e16512 Background: Addressing health disparities in renal cell carcinoma (RCC) has been an enduring challenge globally, with notable variations in incidence and outcomes among different racial groups. Genomic ancestry serves as a valuable tool in capturing biological variations among diverse populations and offers insights into clinical, histopathological, and molecular distinctions. We utilized The Cancer Genetic Ancestry Atlas (TCGAA) to investigate tumor mutation profiles of RCC with focus on the influence of genetic ancestry on the intricate genomic landscape of this malignancy. Methods: Genomic and clinical data of TCGA PanCancer Atlas KIRC were downloaded through the GDC Data Portal. We utilized The Cancer Genome Ancestry Atlas (TCGAA) and the STRUCTURE algorithm for estimation of genetic ancestry. Primary ancestry was specified as comprising greater than or equal to 50% of genetic ancestry from a single reference population. Statistical analyses were performed using chi-square, Cox proportional hazards models, and Kaplan-Meier methods. Results: 64.5% were male and 41% were locally advanced or metastatic (stage III-IV). Genomic analysis revealed 438 individuals with European ancestry (mean European ancestry of 95.78%), 50 patients with African ancestry (mean African ancestry of 77.7%), and 8 patients with Asian ancestry (mean Asian ancestry of 92.5%). The mean age of patients was 61.0, 58.5, and 49.5 for the European, African, and Asian ancestry groups, respectively. African ancestry correlated with a trend towards reduced overall survival (OS) compared to European ancestry (median OS 62.89 vs 90.48 months). African ancestry patients harbored lower frequency of VHL and PBRM1 alterations, but with significant enrichment in MTOR, FREM2, UNC80, LRP2 alterations compared with European ancestry group. Conclusions: This study reveals genetic heterogeneity in RCC across diverse ancestry groups, indicating presence of distinct oncogenic genes and pathways in African American populations.These findings suggest potential contributions to racial disparities in clinical presentation, outcomes, and treatment responses. Future research should include exploring the role of genetic ancestry in tumorigenesis and disease progression, alongside developing targeted therapies to mitigate health inequities and enhance outcomes for all populations. [Table: see text]

You have accessJournal of UrologyCME1 Apr 2023MP55-13 BROTHERS LINKED AGAINST CANCER, CANCER EDUCATION PROGRAM ASSESSING PROSTATE CANCER KNOWLEDGE IN AFRICAN AMERICANS UTILIZING FAITH-BASED PARTNERSHIPS Crystal Casado, Marcus Moses, Jonathan Allotey, Andrew Anderson, and Spencer Krane Crystal CasadoCrystal Casado More articles by this author , Marcus MosesMarcus Moses More articles by this author , Jonathan AlloteyJonathan Allotey More articles by this author , Andrew AndersonAndrew Anderson More articles by this author , and Spencer KraneSpencer Krane More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003308.13AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: In the past decade, cancer mortality rates have declined in the United States, however, African-American (AA) men continue to have a two-fold higher prostate cancer (PCa) incidence and mortality compared to their Caucasian counterparts. While there is no apparent etiologic reason for this disparity, AA men continue to experience significant differences in PCa screening measures, treatment decisions, clinical outcomes, and clinical trial enrollment. To address PCa disparities, Brothers Linked Against Cancer (BLAC), a culturally tailored cancer education initiative, aims to equitably empower and enhance AA’s awareness and understanding of PCa through faith-based partnerships. METHODS: In collaboration with AA churches in New Orleans, LA, BLAC organized PCa awareness events targeting AA men and women over thirty years of age. Participants were instructed to watch BLAC’s 6-minute culturally tailored PCa educational video and complete pre- and post-surveys consisting of demographic questions and knowledge assessments composed of 12 questions from the Knowledge of PCa and Screening Scale. Statistical analyses were performed using t-tests with a p-value <0.05 for significance. RESULTS: A total of 51 participants (86% men, 63% age>65, 49% college-educated, 44% retired) attended BLAC PCa awareness events between March-July 2022. Most men (66%) indicated receiving PCa screening before with 29% of participants reporting a family history of PCa. The mean pretest score for all participants was 8 (69%), with the mean posttest score rising to 10 (83%) (p<0.002). After the events, most participants (93%) endorsed comfort in discussing PCa and (84%) planned to talk to their doctor about PCa screening. CONCLUSIONS: In this pilot study, BLAC successfully fostered community engagement, promoted PCa awareness, and increased the understanding of PCa at partnering AA churches. PCa disparities are multidimensional, and complex health interventions, including trust-building, are needed to address them effectively. Source of Funding: Albert Schweitzer Foundation & Center for Public Service (Tulane University) © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e768 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Crystal Casado More articles by this author Marcus Moses More articles by this author Jonathan Allotey More articles by this author Andrew Anderson More articles by this author Spencer Krane More articles by this author Expand All Advertisement PDF downloadLoading ...

Background Immune checkpoint inhibitors (ICI) improve overall survival (OS) in patients with locally advanced, unresectable, or metastatic urothelial carcinoma (aUC), but response rates can be modest. We compared outcomes between patients with and without prior intravesical Bacillus Calmette-Guerin (BCG), who received ICI for aUC, hypothesizing that prior intravesical BCG would be associated with worse outcomes. Patients and Methods We performed a retrospective cohort study across 25 institutions in US and Europe. We compared observed response rate (ORR) using logistic regression; progression-free survival (PFS) and OS using Kaplan-Meier and Cox proportional hazards. Analyses were stratified by treatment line (first line/salvage) and included multivariable models adjusting for known prognostic factors. Results A total of 1026 patients with aUC were identified; 614, 617, and 638 were included in ORR, OS, PFS analyses, respectively. Overall, 150 pts had history of prior intravesical BCG treatment. ORR to ICI was similar between those with and without prior intravesical BCG exposure in both first line and salvage settings (adjusted odds radios 0.55 [P= .08] and 1.65 [P= .12]). OS (adjusted hazard ratios 1.05 [P= .79] and 1.13 [P= .49]) and PFS (adjusted hazard ratios 1.12 [P= .55] and 0.87 [P= .39]) were similar between those with and without intravesical BCG exposure in first line and salvage settings. Conclusion Prior intravesical BCG was not associated with differences in response and survival in patients with aUC treated with ICI. Limitations include retrospective nature, lack of randomization, presence of selection and confounding biases. This study provides important preliminary data that prior intravesical BCG exposure may not impact ICI efficacy in aUC.

The fifth annual summer research summit organized by the Center of Excellence (COE) in Health Equity, Training and Research, Baylor College of Medicine (BCM), was held on May 17, 2022. The theme of this year’s summit was ‘Academic-Community Partnerships: Change Agents for Advancing Health Equity.’ Given the ongoing pandemic, the summit was conducted virtually through digital platforms. This program was intended for both BCM and external audiences interested in advancing health equity, diversity, and inclusion in healthcare among healthcare providers and trainees, biomedical scientists, social workers, nurses, and individuals involved in talent acquisition and development, such as hiring managers (HR professionals), supervisors, college and hospital affiliate leadership and administrators, as well as diversity and inclusion excellence practitioners. We had attendees from all regions of the United States as well as from Saudi Arabia. The content in this Book of Abstracts encapsulates a summary of the research efforts by the BCM COE scholars (which includes post-baccalaureate students, medical students, clinical fellows, and junior faculty from BCM) as well as the external summit participants. The range of topics in this year’s summit was quite diverse, encompassing disparities in relation to maternal and child health (MCH), immigrant health, cancers, vaccination uptakes, and COVID-19 infections. Various solutions were ardently presented to address these disparities, including community engagement and partnerships, improvement in health literacy, and the development of novel technologies and therapeutics. With this summit, BCM continues to build on its long history of educational outreach initiatives to promote diversity in medicine by focusing on programs aimed at increasing the number of diverse and highly qualified medical professionals ready to introduce effective and innovative approaches to reduce or eliminate health disparities. These programs will improve information resources, clinical education, curricula, research, and cultural competence as they relate to minority health issues and social determinants of health. The year’s summit was a great success! Copyright © 2022 Dongarwar et al. Published by Global Health and Education Projects, Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution License CC BY 4.0.

445 Background: Different metastatic sites have variable prognostic implications in aUC. However, details on response and outcomes with ICI for particular mets is still unknown. We hypothesized that bone and liver mets would have poor response and outcomes with ICIs. Methods: We performed a retrospective cohort study in patients (pts) with aUC who received ICI. We compared overall response rate (ORR) and overall survival (OS) between pts with different mets at ICI initiation. We developed 4 different models: 1) lymph node (LN) only vs other; 2) visceral mets (bone, lung, liver) vs other; 3) bone + liver mets vs bone without liver vs liver without bone vs neither and 4) 6 factor model: a. LN +/- soft tissue/locoregional recurrence b. lung +/- (a) c. bone +/- (b) d. liver +/- (c) e. central nervous system (CNS) +/- (d) and f. other. ORR and OS were compared among groups using multivariable (adjusting for ECOG PS and hemoglobin<10g/dl) logistic regression and cox regression, respectively. Results: We identified 984 pts (24 institutions); 703 and 696 were included in OS and ORR analyses, respectively. Median age at ICI start was 71 (range 32-93), 77% white race, 74% men, 67% ever smokers, 72% pure UC, 18% upper tract UC, 55% extirpative surgery. Prevalence of LN, lung, bone and liver mets at ICI start was 74%, 32%, 27% and 21%, respectively. LN-only mets had significantly higher ORR (44% vs 22%, OR 2.6, p<0.05) and longer mOS (22 vs 8 months, HR 0.5, p<0.05) vs other mets. Visceral mets had significantly lower ORR (21% vs 35%, OR 0.5, p<0.05) and shorter mOS (7 vs 17 months, HR 1.8, p<0.05) vs non-visceral mets. Pts with bone and liver mets had significantly lower ORR and shorter OS vs those with bone or liver mets, which both had significantly lower ORR and shorter OS vs those with neither and with LN +/- local recurrence (Table). Conclusions: In the context of ICI treatment, bone, liver, lung or CNS mets were associated with lower ORR and/or shorter OS, and bone and liver mets were particularly associated with low ORR and short OS. LN-only mets were associated with higher ORR and longer OS. Further work is needed to interrogate site-specific tumor-host immune interactions and identify biomarkers. Research Sponsor: None[Table: see text]

505 Background: Current standard therapy for most pts with aUC is first-line (1L) platinum-based chemotherapy followed by ICI maintenance (or 2L if progression). Shorter time on 1L or between therapy lines may be a surrogate of more aggressive disease and poor outcome, but its prognostic role in ICI response is unclear. We hypothesized that shorter time until start of 2L ICI would be associated with worse outcomes in aUC. Methods: We performed a retrospective multi-institution cohort study in pts with aUC treated with 1L platinum-based chemotherapy, who later received 2L ICI. Pts receiving maintenance ICI were excluded. We calculated the time from start of 1L platinum chemotherapy to start of 2L ICI, dichotomizing the exposure into ≤6 months and >6 months. We compared overall response rate (ORR) to 2L ICI, progression-free survival (PFS) and overall survival (OS) from the start of 2L ICI between the two populations. ORR was compared among groups using multivariable logistic regression and PFS, OS using cox regression. Analysis was adjusted for calculated Bellmunt score. Results: From a total of 1283 pts, 462 received 1L platinum chemotherapy; among those, 350 received 2L ICI. After exclusions, 270, 269 and 260 pts were included in the ORR, PFS and OS analyses, respectively. Median age was 70 years, 78% men, 75% White, 74% with pure urothelial histology, 21% upper tract, 60% received cisplatin in 1L. Pts with time to 2L ICI ≤6 months had significantly higher Bellmunt scores (32% vs 22% score=2, 9% vs 3% score=3). ORR and PFS were comparable between pts with ≤ and >6 months to 2L ICI. However, OS was significantly longer for pts with >6 months to 2L ICI (median [m]OS 13 vs 7 months, p=0.002), (Table). Conclusions: Among pts with aUC treated with 2L ICI, time to 2L ICI ≤6 months from 1L platinum based chemotherapy was associated with similar ORR and PFS but shorter OS. Limitations include retrospective nature, patient selection, confounding factors. More studies are needed on the impact of platinum resistance in pts with aUC treated with ICIs.[Table: see text]

138 Background: HRR PVs can serve as predictive biomarkers and two PARP inhibitors are approved for metastasic CRPC (mCRPC) pts. Published data are predominantly focused on tissue-based assays, but obtaining tissue from mCRPC pts is problematic. In a large tissue based series (PROfound), 4047 mCRPC pts had tumor samples submitted for genomic testing but only 69% had interpretable results. No data were published from PROfound enumerating pts without available tissue to submit. Herein we assess frequency of PVs from selected HRR genes using a ctDNA assay. Methods: 292 mCRPC pts at Tulane Cancer Center were assessed for detectable HRR ctDNA changes using the Guardant 360 assay (which assesses the HRR genes BRCA1, BRCA2, and ATM). Results: 20/292 (6.8%) pts had a PV in ATM. However only 4/292 (1.4%) had > 1% mutant allelic fraction. Germline testing occurred in 18/20 of the ctDNA ATM PV pts and 0/18 had a germline PV. The PROfound series had 6.3% somatic PVs in ATM. 18/292 pts (6.2%) had a PV in BRCA2 and 12/292 (4.1%) had a mutant allelic fraction of > 1%. Germline testing was performed in 17/18 with BRCA2 ctDNA PVs and 9/17 had germline PVs. The PROfound series had 9.7% somatic BRCA2 PVs. BRCA1 PVs were detected in 6/292 (2.1%) pts and 3/292 (1%) had a mutant allelic fraction > 1%. 6/6 of the ctDNA PVs has germline testing and 1/6 had a BRCA1 PV. The PROfound series had 1.3% somatic PVs in BRCA1. Conclusions: Using ctDNA essay, it is feasible to measure PVs in only a small subset of HRR genes in mCRPC pts. These assays fail to detect deep deletions, a known and important mechanism of HRR gene loss. The ctDNA mutant allelic fractions are often low. The ability of ctDNA PVs using this assay to predict treatment effects are unknown.

ObjectivesTo compare clinical outcomes between patients with locally advanced (unresectable) or metastatic urothelial carcinoma (aUC) in the upper and lower urinary tract receiving immune checkpoint inhibitors (ICIs).Patients and MethodsWe performed a retrospective cohort study collecting clinicopathological, treatment, and outcome data for patients with aUC receiving ICIs from 2013 to 2020 across 24 institutions. We compared the objective response rate (ORR), overall survival (OS), and progression‐free survival (PFS) between patients with upper and lower tract UC (UTUC, LTUC). Uni‐ and multivariable logistic and Cox regression were used to assess the effect of UTUC on ORR, OS, and PFS. Subgroup analyses were performed stratified based on histology (pure, mixed) and line of treatment (first line, subsequent line).ResultsOut of a total of 746 eligible patients, 707, 717, and 738 were included in the ORR, OS, and PFS analyses, respectively. Our results did not contradict the hypothesis that patients with UTUC and LTUC had similar ORRs (24% vs 28%; adjusted odds ratio [aOR] 0.73, 95% confidence interval [CI] 0.43–1.24), OS (median 9.8 vs 9.6 months; adjusted hazard ratio [aHR] 0.93, 95% CI 0.73–1.19), and PFS (median 4.3 vs 4.1 months; aHR 1.01, 95% CI 0.81–1.27). Patients with mixed‐histology UTUC had a significantly lower ORR and shorter PFS vs mixed‐histology LTUC (aOR 0.20, 95% CI 0.05–0.91 and aHR 1.66, 95% CI 1.06–2.59), respectively).ConclusionOverall, patients with UTUC and LTUC receiving ICIs have comparable treatment response and outcomes. Subgroup analyses based on histology showed that those with mixed‐histology UTUC had a lower ORR and shorter PFS compared to mixed‐histology LTUC. Further studies and evaluation of molecular biomarkers can help refine patient selection for immunotherapy.

BACKGROUND:While immune checkpoint inhibitors (ICIs) are approved in the first-line (1L) setting for cisplatin-unfit patients with programmed death-ligand 1 (PD-L1)-high tumors or for platinum (cisplatin/carboplatin)-unfit patients, response rates remain modest and outcomes vary with no clinically useful biomarkers (except for PD-L1). OBJECTIVE:We aimed to develop a prognostic model for overall survival (OS) in patients receiving 1L ICIs for advanced urothelial cancer (aUC) in a multicenter cohort study. DESIGN, SETTING, AND PARTICIPANTS:Patients treated with 1L ICIs for aUC across 24 institutions and five countries (in the USA and Europe) outside clinical trials were included in this study. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS:We used a stepwise, hypothesis-driven approach using clinician-selected covariates to develop a new risk score for patients receiving ICIs in the 1L setting. Demographics, clinicopathologic data, treatment patterns, and OS were collected uniformly. Univariate Cox regression was performed on 18 covariates hypothesized to be associated with OS based on published data. Variables were retained for multivariate analysis (MVA) if they correlated with OS (p < 0.2) and were included in the final model if p < 0.05 on MVA. Retained covariates were assigned points based on the beta coefficient to create a risk score. Stratified median OS and C-statistic were calculated. RESULTS AND LIMITATIONS:Among 984 patients, 357 with a mean age of 71 yr were included in the analysis, 27% were female, 68% had pure UC, and 13% had upper tract UC. Eastern Cooperative Oncology Group performance status ≥2, albumin <3.5 g/dl, neutrophil:lymphocyte ratio >5, and liver metastases were significant prognostic factors on MVA and were included in the risk score. C index for new 1L risk score was 0.68 (95% confidence interval 0.65-0.71). Limitations include retrospective nature and lack of external validation. CONCLUSIONS:We developed a new 1L ICI risk score for OS based on data from patients with aUC treated with ICIs in the USA and Europe outside of clinical trials. The score components highlight readily available factors related to tumor biology and treatment response. External validation is being pursued. PATIENT SUMMARY:With multiple new treatments under development and approved for advanced urothelial carcinoma, it can be difficult to identify the best treatment sequence for each patient. The risk score may help inform treatment discussions and estimate outcomes in patients treated with first-line immune checkpoint inhibitors, while it can also impact clinical trial design and endpoints. TAKE HOME MESSAGE: A new risk score was developed for advanced urothelial carcinoma treated with first-line immune checkpoint inhibitors. The score assigned Eastern Cooperative Oncology Group performance status ≥2, albumin <3.5 g/dl, neutrophil:lymphocyte ratio >5, and liver metastases each one point, with a higher score being associated with worse overall survival.

146 Background: The fact that high dose of testosterone (HDT) elicits positive responses in a subset of prostate cancer patients (pts) is surprising and puzzling. Genomics data differentiating responders (Rs) from non-responders (NRs) is sparse. Pts with mutations in DNA repair pathway genes may be particularly sensitive to HDT (see BA Teply et al. Eur Urol 71:499, 2017). Herein we perform exploratory analyses to better understand the role of pathogenic mutations (muts) in ctDNA as a predictive biomarker for patients treated with HDT. Methods: ctDNA essays were performed with the Guardant360 methodology pre-HDT. Point mutations were classified by cancervar (http://cancervar.wglab.org). Truncating mutations (frameshift and nonsense) were manually curated to assess for pathogenicity. All patients had CRPC and were pre-treated with abiraterone and/or enzalutamide. HDT was typically administered as 400 mg testosterone cypionate q 3-4 weeks. Rs were compared to NRs. All Rs had >3 more cycles of HDT and a >50% PSA decline (N = 17). Non-responders had <3 cycles and no PSA decline (N = 23). Only muts with an allelic fraction of >0.5% were analyzed given dubious importance of mutations with lower allelic fractions. Results: AR muts (4/17 vs 6/23 in Rs and NRs) and TP53 muts (10/17 vs 11/23 in Rs and NRs) were similar ( P= 0.85 and 0.49, respectively) but the number of pts with non-AR/non-TP53 muts was distinct (3/17 for Rs, and 12/23 for NRs; P= 0.026). The average number of non-AR/non-TP53 muts (Rs = 0.23 and NRs = 0.83) was higher in the NRs (P = 0.046). When analyzing DNA repair alterations, no differences were noted in those with BRCA1/BRCA2/ATM mutations in the Rs and NRs (1/17 vs 6/23 respectively; P= 0.09). Conclusions: AR and TP53 pathogenic mutations are common in both Rs and NRs but other pathogenic mutations are more common in non-responders. We hypothesize that genetic pathways outside of the AR/TP53 axis drive resistance to HDT. Additional studies are warranted to assess whether or not these pathways drive resistance to HDT. Limitations are acknowledged with regard to the Guardant assay gene selection for CRPC pts.

OBJECTIVES:To compare clinical outcomes with programmed-death ligand-1 immune checkpoint inhibitors (ICIs) in patients with advanced urothelial carcinoma (aUC) who have vs have not undergone radical surgery (RS) or radiation therapy (RT) prior to developing metastatic disease.PATIENTS AND METHODS:We performed a retrospective cohort study collecting clinicopathological, treatment and outcomes data for patients with aUC receiving ICIs across 25 institutions. We compared outcomes (observed response rate [ORR], progression-free survival [PFS], overall survival [OS]) between patients with vs without prior RS, and by type of prior locoregional treatment (RS vs RT vs no locoregional treatment). Patients with de novo advanced disease were excluded. Analysis was stratified by treatment line (first-line and second-line or greater [second-plus line]). Logistic regression was used to compare ORR, while Kaplan-Meier analysis and Cox regression were used for PFS and OS. Multivariable models were adjusted for known prognostic factors.RESULTS:We included 562 patients (first-line: 342 and second-plus line: 220). There was no difference in outcomes based on prior locoregional treatment among those treated with first-line ICIs. In the second-plus-line setting, prior RS was associated with higher ORR (adjusted odds ratio 2.61, 95% confidence interval [CI]1.19-5.74]), longer OS (adjusted hazard ratio [aHR] 0.61, 95% CI 0.42-0.88) and PFS (aHR 0.63, 95% CI 0.45-0.89) vs no prior RS. This association remained significant when type of prior locoregional treatment (RS and RT) was modelled separately.CONCLUSION:Prior RS before developing advanced disease was associated with better outcomes in patients with aUC treated with ICIs in the second-plus-line but not in the first-line setting. While further validation is needed, our findings could have implications for prognostic estimates in clinical discussions and benchmarking for clinical trials. Limitations include the study's retrospective nature, lack of randomization, and possible selection and confounding biases.

BACKGROUND:The crossover from abiraterone acetate (AA) to enzalutamide (ENZA) is a frequent approach in clinical practice. Our aim was to explore the role of genomic alterations as putative biomarkers of response to sequential AA followed by ENZA in mCRPC and their association with clinical outcomes.PATIENTS AND METHODS:This was a multi-center, retrospective analysis of mCRPC patients with circulating-tumor DNA (ctDNA) post-AA and prior to ENZA treatment. Objectives of this analysis were to assess PSA response, time to PSA progression (TTP) and overall survival (OS) in mCRPC patients treated with ENZA following progression on AA with respect to genomic aberrations detected by ctDNA.RESULTS:A total of 28 patients with mCRPC were identified. Median time between AA and ENZA was 3.1 months and median initial PSA prior to ENZA was 35.0 ng/mL. Nine patients (32.1%) achieved PSA responses to ENZA. Most patients (79.0%) achieved confirmed PSA progression with median TTP of 1.6 months (95% CI, 0.7-2.4). Somatic alterations in AR genes were detected in 36.0% of patients with other common alterations detected including 39.0% TP53, 11.0% DNA repair, and 11.0% PTEN. A lack of AR alterations was associated with better PSA response to ENZA (p = 0.04).CONCLUSION:While lack of AR alterations in ctDNA was associated with more favorable outcomes, the present dataset is insufficient to recommend the use of ctDNA to impact clinical decision-making in this setting. Further understanding of the implications of the genomic phenotype in ctDNA of castration-resistant tumors and the potential therapeutic implications is required.

PURPOSE:Urinary tract cancer can be pure urothelial carcinoma, pure nonurothelial carcinoma or variant urothelial carcinoma (defined here as mixed urothelial carcinoma). Little is known regarding outcomes for patients with variant urothelial carcinoma receiving immune checkpoint inhibitors. We hypothesized that variant urothelial carcinoma does not compromise immune checkpoint inhibitor efficacy in patients with advanced urothelial carcinoma.MATERIALS AND METHODS:We performed a retrospective cohort study across 18 institutions. Demographic, clinicopathological, treatment and outcomes data were collected for patients with advanced urothelial carcinoma who received immune checkpoint inhibitors. Patients were divided into pure vs variant urothelial carcinoma subgroups, with variant urothelial carcinoma further divided by type of variant (ie squamous, neuroendocrine etc). We compared overall response rate using univariate and multivariate logistic regression and progression-free survival and overall survival using Kaplan-Meier and univariate and multivariate Cox proportional hazards.RESULTS:Overall 519 patients were identified, with 395, 406 and 403 included in overall response rate, overall survival and progression-free survival analyses, respectively. Overall response rate to immune checkpoint inhibitors between patients with pure vs variant urothelial carcinoma was comparable (28% vs 29%, p=0.90) without significant differences for individual subtypes vs pure urothelial carcinoma. Median overall survival for patients with pure urothelial carcinoma was 11.0 months vs 10.1 months for variant urothelial carcinoma (p=0.60), but only 4.6 months for patients with neuroendocrine features (9 patients, HR 2.75, 95% CI 1.40-5.40 vs pure urothelial carcinoma, p=0.003). Median progression-free survival was 4.1 months for pure vs 5.2 months for variant urothelial carcinoma (p=0.43) and 3.7 months for neuroendocrine features (HR 1.87, 95% CI 0.92-3.79 vs pure urothelial carcinoma, p=0.09).CONCLUSIONS:Overall response rate to immune checkpoint inhibitors was comparable across histological types. However, overall survival was worse for patients with tumors containing neuroendocrine features. Variant urothelial carcinoma should not exclude patients from receiving immune checkpoint inhibitors.

231 Background: Recent literature has highlighted the importance of germline genetic testing in metastatic prostate cancer (PCa)patients (pts). This retrospective study evaluated family history (FH), evaluate treatment outcomes in metastatic patients with pathogenic germline mutations, and compared family history in Caucasian (CA) and Africans Americans (AA). Methods: At Tulane Cancer Center, 428 metastatic PCa pts had germline testing in at least 79 genes. Comprehensive family histories were obtained in all. Analysis of prevalent FH, including breast, ovarian, prostate, and pancreatic cancers was assessed for all metastatic pts. Statistical analyses including chi square were performed. Results: 64 (64/428; 14.9%) pts had at least one or more pathogenic mutations, while 166 (166/428; 38.7%) had were normal. The remaining 199 (199/428; 46.4%) of pts had a variant of uncertain significance (VUS). Pts with a DNA repair pathogenic mutation were more likely to have >2 family members affected by cancer, regardless of cancer type or degree of relationship (p=0.0047); 6 pts without any family history of cancer had a pathogenic mutation. In CA, the presence of either a breast or PCa family history was associated with pathogenic germline findings (p=.022/.0367) However, in AAs neither breast nor prostate cancer predicted pathogenic germline alterations. Conclusions: The correlation between family history of breast and PCa cancer in CA pts with pathogenic mutations is notable as is the finding of >2 family members with cancer predicting germline pathogenic alterations. With AA pathogenic pts, there was no correlation of family history of breast and PCa, which highlights the need to learn more about the genetic factors which influence AA prostate cancer risk.[Table: see text]

BackgroundImmune checkpoint inhibitors (ICIs) represent an appealing treatment for patients with advanced urothelial cancer (aUC) and a poor performance status (PS). However, the benefit of ICIs for patients with a poor PS remains unknown. It was hypothesized that a poor Eastern Cooperative Oncology Group (ECOG) PS (≥2 vs 0‐1) would correlate with shorter overall survival (OS) in patients receiving ICIs.MethodsIn this retrospective cohort study, clinicopathologic, treatment, and outcome data were collected for patients with aUC who were treated with ICIs at 18 institutions (2013‐2019). The overall response rate (ORR) and OS were compared for patients with an ECOG PS of 0 to 1 and patients with an ECOG PS ≥ 2 at ICI initiation. The association between a new ICI in the last 30 and 90 days of life (DOL) and death location was also tested.ResultsOf the 519 patients treated with ICIs, 395 and 384 were included in OS and ORR analyses, respectively, with 26% and 24% having a PS ≥ 2. OS was higher in those with a PS of 0 to 1 than those with a PS ≥ 2 who were treated in the first line (median, 15.2 vs 7.2 months; hazard ratio [HR], 0.62; P = .01) but not in subsequent lines (median, 9.8 vs 8.2 months; HR, 0.78; P = .27). ORRs were similar for patients with a PS of 0 to 1 and patients with a PS ≥ 2 in both lines. Of the 288 patients who died, 10% and 32% started ICIs in the last 30 and 90 DOL, respectively. ICI initiation in the last 30 DOL was associated with increased odds of death in a hospital (odds ratio, 2.89; P = .04).ConclusionsDespite comparable ORRs, ICIs may not overcome the negative prognostic role of a poor PS, particularly in the first‐line setting, and the initiation of ICIs in the last 30 DOL was associated with hospital death location.

200 Background: Circulating tumor-DNA (ctDNA) in mCRPC patients (pts) provides a viable approach for examining the genetic landscape of prostate cancer. In this follow-up, we report ctDNA variants in germline tested mCRPC pts. Methods: ctDNA alterations in 73 genes were detected using Guardant360 (G360) assays. Alteration types assessed were missense, frameshift, insertions, splice variants, truncations, amplifications (amp), deletions, and other. Pts included in the analysis received germline genetic testing (Invitae Corporation, San Francisco, CA) and ctDNA assays at various treatment timepoints. Statistical analyses were performed using chi-square and fisher exact test with p-value <0.05 for significance. Results: Germline and ctDNA testing was completed in 270 mCRPC pts. 13% (35/270) of pts had pathogenic germline alterations. Germline alterations detected were BRCA2 (43%, n=15), ATM (8.5%, n=3), CHEK2 (8.5%, n=3), and BRCA1 (6%, n=2). Of the 673 alterations detected in G360 assays, TP53 (25%, n=167) and AR (17%, n=117) were most commonly observed. ctDNA alteration breakdown for germline negative/positive pts is summarized in Tables A/B. Germline negative pts had more AR alterations compared to germline positive (p = 0.023). Also, germline negative pts presented with more amps (p < 0.001) and germline positive pts with more frameshift alterations (p = 0.005). The association of ctDNA alteration to clinical outcomes in germline positive/negative pts was also assessed and is ongoing. Conclusions: Pts with germline positive alterations had few somatic AR alterations and higher frequency of deleterious mutation in comparison to their germline negative counterparts.[Table: see text][Table: see text]

199 Background: Data on germline DNA repair defects and VUS rates are sparse in African American (AA) men with metastatic prostate cancer (PCa). Methods: Germline testing data from two centers with a significant percentage of metastatic AA PCa patients were combined and compared to Caucasian American (CA) with metastatic PCa. Fourteen canonical DNA repair genes (ATM, BARD1, BRCA1, BRCA2, BRIP1, CHEK2, MLH1, MSH2, MSH6, NBN, PALB2, PMS2, RAD51C, RAD51D) were assessed in all tested patients (pts) using a pathogenic/likely pathogenic (P/LP) classification. Variants of unknown significance (VUS) were assessed in an Invitae-derived dataset with consistent VUS reporting. Results: A total of 105 AA men with metastatic disease were evaluated and 7/105 of these men (6.67%) had P/LP alteration. Among the AA pt alterations, there were 4 pts with BRCA2, 2 pts with BRCA1, and 1 pt with PALB2. A total of 39/417 (9.3%) of CA metastatic patients had P/LP alterations in the canonical 14 genes. No differences were detected in the AA vs CA metastatic comparison (p=0.39). A total of 1/105 (0.95%) AA pts and 23/418 (5.5%) CA had non-BRCA P/LP mutations. The number of non-BRCA P/LP mutations were lower in the AA as compared to the CA men (p=0.045). When evaluating VUS calls in the metastatic AAs using Invitae multi-gene panels, 28/92 (30.43%) pts had a VUS in the canonical 14 genes as compared to 67/366 (18.31%) of the CA men. AAs were more likely than CA to have a VUS (p=0.010). These data indicate that metastatic AA pts and CA are not significantly distinct in the P/LP alterations in 14 canonical DNA repair genes but that there were lower percentages of P/LP in the AA non-BRCA gene subset. Further, when assessing these genes, it is clear that a VUS is more likely to be called in the AA men. Conclusions: Among men with metastatic PCa, AAs have similar rates of inherited P/LP alterations in 14 well accepted DNA repair genes as compared to CA men, however the non-BRCA gene P/LP alterations were less frequent among the AAs. Variants classified as a VUS were clearly higher in these AA pts as compared to the CA pts.

5568 Background: The relevance of germline mutations in metastatic prostate cancer is well established; however, comparison of germline genetics in African American (AA) versus Caucasian (CA) men with metastatic prostate cancer (PCa) is limited. Methods: Germline data from self-identified AA and CA metastatic PCa patients (pts) were collected from 5 academic cancer centers. Various commercial cancer-specific germline testing panels were used to evaluate 12-86 genes. Pathogenic (P) or likely pathogenic (LP) mutations, and variants of unknown significance (VUS), were reported according to ACMG guidelines. Self-reported family history (FH) was annotated for 99% of pts. Statistical analyses included Chi-squared and Fischer’s exact tests. Results: A total of 821 metastatic PCa pts were assessed: 152 AAs and 669 CAs. For P/LP alterations, AAs had a frequency of 11.2% (17/152) as compared to a frequency of 14.6% (98/669) in CAs (p = 0.302). AA pts were more likely to have a VUS than CA pts, 61% vs 43% respectively (OR = 2.09, 95%CI [1.45, 2.99], p < 0.001). BRCA mutations were similar between races, but AA were more likely to have a BRCA1 P/LP alteration (OR = 6.00, 95% CI [1.33, 27.09], p = 0.025). AA pts were less likely to have a P/LP alteration in a non-BRCA gene (OR = 0.34, 95% CI [0.15, 0.80], p = 0.013). Among DNA repair genes, there were no significant difference between AA and CA pts (p = 0.574); however, there was a trend toward AA pts having fewer P/LP alteration in a non-BRCA DNA repair genes (OR = 0.26, 95% CI [0.06, 1.08], p = 0.071). In pts with >1 first degree relative (FDR) with ovarian cancer, P/LP germline alterations were more likely in CAs (OR = 2.33, 95% CI [1.05, 5.17], p = 0.043); but there were no significant differences in AAs (p = 0.098). Those with >2 FDRs with PCa were more likely to have a P/LP change in CAs (OR = 2.32, 95% CI [1.04, 5.15], p = 0.043), but there were no difference in AAs (p = 0.700). In pts with ≥2 FDRs with breast cancer, P/LP germline alterations were more likely in both AAs (OR = 9.36, 95% CI [1.72, 50.84], p = 0.019) and CAs (OR = 3.92, 95% CI [1.79, 8.59], p = 0.001). Conclusions: We did not observe a difference in the overall frequency of germline P/LP alterations between AA and CA men with metastatic PCa but VUSs were more common in AA men. These AA men have an overall frequency of BRCA mutations similar to CA men; however, BRCA1 mutations were more prevalent in these AAs. Non-BRCA P/LP mutations are significantly less frequent in AA pts. A positive family history of >2 FDRs with breast cancer was associated with P/LP alterations in both AA and CA pts.

INTRODUCTION:Castration resistant prostate cancer (CRPC) has been characterized by a reactivation of the androgen receptor (AR) signaling pathway via alterations in androgen metabolism and AR aberrations. High-dose testosterone (HDT) is emerging as an active treatment in metastatic CRPC, however, biomarkers of response are unknown. We hypothesized that responses to HDT might impact the genomic expression of AR alterations found in circulating-tumor DNA (ctDNA). METHODS:Retrospective analysis of mCRPC patients treated with HDT (testosterone cypionate q 2-4 weeks) with available clinical and somatic genomic data using a commercially available assay (Guardant360, Redwood City, CA). Clinical outcomes included PSA response (PSA50), time to PSA progression (TPP) and safety. RESULTS:A total of 33 mCRPC patients were treated with ≥2 testosterone cypionate injections. ctDNA testing revealed alterations in AR (39%), TP53 (48%), and DNA repair genes (12%). HDT was given for median of 4.0 months (95% CI, 2.6-5.3) with 24% of PSA50. Twenty patients were re-challenged with abiraterone (n = 2) or enzalutamide (n = 18) with 30% PSA50. Significant (grade ≥3) adverse events were observed in 5% of patients (grade 4 thrombocytopenia and asthenia). Patients with median baseline ctDNA% of ≥1.10 had numerically worse TPP outcomes and all patients with AR alterations exhibited decreased AR expression post-HDT (n = 9), yet no association between clinical outcomes and ctDNA findings was observed. CONCLUSIONS:HDT led to a decrease in AR copy number and mutations which was independent from responses to therapy. Further understanding of the genomic alterations as potential predictor of response to HDT is needed.

Of the many genes involved in metastatic castration-resistant prostate cancer (mCRPC), TP53 is commonly altered and has a broad mutational landscape. We investigated TP53 in mCRPC using circulating tumor DNA from 143 patients with a variety of annotated treatment histories. TP53 gain-of-function mutations were associated with disease progression while receiving abiraterone/enzalutamide therapy, suggesting a potentially valuable therapeutic category of TP53 mutations in mCRPC. Background: Circulating tumor DNA (ctDNA), which can be assessed by liquid biopsy, can provide valuable genomic information that may affect treatment response in prostate cancer. The aim of this study was to characterize TP53 mutations and treatment history in prostate cancer. Patients and Methods: This study included 143 patients with metastatic castration-resistant prostate cancer who had undergone ctDNA sequencing via Guardant360 testing. The presence or absence of TP53 mutations was analyzed along with treatment history for this group. TP53 mutations were further classified as gain of function (GOF) or not GOF, and analyzed with prior therapies. Results: Chi-square analysis was performed for treatment history and TP53 status (further specified as all TP53 mutations or only TP53 GOF mutations). There were no associations between prior receipt of abiraterone/enzalutamide therapy and all TP53 mutations, or between docetaxel therapy and all TP53 mutations. However, TP53 GOF mutations had a positive association with prior abiraterone/enzalutamide therapy (P - .047). There was no association of TP53 GOF mutations with prior docetaxel therapy. The most frequent alterations co-occurring with all TP53 mutations were in AR, BRAF, EGFR, MYC, and PIK3CA. Common coalterations with TP53 GOF mutations included AR, BRAF, EGFR, RB1, NF1, and PIK3CA. There was an association of RB1 mutations with TP53 GOF mutations, versus RB1 mutations and no TP53 GOF mutations (P = .0036). Conclusion: TP53 GOF mutations may provide a valuable pathway to delineate metastatic castration-resistant prostate cancer TP53 mutations into therapeutic categories. Association with disease progression while receiving abiraterone/enzalutamide therapy was apparent in this study; however, further studies are needed to elaborate the therapeutic and prognostic implications. (C) 2019 Elsevier Inc. All rights reserved.