Bladder-Preserving Trimodality Treatment for High-Grade T1 Bladder Cancer: Results From Phase II Protocol NRG Oncology/RTOG 0926.

Purpose: To investigate the use of radiation with radiosensitizing chemotherapy following repeated transurethral resection (trimodality therapy) as an alternative to radical cystectomy in T1 bladder cancer which has failed Bacillus Calmette-Guerin (BCG).

Patients and methods: Patients with recurrent T1 bladders who had failed BCG and were recommended to undergo cystectomy were treated with trimodality therapy. The primary end point was 3-year freedom from cystectomy. Secondary end points were distant metastasis at 3 and 5 years, local recurrence, disease-specific and overall survival (OS), and safety.

Results: This single-arm phase II study enrolled 37 patients. Efficacy and safety were evaluated in 34 patients after three exclusions. The median follow-up was 5.1 years. The 3-year freedom from cystectomy rate was 88% (lower one-sided 97.5% confidence limit [CI], 72%), meeting the primary study goal. OS at 3 and 5 years was 69% (95% CI, 54 to 85) and 56% (95% CI, 39 to 74), respectively. The distant metastasis rates at 3 and 5 years were 12% (95% CI, 4 to 26) and 19% (95% CI, 7 to 34), respectively. Eight patients died due to urothelial cancer, 12 exhibited local recurrence at 3 years (cumulative incidence: 32%; 95% CI, 17 to 48), 18 experienced grade 3 adverse events, mostly hematological, and one developed grade 4 neutropenia.

Conclusion: Trimodality therapy is an effective potential alternative to radical cystectomy for recurrent high-grade T1 urothelial cancer of the bladder. At 3 years, 88% of the patients remained free of cystectomy.