First-in-human, Study of MATTISSE® Tissue Engineering Chamber in Adult Female Patients Undergoing Breast Reconstruction After Mastectomy for Cancer

Safety objective: To assess the 6 months surgical complications rate of MATTISSE® TEC implant-based immediate breast reconstruction. Adverse events will be recorded.

Minor complications include: * Superficial skin necrosis that requires only debridement * Flap necrosis * Subcutaneous hematoma: any hematoma requiring surgical exploration * Inflammatory reaction * Seroma: defined as that which requires echo-guided puncture at least once after drain removal. * Pain * Delayed wound healing/wound dehiscence: any wound healing problems, detected during clinical examination and not requiring an intervention * Implant malposition * Superficial Venous Thrombosis (Mondor disease) * Capsular contracture Major complications include: * All complications that lead to MATTISSE® TEC removal: * Skin necrosis leading to implant exposure * Infection * Implant malposition leading to implant exposure * Device failure or defect: when the implant breaks or collapses, e.g., the base separates from the shell, failure at the time of surgical placement (fracture of the TEC before placement) * Granuloma.

Performance objective: To assess the efficacy at 6 months post-operation of breast reconstruction using MATTISSE® breast implants in patients undergoing breast reconstitution after total mastectomy surgery for cancer.

Success is defined as: * Tissue expansion (flap enlargement) from implantation up to 6 months post operation --\> A 50% increase in the expanded size at 6 months compared to initial size flap is considered as a success. Indeed, the optimal growth of the flap is expected at 6 months, * Tissue expansion will be assessed using MRI at discharge (after surgery) and 6 months post operative. The volume of flap at 6 months will be compared to the flap size initially implanted. All MRI imaging will be assessed by and independent expert radiologist. Failure is defined as: * less than 50% increase in the expanded size at 6 months compared to initial size flap MATTISSE® Prothesis removal

Evolution of tissue expansion (flap enlargement) from implantation up to 36 months post operation.

Tissue expansion will be assessed using MRI at discharge (after surgery), 12, 24 and 36 months post operative. All MRI imaging will be assessed by and independent expert radiologist.

Evolution of breast softness from inclusion to 36 months

* The breast softness will be assessed by investigator surgeon and patients themselves at discharge (after surgery), 3, 6 ,12, 24 and 36 months as: * Stage 1: Breast is soft * Stage 2: Breast is hard * Stage 3: Breast is hard with distortion * Stage 4: Breast is hard, painful with distortion

Evolution of MATTISSE® TEC resorption until 36 months follow up: the resorption is active between 6 and 12 months after surgery.

MATTISSE® TEC resorption will be observed quantitatively on MRI achieved at 3, 6, 12, 24 and 36 months associated with the touch of the surgeon and patients feeling. The TEC resorption will be classified as: * Absent: no resorption at all. * Small resorption: TEC has been reabsorbed a little bit compared to the initial * Great resorption: TEC has been absorbed a lot but not totally * Total: Shell and base are no longer visible on the MRI and not felt by the surgeon

The volume of the reconstructed breast compared to the volume of the contralateral one at 12, 24 and 36 months

At 12, 24 and 36 months, we will assess during physical examinations, the volume of the reconstructed breast and the volume of the contralateral one.