Evaluation of Hypothyroidism Incidence After Breast Cancer Supraclavicular Irradiation

Prospective, multicentric, comparative, non randomised, in current care study 2 patient groups, non randomised, according to the necessity or not to perform a supra-clavicular irradiation: * Group 1 : patients receiving a supra-clavicular irradiation * Group 2 : patients not receiving a supra-clavicular irradiation. Schedule Projected inclusion duration of 18 months (duration to possibly adapt in order to obtain the number of required patients) Intermediate study of the results in 30 months Duration of follow-up of 60 months