The software used for the collection of the primary endpoint is no longer available.

The medical information delivered to the patient before any surgery constitutes an essential and compulsory step during the initial management of the operated patient.

There are different reasons for the quantity and quality of medical information retained by the patient. An internet platform with personalized and secure access has been developed. This platform contains, among other things, an explanatory video of breast surgery and allows the patient to have access to information on surgical management at any time.

The investigators believe that unlimited access for the duration of the study to this platform could reduce the preoperative anxiety level of patients.

The medical information provided during the pre-operative phase is an essential and mandatory step in the duty to inform during the initial management of the patient undergoing surgery. The different reasons acting on the quantity and quality of the medical information integrated by the patient can be linked to several factors: among others, the information supports, the age, the listening and comprehension capacities, the level of anxiety or the level of education of the patient, thus creating health inequalities. The use of visual communication seems to be more suitable for patients with a low level of education, illiteracy or non-native speakers. Studies have shown that, in addition to oral preoperative information, the introduction of a visual medium with the use of a video has demonstrated a significant reduction in preoperative anxiety and the use of the Internet.

The prevalence of anxiety is high in cancer patients, particularly during the preoperative phase. The EDOP company has developed a personalized and secure Internet platform containing, among other things, an explanatory video on breast surgery. In the current literature, there are no studies on the contribution of the use of video and web platform in the context of preoperative medical information.

In this study, the investigators hypothesize that the unlimited access to the EDOP platform and the possibility to review as many times as necessary the information concerning their surgical intervention could allow, whatever the situation of the patients, to reduce the level of preoperative anxiety, which is always deleterious. Indeed, studies have shown the negative effects of preoperative anxiety on the quantity of anaesthetic used during the operation or on the consumption of analgesics postoperatively. A reduction in preoperative anxiety would therefore be likely to lead in the short term to a reduction in drug treatments and probably to a better state of health.

The main objective is to evaluate the impact of additional personalized preoperative medical information, accessible via a secure internet platform, on anxiety on the morning of surgery, in the context of breast cancer surgery, after conventional oral and written information.

The secondary objectives are to compare between the 2 groups:

• the change in anxiety between the preoperative visit and the morning of the procedure,
• patient satisfaction and understanding of the preoperative medical information received after the preoperative visit, on the morning of the operation, at discharge (between D0 and D3) and at the postoperative visit (6 weeks),
• consultation of other websites and contact with the medical team, on the morning of the operation and at the post-operative visit (6 weeks),
• the quantity of anaesthetic products used during the operation
• the consumption of analgesics during the 15 days after the operation
• consumption of anxiolytics during the 15 postoperative days

For the experimental group:

• To evaluate the use of the EDOP platform,
• To evaluate patient satisfaction with this platform.

This is a Multicenter, prospective, randomized, single-blind study. Only the clinical study technician (CST) will know the patient's group. Nursing staff will be blinded. Self-questionnaires will be filled out by the patients and then retrieved by the CT who will enter the data into the eCRF, with no access to these data by the investigators.

Inclusion Criteria:

• Histologically confirmed breast cancer.
• Indication of breast lumpectomy, oncoplasty or mastectomy.
• Person over 18 years old

Exclusion Criteria:

• Person with a history of breast cancer surgery.
• Person with severely impaired physical and/or psychological health, which, in the opinion of the investigator, may affect the participant's compliance to the study.
• Individuals who have difficulty understanding the French language orally.
• Person who does not have Internet access at home or at work.
• Person placed under court protection.
• Person who is not a member or beneficiary of a national health insurance system.
• Person who has not given oral informed consent after a reflection period.
• Person participating in another research study with an exclusion

Only the clinical research associate (CRA) will know the patient's arm. The rest of the clinical team will be blinded. The self-questionnaires will be completed by the patients and then retrieved by the CRA who will enter the data into the eCRF, with no possible access to this data by the investigators.