ASTRO 2020: Bladder-Sparing Radiochemotherapy Regimens Under Study
Posted: Monday, November 16, 2020
John J. Coen, MD, of 21st Century Oncology, Providence, Rhode Island, and colleagues conducted a phase II study to determine whether distant metastasis–free survival at 3 years would exceed a benchmark of 75% for two separate therapies. The treatments included gemcitabine combined with once-daily radiation and flourouracil (5-FU)/cisplatin supplemented with twice-daily radiation. Both treatments appear to be effective bladder-sparing options for muscle-invasive bladder cancer, according to updated results from NRG/RTOG 0712 presented at the 2020 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 55).
A total of 70 patients with cT2–4a muscle-invasive bladder cancer were enrolled, 66 of whom were eligible to participate. Patients were randomly assigned to receive 5-FU/cisplatin or gemcitabine, with 33 per arm. Trial participants underwent transurethral resection on induction chemoradiation to 40 Gy, or, if they had a complete response, they received consolidation chemoradiation to 64 Gy. Patients not eligible for chemoradiation underwent cystectomy, and all received chemotherapy based on their designated cohort.
The distant metastasis–free survival rate at 3 years with 5-FU/cisplatin was 79%, and it was 85% with gemcitabine; the distant metastasis–free survival rate at 5 years was 70% and 77%, respectively. The bladder-intact distant metastasis–free survival rate at 3 years was 67% with 5-FU/cisplatin and radiotherapy and 72% with gemcitabine and radiotherapy; the bladder-intact distant metastasis–free survival rate at 5 years was 65.1% versus 72.5%, respectively. Post-induction complete response rates were 88% and 76%, respectively. A total of three cystectomies were performed in the 5-FU/cisplatin group and six in the gemcitabine group. Overall survival at 5 years was 74% and 71%.
For the 5-FU/cisplatin plus radiotherapy group, 58% had treatment-related grade 3 to 4 toxicities during protocol treatment, with 56%, 6%, and 6% experiencing grade 3 to 4 hematologic, gastrointestinal, and genitourinary adverse events, respectively. For the gemcitabine plus radiotherapy arm, these results were 52% overall and 43%, 9%, and 6%, respectively.
Disclosure: For full disclosures of the study authors, visit redjournal.org.