Bladder Preservation With Twice-a-Day Radiation Plus Fluorouracil/Cisplatin or Once Daily Radiation Plus Gemcitabine for Muscle-Invasive Bladder Cancer: NRG/RTOG 0712-A Randomized Phase II Trial.

PURPOSE: Fluorouracil plus cisplatin and radiation twice a day (FCT) is an established chemoradiation (CRT) regimen for selective bladder-sparing treatment of muscle-invasive bladder cancer. Gemcitabine and once daily radiation (GD) is a well-supported alternative. The current trial evaluates these regimens.

METHODS: Patients with cT2-4a muscle-invasive bladder cancer were randomly assigned to FCT or GD. Patients underwent transurethral resection and induction CRT to 40 Gy. Patients who achieved a complete response (CR) received consolidation CRT to 64 Gy and others underwent cystectomy. We administered adjuvant gemcitabine/cisplatin chemotherapy. The primary end point was the rate of freedom from distant metastasis at 3 years (DMF3). The trial was not statistically powered to compare regimens, but to assess whether either regimen exceeded a DMF3 benchmark of 75%. Toxicity and efficacy end points, including CR and bladder-intact distant metastasis free survival at 3 years (BI-DMFS3), were assessed.

RESULTS: From December 2008 to April 2014, 70 patients were enrolled, of which 66 were eligible for analysis, 33 per arm. Median follow-up was 5.1 years (range, 0.4 to 7.8 years) for eligible living patients. DMF3 was 78% and 84% for FCT and GD, respectively. BI-DMFS3 was 67% and 72%, respectively. Postinduction CR rates were 88% and 78%, respectively. Of 33 patients in the FCT arm, 21 (64%) experienced treatment-related grade 3 and 4 toxicities during protocol treatment, with 18 (55%), two (6%), and two patients (6%) experiencing grade 3 and 4 hematologic, GI, and genitourinary toxicity, respectively. For the 33 patients in the GD arm, these figures were 18 (55%) overall and 14 (42%), three (9%) and two patients (6%), respectively.

CONCLUSION: Both regimens demonstrated DMF3 greater than 75%. There were fewer toxicities observed in the GD arm. Either gemcitabine and once daily radiation or a cisplatin-based regimen could serve as a base for future trials of systemic therapy.