[en] Full text: During the last 4 years, several incidents/accidents at radiotherapy department occurred in France. The accident at the Public General Hospital in Epinal is the more severe. It was classified level 6 on a 10 degree scale of the ASN/SFRO (Autorite de Surete Nucleaire/Societe Francaise de Radiotherapie Oncologique). This accident is linked to a succession of dysfunctions and human errors. IRSN was elected by the Health Ministry for the identification and medical management of the victims. Concerning the patients treated for their prostate cancer with conformational RT between 2004 and 2005, 24 patients were exposed to 28% excess of dose and suffer from severe late effects (rectitis, cystitis) ranged from grade II to grade IV, some of them suffer from huge dilapidation. Some innovative medical strategies were proposed to the more severe affected patients. A medical follow-up of these patients is actually on the way in parallel to the development of a new research program concerning the improvement of the knowledge and prediction of radiotherapy complications. (author)