(ChemotherapyAdvisor) – Patients with muscle-invasive bladder cancer had significantly higher rates of locoregional disease-free survival when treated with synchronous chemotherapy plus radiotherapy compared with radiotherapy alone, with no significant increase in adverse events, a study in the April 19 issue of the New England Journal of Medicine has concluded.

An accompanying editorial noted, “the landmark study is potentially practice-changing for patients with muscle-invasive bladder cancer.”

The multicenter Phase 3 trial, conducted in the United Kingdom, randomly assigned 360 patients with muscle-invasive bladder cancer to undergo radiotherapy with or without synchronous chemotherapy. Fluorouracil 500mg/m2/day was administered during fractions 1 to 5 and 16 to 20 of radiotherapy and mitomycin C 12mg/m2 on day 1.

At two years, locoregional disease-free survival was 67% in the chemoradiotherapy group and 54% in the radiotherapy group; median follow-up was 69.9 months (HR 0.68; P=0.03).

Five-year rates of overall survival were 48% in the chemoradiotherapy group and 35% in the radiotherapy group (HR 0.82; P=0.16). Grade 3 or 4 adverse events were slightly more common in the chemoradiotherapy group than in the radiotherapy group during treatment (36.0% vs. 27.5%, P=0.07) but not during follow-up (8.3% vs. 15.7%, P=0.07).

“…our study shows that the addition of chemotherapy to radiotherapy improved local control, particularly freedom from invasive recurrence, as compared with radiotherapy alone, and resulted in good long-term bladder function and low rates of salvage cystectomy, all of which are of major importance in this elderly, relatively frail group of patients,” the investigators wrote. “The benefit of synchronous chemotherapy was consistent across both radiation fractionation schedules. Thus, it may be time to reevaluate the relative roles of bladder preservation and surgery in the treatment of muscle-invasive bladder cancer, particularly for patients at high risk for complications from surgery.”

Abstract