[Normal tissue tolerance to external beam radiation therapy: anal canal]

The anal canal is regarded as an organ at risk more often in pelvis radiation, but also in brachytherapy. Acute or chronic complications depend on its different components and are different from the anal margin or the rectum. The toxicity scale can be the NCI CT C version 3, completed by the tardive toxicity SOMALENT scale. The mean dose and maximal dose are recognized as predictors of complications. The maximum recommended dose despite the paucity of literature is 55 Gy.