Tyson, Mark D.

376 Background: Germline genetic testing (GGT) is becoming increasingly important in the management of genitourinary (GU) malignancies as novel targeted drug therapies emerge. Selection for genetic studies and testing has historically been highly selective and based on pathologic characteristics, family history, and age of diagnosis. The aim of our study was to investigate the prevalence of pathogenic variants (PGVs) in inherited cancer susceptibility genes utilizing a universal testing approach and to characterize the rate of PGVs that would have been missed based on current NCCN guidelines. Methods: A multisite single-institutional prospective study (INTERCEPT) offered GGT to all patients with new or active diagnoses of GU malignancies (bladder, prostate, and renal cancers) from April 1, 2018 to March 31, 2020 at Mayo Clinic Arizona, Mayo Clinic Florida and Mayo Clinic Rochester. Participants were offered GGT with a panel of >80 genes through Invitae Corp. Demographic, tumor characteristics and genetic results were evaluated. PGVs were classified as high-, intermediate-, or low- penetrance variants based on published literature. Respective NCCN GU GGT guidelines were used to determine if the PGVs discovered using our universal testing approach would have been missed with guideline-directed GGT. Results: A total of 3095 pan-cancer patients were enrolled in the study; 601 of which had a GU malignancy including: prostate cancer (358 patients), renal cancer (137), and bladder cancer (106). The mean age of enrollment was 66.8 years (SD 9.1), 89% were male, and 85.9% of patients were Non-Hispanic white. PGVs were identified in 82 of all GU patients (13.6%) and variants of undetermined significance (VUS) in 289 (48.1%) patients. PGV prevalence breakdown by cancer type was: 13.7% of prostate, 13.1% renal, and 14.2% bladder cancer patients. The proportion of high penetrance PGVs varied by malignancy type. Of all patients, 326 (54.2%) had advanced (stage III/IV) disease and 377 (64.4%) of these were metastatic upon initial evaluation. The majority of all PGVs identified were incremental, defined as PGVs that would not have been identified based on guideline-concordant GGT: 100% (15/15 patients) with bladder, 77.8% (14/18) with renal, and 57.1% (28/49) with prostate cancer. Conclusions: Universal GGT for prostate, renal and bladder cancer revealed that over 1 in 10 patients harbored potentially actionable PGVs, most of which would not have been identified with guidelines-based GGT. Utilization of GGT can impact our understanding of GU cancer pathogenesis, aid in familial cascade testing, and influence treatment decisions.

BACKGROUND: Little is known about the impact of prior prostate radiation therapy (RT) on the Bacille Calmette-Guerin (BCG) immunotherapy response in patients with non-muscle invasive bladder cancer (NMIBC). OBJECTIVE: We hypothesized that the damaging radiation effects on the bladder could negatively influence BCG efficacy. METHODS: Men with a history of high-risk NMIBC were identified within the Surveillance, Epidemiology, and End Results–Medicare database. All patients completed adequate BCG defined as at least 5 plus 2 treatments completed within 12 months. Patients were stratified into 2 groups: with prior RT for prostate cancer and without prior RT before the diagnosis of NMIBC. The primary endpoint was a 5-year composite for progression defined as disease progression requiring systemic chemotherapy, checkpoint inhibitors, radical or partial cystectomy, or cancer-specific death. RESULTS: We identified 3,466 patients with NMIBC, including 145 with prior RT for prostate cancer. Five-year progression occurred in 471 patients (13.6%). Patients with prior RT were older than patients without prior RT (77.0 vs 75.0 years; P < .001). The distribution of T stage was significantly different at diagnosis between the RT and non-RT groups (RT: Ta, 44.8%; Tis, 18.6%; T1, 36.6%; without RT: Ta, 40.9%; Tis, 10.8%; T1, 48.3%; P = .002). No difference in the risk of total progression was observed between patients with and without prior RT ( P = .67). Similarly, no difference was observed after multivariable adjustment (hazard ratio, 0.99; 95% CI, 0.61-1.58; P = .95). CONCLUSION: For patients with NMIBC who undergo adequate BCG treatment, prior RT for prostate cancer was not associated with worse 5-year progression-free survival.

TPS582 Background: The majority of patients with bladder cancer present with non-muscle invasive disease (Chang 2016; Woldu 2017; Kates 2020; Li 2020). The standard of care for treatment of high risk NMIBC involves transurethral resection of the bladder tumor (TURBT) followed by intravesical Bacillus Calmette-Guerin (BCG) or chemotherapy. Although the response rate to BCG therapy is high, many patients recur within 1–5 years (Matulay JU 2021). For patients who have BCG unresponsive disease after adequate course of BCG, there are limited options. While radical cystectomy (RC) is still considered the standard of care, most patients are reluctant to undergo RC and their options are limited to intravesical chemotherapy or pembrolizumab. Enfortumab vedotin (EV) is an antibody-drug conjugate directed to Nectin-4, which is highly expressed in bladder tumors. In EV-301, a phase 3 study, EV showed an OS benefit vs chemotherapy in patients with locally advanced or metastatic urothelial carcinoma (la/mUC) who had previously received platinum-based therapy and a PD-1 or PD-L1 inhibitor (Powles NEJM 2021). Based on its demonstrated benefit in la/mUC, EV is currently being evaluated in earlier UC settings. The purpose of this study is to investigate the intravesical administration of EV for patients with NMIBC. Methods: EV-104 (NCT05014139) is a phase 1, open-label, multicenter, dose-escalation and dose-expansion study designed to evaluate the safety, tolerability, PK, and antitumor activity of intravesical EV in adults with high-risk BCG-unresponsive NMIBC (carcinoma in situ with or without papillary disease) who are ineligible for or refuse RC. The dose escalation part of the trial aims to identify the maximum tolerated dose (MTD) and/or recommended dose of intravesical EV. The dose expansion part will evaluate patients at the MTD or recommended dose and further characterize safety and antitumor activity of intravesical EV. The study treatment regimen will include an induction phase, where patients will receive intravesical EV weekly for 6 weeks followed by monthly maintenance for a total of 9 additional EV doses. Patients will be assessed for response every 3 months by cystoscopy and urine cytology, while on study. Safety and antitumor activity endpoints will be summarized using descriptive statistics. The study is currently enrolling in the US with additional sites planned in Canada and the EU. Clinical trial information: NCT05014139 .

The NCCN Guidelines for Prostate Cancer Early Detection provide recommendations for individuals with a prostate who opt to participate in an early detection program after receiving the appropriate counseling on the pros and cons. These NCCN Guidelines Insights provide a summary of recent updates to the NCCN Guidelines with regard to the testing protocol, use of multiparametric MRI, and management of negative biopsy results to optimize the detection of clinically significant prostate cancer and minimize the detection of indolent disease.