[Rationale and progress of the phase III trial: intensification of the treatment of locally advanced squamous cell carcinoma of the anal canal].

Concomitant radiotherapy (5FU-MMC) was proved to be useful in locally advanced anal canal carcinoma. Nevertheless, it remains 30% of failures after this conservative treatment. The tolerance and efficiency of a neoadjuvant chemotherapy (5-FU-CDDP) were validated by a phase II trial including 80 patients, which obtained 73% of colostomy free survival and 70% of relapse free survival at 3-year follow-up. Its usefulness is studied in an ongoing phase III trial, as well as the dose escalation of the boost, from 15 Gy to 25-25 Gy. The results of the 101 first included patients are studied by an intermediate analyze. In July 2003, 222 patients were enrolled by 33 investigating centres out of the 350 planned patients until the end of the trial in December 2004.