1. Data collection Data are obtained from the database of the gynecologic department of the Montpellier University Hospital, using the Medicalization Program of the Information Systems. The patient who have had a BCS for breast cancer between 2016 and 2017 are selected. The investigator then include consecutively 10 patients who have had a preoperative MRI and a preoperative and intraoperative 3D optical scan of the chest and who meet eligibility criteria. A subject identification code is assigned by the investigator to each subject to anonymized the data. A subject identification code list allows the investigator to keep a confidential list of names of all the patients included in the study on the protected central computer server of Montpellier University Hospital.