Roles of Androgen Receptor Signaling in Urothelial Carcinoma.

Preclinical and clinical data suggest that androgen receptor signaling strongly contributes to bladder cancer development. The roles of the androgen receptor in bladder carcinogenesis have obvious implications for understanding the strong male sex bias in this disease and for potential therapeutic strategies as well. In this review, we summarize what is known about androgen receptor signaling in urothelial carcinoma as well as in tumor-infiltrating immune cells, reviewing preclinical and clinical data. We also highlight clinical trial efforts in this area.

Gemcitabine as first-line therapy for high-grade non-muscle invasive bladder cancer: results from a tertiary center in the contemporary BCG-shortage era.

Background: To evaluate the safety profile and efficacy of intravesical gemcitabine as first-line adjuvant therapy for non-muscle invasive bladder cancer (NMIBC) in the setting of ongoing Bacillus Calmette-Guérin (BCG) shortage. Methods: We performed an institutional, retrospective review of patients treated with intravesical gemcitabine induction and maintenance therapy from March 2019 to October 2021. Patients with intermediate or high-risk NMIBC who were BCG-naïve or experienced a high-grade (HG) recurrence after 12 months since the last dose of BCG were included in the analysis. The primary endpoint was complete response (CR) rate at the 3-month visit. Secondary endpoints were recurrence-free survival (RFS) and assessment of adverse events. Results: A total of 33 patients were included. All had HG disease and 28 (84.8%) were BCG-naive. The median follow-up was 21.4 months (range, 4.1-39.4). Tumor stages were cTa in 39.4%, cT1 in 54.5%, and cTis in 6.1% of patients. Most patients (90.9%) were in the AUA high-risk category. The 3-month CR was 84.8%. Among patients who achieved CR with adequate follow-up, 86.9% (20/23) remained disease-free at 6 months. The 6-month and 12-month RFS were 87.2% and 76.5%, respectively. The estimated median RFS was not reached. Approximately 78.8% of patients were able to complete full induction. Common adverse events (incidence ≥10%) included dysuria and fatigue/myalgia. Conclusions: Intravesical gemcitabine for intermediate and high-risk NMIBC in areas where BCG supply is limited was safe and feasible at short-term follow-up. Larger prospective studies are needed to better ascertain the oncologic efficacy of gemcitabine.

Safety, Tolerability, and Preliminary Efficacy of TAR-200 in Patients With Muscle-invasive Bladder Cancer Who Refused or Were Unfit for Curative-intent Therapy: A Phase 1 Study.

PURPOSE: Half of patients with muscle-invasive bladder cancer worldwide may not receive curative-intent therapy. Elderly or frail patients are most affected by this unmet need. TAR-200 is a novel, intravesical drug delivery system that provides sustained, local release of gemcitabine into the bladder over a 21-day dosing cycle. The phase 1 TAR-200-103 study evaluated the safety, tolerability, and preliminary efficacy of TAR-200 in patients with muscle-invasive bladder cancer who either refused or were unfit for curative-intent therapy. MATERIALS AND METHODS: Eligible patients had cT2-cT3bN0M0 urothelial carcinoma of the bladder. TAR-200 was inserted for 4 consecutive 21-day cycles over 84 days. The primary end points were safety and tolerability at 84 days. Secondary end points included rates of clinical complete response and partial response as determined by cystoscopy, biopsy, and imaging; duration of response; and overall survival. RESULTS: Median age of the 35 enrolled patients was 84 years, and most were male (24/35, 68.6%). Treatment-emergent adverse events related to TAR-200 occurred in 15 patients. Two patients experienced treatment-emergent adverse events leading to removal of TAR-200. At 3 months, complete response and partial response rates were 31.4% (11/35) and 8.6% (3/35), respectively, yielding an overall response rate of 40.0% (14/35; 95% CI 23.9-57.9). Median overall survival and duration of response were 27.3 months (95% CI 10.1-not estimable) and 14 months (95% CI 10.6-22.7), respectively. Progression-free rate at 12 months was 70.5%. CONCLUSIONS: TAR-200 was generally safe, well tolerated, and had beneficial preliminary efficacy in this elderly and frail cohort with limited treatment options.

The androgen receptor in bladder cancer.

Bladder cancer is the ninth most common cancer worldwide with a striking sex-based difference in incidence. Emerging evidence indicates that the androgen receptor (AR) might promote the development, progression and recurrence of bladder cancer, contributing to the observed sex differences. Targeting androgen-AR signalling has promise as potential therapy for bladder cancer and helps to suppress progression of this disease. In addition, the identification of a new membrane AR and AR-regulated non-coding RNAs has important implications for bladder cancer treatment. The success of human clinical trials of targeted-AR therapies will help in the development of improved treatments for patients with bladder cancer.

Risk-Based Assessment Of the Impact Of Intravesical Therapy on Recurrence-Free Survival Rate Following Resection of Suspected Low-grade, Non-muscle-invasive Bladder Cancer (NMIBC): A Southwest Oncology Groups (SWOG) S0337 Posthoc Analysis.

BACKGROUND: Nonmuscle invasive bladder cancer (NMIBC) has an elevated risk of recurrence, and immediate postresection intravesical instillation of chemotherapy (IVC) significantly reduces the risk of recurrence. Questions remain about which subpopulation may maximally benefit from IVC. Our aim was to develop risk groups based on recurrence risk in NMIBC, and then evaluate the impact of a single, postoperative instillation of IVC on the subsequent risk of recurrence for each risk group. MATERIAL AND METHODS: Using the SWOG S0337 trial cohort, we performed a posthoc analysis of 345 patients who were diagnosed with suspected low-grade NMIBC, underwent transurethral resection of the bladder tumor (TURBT), and received post-operative IVC (gemcitabine vs. saline). Using regression tree analysis, the regression tree stratified patients based on their risk of recurrence into low-risk - single tumor and aged < 57 years, intermediate-risk - single tumor and aged ≥ 57 years, and high-risk - multiple tumors. We used Cox proportional hazard models to test the impact of recurrence-free rate, and after adjustment to available covariates. RESULTS: Median age of the cohort was 66.5 (IQR: 59.7-75.8 years) with 85% of patients being males. Median overall follow-up time was 3.07 years (IQR: 0.75-4.01 years). When testing the impact of treatment in each risk group separately, we found that patients in the intermediate-risk treated with gemcitabine had a 24-month recurrence free rate of 77% (95% CI: 68%-86%) vs. 59% (95% CI: 49%-70%) in the saline group. This survival difference was confirmed on multivariable analysis (hazard ratio: 0.39, 95% CI: 23%-66%, P < 0.001). This group represented 53% of our cohort. Conversely, we did not observe a significant difference in recurrence-free survival among patients in the low- (P = 0.7) and high-risk (P = 0.4) groups. CONCLUSION: Our findings indicate that older patients with a single tumor of suspected low-grade NMIBC at TURBT maximally benefit from immediate postresection IVC (gemcitabine).

Bladder Cancer Extracellular Vesicles Elicit a CD8 T Cell-Mediated Antitumor Immunity.

Tumor-derived extracellular vesicles (TEVs) play crucial roles in mediating immune responses, as they carry and present functional MHC-peptide complexes that enable them to modulate antigen-specific CD8+ T-cell responses. However, the therapeutic potential and immunogenicity of TEV-based therapies against bladder cancer (BC) have not yet been tested. Here, we demonstrated that priming with immunogenic Extracellular Vesicles (EVs) derived from murine MB49 BC cells was sufficient to prevent MB49 tumor growth in mice. Importantly, antibody-mediated CD8+ T-cell depletion diminished the protective effect of MB49 EVs, suggesting that MB49 EVs elicit cytotoxic CD8+ T-cell-mediated protection against MB49 tumor growth. Such antitumor activity may be augmented by TEV-enhanced immune cell infiltration into the tumors. Interestingly, MB49 EV priming was unable to completely prevent, but significantly delayed, unrelated syngeneic murine colon MC-38 tumor growth. Cytokine array analyses revealed that MB49 EVs were enriched with pro-inflammatory factors that might contribute to increasing tumor-infiltrating immune cells in EV-primed MC-38 tumors. These results support the potential application of TEVs in personalized medicine, and open new avenues for the development of adjuvant therapies based on patient-derived EVs aimed at preventing disease progression.

Increased risk of high-grade prostate cancer among testicular cancer survivors.

INTRODUCTION: Testicular cancer survivors (TCS) have an increased risk of additional cancers, including prostate cancer. Our understanding of the natural history of prostate cancer in testicular cancer survivors is very limited due to its rare incidence. METHODS: Using the Surveillance, Epidemiology, and End Results (SEER) Registry from 1978 to 2011, we identified 282 TCS with subsequent prostate cancer and examined the tumor grade and clinical outcomes in contrast to men with primary prostate cancer in the general population. RESULTS: TCS with a subsequent prostate cancer diagnosis were more likely to be diagnosed at a younger age than men with primary prostate cancer (65.2% vs. 37.6% for age ≤65, 34.8% vs. 62.4% for age >65, p<0.001) and were more likely to have grade III/IV tumors (46.2% vs. 37.0%, p<0.002). Longer latency between testicular and prostate cancer diagnoses was associated with a higher risk of grade III/IV (p<0.001) cancer. Despite the increased risk for high-grade tumors, 10-year prostate cancer-specific survival and overall survival were not significantly different between TCS and men with primary prostate cancer. Based on the available information in SEER, we found that prior history of radiotherapy for testicular cancer had no impact on tumor grade or survival outcomes. CONCLUSIONS: Prostate cancer in TCS was more likely to be diagnosed at a younger age and with higher grades. Risks of grade III/IV disease increased with longer latency between testicular and prostate cancer diagnoses. Radiotherapy for testicular cancer did not appear to have a significant impact on the outcome of subsequent prostate cancer.

Use of angiotensin converting enzyme inhibitors is associated with reduced risk of late bladder toxicity following radiotherapy for prostate cancer.

BACKGROUND AND PURPOSE: Genome-wide association studies (GWAS) of late hematuria following prostate cancer radiotherapy identified single nucleotide polymorphisms (SNPs) near AGT, encoding angiotensinogen. We tested the hypothesis that patients taking angiotensin converting enzyme inhibitors (ACEi) have a reduced risk of late hematuria. We additionally tested genetically-defined hypertension. MATERIALS AND METHODS: Prostate cancer patients undergoing potentially-curative radiotherapy were enrolled onto two multi-center observational studies, URWCI (N = 256) and REQUITE (N = 1,437). Patients were assessed pre-radiotherapy and followed prospectively for development of toxicity for up to four years. The cumulative probability of hematuria was estimated by the Kaplan-Meier method. Multivariable grouped relative risk models assessed the effect of ACEi on time to hematuria adjusting for clinical factors and stratified by enrollment site. A polygenic risk score (PRS) for blood pressure was tested for association with hematuria in REQUITE and our Radiogenomics Consortium GWAS. RESULTS: Patients taking ACEi during radiotherapy had a reduced risk of hematuria (HR 0.51, 95%CI 0.28 to 0.94, p = 0.030) after adjusting for prior transurethral prostate and/or bladder resection, heart disease, pelvic node radiotherapy, and bladder volume receiving 70 Gy, which are associated with hematuria. A blood pressure PRS was associated with hypertension (odds ratio per standard deviation 1.38, 95%CI 1.31 to 1.46, n = 5,288, p < 0.001) but not hematuria (HR per standard deviation 0.96, 95%CI 0.87 to 1.06, n = 5,126, p = 0.41). CONCLUSIONS: Our study is the first to show a radioprotective effect of ACEi on bladder in an international, multi-site study of patients receiving pelvic radiotherapy. Mechanistic studies are needed to understand how targeting the angiotensin pathway protects the bladder.

Improving Rates of Immediate Postoperative Intravesical Chemotherapy with Gemcitabine for Low-Grade Bladder Cancer: An Implementation Analysis.

INTRODUCTION: We sought to demonstrate how an implementation science framework can be used to increase rates of postoperative intravesical chemotherapy with gemcitabine in patients with low-grade, nonmuscle-invasive bladder cancer, thereby improving the quality of cancer care. METHODS: An audit performed at 2 University of Rochester Medical Center hospitals involved in the SWOG S0337 trial identified low usage rates of postoperative intravesical chemotherapy once study accrual closed. The Consolidated Framework for Implementation Research guided an evaluation of barriers to adoption of this evidence-based practice. Methods employed included an online survey of urologists' perceptions of postoperative gemcitabine, face-to-face interviews with key stakeholders and direct observation of utilization processes. Subsequent implementation strategies were mapped to identified barriers; educational training for urologists and support staff and refining workflow processes were critical aspects of the intervention. Repeat usage audits measured practice change at 1 year. RESULTS: The pre-intervention rate of appropriate use of intravesical gemcitabine was 11% at Strong Memorial Hospital and increased to 78% after 4 months and 88% after 12 months. The pre-intervention rate was 37% at Highland Hospital and increased to 82% after 4 months and 94% after 12 months. Over the period audited, 8 patients received gemcitabine who ultimately had nonlow-grade histology. CONCLUSIONS: Implementation science can be used to improve the impact of evidence-based findings in urological practice. The Consolidated Framework for Implementation Research has been used extensively in the literature and was adapted for postoperative intravesical chemotherapy with gemcitabine. This approach is feasible, generalizable, and results in durable practice change.