The goal of this retrospective observational trial is to compare two different devices, used in implant-based breast reconstruction, called acellular dermal matrices, which are a sort of collagen patch that integrates with the tissues of the patient and helps in contrasting the collateral effects of radiotherapy (capsular contracture, implant loss)

The main questions the study aims to answer are:

• is one of the two matrices better than the other? (better results with fewer complications)
• is there a group of patients who benefit more than another from the use of this type of devices?
• is there an adm which works better in one specific subgroup of patients? Participants have undergone mastectomy, radiotherapy and implant reconstruction with the aid of two different kinds of acellular dermal matrices.

Researchers will compare patients who receive the porcine-derived adm and the patients who receive bovine-derived adm to see if there is a difference in terms of capsular contracture reduction, aestethic result and complications.

Radiotherapy is highly effective in breast cancer treatment, yet it impairs satisfactory implant-based reconstruction, due to high rates of capsular contracture and implant loss. This said, a fervent investigtion exists upon solutions that can make implant-based reconstruction safer and aesthetically satisfying, including the use of acellular dermal matrices. We retrospectively want to analyze our ADM-assisted post-RT implant-based breast reconstructions comparing two different matrices (porcine and bovine), when autologous reconstruction was contraindicated, to assess eventual differences in efficacy and risk profile of the devices. We want to further stratify the population in 4 groups based on clinical presentation to assess if there was a group where ADMs proves to perform better (Group A - previous quadrantectomy, Group B - previous mastectomy and expander reconstruction, Group C - previous mastectomy and implant reconstruction, Group D - prior quadrantectomy followed by mastectomy and implant reconstruction).

Inclusion Criteria:

• at least 6 months follow up
• breast reconstruction with implant + acellular dermal matrix after mastectomy and radiotherapy

Exclusion Criteria:

• mastectomy flap <1 cm
• autoimmune disease
• prolonged use of corticosteroids

female patients undergoing breast reconstruction after mastectomy

The study focuses on female patients undergoing implant based reconstruction after radiotherapy assisted by the use of an acellular dermal matrix.