Mitomycin or cisplatin chemoradiation with or without maintenance chemotherapy for treatment of squamous-cell carcinoma of the anus (ACT II): a randomised, phase 3, open-label, 2X2 factorial trial

Chemoradiation became the standard of care for anal cancer after the ACT I trial. However, only two-thirds of patients achieved local control, with 5-year survival of 50%; therefore, better treatments are needed. We investigated whether replacing mitomycin with cisplatin in chemoradiation improves response, and whether maintenance chemotherapy after chemoradiation improves survival. Methods: In this 2X2 factorial trial, we enrolled patients with histologically confirmed squamous-cell carcinoma of the anus without metastatic disease from 59 centres in the UK. Patients were randomly assigned to one of four groups, to receive either mitomycin (12 mg/m2 on day 1) or cisplatin (60 mg/m2 on days 1 and 29), with fluorouracil (1000 mg/m2 per day on days 1a4 and 29a32) and radiotherapy (50ADT4 Gy in 28 daily fractions); with or without two courses of maintenance chemotherapy (fluorouracil and cisplatin at weeks 11 and 14). The random allocation was generated by computer and patients assigned by telephone. Randomisation was done by minimisation and stratified by tumour site, T and N stage, sex, age, and renal function. Neither patients nor investigators were masked to assignment. Primary endpoints were complete response at 26 weeks and acute toxic effects (for chemoradiation), and progression-free survival (for maintenance). The primary analyses were done by intention to treat. This study is registered at controlled-trials.com, number 26715889.