Characterization and management of NMIBC recurrences after TMT: a matched cohort analysis

Abstract

Introduction and objective: Bladder preservation with trimodal therapy (TMT) has emerged as a feasible alternative strategy to treat localized muscle invasive bladder cancer (MIBC). There is lack of consensus regarding the treatment of local recurrence following TMT. The aim of this paper is to determine whether traditional NMIBC therapies can be applied to the management of NMIBC recurrences following TMT.

Methods: Using our institutional bladder cancer radiotherapy database, all patients with recurrent NMIBC following TMT were identified between 2008-2019. TMT patients were initially treated with maximal TURBT followed by combination chemotherapy/radiotherapy (weekly cisplatin 40 mg/m² and 64-66 Gy to the bladder) with localizing Lipiodol injections. We compared NMIBC recurrent patients to a cohort of matched controls with primary NMIBC, hypothesizing that post-TMT patients treated with traditional NMIBC therapies would have outcomes similar to patients with primary NMIBC. Primary NMIBC patients were derived from our local NMIBC database and matching was based on clinical stage and grade in a 5:1 manner (controls:cases). Recurrences in the TMT group were managed according to the standard therapy for NMIBC. A descriptive analysis was performed between patients undergoing TMT with NMIBC recurrence and patients initially diagnosed with de novo NMIBC. Overall survival was calculated for each group and analyzed using the Kaplan-Meier method and Cox proportional hazards modeling. Recurrence-free and cystectomy-free survival were analyzed using competing risk methods.

Results: Twelve patients out of 124 patients in the TMT cohort had NMIBC recurrence and were compared to 60 patients in a control group who were diagnosed with de-novo NMIBC. Median age of the TMT group was 78 [54 - 84] years versus 66 [23 - 88] years for the non-TMT group. Median follow-up for was 3.6 years versus 5.4 years in the non-TMT group. The clinical stage of the TMT NMIBC recurrences was Ta (n = 4), T1 (n = 3), CIS (n = 5). During the follow-up period, 38 (63%) further recurrences occurred in the non-TMT group compared to 2 (17%) in TMT group (P = 0.004). One patient (8%) from the TMT group required a cystectomy compared to 11 (18%) in the non-TMT group (P = 0.68). There were 2 non-cancer deaths (17%) in TMT group compared to one (2%) in the non-TMT group.

Conclusion: Our study demonstrates NMIBC recurrences post TMT can be successfully managed with endoscopic and adjuvant intravesical therapies.

Keywords: Bladder cancer; MIBC; NMIBC; TMT.