Long-term outcomes among patients who achieve complete or near-complete responses after the induction phase of bladder-preserving combined modality therapy for muscle-invasive bladder cancer: A pooled analysis of RTOG 9906 and 0233.

284 Background: Bladder preserving combined-modality therapy for muscle-invasive bladder cancer (MIBC) includes transurethral resection and concurrent chemo-RT given in two phases. After the induction phase with chemo-RT to 40 Gy the tumor response is assessed by cystoscopic biopsies and urine cytology. Early salvage cystectomy is promptly offered in case of persistent disease, otherwise patients proceed to consolidation chemo-RT to 64 Gy. The two most recent RTOG protocols 9906 and 0233 allowed patients with near-complete response (Ta or Tis) after the induction phase to proceed to consolidation. Methods: We performed a pooled analysis of 119 eligible patients with MIBC enrolled on RTOG trials 9906 and 0233, who were classified as having a complete (T0) or near-complete (Ta or Tis) response after induction chemo-RT and completed consolidation with a total RT dose of at least 60 Gy. We estimated bladder recurrence, salvage cystectomy rates and disease-specific survival by the cumulative incidence method a...