1.84-3.93; P < .001).

Conclusions and Relevance

In this secondary analysis of a randomized clinical trial of males with unfavorable risk PC, young age, PSA of 10 ng/mL or more, and a Gleason score of 8 to 10 estimated a shorter time to PSA failure. A subgroup of males at very high-risk for early PSA failure, as defined by our study, may benefit from treatment escalation with androgen receptor signaling inhibitors or cytotoxic chemotherapy and should be the subject of a prospective randomized clinical trial.

Trial Registration

NCT00116142.

Early Endpoints in High-risk Localized Prostate Cancer: Exploratory Analysis of Three Radiation Therapy Oncology Group Phase 3 Studies

BACKGROUND

Early endpoints in clinical trials of high-risk localized prostate cancer (HRLPC) that resemble those monitored in real-world practice could expedite clinical development.

OBJECTIVE

To assess the association of prostate-specific antigen (PSA) recurrence (PSA-R)-based early endpoints with metastasis-free survival (MFS), overall survival (OS), and prostate cancer (PC)-specific survival (PCSS), and to identify clinically undetectable disease.

DESIGN, SETTING, AND PARTICIPANTS

A post hoc analysis of patients with HRLPC from Radiation Therapy Oncology Group studies 9202, 9902, and 0521 was performed.

INTERVENTION

Long-term adjuvant androgen-deprivation therapy (ADT) and post-primary definitive radiotherapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Event-free survival (EFS; PSA-R, locoregional recurrence [LRR], distant metastasis [DM], or death), biochemical failure (PSA-R), general clinical failure (PSA-R, LRR, DM, ADT initiation, or death), and no evidence of disease (NED; alive patients without PSA-R, LRR, DM, and subsequent PC therapy, and with testosterone recovery) were assessed for association with MFS, OS, and PCSS using correlation and landmark analyses, Kaplan-Meier method, and Cox proportional-hazard model. PSA-R was defined as PSA nadir + 2 ng/ml; PSA nadir + 2 ng/ml and rising; PSA >5, 10, and 25 ng/ml; or PSA doubling time (PSADT) <6 mo.

RESULTS AND LIMITATIONS

Among assessed early endpoints, EFS with PSA nadir + 2 ng/ml and rising, or with PSA >5 ng/ml was associated with MFS, OS, and PCSS. No development of EFS with PSADT <6 mo or ADT initiation event or achievement of NED at 3 yr was associated with prolonged OS, MFS, and PCSS (hazard ratio [95% confidence interval], 0.53 [0.45-0.64], 0.63 [0.52-0.76], and 0.26 [0.18-0.36], or 0.56 [0.48-0.66], 0.62 [0.52-0.74], and 0.26 [0.19-0.37]) after the landmark time. Older studies performed before the current guidance should be interpreted with caution.

CONCLUSIONS

We identified EFS with PSA nadir + 2 ng/ml and rising, PSA >5 ng/ml, or PSADT <6 mo ± ADT initiation and NED as potentially promising early endpoints in HRLPC that should be validated further.

PATIENT SUMMARY

We identified novel clinical measures that may expedite the development of new medicines for patients with localized prostate cancer at a high risk of progression. These measures, which took into account prostate-specific antigen assessments and other clinical characteristics, should be confirmed in future studies. We also defined a novel measure of no evidence of disease that can help treating physicians identify patients with clinically undetectable disease.

MRI-derived tumor volume as a predictor of biochemical recurrence and adverse pathology in patients after radical prostatectomy: a propensity score matching study

PURPOSE

To investigate the predictive value of MRI-derived tumor volume (TV) of biochemical recurrence (BCR) and adverse pathology (AP) in patients following radical prostatectomy (RP).

METHODS

The data of 565 patients receiving RP in a single institution between 2010 and 2021 were retrospectively analyzed. All suspicious tumor foci were delineated manually using ITK-SNAP software as the regions of interest (ROIs). The sum of the TV of all lesions was calculated automatically based on the voxel in the ROIs to acquire the final TV parameter. TV was categorized as low-volume (≤ 6.5 cm³) and high-volume (> 6.5 cm³) based on the cut-off value. Univariate and multivariate Cox and logistic regression analyses were performed to identify independent predictors of BCR and AP. The Kaplan-Meier with the log-rank test was conducted to compare the BCR-free survival (BFS) between the low and high-volume groups.

RESULTS

All the included patients were divided into the low-volume group (n = 337) and the high-volume group (n = 228). The TV was an independent predictor of BFS in the multivariate Cox regression analysis (Hazard Ratio (HR) [95% CI]: 1.550 [1.066-2.256], P = 0.022). The Kaplan-Meier analysis demonstrated that low volume was associated with a better BFS than high volume before propensity score matching (PSM) (P < 0.001). One hundred and fifty-eight pairs were obtained by 1:1 PSM to balance the baseline parameters between the two groups. After the PSM, low-volume remained to be associated with a better BFS than high-volume (P = 0.006). TV as a categorical variable was an independent factor of AP in multivariate logistic regression analysis (Odd ratio (OR) [95% CI]: 1.821 [1.064-3.115], P = 0.029). After balancing the potential factors influencing AP by 1:1 PSM, 162 new pairs were identified. The high-volume group had a higher AP rate than the low-volume group after PSM (75.9 vs. 64.8%, P = 0.029).

CONCLUSION

We adopted a novel approach to acquiring the TV on preoperative MRI. TV was significantly associated with BFS and AP of patients undergoing RP, which was further illustrated by PSM analysis. MRI-derived TV may serve as a predictive marker for assessing BFS and AP in further studies, which will facilitate clinical decision-making and patient counseling.

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.

Surrogacy Beyond Prognosis: The Importance of “Trial-Level” Surrogacy

Many candidate surrogate endpoints are currently assessed using a 2-level statistical approach, which consists in checking whether (1) the potential surrogate is associated with the final endpoint in individual patients and (2) the effect of treatment on the surrogate can be used to reliably predict the effect of treatment on the final endpoint. In some situations, condition (1) is fulfilled but condition (2) is not. We use concepts of causal inference to explain this apparently paradoxical situation, illustrating this review with 2 contrasting examples in operable breast cancer: the example of pathological complete response (pCR) and that of disease-free survival (DFS). In a previous meta-analysis, pCR has been shown to be a strong and independent prognostic factor for event-free survival (EFS) and overall survival (OS) after neoadjuvant treatment of operable breast cancer. Yet, in randomized trials, the effects of experimental treatments on pCR have not translated into predictable effects on EFS or OS, making pCR an “individual-level” surrogate, but not a “trial-level” surrogate. In contrast, DFS has been shown to be an acceptable surrogate for OS at both the individual and trial levels in early, HER2-positive breast cancer. The distinction between the prognostic and predictive roles of a tentative surrogate, not always made in the literature, avoids unnecessary confusion and allows better understanding of what it takes to validate a surrogate endpoint that is truly able to replace a final endpoint.

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.

PSMA-PET/MRI-Based Focal Dose Escalation in Patients with Primary Prostate Cancer Treated with Stereotactic Body Radiation Therapy (HypoFocal-SBRT): Study Protocol of a Randomized, Multicentric Phase III Trial

Technical advances in radiotherapy (RT) treatment planning and delivery have substantially changed RT concepts for primary prostate cancer (PCa) by (i) enabling a reduction of treatment time, and by (ii) enabling safe delivery of high RT doses. Several studies proposed a dose-response relationship for patients with primary PCa and especially in patients with high-risk features, as dose escalation leads to improved tumor control. In parallel to the improvements in RT techniques, diagnostic imaging techniques like multiparametric magnetic resonance imaging (mpMRI) and positron-emission tomography targeting prostate-specific-membrane antigen (PSMA-PET) evolved and enable an accurate depiction of the intraprostatic tumor mass for the first time. The HypoFocal-SBRT study combines ultra-hypofractionated RT/stereotactic body RT, with focal RT dose escalation on intraprostatic tumor sides by applying state of the art diagnostic imaging and most modern RT concepts. This novel strategy will be compared with moderate hypofractionated RT (MHRT), one option for the curative primary treatment of PCa, which has been proven by several prospective trials and is recommended and carried out worldwide. We suspect an increase in relapse-free survival (RFS), and we will assess quality of life in order to detect potential changes.

Computer extracted gland features from H&E predicts prostate cancer recurrence comparably to a genomic companion diagnostic test: a large multi-site study

Existing tools for post-radical prostatectomy (RP) prostate cancer biochemical recurrence (BCR) prognosis rely on human pathologist-derived parameters such as tumor grade, with the resulting inter-reviewer variability. Genomic companion diagnostic tests such as Decipher tend to be tissue destructive, expensive, and not routinely available in most centers. We present a tissue non-destructive method for automated BCR prognosis, termed "Histotyping", that employs computational image analysis of morphologic patterns of prostate tissue from a single, routinely acquired hematoxylin and eosin slide. Patients from two institutions (n = 214) were used to train Histotyping for identifying high-risk patients based on six features of glandular morphology extracted from RP specimens. Histotyping was validated for post-RP BCR prognosis on a separate set of n = 675 patients from five institutions and compared against Decipher on n = 167 patients. Histotyping was prognostic of BCR in the validation set (p < 0.001, univariable hazard ratio [HR] = 2.83, 95% confidence interval [CI]: 2.03-3.93, concordance index [c-index] = 0.68, median years-to-BCR: 1.7). Histotyping was also prognostic in clinically stratified subsets, such as patients with Gleason grade group 3 (HR = 4.09) and negative surgical margins (HR = 3.26). Histotyping was prognostic independent of grade group, margin status, pathological stage, and preoperative prostate-specific antigen (PSA) (multivariable p < 0.001, HR = 2.09, 95% CI: 1.40-3.10, n = 648). The combination of Histotyping, grade group, and preoperative PSA outperformed Decipher (c-index = 0.75 vs. 0.70, n = 167). These results suggest that a prognostic classifier for prostate cancer based on digital images could serve as an alternative or complement to molecular-based companion diagnostic tests.

Computationally Derived Cribriform Area Index from Prostate Cancer Hematoxylin and Eosin Images Is Associated with Biochemical Recurrence Following Radical Prostatectomy and Is Most Prognostic in Gleason Grade Group 2

BACKGROUND

The presence of invasive cribriform adenocarcinoma (ICC), an expanse of cells containing punched-out lumina uninterrupted by stroma, in radical prostatectomy (RP) specimens has been associated with biochemical recurrence (BCR). However, ICC identification has only moderate inter-reviewer agreement.

OBJECTIVE

To investigate quantitative machine-based assessment of the extent and prognostic utility of ICC, especially within individual Gleason grade groups.

DESIGN, SETTING, AND PARTICIPANTS

A machine learning approach was developed for ICC segmentation using 70 RP patients and validated in a cohort of 749 patients from four sites whose median year of surgery was 2007 and with median follow-up of 28 mo. ICC was segmented on one representative hematoxylin and eosin RP slide per patient and the fraction of tumor area composed of ICC, the cribriform area index (CAI), was measured.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The association between CAI and BCR was measured in terms of the concordance index (c index) and hazard ratio (HR).

RESULTS AND LIMITATIONS

CAI was correlated with BCR (c index 0.62) in the validation set of 411 patients with ICC morphology, especially those with Gleason grade group 2 cancer (n = 192; c index 0.66), and was less prognostic when patients without ICC were included (c index 0.54). A doubling of CAI in the group with ICC morphology was prognostic after controlling for Gleason grade, surgical margin positivity, preoperative prostate-specific antigen level, pathological T stage, and age (HR 1.19, 95% confidence interval 1.03-1.38; p = 0.018).

CONCLUSIONS

Automated image analysis and machine learning could provide an objective, quantitative, reproducible, and high-throughput method of quantifying ICC area. The performance of CAI for grade group 2 cancer suggests that for patients with little Gleason 4 pattern, the ICC fraction has a strong prognostic role.

PATIENT SUMMARY

Machine-based measurement of a specific cell pattern (cribriform; sieve-like, with lots of spaces) in images of prostate specimens could improve risk stratification for patients with prostate cancer. In the future, this could help in expanding the criteria for active surveillance.

Surrogate Endpoints in Localized Prostate Cancer

Randomized clinical trials assessing novel therapies in men with localized prostate cancer frequently require large patient numbers and more than a decade of follow-up to demonstrate improvements in overall survival. As the landscape of treatment options for prostate cancer is rapidly changing, clinical trials requiring long follow-up threaten to impede treatment improvements and run the risk of results being obsolete by the time that they are reported in publication. To address these issues, there has been tremendous interest in identifying an intermediate clinical endpoint that can be assessed earlier in the disease course to serve as a robust surrogate for overall survival in men with localized prostate cancer. Herein we review the relevant data for surrogate endpoints in localized prostate cancer, highlighting the work performed by the Intermediate Clinical Endpoints in Cancer of the Prostate Working Group identifying metastasis-free survival as a valid surrogate for men treated for localized prostate cancer.

Promoting cell proliferation, cell cycle progression, and glycolysis: Glycometabolism-related genes act as prognostic signatures for prostate cancer

BACKGROUND

The Warburg effect seen in most solid tumors occurs only in the late stages of prostate cancer (PCa). Currently, the management of patients with low-risk localized PCa and patients after radical therapy remains a challenge. Our objective here was to evaluate glycometabolism-related genes as prognostic signatures for PCa.

METHODS

The International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA) databases and glycometabolism-related gene sets were obtained online. Glycometabolic prognostic signatures were identified and validated in a TCGA cohort and tested in an ICGC cohort. We used the gene set enrichment analysis to reveal biological processes associated with the glycometabolism-related signatures. Novel glycometabolism-related genes were selected for verifying their oncogenic phenotypes in vitro.

RESULTS

Two glycometabolic prognostic signatures were applied respectively to construct risk score formulas for PCa. Survival and receiver operating characteristic curve analyses were performed to detect the value of these prognostic signatures. We performed univariate and multivariate Cox regression analyses in the TCGA cohort, demonstrating the independence of the prognostic signatures. Three glycometabolism-related genes were found to be novel PCa-associated genes. These were shown to affect proliferation, cell cycle progression, and glycolysis of DU145 and PC3 cells in different degrees.

CONCLUSION

The present research represents the first glycometabolic and high-throughput investigation on PCa, revealing potential biomarkers and treatment targets. We confirm the vital role of glycometabolism in PCa and provide essential resources for future exploration of metabolism in PCa.

Event-Free Survival, a Prostate-Specific Antigen-Based Composite End Point, Is Not a Surrogate for Overall Survival in Men With Localized Prostate Cancer Treated With Radiation

PURPOSE

Recently, we have shown that metastasis-free survival is a strong surrogate for overall survival (OS) in men with intermediate- and high-risk localized prostate cancer and can accelerate the evaluation of new (neo)adjuvant therapies. Event-free survival (EFS), an earlier prostate-specific antigen (PSA)-based composite end point, may further expedite trial completion.

METHODS

EFS was defined as the time from random assignment to the date of first evidence of disease recurrence, including biochemical failure, local or regional recurrence, distant metastasis, or death from any cause, or was censored at the date of last PSA assessment. Individual patient data from trials within the Intermediate Clinical Endpoints in Cancer of the Prostate-ICECaP-database with evaluable PSA and disease follow-up data were analyzed. We evaluated the surrogacy of EFS for OS using a 2-stage meta-analytic validation model by determining the correlation of EFS with OS (patient level) and the correlation of treatment effects (hazard ratios [HRs]) on both EFS and OS (trial level). A clinically relevant surrogacy was defined a priori as an R² ≥ 0.7.

RESULTS

Data for 10,350 patients were analyzed from 15 radiation therapy-based trials enrolled from 1987 to 2011 with a median follow-up of 10 years. At the patient level, the correlation of EFS with OS was 0.43 (95% CI, 0.42 to 0.44) as measured by Kendall's tau from a copula model. At the trial level, the R² was 0.35 (95% CI, 0.01 to 0.60) from the weighted linear regression of log(HR)-OS on log(HR)-EFS.

CONCLUSION

EFS is a weak surrogate for OS and is not suitable for use as an intermediate clinical end point to substitute for OS to accelerate phase III (neo)adjuvant trials of prostate cancer therapies for primary radiation therapy-based trials.

Benefits and Risks of Primary Treatments for High-risk Localized and Locally Advanced Prostate Cancer: An International Multidisciplinary Systematic Review

CONTEXT

The optimal treatment for men with high-risk localized or locally advanced prostate cancer (PCa) remains unknown.

OBJECTIVE

To perform a systematic review of the existing literature on the effectiveness of the different primary treatment modalities for high-risk localized and locally advanced PCa. The primary oncological outcome is the development of distant metastases at ≥5 yr of follow-up. Secondary oncological outcomes are PCa-specific mortality, overall mortality, biochemical recurrence, and need for salvage treatment with ≥5 yr of follow-up. Nononcological outcomes are quality of life (QoL), functional outcomes, and treatment-related side effects reported.

EVIDENCE ACQUISITION

Medline, Medline In-Process, Embase, and the Cochrane Central Register of Randomized Controlled Trials were searched. All comparative (randomized and nonrandomized) studies published between January 2000 and May 2019 with at least 50 participants in each arm were included. Studies reporting on high-risk localized PCa (International Society of Urologic Pathologists [ISUP] grade 4-5 [Gleason score {GS} 8-10] or prostate-specific antigen [PSA] >20 ng/ml or ≥ cT2c) and/or locally advanced PCa (any PSA, cT3-4 or cN+, any ISUP grade/GS) or where subanalyses were performed on either group were included. The following primary local treatments were mandated: radical prostatectomy (RP), external beam radiotherapy (EBRT) (≥64 Gy), brachytherapy (BT), or multimodality treatment combining any of the local treatments above (±any systemic treatment). Risk of bias (RoB) and confounding factors were assessed for each study. A narrative synthesis was performed.

EVIDENCE SYNTHESIS

Overall, 90 studies met the inclusion criteria. RoB and confounding factors revealed high RoB for selection, performance, and detection bias, and low RoB for correction of initial PSA and biopsy GS. When comparing RP with EBRT, retrospective series suggested an advantage for RP, although with a low level of evidence. Both RT and RP should be seen as part of a multimodal treatment plan with possible addition of (postoperative) RT and/or androgen deprivation therapy (ADT), respectively. High levels of evidence exist for EBRT treatment, with several randomized clinical trials showing superior outcome for adding long-term ADT or BT to EBRT. No clear cutoff can be proposed for RT dose, but higher RT doses by means of dose escalation schemes result in an improved biochemical control. Twenty studies reported data on QoL, with RP resulting mainly in genitourinary toxicity and sexual dysfunction, and EBRT in bowel problems.

CONCLUSIONS

Based on the results of this systematic review, both RP as part of multimodal treatment and EBRT + long-term ADT can be recommended as primary treatment in high-risk and locally advanced PCa. For high-risk PCa, EBRT + BT can also be offered despite more grade 3 toxicity. Interestingly, for selected patients, for example, those with higher comorbidity, a shorter duration of ADT might be an option. For locally advanced PCa, EBRT + BT shows promising result but still needs further validation. In this setting, it is important that patients are aware that the offered therapy will most likely be in the context a multimodality treatment plan. In particular, if radiation is used, the combination of local with systemic treatment provides the best outcome, provided the patient is fit enough to receive both. Until the results of the SPCG15 trial are known, the optimal local treatment remains a matter of debate. Patients should at all times be fully informed about all available options, and the likelihood of a multimodal approach including the potential side effects of both local and systemic treatment.

PATIENT SUMMARY

We reviewed the literature to see whether the evidence from clinical studies would tell us the best way of curing men with aggressive prostate cancer that had not spread to other parts of the body such as lymph glands or bones. Based on the results of this systematic review, there is good evidence that both surgery and radiation therapy are good treatment options, in terms of prolonging life and preserving quality of life, provided they are combined with other treatments. In the case of surgery this means including radiotherapy (RT), and in the case of RT this means either hormonal therapy or combined RT and brachytherapy.

Prospective study to define the clinical utility and benefit of Decipher testing in men following prostatectomy

Background

Genomic classifiers (GC) have been shown to improve risk stratification post prostatectomy. However, their clinical benefit has not been prospectively demonstrated. We sought to determine the impact of GC testing on postoperative management in men with prostate cancer post prostatectomy.

Methods

Two prospective registries of prostate cancer patients treated between 2014 and 2019 were included. All men underwent Decipher tumor testing for adverse features post prostatectomy (Decipher Biosciences, San Diego, CA). The clinical utility cohort, which measured the change in treatment decision-making, captured pre- and postgenomic treatment recommendations from urologists across diverse practice settings (n = 3455). The clinical benefit cohort, which examined the difference in outcome, was from a single academic institution whose tumor board predefined “best practices” based on GC results (n = 135).

Results

In the clinical utility cohort, providers’ recommendations pregenomic testing were primarily observation (69%). GC testing changed recommendations for 39% of patients, translating to a number needed to test of 3 to change one treatment decision. In the clinical benefit cohort, 61% of patients had genomic high-risk tumors; those who received the recommended adjuvant radiation therapy (ART) had 2-year PSA recurrence of 3 vs. 25% for those who did not (HR 0.1 [95% CI 0.0–0.6], p = 0.013). For the genomic low/intermediate-risk patients, 93% followed recommendations for observation, with similar 2-year PSA recurrence rates compared with those who received ART (p = 0.93).

Conclusions

The use of GC substantially altered treatment decision-making, with a number needed to test of only 3. Implementing best practices to routinely recommend ART for genomic-high patients led to larger than expected improvements in early biochemical endpoints, without jeopardizing outcomes for genomic-low/intermediate-risk patients.