Accelerated superfractionated radiotherapy with concomitant boost for invasive bladder cancer

PURPOSE: To determine the toxicity and clinical effectiveness of accelerated superfractionated radiotherapy with delayed concomitant boost (ASCBRT) in locally invasive carcinoma of the bladder. METHODS AND MATERIALS: Between July 1997 and December 2001, 87 patients (unsuitable or refusing cystectomy) with invasive bladder cancer underwent ASCBRT. The mean patient age was 66 years (range 40-90). The stage distribution was as follows: 2 T1, 51 T2, 13 T3, and 21 T4. Initially, the whole pelvis was treated by 1.8-Gy conventional daily fractions up to a total dose of 45 Gy. A small field boost covering gross disease was added as a second daily fraction (1.5 Gy) during the last 3 weeks of the 5-week schedule up to a total dose of 67.5 Gy. The interfraction interval was a minimum of 6 h. The patients were evaluated in follow-up for toxicity, local control, and survival. RESULTS: All but 2 patients completed the study protocol. Grade 3 acute urinary toxicity was observed in 2 patients. Grade 2 and 3 late bladder toxicity was observed in 12 patients and 1 patient, respectively. Grade 2 and 3 late bowel toxicity was observed in 5 and 3 patients, respectively. The 3-year actuarial local control, distant disease control, cause-specific survival, and overall survival rate was 64%, 78%, 58%, and 46%, respectively. Multivariate analysis revealed T stage as independent predictor of complete response. For Stage T2 and T3, the 3-year local control rate was 77% and 48%, respectively. At the last follow-up, 53 patients (61%) were still alive with a survival time between 6 and 62 months. CONCLUSION: ASCBRT is feasible with acceptable tolerance even in relatively old patients with Stage T3 or greater tumor. The encouraging locoregional control and survival results of this institutional experience, favorable compared with conventional radical and other accelerated fractionated (with or without a concomitant boost) RT series, make ASCBRT worthy of further study in a Phase III trial.