Radiotherapy with concurrent carbogen and nicotinamide in bladder carcinoma

Phase II clinical studies suggest that hypoxic modification with carbogen and nicotinamide (CON) may increase the efficacy of radiotherapy (RT).

Three hundred thirty-three patients with locally advanced bladder carcinoma were randomly assigned to RT alone versus RT with CON. A schedule of either 55 Gy in 20 fractions in 4 weeks or 64 Gy in 32 fractions in 6.5 weeks was used. The primary end point was cystoscopic control at 6 months (CC(6m)) and secondary end points were overall survival (OS), local relapse-free survival (RFS), urinary and rectal morbidity.

CC(6m) was 81% for RT + CON and 76% for RT alone (P = .3); however, just more than half of patients underwent cystoscopy at that time. Three-year estimates of OS were 59% and 46% (P = .04) and 3-year estimates of RFS were 54% and 43% (P = .06) for RT + CON versus RT alone. Risk of death was 14% lower with RT + CON (P = .04). In multivariate comparison, RT + CON significantly reduced the risk of relapse (P = .05) and death (P = .03). There was no evidence that differences in late urinary or GI morbidity between treatment groups or between fractionation schedules were significant.

RT + CON produced a small nonsignificant improvement in CC(6m). Differences in OS, risk of death, and local relapse were significantly in favor of RT + CON. Late morbidity was similar in both trial arms. Results indicate a benefit of adding CON to radical RT.