Patterns of Failure After Definitive Trimodality Therapy for Muscle-Invasive Bladder Cancer.

Background: Real-world outcomes, especially patterns of failure, are limited for patients with muscle-invasive bladder cancer (MIBC) treated with trimodality therapy (TMT). We aim to evaluate patterns of failure after TMT for MIBC in a typical heterogeneous population.

Methods: In the national Veterans Affairs database, patients with urothelial histology, MIBC (T2-4a/N0-3/M0) who underwent definitive intent TMT between 2000-2018. Successful TMT was defined as ≥ 50% definitive radiation dose and ≥ 1 cycle chemotherapy. Endpoints of any recurrence, metastatic (nonbladder) recurrence (MR), and local (bladder) recurrence (LR) evaluated in multivariable Fine-Gray models. Times to recurrence calculated from radiation start date.

Results: In 347 patients with MIBC treated with TMT, 65% of patients were deemed ineligible for surgery while 35% were surgically eligible but elected for TMT. Median follow-up time was 77 months. Median overall survival was 32.4 months (95% CI: 28.2-36.7). 154 (44%) patients had no recurrence. 130 (37%) patients developed MR, median time 9.9 months. 117 (34%) patients developed LR, median time 8.7 months. In multivariable models, lymph node positive (LN+) disease (HR:3.31, 95% CI: 1.45-7.55, P < .01) and pretreatment hydronephrosis (HR:1.62, 95% CI:1.11-2.36, P = .01) were associated with higher rates of MR. No patient, tumor, or treatment variables were associated with LR.

Conclusions: Across a multi-institutional and heterogeneous population, TMT is an effective treatment for many real-world patients with MIBC. However, a notable proportion of patients develop MR and/or LR which emphasizes the need for post-treatment surveillance and improved treatment pathways. Identified high risk features (LN+ disease, pretreatment hydronephrosis) and other markers should be further investigated to delineate the patients at high risk of TMT failure who therefore may potentially benefit from augmented treatment, such as additional systemic therapy.