Session: LBA02: Late-Breaking Abstracts II - Cancer
LBA02-04: Outcomes and Genomic Characteristics of Newly Diagnosed High Grade Ta Papillary Urothelial Carcinoma Treated with Intravesical Chemotherapy vs Bacillus Calmette Guerin (BCG): A Comparative Study During the BCG Shortage
Introduction: Appropriate risk stratification of non-muscle invasive bladder cancer remains a central component of deciding treatment. Current criteria used to determine risk of disease recurrence and progression are based largely on historic cohorts before standardization of adjuvant intravesical treatments. The ongoing BCG shortage emphasizes the need for accurate contemporary data to best allocate BCG when supplies are limited. During periods of BCG shortage, our institution restricted BCG utilization to only those with HGT1 or carcinoma in situ (CIS), thus patients with HGTa without CIS were “naturally randomized” to receive either BCG or intravesical chemotherapy based on the time period of their initial diagnosis. Methods: Retrospective review of an institutional database identified patients with newly diagnosed HGTa without CIS treated at MSKCC from 2017-2021. BCG restrictions were in effect between 01/19 and 04/20. Progression was defined as = T1 disease or radical cystectomy. The association of clinicopathologic variables and recurrence was performed with univariable Cox regression. Kaplan-Meier curves were used to visualize time to recurrence and progression. Results: We identified 307 patients with papillary HGTa without CIS, 236 who were treated with BCG, and 71 with intravesical chemotherapy (N=60 mitomycin C, N=11 gemcitabine). Median follow up was 24 months for the BCG treated group, and 18 months from the chemotherapy treated group. There were no significant differences between the two groups regarding age, gender, tumor size, or tumor multiplicity. Targeted exon sequencing of pre-treatment tumors in 59 patients was performed and demonstrated no significant differences between treatment groups. Cumulative risk of high-grade recurrences was similar between the chemotherapy and BCG groups, with 86% vs 90% and 78% vs 82% recurrence-free survival at 6 and 12 months, respectively. Similarly, progression free survival was 89% at 12 months for both groups, but further follow up is needed. Conclusions: In this “naturally randomized” study, we report comparable clinical efficacy between chemotherapy and BCG immunotherapy, suggesting that intravesical chemotherapy is a reasonable alternative during the BCG shortage for patients with newly diagnosed HGTa without CIS. While our data is encouraging, there remains a critical need for better alternatives to BCG, especially for patients with higher risk non-muscle invasive bladder cancer. SOURCE OF Funding: NCI
