Oncological Safety of Prepectoral Implant-Based Breast Reconstruction After Conservative Mastectomy: Insights from 842 Consecutive Breast Cancer Patients.

Background: Implant-based breast reconstruction (IBBR) following conservative mastectomy is the most common approach for women undergoing breast cancer surgery. The aim of this study was to compare the oncological outcomes of conservative mastectomy combined with prepectoral IBBR to the subpectoral technique.

Methods: The clinical and demographic data of consecutive breast cancer patients who underwent conservative mastectomy with either prepectoral or subpectoral IBBR between January 2018 and December 2023 were retrospectively analyzed. The primary outcome was the impact of conservative mastectomy with prepectoral IBBR on local recurrence-free survival (LRFS). Secondary outcomes included distant disease-free survival (DDFS) and overall survival (OS).

Results: A total of 842 women (with a median age of 46 years and a range of 20-79 years) were included in the study. Of these, 648 patients (77.0%) underwent prepectoral IBBR, while 194 (23.0%) received subpectoral IBBR. The median follow-up was 32 months (3-74). Locoregional relapse occurred in 19 patients (2.9%) in the prepectoral group and 14 (7.2%) in the subpectoral group. Distant metastases were observed in 21 (3.2%) patients in the prepectoral group and 11 (5.7%) in the subpectoral group. Deaths were reported in eight patients (1.2%) in the prepectoral group and five (2.6%) in the subpectoral group. There were no statistically significant differences between the two groups in terms of the LRFS, DDFS, and OS (p = 0.676; p = 0.994; p = 0.940, respectively).

Conclusions: Our study indicates that conservative mastectomy combined with prepectoral IBBR produces similar results to those of the subpectoral approach, with no significant differences in LRFS, DDFS, and OS.