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].