Long-term results of a concomitant boost radiotherapy technique for elderly patients with muscle-invasive bladder cancer.

ABSTRACT

OBJECTIVES: To evaluate the long-term clinical efficacy and toxicity of concomitant boost radiotherapy (CBRT) in elderly patients with invasive bladder cancer. METHODS AND MATERIALS Elderly patients (n=188; mean 75-year-old, range 70-91 years; 88.3% male/11.7% female) with T1-T4a bladder carcinoma were irradiated with CBRT. A total of 24 (12.8%) patients were diagnosed at stage T1, 117 (62.2%) were at stage T2, 28 (14.9%) at were stage T3a, 14 (7.4%) were stage T3b, and 5 (2.7%) were stage T4a. A dose of 45Gy in 1.8Gy fractions was administered to the whole pelvis 5 days/week over 5 weeks. A concomitant boost limited to the bladder tumor area plus margin or whole bladder of 22.5Gy in 1.5Gy fractions was administered from weeks 3×5. Thus, irradiation totalled 67.5Gy over 5 weeks. The interfraction interval was ≥6h/treatment day. We assessed prognostic factors for overall survival (OS), cause-specific survival (CSS) and relapse-free survival (RFS). RESULTS: Median follow-up was 46.2 months (range 4.7-155.7 months). Median overall survival was 27 months (95% CI21-33 months). In this study, 146 (77.7%) patients had complete response, 39 (20.7%) had residual disease and 4 (1.6%) had progressive disease. The mean 3-, 5- and 10-year OS rates were respectively 41.2% (S.E.±0.036), 29% (S.E.±0.034), and 13.8% (S.E.±0.031). Significant prognostic factors for OS and CSS, by multivariate analysis, were tumor T-stage and urothelial obstruction. CONCLUSION: This CBRT protocol provided excellent results with a high complete response rate and good tolerance. This approach may therefore be particularly appropriate for elderly patients with invasive bladder cancer.