A non-randomized, mono-centric, prospective interventional study that will assess the efficacy of the loco-regional anesthesia PECS on the rate of chronic pain, 6 month after a patient will have either received a mastectomy or a mastectomy associated with axillary nodes dissection, and/or a reconstruction by prosthesis.

The aim of this study is to assess the care given to treat breast cancer while the patient receives a total mastectomy. It is done by evaluating the technique of anesthesia PECS used during this procedure so that the rate of chronic pain can be measured 6 month after the operation.

As well as total mastectomy, patients are also eligible for an axillary lymph node dissection (ALND) and a reconstruction of the breast by prosthesis as options.

Other objectives of the study include:

• Evaluating the effectiveness of the PECS anesthesia technique on the trajectory of acute post-operative pain and on chronic pain after 12 month of the surgery
• Evaluating the type and intensity of the pain
• Evaluating the quality of life
• Study the link between chronic pain and the trajectory of acute pain.

Inclusion Criteria:

• Patients with unilateral breast cancer
• Surgery must be a total mastectomy +/- axillary lymph node dissection and +/- reconstruction by prosthesis; unless first surgery was performed more than 5 years prior to total mastectomy without any residual pain
• Age ≥ 18 ans
• Non-opposition of patients

Exclusion Criteria:

• Reconstruction by other than prosthesis
• Previous breast surgery in the last year
• Hypersensitivity or allergy of anaesthetics
• Coagulopathy and local infections
• Pregnant or breastfeeding
• Patients under guardianship