[Anal cancer].

Anal canal epidermoid carcinomas represent 1.2% of digestive cancers and 6% of ano-rectal cancers. For localized diseases, the treatment is based on radiotherapy with or without chemotherapy (5-FU and cisplatin or mitomycin), according to tumour and nodal extension. The recommended treatment dose is 45 Gy in the anal canal, the mesorectum, pararectal lymph nodes, and inguinal lymph nodes. An additional dose of 15 to 20 Gy is delivered in the initial tumour for good responders. Salvage surgery is necessary in case of poor response. The organs at risk to be considered are bladder, femur heads, small intestine and vulva. The objective of this work is to summarize the epidemiological and radio-anatomic and prognostic characteristics of this tumour. The conformal radiotherapy technique is illustrated by a case report.