Trends in Utilization and Medicare Spending on Short-Course Radiation Therapy for Breast and Prostate Cancer: An Episode-Based Analysis From 2015 to 2019

PURPOSE

Evidence supports the value of shorter, similarly efficacious, and potentially more cost-effective hypofractionated radiation therapy (RT) regimens in many clinical scenarios for breast cancer (BC) and prostate cancer (PC). However, practice patterns vary considerably. We used the most recent Centers for Medicare and Medicaid Services data to assess trends in RT cost and practice patterns among episodes of BC and PC.

METHODS AND MATERIALS

We performed a retrospective cohort analysis of all external beam RT episodes for BC and PC from 2015 to 2019 to assess predictors of short-course RT (SCRT) use and calculated spending differences. Multivariable logistic regression defined adjusted odds ratios of receipt of SCRT over longer-course RT (LCRT) by treatment modality, age, year of diagnosis, type of practice, and the interaction between year and treatment setting. Medicare spending was evaluated using multivariable linear regression controlling for duration of RT regimen (SCRT vs LCRT) in addition to the above covariables.

RESULTS

Of 143,729 BC episodes and 114,214 PC episodes, 63,623 (44.27%) and 25,955 (22.72%) were SCRT regimens, respectively. Median total spending for SCRT regimens among BC episodes was $9418 (interquartile range [IQR], $7966-$10,983) versus $13,602 (IQR, $11,814-$15,499) for LCRT. Among PC episodes, median total spending was $6924 (IQR, $4,509-$12,905) for stereotactic body RT, $18,768 (IQR, $15,421-$20,740) for moderate hypofractionation, and $27,319 (IQR, $25,446-$29,421) for LCRT. On logistic regression, receipt of SCRT was associated with older age among both BC and PC episodes as well as treatment at hospital-affiliated over freestanding sites (P < .001 for all).

CONCLUSIONS

In this evaluation of BC and PC RT episodes from 2015 to 2019, we found that shorter-course RT resulted in lower costs than longer-course RT. SCRT was also more common in hospital-affiliated sites. Future research focusing on potential payment incentives encouraging SCRT when clinically appropriate in the 2 most common cancers treated with RT will be valuable as the field continues to prospectively evaluate cost-effective hypofractionation in other disease sites.

Neighborhood Deprivation, Race and Ethnicity, and Prostate Cancer Outcomes Across California Health Care Systems

Importance

Non-Hispanic Black (hereafter, Black) individuals experience worse prostate cancer outcomes due to socioeconomic and racial inequities of access to care. Few studies have empirically evaluated these disparities across different health care systems.

Objective

To describe the racial and ethnic and neighborhood socioeconomic status (nSES) disparities among residents of the same communities who receive prostate cancer care in the US Department of Veterans Affairs (VA) health care system vs other settings.

Design, Setting, and Participants

This cohort study obtained data from the VA Central Cancer Registry for veterans with prostate cancer who received care within the VA Greater Los Angeles Healthcare System (VA cohort) and from the California Cancer Registry (CCR) for nonveterans who received care outside the VA setting (CCR cohort). The cohorts consisted of all males with incident prostate cancer who were living within the same US Census tracts. These individuals received care between 2000 and 2018 and were followed up until death from any cause or censoring on December 31, 2018. Data analyses were conducted between September 2022 and December 2023.

Exposures

Health care setting, self-identified race and ethnicity (SIRE), and nSES.

Main Outcomes and Measures

The primary outcome was all-cause mortality (ACM). Cox proportional hazards regression models were used to estimate hazard ratios for associations of SIRE and nSES with prostate cancer outcomes in the VA and CCR cohorts.

Results

Included in the analysis were 49 461 males with prostate cancer. Of these, 1881 males were in the VA cohort (mean [SD] age, 65.3 [7.7] years; 833 Black individuals [44.3%], 694 non-Hispanic White [hereafter, White] individuals [36.9%], and 354 individuals [18.8%] of other or unknown race). A total of 47 580 individuals were in the CCR cohort (mean [SD] age, 67.0 [9.6] years; 8183 Black individuals [17.2%], 26 206 White individuals [55.1%], and 13 191 individuals [27.8%] of other or unknown race). In the VA cohort, there were no racial disparities observed for metastasis, ACM, or prostate cancer-specific mortality (PCSM). However, in the CCR cohort, the racial disparities were observed for metastasis (adjusted odds ratio [AOR], 1.36; 95% CI, 1.22-1.52), ACM (adjusted hazard ratio [AHR], 1.13; 95% CI, 1.04-1.24), and PCSM (AHR, 1.15; 95% CI, 1.05-1.25). Heterogeneity was observed for the racial disparity in ACM in the VA vs CCR cohorts (AHR, 0.90 [95% CI, 0.76-1.06] vs 1.13 [95% CI, 1.04-1.24]; P = .01). No evidence of nSES disparities was observed for any prostate cancer outcomes in the VA cohort. However, in the CCR cohort, heterogeneity was observed for nSES disparities with ACM (AHR, 0.82; 95% CI, 0.80-0.84; P = .002) and PCSM (AHR, 0.86; 95% CI, 0.82-0.89; P = .007).

Conclusions and Relevance

Results of this study suggest that racial and nSES disparities were wider among patients seeking care outside of the VA health care system. Health systems-related interventions that address access barriers may mitigate racial and socioeconomic disparities in prostate cancer.

Genetic risk and likelihood of prostate cancer detection on first biopsy by ancestry

Despite differences in prostate cancer risk across ancestry groups, relative performance of prostate cancer genetic risks scores (GRS) for positive biopsy prediction in different ancestry groups is unknown. This cross-sectional retrospective analysis examines the association between a polygenic hazard score (PHS290) and risk of prostate cancer diagnosis upon first biopsy in male Veterans using two-sided tests. Our analysis included 36,717 Veterans (10,297 of African ancestry). Unadjusted rates of positive first prostate biopsy increased with higher genetic risk (low risk: 34%, high risk: 58%; p < .001). Among men of African ancestry, higher genetic risk was associated with increased prostate cancer detection on first biopsy (OR 2.18, 95% CI 1.93-2.47), but the effect was stronger among men of European descent (OR 3.89, 95% CI 3.62-4.18). These findings suggest that incorporating genetic risk into prediction models could better personalize biopsy decisions, although further study is needed to achieve equitable genetic risk stratification among ancestry groups.

Association between prediagnostic prostate-specific antigen and prostate cancer probability in Black and non-Hispanic White men

BACKGROUND

Although Black men are more likely than non-Hispanic White men to develop and die from prostate cancer, limited data exist to guide prostate-specific antigen (PSA) screening protocols in Black men. This study investigated whether the risk for prostate cancer was higher than expected among self-identified Black than White veterans based on prebiopsy PSA level.

METHODS

Multivariable logistic regression models were estimated to predict the likelihood of prostate cancer diagnosis on first biopsy for 75,295 Black and 207,658 White male veterans. Self-identified race, age at first PSA test, prebiopsy PSA, age at first biopsy, smoking status, statin use, and socioeconomic factors were used as predictors. The adjusted predicted probabilities of cancer detection on first prostate biopsy from the logistic models at different PSA levels were calculated.

RESULTS

After controlling for PSA and other covariates, Black veterans were 50% more likely to receive a prostate cancer diagnosis on their first prostate biopsy than White veterans (odds ratio [OR], 1.50; 95% CI, 1.47-1.53; p < .001). At a PSA level of 4.0 ng/mL, the probability of prostate cancer for a Black man was 49% compared with 39% for a White man. This model indicated that Black veterans with a PSA of 4.0 ng/mL have an equivalent risk of prostate cancer as White veterans with a PSA of 13.4 ng/mL.

CONCLUSIONS

The findings indicate that, at any given PSA level, Black men are more likely to harbor prostate cancer than White men. Prospective studies are needed to better evaluate risks and benefits of PSA screening in Black men and other high-risk populations.

Radiation Therapy Summary of the AUA/ASTRO Guideline on Clinically Localized Prostate Cancer

PURPOSE

Our purpose was to develop a summary of recommendations regarding the management of patients with clinically localized prostate cancer based on the American Urologic Association/ ASTRO Guideline on Clinically Localized Prostate Cancer.

METHODS

The American Urologic Association and ASTRO convened a multidisciplinary, expert panel to develop recommendations based on a systematic literature review using an a priori defined consensus-building methodology. The topics covered were risk assessment, staging, risk-based management, principles of management including active surveillance, surgery, radiation, and follow-up after treatment. Presented are recommendations from the guideline most pertinent to radiation oncologists with an additional statement on health equity, diversity, and inclusion related to guideline panel composition and the topic of clinically localized prostate cancer.

SUMMARY

Staging, risk assessment, and management options in prostate cancer have advanced over the last decade and significantly affect shared decision-making for treatment management. Current advancements and controversies discussed to guide staging, risk assessment, and treatment recommendations include the use of advanced imaging and tumor genomic profiling. An essential active surveillance strategy includes prostate-specific antigen monitoring and periodic digital rectal examination with changes triggering magnetic resonance imaging and possible biopsy thereafter and histologic progression or greater tumor volume prompting consideration of definitive local treatment. The panel recommends against routine use of adjuvant radiation therapy (RT) for patients with prostate cancer after prostatectomy with negative nodes and an undetectable prostate-specific antigen, while acknowledging that patients at highest risk of recurrence were relatively poorly represented in the 3 largest randomized trials comparing adjuvant RT to early salvage and that a role may exist for adjuvant RT in selected patients at highest risk. RT for clinically localized prostate cancer has evolved rapidly, with new trial results, therapeutic combinations, and technological advances. The recommendation of moderately hypofractionated RT has not changed, and the updated guideline incorporates a conditional recommendation for the use of ultrahypofractionated treatment. Health disparities and inequities exist in the management of clinically localized prostate cancer across the continuum of care that can influence guideline concordance.

Characterizing prostate cancer risk through multi-ancestry genome-wide discovery of 187 novel risk variants

The transferability and clinical value of genetic risk scores (GRSs) across populations remain limited due to an imbalance in genetic studies across ancestrally diverse populations. Here we conducted a multi-ancestry genome-wide association study of 156,319 prostate cancer cases and 788,443 controls of European, African, Asian and Hispanic men, reflecting a 57% increase in the number of non-European cases over previous prostate cancer genome-wide association studies. We identified 187 novel risk variants for prostate cancer, increasing the total number of risk variants to 451. An externally replicated multi-ancestry GRS was associated with risk that ranged from 1.8 (per standard deviation) in African ancestry men to 2.2 in European ancestry men. The GRS was associated with a greater risk of aggressive versus non-aggressive disease in men of African ancestry (P = 0.03). Our study presents novel prostate cancer susceptibility loci and a GRS with effective risk stratification across ancestry groups.

In Reply to "Pathogenic/Likely Pathogenic Somatic CDK12 Mutations in Black Men With Prostate Cancer"

This letter to the editor responds to comments by Sartor et al regarding recent findings on the clinical relevance of CDK12 pathogenic mutations.

Trimodal Therapy Using an MR-guided Radiation Therapy Partial Bladder Tumor Boost in Muscle Invasive Bladder Cancer

Purpose

Bladder preservation with trimodal therapy (TMT; maximal tumor resection followed by chemoradiation) is an effective paradigm for select patients with muscle invasive bladder cancer. We report our institutional experience of a TMT protocol using nonadaptive magnetic resonance imaging-guided radiation therapy (MRgRT) for partial bladder boost (PBB).

Methods and Materials

A retrospective analysis was performed on consecutive patients with nonmetastatic muscle invasive bladder cancer who were treated with TMT using MRgRT between 2019 and 2022. Patients underwent intensity modulated RT-based nonadaptive MRgRT PBB contoured on True fast imaging with steady state precession (FISP) images (full bladder) followed sequentially by computed tomography-based RT to the whole empty bladder and pelvic lymph nodes with concurrent chemotherapy. MRgRT treatment time, table shifts, and dosimetric parameters of target coverage and normal tissue exposure were described. Prospectively assessed acute and late genitourinary and gastrointestinal (GI) toxicity were reported. Two-year local control was assessed with Kaplan-Meier methods.

Results

Seventeen patients were identified for analysis. PBB planning target volume margins were ≤8 mm in 94% (n = 16) of cases. Dosimetric target coverage parameters were favorable and all normal tissue dose constraints were met. For MRgRT PBB fractions, median table shifts were 0.4 cm (range, 0-3.15), 0.45 cm (0-2.65), and 0.75 cm (0-4.8) in the X, Y, and Z planes, respectively. Median treatment time for MRgRT PBB fractions was 9 minutes (range, 6.9-17.4). We identified 32 out of 100 total MRgRT fractions that may have benefitted from online adaptation based on changes in organ position relative to planning target volume, predominantly because of small bowel (13/32, 41%) or rectum (8/32, 25%). Two patients discontinued RT prematurely. The incidence of highest-grade acute genitourinary toxicity was 1 to 2 (69%) and 3 (6%), whereas the incidence of acute GI toxicity was 1 to 2 (81%) and 3 (6%). There were no late grade 3 events; 17.6% had late grade 2 cystitis and none had late GI toxicity. With median follow-up of 18.2 months (95% CI, 12.4-22.5), the local control rate was 92%, and no patient has required salvage cystectomy.

Conclusions

Nonadaptive MRgRT PBB is feasible with favorable dosimetry and low resource utilization. Larger studies are needed to evaluate for potential benefits in toxicity and local control associated with this approach in comparison to standard treatment techniques.

Mathematical modeling of radiotherapy: impact of model selection on estimating minimum radiation dose for tumor control

Introduction

Radiation therapy (RT) is one of the most common anticancer therapies. Yet, current radiation oncology practice does not adapt RT dose for individual patients, despite wide interpatient variability in radiosensitivity and accompanying treatment response. We have previously shown that mechanistic mathematical modeling of tumor volume dynamics can simulate volumetric response to RT for individual patients and estimation personalized RT dose for optimal tumor volume reduction. However, understanding the implications of the choice of the underlying RT response model is critical when calculating personalized RT dose.

Methods

In this study, we evaluate the mathematical implications and biological effects of 2 models of RT response on dose personalization: (1) cytotoxicity to cancer cells that lead to direct tumor volume reduction (DVR) and (2) radiation responses to the tumor microenvironment that lead to tumor carrying capacity reduction (CCR) and subsequent tumor shrinkage. Tumor growth was simulated as logistic growth with pre-treatment dynamics being described in the proliferation saturation index (PSI). The effect of RT was simulated according to each respective model for a standard schedule of fractionated RT with 2 Gy weekday fractions. Parameter sweeps were evaluated for the intrinsic tumor growth rate and the radiosensitivity parameter for both models to observe the qualitative impact of each model parameter. We then calculated the minimum RT dose required for locoregional tumor control (LRC) across all combinations of the full range of radiosensitvity and proliferation saturation values.

Results

Both models estimate that patients with higher radiosensitivity will require a lower RT dose to achieve LRC. However, the two models make opposite estimates on the impact of PSI on the minimum RT dose for LRC: the DVR model estimates that tumors with higher PSI values will require a higher RT dose to achieve LRC, while the CCR model estimates that higher PSI values will require a lower RT dose to achieve LRC.

Discussion

Ultimately, these results show the importance of understanding which model best describes tumor growth and treatment response in a particular setting, before using any such model to make estimates for personalized treatment recommendations.

Trends in Utilization and Medicare Spending on Shorter vs. Longer Radiotherapy Courses for Breast and Prostate Cancer

PURPOSE/OBJECTIVE(S)

Evidence based research supports shorter, similarly efficacious, and potentially more cost-effective hypofractionated treatment regimens in many clinical scenarios for breast cancer (BC) and prostate cancer (PC). However, practice patterns of hospital-affiliated and standalone facilities vary considerably. We used the most recent Centers for Medicare and Medicaid Services data to assess trends in radiotherapy (RT) costs and practice patterns among episodes of BC and PC.

MATERIALS/METHODS

We performed a retrospective cohort analysis of all external beam episodes for BC and PC from 2015-2019. For patients with BC, receipt of shorter-course RT (SCRT) was defined as receiving 11-20 fractions of external beam radiation therapy (including IMRT), and conventional RT as >20 fractions. For patients with PC, SBRT was defined as receipt of <10 fractions and moderate hypofractionation as 10-30 fractions (SCRT defined as SBRT and moderate hypofractionation), and >30 fractions for conventional RT. Total Medicare spending were defined as the sum of winsorized payment for professional and technical services furnished during the episode in 2019 dollars. Multivariable logistic regression defined adjusted odds ratios (ORs) of receipt of SCRT over conventional RT by treatment modality, age, year of diagnosis, type of practice, as well as a time*treatment setting interaction term. Medicare spending was evaluated using multivariable linear regression controlling for duration of RT regimen (SCRT vs conventional) in addition to the covariables above.

RESULTS

Of 47,283 BC episodes and 45,917 PC episodes, 23,705 (50.13%) and 9,125 (19.87%) were SCRT, respectively. Median total spending for SCRT among BC episodes was $9,324 (IQR, $7,916-$10,921) vs. $13,372 (IQR, $11,511-$15,283) for conventional RT. Among PC episodes, median total spending was $12,917 (IQR, $9,551-$15,271) for SBRT, $18,944 (IQR, $16,530-$20,615) for moderate hypofractionation, and $26,935 (IQR, $25,062-$28,959) for conventional RT. For both cancers, total episode spending was reduced with SCRT utilization [(BC adjusted β, -$4,200; p<0.001), (PC adjusted β, -$8,747; p<0.001)], older age, and non-IMRT-based treatment. On logistic regression, receipt of SCRT was associated with older age among both BC and PC episodes (p<0.001), as well as treatment at hospital-affiliated over freestanding sites [(BC OR [95% CI], 1.41 [1.29-1.54], p<0.001), (PC OR, 1.64 [1.39-1.94], p<0.001)].

CONCLUSION

In this evaluation of all BC and PC RT episodes from 2015-2019, we found that shorter-course RT resulted in increased cost-savings vs. conventional RT. SCRT was also more common in hospital-affiliated sites. Further research is needed to devise payment incentives that encourage SCRT when clinically applicable in the two most common sites treated with RT, and to prospectively study cost-effective hypofractionation in other disease sites.

Adrenal Stereotactic Body Radiation Therapy: Do Dosimetric Factors Predict for Grade 2+ Lymphopenia?

PURPOSE/OBJECTIVE(S)

Recent studies suggest improvement in outcomes in multiple oligometastatic tumor sites with immunotherapy (IO) and radiation therapy (RT). However, RT may induce lymphopenia that can be immunosuppressive and dosimetric consensus is lacking on parameters predicting grade ≥2 lymphopenia. In this study, we evaluated lymphopenia post receipt of stereotactic body RT (SBRT) for adrenal metastases to see if we could identify any modifiable treatment planning factors.

MATERIALS/METHODS

Patients with adrenal oligometastases who were treated with conventional SBRT or MRI-guided (MRgSBRT), had absolute lymphocyte count (ALC) and white blood cell count (WBC) data available within 6 weeks before and after their radiation treatment, and had contouring data available for review were included in this IRB approved retrospective study. Lymphopenia was graded for ALC as: Grade 1 (1.0-0.8 no/ul), Grade 2 (<0.8 - 0.5 no/ul), Grade 3 (<0.5-0.2 no/ul), Grade 4 (<0.2 no/ul). The vertebral bodies (VB), at the level of the planning treatment volume (PTV) and one above and below, and the spleen were contoured. Dosimetric variables of interest included spleen and VB mean dose (Gy) as well as V2.5-20 Gy in 2.5 Gy increments. Regression analyses were used to identify dosimetric variables associated with absolute and relative difference in ALC post-SBRT.

RESULTS

A total of 30 patients were identified with a slight male predominance (N = 17, 57%) and most commonly left adrenal (N = 17) versus right adrenal (N = 10, 33%) or bilateral metastases (N = 3, 10%). Grade 2+ lymphopenia was observed in N = 7 patients pre-SBRT (23%) and N = 17 patients post-SBRT (57%). N = 26 (87%) of the patients had previous chemotherapies and N = 17 (57%) had previous immunotherapy. Multiple primary tumor types were represented with the most common non-small cell lung cancer (N = 14, 47%), followed by melanoma (N = 4, 13%) and small cell lung cancer (N = 3, 10%). Most patients were treated with non-MRgSBRT (N = 19, 63%) vs MRgRT (N = 11, 37%) and all received SBRT in 5 fractions with median dose 50 Gy (Range: 25 - 60 Gy). The median pre-SBRT ALC was 1.13 (Range: 0.39 - 2.96) and median post-SBRT ALC was 0.72 (Range: 0.11 - 4.15). On linear regression analysis, there was no significant association between post SBRT ALC nor lymphopenia grade with splenic or vertebral body dose, treatment laterality, or SBRT dose.

CONCLUSION

In this retrospective series of predominately metastatic lung cancer patients treated with adrenal SBRT, we observed high rates of post SBRT grade 2+ lymphopenia, yet no dosimetric parameter was predictive, not even for left-sided lesions. Future work includes clinical validation of these findings in a larger population, likely with multi-institutional collaboration, and further study of the investigation of the IO/RT sequencing issues in such heavily pre-treated patients.

Health Equity Achievement in Radiation Therapy (HEART) Score: A Social Prognosis

PURPOSE/OBJECTIVE(S)

The aim of this study was to develop a Health Equity Achievement in Radiation Therapy (HEART) score that can help identify patients at risk of experiencing suboptimal quality-of-care (QoC) early on in the patient-provider encounter and prior to initiation of treatment. Such a score may improve shared decision making to improve QoC.

MATERIALS/METHODS

A retrospective analysis was conducted using the National Cancer Database (NCDB) for prostate cancer cases between 2004-2017. Sociodemographic factors, clinical characteristics, and treatment information were collected. A composite HEART score was built to predict suboptimal QoC, defined as treatment refusal, incomplete treatment, or treatment delay. 70% of the data was allocated to training and 30% to validating a logistic regression model through which a nomogram was constructed.

RESULTS

A total of 1,599,785 patients were included in the analysis, of whom 126,917 (7.9%) had at least one suboptimal QoC. The strongest predictors were Black race, uninsured status, lower educational status, geographic location, and nodal disease (Table). The nomogram demonstrated a fair ability to predict quality metrics, with an area under the receiver operating characteristic curve (AUC) of 0.57 in the test group. The nomogram facilitated graphic interpretation of systemic factors in contributing to suboptimal QoC.

CONCLUSION

With observed potential for predicting suboptimal QoC outcomes in patients with prostate cancer by considering systemic barriers, this NCDB-based nomogram has potential utility as a tool for identifying patients who may benefit from additional social support, including the financial resources associated with these services, to improve access to care. Further validation in diverse datasets is needed to improve performance and generalizability to broader patient populations and different disease sites.

Accurate, repeatable, and geometrically precise diffusion-weighted imaging on a 0.35 T magnetic resonance imaging-guided linear accelerator

Background and purpose

Diffusion weighted imaging (DWI) allows for the interrogation of tissue cellularity, which is a surrogate for cellular proliferation. Previous attempts to incorporate DWI into the workflow of a 0.35 T MR-linac (MRL) have lacked quantitative accuracy. In this study, accuracy, repeatability, and geometric precision of apparent diffusion coefficient (ADC) maps produced using an echo planar imaging (EPI)-based DWI protocol on the MRL system is illustrated, and in vivo potential for longitudinal patient imaging is demonstrated.

Materials and methods

Accuracy and repeatability were assessed by measuring ADC values in a diffusion phantom at three timepoints and comparing to reference ADC values. System-dependent geometric distortion was quantified by measuring the distance between 93 pairs of phantom features on ADC maps acquired on a 0.35 T MRL and a 3.0 T diagnostic scanner and comparing to spatially precise CT images. Additionally, for five sarcoma patients receiving radiotherapy on the MRL, same-day in vivo ADC maps were acquired on both systems, one of which at multiple timepoints.

Results

Phantom ADC quantification was accurate on the 0.35 T MRL with significant discrepancies only seen at high ADC. Average geometric distortions were 0.35 (±0.02) mm and 0.85 (±0.02) mm in the central slice and 0.66 (±0.04) mm and 2.14 (±0.07) mm at 5.4 cm off-center for the MRL and diagnostic system, respectively. In the sarcoma patients, a mean pretreatment ADC of 910x10-6 (±100x10-6) mm2/s was measured on the MRL.

Conclusions

The acquisition of accurate, repeatable, and geometrically precise ADC maps is possible at 0.35 T with an EPI approach.

An Analysis of Patients Treated with Stereotactic Body Radiotherapy for Metastatic Urinary Tract Tumors to Identify Predictors of Response

PURPOSE/OBJECTIVE(S)

To identify selection criteria linked to outcomes in patients treated with stereotactic body radiotherapy (SBRT) for metastatic tumors of the urinary tract (UT).

MATERIALS/METHODS

Single institution retrospective analysis of SBRT treated patients for oligometastatic/progressive UT tumors from 2006-2022. Charts were queried for M1 status at diagnosis or during disease course, treatment details (surgery, SBRT, systemic therapy), metabolic status (diabetes [DM], BMI) and outcomes. A linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics portrayed the cohort, and analyses were done at patient and site level. Time-to-event analyses, including overall survival (OS) and progression-free survival (PFS) from SBRT, were assessed by the Kaplan-Meier method. Cox regression was used for univariable (UVA) and multivariable analyses (MVA) to identify predictors of outcomes.

RESULTS

A total of 35 patients were treated at 44 metastatic sites, including: bone (25%), node (36.4%), lung (20.5%), soft tissue (13.6%) and liver (4.5%). Most were male (74.3%) with a median age of 70 (range: 51-89), without DM (60%) having a median BMI of 29.8, and ECOG <2 (97.1%) at time of SBRT. Six (17.1%) patients were M1 at diagnosis. Of the 29 non-M1 patients, 86.2% received definitive local therapy (LT), 58.6% had at least T3/N+ disease, 75.8% received systemic therapy with a median of 2 agents (range: 1-6) prior to SBRT. Sixteen (45.7%) received immunotherapy (IO) with most receiving this before (75%) and after (56.2%) SBRT. Six patients had positive PD-L1 status (n = 10). The median RT dose, fractionation and BED was 40 Gy (range: 14-46), 5 fractions, and 72 (range: 28-132), respectively. At a median follow-up of 34.8, the median OS was 18.4 m (range: 9.3-27.4) with a 2-year OS of 35.9%. At patient level, 62.8% recurred after SBRT. The median PFS after SBRT was 5.3 m (range: 1.8-8.7) with a 2-yr PFS of 29.3%. Patient-level PFS was improved with LT (6.7 vs 1.4 m; p = 0.001) and DM (NR vs 2.9 m; p = 0.015), whereas improved OS was related with LT (18.9 vs 6.6 m; p = 0.03), DM (p = 0.04), ECOG (p = 0.004), and no relapse after SBRT (NR vs 9.8 m; p <0.001). Exposure to < 3 systemic agents prior to SBRT portended better PFS (6.7 vs 2.6 m; p = 0.04) without any impact by IO. At site level, 20.4% of sites had local relapse with 4 being the first event. Site was related with PFS (p = 0.009) with order of increased relapse risk being liver > bone > soft tissue > node > lung. No dosimetric feature was related with recurrence risk. On MVA, both DM (p = 0.02) and LT (p = 0.002) were predictive for PFS. Only recurrence after SBRT predicted for OS on MVA (HR: 6.7, 95% CI: 1.4-31; p = 0.014). In the IO subset, median PFS was 5.3 m and OS was 9.4 m, with no difference seen with IO-SBRT sequence or PDL1 status.

CONCLUSION

Optimized selection criteria for metastasis-directed therapy in patients with UT tumors is unclear, notably with IO. Future studies may benefit by assessing circulating tumor markers prior to SBRT.

Multidisciplinary Management of Primary Urethral Cancer with Radiotherapy

PURPOSE/OBJECTIVE(S)

Primary urethral cancer (PUC) is a rare form of genitourinary malignancy with a paucity of data to guide management. We analyzed PUC patients for clinicopathologic characteristics and treatment approach (radiotherapy [RT] with/without consolidative surgery) to identify predictors of outcome and RT response.

MATERIALS/METHODS

We conducted a single-institution retrospective review of patients treated with RT for PUC between 2002 to 2020. Each patient underwent multidisciplinary evaluation (including cystoscopy) as well as imaging to confirm tumor origin in the urethra. The linear quadratic formula was used to calculate the biologically effective dose (BED) using an α/β of 10 for tumor. Descriptive statistics were used to characterize the cohort. Fisher's Exact test was used to compare groups. Time-to-event analyses was conducted with the Kaplan-Meier method; outcomes included overall survival (OS) and time to recurrence (TTR) from diagnosis. Cox regression analysis assessed predictors of outcomes.

RESULTS

A total of 17 patients were identified for analysis. Median age was 63 years (range: 34-86); the majority were female (76.5%) and white (82.4%). Tumors were localized in the proximal (n = 6) or distal (n = 11) urethra. Histology included urothelial (11.8%), squamous (35.3%), adenocarcinoma (29.4%) and mixed (23.5%). Ten patients (58.8%) had cT3 or higher disease with 10 being cN0 (58.8%), 1 cN1 (5.9%), 5 cN2 (29.4%) and 1 cNx (5.9%). Median tumor size was 4.8 cm (range: 0.5-12 cm). The majority (88.2%) were treated with definitive chemoRT with 70.5% receiving platinum therapy. Median RT dose was 59.4 Gy (range: 39.6-70.2) with a median of 30 fractions. One patient underwent upfront cystourethrectomy and 6 (35.3%) underwent consolidative surgery at a median of 2.3 months after RT. Five patients (29.4%) had a complete response (CR) and 70.6% had a partial response (PR) to RT. Of the 7 patients who underwent surgical resection the final pathology was ypTis (28.5%), ypT1 (14.2%), ypT2 (14.2%), ypT4 (28.5%) and pT2 (14.2%). A median of 16 lymph nodes were removed with 1 patient having pN2 and all others pN0. Four patients (66.6%) were downstaged by chemoRT prior to surgery. At a median follow-up time of 8.4 years, the median OS was 37.9 months (range: 23.2-52.7), which was associated with a 5-year OS of 37.2%. Twelve (70.5%) patients recurred with a median TTR of 6.3 months (range 4.8-7.7). No demographics, staging methods, or tumor characteristics were associated with OS or TTR. Urothelial histology was associated with CR following chemoRT (p = 0.02). RT dose (continuous) was associated with OS (p = 0.018) as well as a BED (HR: 0.90, 95% CI: 0.84-0.97; p = 0.01). A BED > 55 Gy was associated with improved median OS (56.4 vs 9.13 months, p = 0.006).

CONCLUSION

Analysis of PUC patients treated with multimodal therapy found higher rates of CR in patients with urothelial histology and increased OS in patients treated with a BED > 55 Gy. Neoadjuvant chemoRT may downstage disease prior to surgical extirpation.

Sociocultural factors associated with physical activity in Black prostate cancer survivors

PURPOSE

Prostate cancer disproportionately affects Black men. Physical activity protects long-term health and quality of life outcomes in prostate cancer survivors. This study aimed to identify sociocultural factors related to physical activity among Black prostate cancer survivors to inform culturally tailored intervention development.

METHODS

This secondary analysis included data from 257 men who identified as Black or African American and were diagnosed with prostate cancer between 2013 and 2018. Participants completed validated self-report measures of perceived history of racial discrimination, religiosity, fatalism, sociodemographic (e.g., age, ethnicity, income) and clinical characteristics (e.g., years since diagnosis, comorbidity burden), and leisure-time physical activity. Regression analyses were conducted to examine the associations between sociocultural factors and mild, moderate, and vigorous physical activity.

RESULTS

Participants were on average 68.7 years old (SD = 7.7), and most were non-Hispanic (97.3%), married (68.9%), reported an annual household income above $50,000 (57.1%), received at least some college education (74.1%), and were overweight or had obesity (78.5%). Participants reported on average 88.1 (SD = 208.6) min of weekly mild physical activity, and most did not meet guidelines for weekly moderate (80.5%) or vigorous (73.0%) physical activity. After adjusting for covariates, older age and greater religiosity were associated with mild physical activity (ps ≤ 0.05). Higher levels of fatalism were associated with lower odds of meeting guidelines for moderate physical activity (OR = 0.87, 95% CI = 0.77-0.99).

CONCLUSIONS

Sociocultural factors such as religiosity and fatalism may be associated with some forms of physical activity in Black prostate cancer survivors. These findings suggest that incorporating faith-based practices into health behavior interventions may be appropriate for this population.

Evidence of Novel Susceptibility Variants for Prostate Cancer and a Multiancestry Polygenic Risk Score Associated with Aggressive Disease in Men of African Ancestry

BACKGROUND

Genetic factors play an important role in prostate cancer (PCa) susceptibility.

OBJECTIVE

To discover common genetic variants contributing to the risk of PCa in men of African ancestry.

DESIGN, SETTING, AND PARTICIPANTS

We conducted a meta-analysis of ten genome-wide association studies consisting of 19378 cases and 61620 controls of African ancestry.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Common genotyped and imputed variants were tested for their association with PCa risk. Novel susceptibility loci were identified and incorporated into a multiancestry polygenic risk score (PRS). The PRS was evaluated for associations with PCa risk and disease aggressiveness.

RESULTS AND LIMITATIONS

Nine novel susceptibility loci for PCa were identified, of which seven were only found or substantially more common in men of African ancestry, including an African-specific stop-gain variant in the prostate-specific gene anoctamin 7 (ANO7). A multiancestry PRS of 278 risk variants conferred strong associations with PCa risk in African ancestry studies (odds ratios [ORs] >3 and >5 for men in the top PRS decile and percentile, respectively). More importantly, compared with men in the 40-60% PRS category, men in the top PRS decile had a significantly higher risk of aggressive PCa (OR = 1.23, 95% confidence interval = 1.10-1.38, p = 4.4 × 10-4).

CONCLUSIONS

This study demonstrates the importance of large-scale genetic studies in men of African ancestry for a better understanding of PCa susceptibility in this high-risk population and suggests a potential clinical utility of PRS in differentiating between the risks of developing aggressive and nonaggressive disease in men of African ancestry.

PATIENT SUMMARY

In this large genetic study in men of African ancestry, we discovered nine novel prostate cancer (PCa) risk variants. We also showed that a multiancestry polygenic risk score was effective in stratifying PCa risk, and was able to differentiate risk of aggressive and nonaggressive disease.

Actionable Genomic Alterations in Prostate Cancer Among Black and White United States Veterans

Black Veterans have higher a incidence of localized and metastatic prostate cancer compared to White Veterans yet are underrepresented in reports of frequencies of somatic and germline alterations. This retrospective analysis of somatic and putative germline alterations was conducted in a large cohort of Veterans with prostate cancer (N = 835 Black, 1613 White) who underwent next generation sequencing through the VA Precision Oncology Program, which facilitates molecular testing for Veterans with metastatic cancer. No differences were observed in gene alterations for FDA approved targetable therapies (13.5% in Black Veterans vs. 15.5% in White Veterans, P = .21), nor in any potentially actionable alterations (25.5% vs. 28.7%, P =.1). Black Veterans had higher rates of BRAF (5.5% vs. 2.6%, P < .001) alterations, White Veterans TMPRSS2 fusions (27.2% vs. 11.7%, P < .0001). Putative germline alteration rates were higher in White Veterans (12.0% vs. 6.1%, P < .0001). Racial disparities in outcome are unlikely attributable to acquired somatic alterations in actionable pathways.

Recruiting African American Prostate Cancer Survivors for a Population-based Biobank Study

BACKGROUND

Prostate cancer affects African American men disproportionately compared with men of other racial/ethnic groups. To identify biological bases for this health disparity, we sought to create a state-wide biobank of African American prostate cancer survivors in Florida.

METHODS

African American men diagnosed with prostate cancer between 2013 and 2017 and living in Florida at diagnosis were identified through the State of Florida's cancer registry. Individuals were approached via mail and telephone, assessed for eligibility, and asked for informed consent. χ2 and t tests were conducted to identify differences between eligible and reachable individuals (i.e., had valid contact information) versus consented participants.

RESULTS

Of the 5,960 eligible and reachable individuals, 3,904 were eligible and contacted at least once, and 578 consented [overall consent rate = 10% (578/5,960); adjusted consent rate = 15% (578/3,904)]. Statistically significant (Ps < 0.05) but small differences in demographic and clinical variables were observed. Consented participants were less likely to be older than 64 (35% vs. 41%) and less likely to have received radiotherapy (36% vs. 41%) and hormone therapy (16% vs. 21%), but more likely to have regional prostate cancer (13% vs. 11%) and have undergone surgery (44% vs. 39%). Consented participants did not differ from reachable individuals on other demographic and clinical factors (Ps > 0.05).

CONCLUSIONS

Recruiting African American prostate cancer survivors to biobanking research through a cancer registry is feasible. However, the consent rate was low, and existing challenges limit consent and participation.

IMPACT

Strategies for overcoming barriers to informed consent and increasing participation in biospecimen research are needed to address cancer disparities.

Management of patients with advanced prostate cancer-metastatic and/or castration-resistant prostate cancer: Report of the Advanced Prostate Cancer Consensus Conference (APCCC) 2022

BACKGROUND

Innovations in imaging and molecular characterisation together with novel treatment options have improved outcomes in advanced prostate cancer. However, we still lack high-level evidence in many areas relevant to making management decisions in daily clinical practise. The 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) addressed some questions in these areas to supplement guidelines that mostly are based on level 1 evidence.

OBJECTIVE

To present the voting results of the APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

The experts voted on controversial questions where high-level evidence is mostly lacking: locally advanced prostate cancer; biochemical recurrence after local treatment; metastatic hormone-sensitive, non-metastatic, and metastatic castration-resistant prostate cancer; oligometastatic prostate cancer; and managing side effects of hormonal therapy. A panel of 105 international prostate cancer experts voted on the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted on 198 pre-defined questions, which were developed by 117 voting and non-voting panel members prior to the conference following a modified Delphi process. A total of 116 questions on metastatic and/or castration-resistant prostate cancer are discussed in this manuscript. In 2022, the voting was done by a web-based survey because of COVID-19 restrictions.

RESULTS AND LIMITATIONS

The voting reflects the expert opinion of these panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results are reported in the supplementary material. We report here on topics in metastatic, hormone-sensitive prostate cancer (mHSPC), non-metastatic, castration-resistant prostate cancer (nmCRPC), metastatic castration-resistant prostate cancer (mCRPC), and oligometastatic and oligoprogressive prostate cancer.

CONCLUSIONS

These voting results in four specific areas from a panel of experts in advanced prostate cancer can help clinicians and patients navigate controversial areas of management for which high-level evidence is scant or conflicting and can help research funders and policy makers identify information gaps and consider what areas to explore further. However, diagnostic and treatment decisions always have to be individualised based on patient characteristics, including the extent and location of disease, prior treatment(s), co-morbidities, patient preferences, and treatment recommendations and should also incorporate current and emerging clinical evidence and logistic and economic factors. Enrolment in clinical trials is strongly encouraged. Importantly, APCCC 2022 once again identified important gaps where there is non-consensus and that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with healthcare providers worldwide. At each APCCC, an expert panel votes on pre-defined questions that target the most clinically relevant areas of advanced prostate cancer treatment for which there are gaps in knowledge. The results of the voting provide a practical guide to help clinicians discuss therapeutic options with patients and their relatives as part of shared and multidisciplinary decision-making. This report focuses on the advanced setting, covering metastatic hormone-sensitive prostate cancer and both non-metastatic and metastatic castration-resistant prostate cancer.

TWITTER SUMMARY

Report of the results of APCCC 2022 for the following topics: mHSPC, nmCRPC, mCRPC, and oligometastatic prostate cancer.

TAKE-HOME MESSAGE

At APCCC 2022, clinically important questions in the management of advanced prostate cancer management were identified and discussed, and experts voted on pre-defined consensus questions. The report of the results for metastatic and/or castration-resistant prostate cancer is summarised here.

Differential Expression of miRNAs Contributes to Tumor Aggressiveness and Racial Disparity in African American Men with Prostate Cancer

Prostate cancer is the leading cancer in incidence and second leading cause of cancer mortality in US men. African American men have significantly higher incidence and mortality rates from prostate cancer than European American men. Previous studies reported that the disparity in prostate cancer survival or mortality can be explained by different biological backgrounds. microRNAs (miRNAs) regulate gene expression of their cognate mRNAs in many cancers. Therefore, miRNAs may be a potentially promising diagnostic tool. The role of miRNAs in prostate cancer aggressiveness and racial disparity has not been fully established. The goal of this study is to identify miRNAs associated with aggressiveness and racial disparity in prostate cancer. Here we report miRNAs that are associated with tumor status and aggressiveness in prostate cancer using a profiling approach. Further, downregulated miRNAs in African American tissues were confirmed by qRT-PCR. These miRNAs have also been shown to negatively regulate the expression of the androgen receptor in prostate cancer cells. This report provides a novel insight into understanding tumor aggressiveness and racial disparities of prostate cancer.

Abstract 1896: Dysregulation of DNA methylation in prostate cancer among African American men

Men of African ancestry have the higher incidence and mortality rates of prostate cancer (PCa) worldwide. These health disparities may be contributed by environmental or biological factors, such as epigenomics. Differential DNA methylation can influence carcinogenesis and disease progression. Indeed, the most common molecular event in PCa is dysregulation of DNA methylation. Among these epigenetic changes, some specific changes may be associated with poor outcomes. Numerous studies reported that differential DNA methylation influences the likelihood of developing PCa and affects its progression. However, most studies were based on European American patients. There is a need to investigate methylation profiles to evaluate potential African American-specific methylated genes, since differential DNA methylation may influence health disparities in PCa. This study aimed to investigate differentially DNA methylated genes between tumor vs. adjacent normal, and aggressive vs. indolent PCa (based on Gleason Score) in 120 African American patients from Florida. Genomic DNA samples were extracted by macro-dissection from FFPE. DNA methylation patterns were assessed using the human Illumina Infinium Methylation EPIC array. We identified 5,097 differentially methylated CpG-sites (q&lt;0.01, lΔβl &gt; 0.2) A few representative differentially methylated regions (DMRs) include immune genes, such as CD40, OX40L, Galectin 3, and STING, in prostate tumor tissues as compared with normal tissues. There was also a clear global increase of methylation level in the tumor samples compared to the normal tissues. Regarding PCa aggressiveness, 6,775 (Hypo:4,252, and Hyper: 2,523) differentially methylated CpG-sites (q&lt;0.05, lΔβl &gt; 0.1) were identified when two groups GG1 (Gleason score 6) vs GG4/5 (Gleason score 8≤) were compared. Among these 6,775 CpG-sites, many CpG-probes are consistently significant in more than one comparison. For example, 1,182 hyper and 1,660 hypo-methylation sites were identified in the comparison between GG1 and GG2/3 (Gleason score 7), while 362 hyper- and 1,640 hypo-methylation sites were found in the GG2/3 vs GG4/5 comparison. A small fraction of probes (51 hyper and 155 hypomethylated probes) was consistently found in all comparisons. These genes, MMP16, CDH13, CCND2, and SEPT9, were previously reported to have a role in PCa progression. This study identified several differentially methylated genes, associated with risk or aggressiveness. Most of these changes appear to overlap in different comparisons, thus GG1 vs. GG2/3 or GG2/3 vs. GG4/5 comparison. Many differentially methylated genes identified here have previously been associated with PCa risk or tumor aggressiveness. These results will shed light on potential mechanisms contributing to PCa disparities in African American population.

Citation Format: Anders Berglund, Kosj Yamoah, Carlos Diaz Osterman, Julie Dutil, Jaime Matta, Gilberto Ruiz-Deya, Liang Wang, Hyun Park, Tamara Lotan, Ryan Putney, Sungjune Kim, Seung Joon Kim, Clement Gwede, Rana Falahat, James Mule, Youngchul Kim, Ratna Chakrabarti, Jong Y. Park. Dysregulation of DNA methylation in prostate cancer among African American men [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 1896.

Abstract P2-03-22: Assessment of the relationship between duration of treatment with hormonal therapy and the detection of ESR1 mutations in hormone-receptor positive, HER2 negative, breast cancer

Background Hormonal therapeutic agents such as the selective estrogen receptor modulator, tamoxifen, as well as the aromatase inhibitors (AIs), anastrozole, exemestane, and letrozole, are a mainstay in the treatment of patients with hormone-receptor positive (HR+) breast cancer. Despite the effectiveness of hormonal therapy in the treatment of patients with HR+ breast cancer, acquired resistance to both AIs and tamoxifen does occur, often associated with mutations of the estrogen receptor 1 (ESR1). Although the acquisition of ESR1 mutations in patients with HR+ breast cancer treated with hormonal therapy has been established as a mechanism of resistance, there is a paucity of data on the relationship between the duration of treatment with hormonal therapies and the development of ESR1 mutations. Using a cohort of patients with HR+ breast cancer who underwent next generation sequencing (NGS) as part of routine clinical care, we aim to assess the relationship between the duration of exposure to aromatase inhibitors and the detection of ESR1 mutations. The results of this study will further our understanding of ESR1-mutations and provide insight into strategies to optimize therapy for patients with HR+ breast cancers. Methods This is a retrospective analysis of patients 18 years of age or older treated at a single academic cancer center in the USA, diagnosed with HR+, HER2-negative breast cancer and who have received somatic NGS as part of clinical care over a six-year period through July 2019. Demographic, disease-related, and treatment related variables were collected along with genomic testing variables (ie. ESR1-mutation status) for each patient who met the inclusion criteria. Two patient groups were formed on the basis of ESR1-mutation status (present vs. absent) and compared on the basis of duration of treatment with AI, and other clinical and demographic categories. Results A total of 247 patients who were diagnosed with HR-positive, HER2-negative breast cancer and received NGS were identified and are included in this analysis. A total of 138 (56%) patients were assessed via tissue based NGS and 109 (44%) by liquid biopsy. The median age at time of sequencing was 58 years [57 years (ESR1-absent) vs. 60 years (ESR1-present); p =0.009]. The majority of patients were white (83%) and post-menopausal (57%). Invasive ductal carcinoma was the most common histological type (82%). Nearly all (96%) patients had stage IV disease at time of sequencing and ESR1 mutations were found exclusively in those with stage IV disease. ESR1 mutations were identified in 62 patients (25%). The median duration of treatment with aromatase inhibitors prior to testing was 19.3 months in both groups (ESR1 mutations absent vs. detected). There was no difference in prior tamoxifen use between groups (absent 43%, present 48%; p=0.48). In patients tested by tissue based NGS, ESR1 mutations were more frequently detected in metastatic sites (28% vs. 13%; p=0.03). Twenty-two patients for whom NGS did not identify an ESR1 mutation prior to July 2019 received subsequent NGS testing. Of these 22 patients, six (27%) had ESR1 mutations detected by subsequent NGS. In these six patients, ESR1-mutations were detected by NGS a median of 2.2 years (range 1.7 years to 2.6 years) after prior NGS. Conclusion There was no difference in duration of treatment with aromatase inhibitor therapy in patients with ESR1 mutations vs. those without ESR1 mutations detected by NGS. Patients with ESR1 mutations tended to be older. Although the detection of ESR1 mutations is associated with acquired therapy resistance and progression on treatment, a longer duration of treatment may make the emergence of ESR1 mutations more likely. These counterbalancing factors may have contributed to the results reported here.

Citation Format: Hannah Ayettey-Anie, Kamran A. Ahmed, Iman Washington, Kosj Yamoah, Todd Knepper. Assessment of the relationship between duration of treatment with hormonal therapy and the detection of ESR1 mutations in hormone-receptor positive, HER2 negative, breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-03-22.

Management of Patients with Advanced Prostate Cancer. Part I: Intermediate-/High-risk and Locally Advanced Disease, Biochemical Relapse, and Side Effects of Hormonal Treatment: Report of the Advanced Prostate Cancer Consensus Conference 2022

BACKGROUND

Innovations in imaging and molecular characterisation and the evolution of new therapies have improved outcomes in advanced prostate cancer. Nonetheless, we continue to lack high-level evidence on a variety of clinical topics that greatly impact daily practice. To supplement evidence-based guidelines, the 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) surveyed experts about key dilemmas in clinical management.

OBJECTIVE

To present consensus voting results for select questions from APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

Before the conference, a panel of 117 international prostate cancer experts used a modified Delphi process to develop 198 multiple-choice consensus questions on (1) intermediate- and high-risk and locally advanced prostate cancer, (2) biochemical recurrence after local treatment, (3) side effects from hormonal therapies, (4) metastatic hormone-sensitive prostate cancer, (5) nonmetastatic castration-resistant prostate cancer, (6) metastatic castration-resistant prostate cancer, and (7) oligometastatic and oligoprogressive prostate cancer. Before the conference, these questions were administered via a web-based survey to the 105 physician panel members ("panellists") who directly engage in prostate cancer treatment decision-making. Herein, we present results for the 82 questions on topics 1-3.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Consensus was defined as ≥75% agreement, with strong consensus defined as ≥90% agreement.

RESULTS AND LIMITATIONS

The voting results reveal varying degrees of consensus, as is discussed in this article and shown in the detailed results in the Supplementary material. The findings reflect the opinions of an international panel of experts and did not incorporate a formal literature review and meta-analysis.

CONCLUSIONS

These voting results by a panel of international experts in advanced prostate cancer can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers prioritise areas for future research. Diagnostic and treatment decisions should always be individualised based on patient and cancer characteristics (disease extent and location, treatment history, comorbidities, and patient preferences) and should incorporate current and emerging clinical evidence, therapeutic guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2022 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with health care providers and patients worldwide. At each APCCC, a panel of physician experts vote in response to multiple-choice questions about their clinical opinions and approaches to managing advanced prostate cancer. This report presents voting results for the subset of questions pertaining to intermediate- and high-risk and locally advanced prostate cancer, biochemical relapse after definitive treatment, advanced (next-generation) imaging, and management of side effects caused by hormonal therapies. The results provide a practical guide to help clinicians and patients discuss treatment options as part of shared multidisciplinary decision-making. The findings may be especially useful when there is little or no high-level evidence to guide treatment decisions.

Shorter Radiation Regimens and Treatment Noncompletion Among Patients With Breast and Prostate Cancer in the United States: An Analysis of Racial Disparities in Access and Quality

PURPOSE

Compared with conventional external-beam radiation therapy (cEBRT) for patients with breast cancer (BC) and prostate cancer (PC), shorter radiation regimens may be associated with lower treatment noncompletion rates. We assess disparities in receipt of shorter radiation regimens and treatment noncompletion for BC and PC.

PATIENTS AND METHODS

The 2004-2017 National Cancer Database was queried for adjuvant cEBRT or hypofractionated EBRT (hEBRT) for nonmetastatic BC; and definitive cEBRT, moderate hypofractionation (mEBRT), or stereotactic body radiotherapy (SBRT) for localized PC. Multivariable logistic regression identified factors associated with treatment noncompletion and receipt of shorter regimens.

FINDINGS

We identified 170,386 men with PC (median age [interquartile range], 70 [64-75] years; Black, 17.5%; White, 82.5%) and 306,846 women with BC (61 [52-69] years; Black, 12.3%; White, 87.7%). Among patients who received cEBRT for PC, Black men had higher treatment noncompletion rates compared with White (14.1% v 13.0%; odds ratio [95% CI] 1.07 [1.03 to 1.12]; P < .001). In contrast, treatment noncompletion was not disparate with SBRT (Black 1.6% v White 1.3%; 1.20 [0.72 to 2.00], P = .49) or mEBRT (Black 9.0% v White 7.1%; 1.05 [0.72 to 1.54], P = .79). From 2004 to 2017, SBRT (0.07% to 11.8%; 1.32 [1.31 to 1.33]) and mEBRT (0.35% to 9.1%; 1.27 [1.25 to 1.28]) increased (both P < .001); however, Black men were consistently less likely to receive SBRT (7.4% v White, 8.3%; 0.84 [0.79 to 0.89], P < .001). Among women with BC, there were no racial differences in treatment noncompletion; however, hEBRT was associated with lower treatment noncompletion rates (1.0% v cEBRT 2.3%; 0.39 [0.35 to 0.44], P < .001). Although hEBRT for BC increased (0.8% to 35.6%) between 2004 and 2017, Black women were less likely to receive hEBRT (10.4% v 15.3%; 0.78 [0.75 to 0.81], P < .001).

INTERPRETATION

Black patients were consistently less likely to receive hypofractionated radiation for PC or BC, despite evidence suggesting that shorter regimens may lower rates of treatment noncompletion with similar oncologic outcomes.

Incorporating Prostate-specific Membrane Antigen Positron Emission Tomography in Management Decisions for Men with Newly Diagnosed or Biochemically Recurrent Prostate Cancer

CONTEXT

Prostate-specific membrane antigen (PSMA) is a promising molecular target for prostate cancer (PCa) that has allowed the development of a novel diagnostic approach to PCA in the primary and recurrent settings.

OBJECTIVE

To summarize available data and recommendations regarding the use of PSMA in newly diagnosed and recurrent PCa via a narrative review.

EVIDENCE ACQUISITION

A literature review was conducted using MEDLINE (via PubMed) and Scopus. The search strategy included meta-analyses, reviews, and original studies on staging and restaging with ⁶⁸Ga-PSMA positron emission tomography (PET)/computed tomography (CT).

EVIDENCE SYNTHESIS

Studies comparing PSMA-targeted imaging and conventional imaging suggest superior performance of PSMA-targeted imaging in primary and recurrent PCa, albeit with several clinically relevant limitations. Pretreatment ⁶⁸Ga-PSMA PET/CT allowed more accurate PCa staging in compared to routine practice for high-risk cases, and identified a number of otherwise unknown metastatic lesions. In biochemically recurrent PCa, PSMA PET can reveal sites of recurrence with greater sensitivity and specificity than conventional imaging, potentially detecting a major proportion of occult disease. This review will help providers in applying the most up-to-date and relevant literature to (1) determine which patients truly have oligometastatic disease and (2) ascertain who is most likely to experience a meaningful response to local consolidation in the biochemical recurrence setting.

CONCLUSIONS

Data on PSMA diagnostic studies in primary and recurrent PCa highlight the accuracy and clinical application of PSMA PET. While this review and the evidence to date might lead to a perception of superiority in metastasis directed therapy, fundamental lack of phase III clinical trials with clinically meaningful outcomes are yet to be determined.

PATIENT SUMMARY

PSMA (prostate-specific membrane antigen) scans have shown great promise for initial evaluation of prostate cancer (PCa) and in detection of PCa recurrence. The benefits are more apparent for initial staging of PCa. There are more limited clinical trial results for PCa recurrence on how best to use this new technique to guide cancer treatment.

RF05 | PSUN358 ANPEP: A potential regulator of tumor cell - macrophage metabolic interactions in prostate cancer of African American men

African American men (AA) are more than twice as likely to die of prostate cancer (PCa) compared to European American men (EA). Among many contributing factors, unraveling the metabolic derangements in PCa of AA holds a promise in reducing health disparity. We recently discovered that aminopeptidase N (ANPEP, CD13) represents one of the differentially expressed genes in PCa of AA compared with EA. While ANPEP plays regulatory and/or modulatory functions in many immune and metabolic pathological conditions, its role in PCa remains unknown. We sought to investigate the metabolic functions of ANPEP in PCa development and exploit its role as a therapeutic vulnerability, particularly in AA men. Accordingly, we prospectively examined the differential gene expression of PCa from clinically matched AA and EA in the VANDAAM clinical trial. The VANDAAM study is a validation study of DecipherTM genomic testing in 240 men with localized PCa. Our findings indicate that ANPEP is the top differentially expressed gene between AA and EA men. To explore the molecular mechanisms of ANPEP in PCa in unbiased fashion, we combined computational and experimental approaches. Our preliminary computational analyses revealed that ANPEP correlates with signatures of cholesterol transport, estrogen and androgen receptor (AR) signaling. Based on our recent study demonstrating dominance of these signatures in macrophage-rich PCa, we reasoned that ANPEP expression may be driven in part by high macrophage infiltration in AA. Thus, we compared immune cell repertoire in patients with high ANPEP and low ANPEP by deconvoluting immune cell content using the in silico approach, CIBERSORT. These analyses illustrated that only AA patients with high ANPEP expression significantly accumulated high content of M1 inflammatory macrophages. Immune phenotyping of prostate tumors demonstrated that ANPEP indeed represents a marker of M1 inflammatory macrophages and tumor-associated macrophages. In conclusion, these findings suggest that ANPEP is a macrophage related protein in PCa with a potential role in cholesterol transport and / or androgen signaling. Future work will focus on the functional role of ANPEP activity in the tumor immune microenvironment using Liquid chromatography-high resolution mass spectrometry (LC-HRMS) and explants derived from AA and EA prostate cancer patients.

Presentation: Saturday, June 11, 2022 1:00 p.m. - 1:05 p.m., Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Genomic Testing in Localized Prostate Cancer Can Identify Subsets of African Americans With Aggressive Disease

BACKGROUND

Personalized genomic classifiers have transformed the management of prostate cancer (PCa) by identifying the most aggressive subsets of PCa. Nevertheless, the performance of genomic classifiers to risk classify African American men is thus far lacking in a prospective setting.

METHODS

This is a prospective study of the Decipher genomic classifier for National Comprehensive Cancer Network low- and intermediate-risk PCa. Study-eligible non-African American men were matched to African American men. Diagnostic biopsy specimens were processed to estimate Decipher scores. Samples accrued in NCT02723734, a prospective study, were interrogated to determine the genomic risk of reclassification (GrR) between conventional clinical risk classifiers and the Decipher score.

RESULTS

The final analysis included a clinically balanced cohort of 226 patients with complete genomic information (113 African American men and 113 non-African American men). A higher proportion of African American men with National Comprehensive Cancer Network-classified low-risk (18.2%) and favorable intermediate-risk (37.8%) PCa had a higher Decipher score than non-African American men. Self-identified African American men were twice more likely than non-African American men to experience GrR (relative risk [RR] = 2.23, 95% confidence interval [CI] = 1.02 to 4.90; P = .04). In an ancestry-determined race model, we consistently validated a higher risk of reclassification in African American men (RR = 5.26, 95% CI = 1.66 to 16.63; P = .004). Race-stratified analysis of GrR vs non-GrR tumors also revealed molecular differences in these tumor subtypes.

CONCLUSIONS

Integration of genomic classifiers with clinically based risk classification can help identify the subset of African American men with localized PCa who harbor high genomic risk of early metastatic disease. It is vital to identify and appropriately risk stratify the subset of African American men with aggressive disease who may benefit from more targeted interventions.

Substantial Gleason reclassification in Black men with national comprehensive cancer network low-risk prostate cancer - A propensity score analysis

BACKGROUND

Emerging evidence suggests that a subset of Black men with National Comprehensive Cancer Network (NCCN) low-risk prostate cancer (PCa) may harbor high volume and genomically aggressive disease. However, limited, and ambiguous research exist to evaluate the risk of extreme Gleason reclassification in Black men with low-risk PCa.

METHODS

This retrospective cohort study included 45,674 low-risk PCa patients who underwent prostatectomy and were not on active surveillance, from National Cancer Database (NCDB). A propensity score matched-pair design was employed, and the final cohort was limited to 1:1 matched 12,340 patients. Gleason score reclassification was used as primary endpoint. As such, any migration to pathologic Gleason score ≥7(3 + 4) was identified as overall, whereas migration to ≥7(4 + 3) was defined as extreme reclassification. A conditional Poisson regression model was used to estimate the risk of reclassification. Whereas spline model was used to estimate the impact of increasing time to treatment as a non-linear function on Gleason reclassification between race group.

RESULTS

Upon matching there were no differences in the baseline characteristics between race groups. In a matched cohort, higher proportion of low-risk Black men (6.6%) reported extreme reclassification to pathologic Gleason score than White men (5.0%), p < 0.001. In a conditional Poisson regression model adjusted for time to treatment, the risk of overall (RR = 1.09, 95% CI, 1.05-1.13, p < 0.001) and extreme (RR = 1.30, 95% CI, 1.12-1.50, p = 0.004) reclassification was significantly higher in Black men as compared to their White counterpart. In spline model, the probability of Gleason reclassification in Black men was elevated with increasing time to treatment, especially after 180 days (53% vs. 43% between Black and White men).

CONCLUSION

Risk of Gleason score reclassification is disparately elevated in Black men with low-risk PCa. Furthermore, time to treatment can non-linearly impact Gleason reclassification in Black men.

Identifying and overcoming barriers to participation of minority populations in clinical trials: Lessons learned from the VanDAAM study

Participation in cancer research trials by minority populations is imperative in reducing disparities in clinical outcomes. Even with increased awareness of the importance of minority patient inclusion in clinical research to improve cancer care and survival, significant barriers persist in accruing and retaining minority patients into clinical trials. This study sought to identify and address barriers to minority accrual to a minimal risk clinical research study in real-time.

What Experts Think About Prostate Cancer Management During the COVID-19 Pandemic: Report from the Advanced Prostate Cancer Consensus Conference 2021

Patients with advanced prostate cancer (APC) may be at greater risk for severe illness, hospitalisation, or death from coronavirus disease 2019 (COVID-19) due to male gender, older age, potential immunosuppressive treatments, or comorbidities. Thus, the optimal management of APC patients during the COVID-19 pandemic is complex. In October 2021, during the Advanced Prostate Cancer Consensus Conference (APCCC) 2021, the 73 voting members of the panel members discussed and voted on 13 questions on this topic that could help clinicians make treatment choices during the pandemic. There was a consensus for full COVID-19 vaccination and booster injection in APC patients. Furthermore, the voting results indicate that the expert's treatment recommendations are influenced by the vaccination status: the COVID-19 pandemic altered management of APC patients for 70% of the panellists before the vaccination was available but only for 25% of panellists for fully vaccinated patients. Most experts (71%) were less likely to use docetaxel and abiraterone in unvaccinated patients with metastatic hormone-sensitive prostate cancer. For fully vaccinated patients with high-risk localised prostate cancer, there was a consensus (77%) to follow the usual treatment schedule, whereas in unvaccinated patients, 55% of the panel members voted for deferring radiation therapy. Finally, there was a strong consensus for the use of telemedicine for monitoring APC patients. PATIENT SUMMARY: In the Advanced Prostate Cancer Consensus Conference 2021, the panellists reached a consensus regarding the recommendation of the COVID-19 vaccine in prostate cancer patients and use of telemedicine for monitoring these patients.

Management of Patients with Advanced Prostate Cancer: Report from the Advanced Prostate Cancer Consensus Conference 2021

BACKGROUND

Innovations in treatments, imaging, and molecular characterisation in advanced prostate cancer have improved outcomes, but various areas of management still lack high-level evidence to inform clinical practice. The 2021 Advanced Prostate Cancer Consensus Conference (APCCC) addressed some of these questions to supplement guidelines that are based on level 1 evidence.

OBJECTIVE

To present the voting results from APCCC 2021.

DESIGN, SETTING, AND PARTICIPANTS

The experts identified three major areas of controversy related to management of advanced prostate cancer: newly diagnosed metastatic hormone-sensitive prostate cancer (mHSPC), the use of prostate-specific membrane antigen ligands in diagnostics and therapy, and molecular characterisation of tissue and blood. A panel of 86 international prostate cancer experts developed the programme and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 107 pre-defined questions, which were developed by both voting and non-voting panel members prior to the conference following a modified Delphi process.

RESULTS AND LIMITATIONS

The voting reflected the opinions of panellists and did not incorporate a standard literature review or formal meta-analysis. The answer options for the consensus questions received varying degrees of support from panellists, as reflected in this article and the detailed voting results reported in the Supplementary material.

CONCLUSIONS

These voting results from a panel of experts in advanced prostate cancer can help clinicians and patients to navigate controversial areas of management for which high-level evidence is scant. However, diagnostic and treatment decisions should always be individualised according to patient characteristics, such as the extent and location of disease, prior treatment(s), comorbidities, patient preferences, and treatment recommendations, and should also incorporate current and emerging clinical evidence and logistic and economic constraints. Enrolment in clinical trials should be strongly encouraged. Importantly, APCCC 2021 once again identified salient questions that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference is a forum for discussing current diagnosis and treatment options for patients with advanced prostate cancer. An expert panel votes on predefined questions focused on the most clinically relevant areas for treatment of advanced prostate cancer for which there are gaps in knowledge. The voting results provide a practical guide to help clinicians in discussing treatment options with patients as part of shared decision-making.

Abstract 3675: Epigenetic variations associated with therapy resistance among prostate tumors from Puerto Rican men

Prostate cancer (PCa) is the leading cause of cancer-related death in Puerto Rican (PR) men, a population at higher risk of developing the disease than other Hispanic/Latino groups. But the relationship between this phenomenon and epigenetics, and how this relationship explains PCa racial and ethnic health disparities are controversial. The purpose of this study was to expand on the knowledge regarding epigenetic differences in terms of DNA methylation to enable risk stratification and treatment selection in this genetically admixed population. In addition, we aim to assess differential DNA methylation patterns associated with drug resistance in PCa in PR Hispanic/Latino men. Since epigenetic changes and modifications represent critical components of carcinogenesis and progression, we are expecting differential methylation levels between aggressive vs. indolent, and resistant vs. non-resistant cases. Prostate tumors from PR men were stratified based on Gleason score. Methylation levels were measured by Illumina Infinium Methylation EPIC BeadChip DNA methylation platform, and bioinformatic analyses. In parallel, DNA methylation profiles were also analyzed using genomic DNA from PCa cells selected for resistance to androgen depletion, enzalutamide resistance, or docetaxel resistance. We identified 1,225 differentially methylated genes in prostate tumors compared with normal adjacent tissues, and 141 differentially methylated genes between aggressive vs. indolent tumors. Additionally, 723 differentially methylated genes were found in therapy resistant cell lines compared to parental controls. Analysis of the methylated genes obtained from aggressive prostate tumors from Puerto Rican patients and therapy-resistant PCa cell lines revealed four overlapping methylated genes: RNF220, FAM65B, PRDM16, and DGKH. Further analysis of PCa cells resistant to androgen depletion, enzalutamide, or docetaxel demonstrated impaired cellular migration of resistant phenotypes upon DNA methyltransferase (DNMT) inhibition using 5-azacytidine or zebularine compared to parental cell lines. DNMT1 was associated with resistance in PCa cell lines, and future studies will include silencing of methyltransferases will evaluation of drug re-sensitization. These findings provide critical insight into the epigenetic landscape of aggressive prostate tumors among PR men and highlight several candidate methylation biomarkers for assessing risk in this population.

Citation Format: Carlos J. Diaz Osterman, Anders Berglund, Shannalee Martinez, Camila Luis, Julie Dutil, Jaime Matta, Jarline Encarnacion-Medina, Carmen Ortiz-Sanchéz, Liang Wang, Jasreman Dhillon, Youngchul Kim, Hyun Y. Park, Gilbert Ruiz-Deya, Kosj Yamoah, Jong Y. Park. Epigenetic variations associated with therapy resistance among prostate tumors from Puerto Rican men [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3675.

ANPEP: A Potential Regulator of Tumor Cell—Immune Metabolic Interactions in Prostate Cancer of Men of African Descent

PURPOSE

Prostate cancer (PCa) is the leading cause of male cancer deaths in Africa. In USA, African American men (AA) experience higher mortality rate compared to European American men (EA). While socioeconomics factors contribute toward these disparities, distinct molecular mechanisms in AA remain important drivers. For example, in previous work, we discovered that PCa form AA men harbored a significantly higher expression of Aminopeptidase N (ANPEP) as compared with EA. Aminopeptidase N regulates immune cell function and mediates tumor cell migration but its role in PCa remains uninvestigated.

METHODS

We explored ANPEP expression related to a range of genomic classifiers in multiple datasets. We then prospectively examined the differentially expressed genes in PCa tissues collected from 120 AA and 120 EA patients enrolled on the VANDAAM clinical trial. We further correlated ANPEP expression with various signatures related to immune and metabolic activity. We also experimentally examined the expression of ANPEP in different components of tumor microenvironment.

RESULTS

In the VANDAAM study, ANPEP represents the top differentially expressed gene between AA and EA men. Our data driven approach revealed that ANPEP correlates with signature of cholesterol transport and androgen signaling. Interestingly, these signatures dominate in PCa with high macrophage infiltration. Deconvolution of immune cell content using computational approaches indeed demonstrated that only AA patients with high ANPEP expression significantly accumulated high content of inflammatory macrophages. Further experimental findings showed that ANPEP indeed represents a marker of tumor-associated macrophages, a type of immune cells known to contribute to PCa progression.

CONCLUSION

We have identified ANPEP as a macrophage-related gene with a potential role in cholesterol metabolism and AR signaling in AA. Future work will focus on the functional role of ANPEP activity in the tumor immune microenvironment using Liquid chromatography-high resolution mass spectrometry and explants derived from AA and EA PCa patients.

Novel Transcriptomic Interactions Between Immune Content and Genomic Classifier Predict Lethal Outcomes in High-grade Prostate Cancer

Grade group 4 and 5 (GG-45) prostate cancer (PCa) patients are at the highest risk of lethal outcomes, yet lack genomic risk stratification for prognosis and treatment selection. Here, we assess whether transcriptomic interactions between tumor immune content score (ICS) and the Decipher genomic classifier can identify most lethal subsets of GG-45 PCa. We utilized whole transcriptome data from 8071 tumor tissue (6071 prostatectomy and 2000 treatment-naïve biopsy samples) to derive four immunogenomic subtypes using ICS and Decipher. When compared across all grade groups, GG-45 samples had the highest proportion of most aggressive subtype-ICS^High/Decipher^High. Subsequent analyses within the GG-45 patient samples (n = 1420) revealed that the ICS^High/Decipher^High subtype was associated with increased genomic radiosensitivity. Additionally, in a multivariable model (n = 335), ICS^High/Decipher^High subtype had a significantly higher risk of distant metastasis (hazard ratio [HR] = 5.41; 95% confidence interval [CI], 2.76-10.6; p ≤  0.0001) and PCa-specific mortality (HR = 10.6; 95% CI, 4.18-26.94; p ≤  0.0001) as compared with ICS^Low/Decipher^Low. The novel immunogenomic subtypes establish a very strong synergistic interaction between ICS and Decipher in identifying GG-45 patients who experience the most lethal outcomes. PATIENT SUMMARY: In this analysis, we identified a novel interaction between the total immune content of prostate tumors and genomic classifier to identify the most lethal subset of patients with grade groups 4 and 5. Our results will aid in the subtyping of aggressive prostate cancer patients who may benefit from combined immune-radiotherapy modalities.

Changing Radiotherapy Paradigms in Penile Cancer

Radiation therapy (RT) has not been prominent in the treatment of penile cancer because of poorly reproducible results when used in the adjuvant setting. A genomic signature has recently been described that assays radiosensitivity of tumors and informs radiotherapy doses in these cases. Clinical validation in more than 1600 patients demonstrated associations with both overall survival and time to first recurrence. In addition, the signature predicted and quantified the therapeutic benefit of RT for each individual patient. Since penile cancer patients were not part of this analysis, we applied the model to patients with primary and nodal penile cancer tissue and clinical outcomes.

Patient summary: Radiotherapy has not been widely used for treatment of penile cancer. New genetic data suggest that radiation doses commonly used to treat penile cancer are too low. This would explain prior poor results using radiation in this disease.

A Rare Germline HOXB13 Variant Contributes to Risk of Prostate Cancer in Men of African Ancestry

A rare African ancestry-specific germline deletion variant in HOXB13 (X285K, rs77179853) was recently reported in Martinican men with early-onset prostate cancer. Given the role of HOXB13 germline variation in prostate cancer, we investigated the association between HOXB13 X285K and prostate cancer risk in a large sample of 22 361 African ancestry men, including 11 688 prostate cancer cases. The risk allele was present only in men of West African ancestry, with an allele frequency in men that ranged from 0.40% in Ghana and 0.31% in Nigeria to 0% in Uganda and South Africa, with a range of frequencies in men with admixed African ancestry from North America and Europe (0-0.26%). HOXB13 X285K was associated with 2.4-fold increased odds of prostate cancer (95% confidence interval [CI] = 1.5-3.9, p = 2 × 10^-4), with greater risk observed for more aggressive and advanced disease (Gleason ≥8: odds ratio [OR] = 4.7, 95% CI = 2.3-9.5, p = 2 × 10^-5; stage T3/T4: OR = 4.5, 95% CI = 2.0-10.0, p = 2 × 10^-4; metastatic disease: OR = 5.1, 95% CI = 1.9-13.7, p = 0.001). We estimated that the allele arose in West Africa 1500-4600 yr ago. Further analysis is needed to understand how the HOXB13 X285K variant impacts the HOXB13 protein and function in the prostate. Understanding who carries this mutation may inform prostate cancer screening in men of West African ancestry. PATIENT SUMMARY: A rare African ancestry-specific germline deletion in HOXB13, found only in men of West African ancestry, was reported to be associated with an increased risk of overall and advanced prostate cancer. Understanding who carries this mutation may help inform screening for prostate cancer in men of West African ancestry.

Racial and Ethnic Disparities in Prostate Cancer Outcomes in the Veterans Affairs Health Care System

IMPORTANCE

Prostate cancer (PCa) disproportionately affects African American men, but research evaluating the extent of racial and ethnic disparities across the PCa continuum in equal-access settings remains limited at the national level. The US Department of Veterans Affairs (VA) Veterans Hospital Administration health care system offers a setting of relatively equal access to care in which to assess racial and ethnic disparities in self-identified African American (or Black) veterans and White veterans.

OBJECTIVE

To determine the extent of racial and ethnic disparities in the incidence of PCa, clinical stage, and outcomes between African American patients and White patients who received a diagnosis or were treated at a VA hospital.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 7 889 984 veterans undergoing routine care in VA hospitals nationwide from 2005 through 2019 (incidence cohort). The age-adjusted incidence of localized and de novo metastatic PCa was estimated. Treatment response was evaluated, and PCa-specific outcomes were compared between African American veterans and White veterans. Residual disparity in PCa outcome, defined as the leftover racial and ethnic disparity in the outcomes despite equal response to treatment, was estimated.

EXPOSURES

Self-identified African American (or Black) and White race and ethnicity.

MAIN OUTCOMES AND MEASURES

Time to distant metastasis following PCa diagnosis was the primary outcome. Descriptive analyses were used to compare baseline demographics and clinic characteristics. Multivariable logistic regression was used to evaluate race and ethnicity association with pretreatment clinical variables. Multivariable Cox regression was used to estimate the risk of metastasis.

RESULTS

Data from 7 889 984 veterans from the incidence cohort were used to estimate incidence, whereas data from 92 269 veterans with localized PCa were used to assess treatment response. Among 92 269 veterans, African American men (n = 28 802 [31%]) were younger (median [IQR], 63 [58-68] vs 65 [62-71] years) and had higher prostate-specific antigen levels (>20 ng/mL) at the time of diagnosis compared with White men (n = 63 467; [69%]). Consistent with US population-level data, African American veterans displayed a nearly 2-fold greater incidence of localized and de novo metastatic PCa compared with White men across VA centers nationwide. Among veterans screened for PCa, African American men had a 29% increased risk of PCa detection on a diagnostic prostate biopsy compared with White (hazard ratio, 1.29; 95% CI, 1.27-1.31; P < .001). African American men who received definitive primary treatment of PCa experienced a lower risk of metastasis (hazard ratio, 0.89; 95% CI, 0.83-0.95; P < .001). However, African American men who received nondefinitive treatment classified as “other” were more likely to develop metastasis (adjusted hazard ratio, 1.29; 95% CI, 1.17-1.42; P < .001). Using the actual rate of metastasis from veterans who received definitive primary treatment, a persistent residual metastatic burden for African American men was observed across all National Comprehensive Cancer Network risk groups (low risk, 4 vs 2 per 100 000; intermediate risk, 13 vs 6 per 100 000; high risk, 19 vs 9 per 100 000).

CONCLUSIONS AND RELEVANCE

This cohort analysis found significant disparities in the incidence of localized and metastatic PCa between African American veterans and White veterans. This increased incidence is a major factor associated with the residual disparity in PCa metastasis observed in African American veterans compared with White veterans despite their nearly equal response to treatment.

Abstract PO-153: ANPEP: A potential regulator of tumor-immune metabolic interactions in African American men with prostate cancer

In prostate cancer (PCa), lack of TMPRSS2-ETS gene fusion (ETSnegative) has been a hallmark of tumor in African American (AA) as compared with European American (EA) men. To elucidate biologic features associated with ETSnegative PCa in AA men, we identified aminopeptidase N (ANPEP) as ETS-regulated gene with preferential overexpression in AA. Aminopeptidase N is involved in endocytosis, cholesterol, amino acid transport and peptide hydrolysis. In the current work, we sought to investigate the role of ANPEP in a PCa development and exploit its role in PCa metabolism as a therapeutic vulnerability, particularly in AA tumors. Methods To understand the role of ANPEP in PCa progression and therapeutic vulnerability, we determined the expression of ANPEP in different component of tumor microenvironment. We also developed a consumption and release metabolomic platform to assess the impact of ANPEP on transport of cholesterol, fatty acids and a number of relevant amino acids. Additionally, we assessed the availability of these metabolites and their end products in plasma samples of PCa patients. Results Using publicly available datasets, we showed that prostate tumors form AA men harbor the highest expression of ANPEP as compared with other groups. Using further data mining and experimental approaches, we found that aminopeptidase N is predominantly expressed on macrophages compared with prostate tumor cells, T cell, B cells, neutrophils and dendritic cells. Expression of ANPEP predominantly correlated with various amino acid transporters which also tend to be differentially expressed by ETS status. We have successfully developed a metabolomics-based approach to assess the consumption of more than 15 metabolites in prostate cancer cells and patient derived explants. Conclusion We have identified ANPEP as a macrophage-related gene with a potential role in tumor metabolism. Future work will focus on investigating functional role of ANPEP in the tumor immune microenvironment using our unique metabolic consumption/release assay in explants derived from AA and EA prostate cancer patients.

Citation Format: Asmaa E. El-Kenawi, Shivanshu Awasthi, Amparo N. Serna, Jasreman Dhillon, Kosj Yamoah. ANPEP: A potential regulator of tumor-immune metabolic interactions in African American men with prostate cancer [abstract]. In: Proceedings of the AACR Virtual Conference: 14th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2021 Oct 6-8. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr PO-153.

Dysregulation of DNA Methylation and Epigenetic Clocks in Prostate Cancer among Puerto Rican Men

In 2021, approximately 248,530 new prostate cancer (PCa) cases are estimated in the United States. Hispanic/Latinos (H/L) are the second largest racial/ethnic group in the US. The objective of this study was to assess DNA methylation patterns between aggressive and indolent PCa along with ancestry proportions in 49 H/L men from Puerto Rico (PR). Prostate tumors were classified as aggressive (n = 17) and indolent (n = 32) based on the Gleason score. Genomic DNA samples were extracted by macro-dissection. DNA methylation patterns were assessed using the Illumina EPIC DNA methylation platform. We used ADMIXTURE to estimate global ancestry proportions. We identified 892 differentially methylated genes in prostate tumor tissues as compared with normal tissues. Based on an epigenetic clock model, we observed that the total number of stem cell divisions (TNSC) and stem cell division rate (SCDR) were significantly higher in tumor than adjacent normal tissues. Regarding PCa aggressiveness, 141 differentially methylated genes were identified. Ancestry proportions of PR men were estimated as African, European, and Indigenous American; these were 24.1%, 64.2%, and 11.7%, respectively. The identification of DNA methylation profiles associated with risk and aggressiveness of PCa in PR H/L men will shed light on potential mechanisms contributing to PCa disparities in PR population.

Evaluating Prostate-Specific Antigen Screening for Young African American Men With Cancer

BACKGROUND

Despite higher risks associated with prostate cancer, young African American men are poorly represented in prostate-specific antigen (PSA) trials, which limits proper evidence-based guidance. We evaluated the impact of PSA screening, alongside primary care provider utilization, on prostate cancer outcomes for these patients.

METHODS

We identified African American men aged 40-55 years, diagnosed with prostate cancer between 2004 and 2017 within the Veterans Health Administration. Inverse probability of treatment-weighted propensity scores were used in multivariable models to assess PSA screening on PSA levels higher than 20, Gleason score of 8 or higher, and metastatic disease at diagnosis. Lead-time adjusted Fine-Gray regression evaluated PSA screening on prostate cancer-specific mortality (PCSM), with noncancer death as competing events. All statistical tests were 2-sided.

RESULTS

The cohort included 4726 patients. Mean age was 51.8 years, with 84-month median follow-up. There were 1057 (22.4%) with no PSA screening prior to diagnosis. Compared with no screening, PSA screening was associated with statistically significantly reduced odds of PSA levels higher than 20 (odds ratio [OR] = 0.56, 95% confidence interval [CI] = 0.49 to 0.63; P < .001), Gleason score of 8 or higher (OR = 0.78, 95% CI = 0.69 to 0.88; P < .001), and metastatic disease at diagnosis (OR = 0.50, 95% CI = 0.39 to 0.64; P < .001), and decreased PCSM (subdistribution hazard ratio = 0.52, 95% CI = 0.36 to 0.76; P  < .001). Primary care provider visits displayed similar effects.

CONCLUSIONS

Among young African American men diagnosed with prostate cancer, PSA screening was associated with statistically significantly lower risk of PSA levels higher than 20, Gleason score of 8 or higher, and metastatic disease at diagnosis and statistically significantly reduced risk of PCSM. However, the retrospective design limits precise estimation of screening effects. Prospective studies are needed to validate these findings.

Prostate tumors of native men from West Africa show biologically distinct pathways-A comparative genomic study

BACKGROUND

Native African men (NAM) experience a disproportionate burden of prostate cancer (PCa) and have higher mortality rates compared to European American men (EAM). While socioeconomic status has been implicated as a driver of this disparity, little is known about the genomic mechanisms and distinct biological pathways that are associated with PCa of native men of African origin.

METHODS

To understand biological factors that contribute to this disparity we utilized a total of 406 multi-institutional localized PCa samples, collected by Men of African Descent and Carcinoma of the Prostate biospecimen network and Moffitt Cancer Center/University of Pennsylvania Health science system. We performed comparative genomics and immunohistochemistry to identify the biomarkers that are highly enriched in NAM from west Africa and compared them with African American Men (AAM) and EAM. Quantified messenger RNA expression and Median H scores based on immune reactivity of staining cells, were compared using Mann Whitney test. For gene expression analysis, p values were further adjusted for multiple comparisons using false discovery rates.

RESULTS

Immunohistochemical analysis on selected biomarkers showed a consistent association between ETS related gene (ERG) status and race with 83% of NAM exhibiting tumors that lacked TMPRSS2-ERG translocation (ERG^negative ) as compared to AAM (71%) and EAM (52%). A higher proportion of NAM (29%) were also found to be double negative (ERG^negative and PTEN^Loss ) as compared to AAM (6%) and EAM (7%). NAM tumors had significantly higher immunoreactivity (H-score) for PSMA, and EZH2, whereas they have lower H-score for PTEN, MYC, AR, RB and Racemase, (all p < .05). Comparative genomics revealed that NAM had significant transcriptomic variability in AR-activity score. In pathways enrichment analysis NAM tumors exhibited the enrichment of proinflammatory pathways including cytokine, interleukins, inflammatory response, and nuclear factor kappa B signaling.

CONCLUSIONS

Prostate tumors in NAM are genomically distinct and are characterized by the dysregulation of several biomarkers. Furthermore, these tumors are also highly enriched for the major proinflammatory pathways. These distinct biological features may have implications for diagnosis and response to targeted therapy among Black men, globally.