Whenever an innovative treatment or a research protocol is proposed to a patient, the "loi Huriet" requires a written consent from the patient. This is an important change in the field of the interrelation between the doctor and his patient. To evaluate the impact of this written consent we asked 215 patients who have signed a consent form to answer a questionnaire at the end of their radiation treatment. The signature appears as an important event. The majority of the patients (70%) is not shocked by this procedure. In 97% of cases, in spite of this written relation, the patients keep intact their confidence in their doctor. Sometimes this consent form may improve the information given to the patient and it should not be seen as an obstacle for the development of research trials. There are still many problems to be solved as regards the information of the patient and the application of the "loi Huriet".