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

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.

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

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.

• 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

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

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.

Aesthetic breast appearance will be assessed before surgery, 6 at 12, 24 and 36 months post-surgery using standardized photographs. The assessment will be done by the surgeon and 2 independent external specialists who validated standardized photographs.

The following scoring points will be used:

• Excellent: Treated breast nearly identical to that before surgery
• Good: Treated breast slightly different to that before surgery
• Fair: Treated breast clearly different to that before surgery but not seriously distorted
• Poor: Treated breast seriously distorted compared to that before surgery

Flap volume at 12, 24 and 36 months is compared at that assessed at 6 months using MRI.

All MRI imaging will be assessed by and independent expert radiologist.

Impact of the flap transfer on the donor site will be assessed at surgery, 3, 6, 12, 24 and 36 months post-surgery using different parameters:

• Tissue necrosis (Yes/ No)
• Symmetry of the donor site area (comparing to the other side of the patient): Yes/ No

Pain score will be assessed at inclusion, discharge, 3, 6, 12, 24 and 36 month using a 10 Visual Analogue Scale [VAS, 0 (no pain) and 10 (worst possible pain)]

Quality of life and patients' satisfaction will be done through the BREAST-Q© questionnaire (module of reconstruction pre and post-surgery version) at inclusion and at 3, 6 and 12 months post operative. The quality of life is evaluated through 2 scales (psychological well-being and physical well-being: breast).

The satisfaction is evaluated with 1 scale : (satisfaction with breast).

• Surgeons' satisfaction regarding the use of MATTISSE® TEC and implantation procedure will be assessed on: Global satisfaction of the surgeon (5 points Likert scale)

• Ease of use
• Material ergonomics
• Ease of insertion
• Ease of fixing

Complete blood counts evolution will be assessed at inclusion, at discharge, and at 3 and 6 months post-implantation, by measuring Hemoglobin , leukocytes Lymphocyte rate Neutrophil rate and Thrombocytes

Units:

• Hemoglobin : g/L
• leukocytes :10⁹/L
• Lymphocyte rate : %
• Neutrophil rate : %
• Thrombocytes : 10⁹/L

C-reactive protein evolution will be assessed at inclusion, at discharge, and at 3 and 6 months post-implantation, by measuring CRP

Unit:

• CRP : nmoL/L

Total protein evolution will be assessed at inclusion, at discharge, and at 3 and 6 months post-implantation, by total protein assay

Unit:

Total protein: Normal or Not normal

Protein electrophoresis will be assessed at inclusion, at discharge, and at 3 and 6 months post-implantation, by performing protein electrophoresis.

Unit :

Protein electrophoresis: Normal or Not normal

Safety up to 36 months, will be assessed by measuring the complication rate after breast reconstruction using MATTISSE® TEC. Adverse events up to 36 months post operation will be recorded.