Long-term outcomes in patients with muscle-invasive bladder cancer after bladder-preserving combined-modality therapy: A pooled analysis of RTOG 8802, 8903, 9506, 9706, 9906, and 0233.

Abstract

264 Background: Multiple prospective RTOG studies have evaluated bladder preserving combined-modality therapy (CMT) including local resection with chemo-radiation for the treatment of muscle invasive bladder cancer (MIBC) reserving cystectomy for salvage. Here we report a pooled analysis of long-term outcomes. Methods: We performed a pooled analysis of 468 patients (pts) with MIBC enrolled on six RTOG bladder preservation studies, including five Phase II studies: RTOG 8802, 9506, 9706, 9906, and 0233, and one phase III study: 8903. Overall survival (OS) was estimated with the Kaplan-Meier method, and disease specific survival (DSS), local failure (LF) and distant metastasis (DM) were estimated by the cumulative incidence method. Results: The median age of the pts was 66 (range, 34-93), and the majority had a Zubrod performance status (PS) of 0 (89.1%). The most common tumor histology was transitional cell carcinoma (94.2%). Clinical tumor stage distribution included 60.6% T2, 29.1% T3a, 6.2% T3b, and 3.9% T4a. A complete response to CMT was observed in 72.0% of pts. With a median follow-up of 4.29 years among all pts, and 7.80 years among survivors (n=205), the 5-year and 10-year results were as follows (Table). Examining outcomes by subgroups, higher clinical T-stage (T2 vs. T3/T4) was associated with decreased DSS (5-year DSS: 74% vs. 66%; 10-year DSS: 69% vs. 60%; p=0.05), and OS (5-year OS: 62% vs. 49%; 10-year OS: 41% vs. 30%; p=0.002). On multivariate analysis, after adjusting for age and PS, higher T-stage was associated with decreased DSS (Hazard ratio: 1.65; 95% confidence interval: 1.19-2.27; p=0.002). Among pts with non-transitional cell carcinoma histology (n=29), the 5-year and 10-year DSS was 66% and 60%, respectively, and 5-year and 10-year OS was 41% and 21%. Conclusions: This pooled analysis of RTOG trials of bladder preserving CMT for MIBC demonstrates long-term OS and DSS comparable to modern immediate cystectomy-based strategies with and without neoadjuvant chemotherapy. CMT can be considered as an alternative to radical cystectomy in selected pts. [Table: see text]