Breast-Sharing for Post-Mastectomy Reconstruction: Innovations in Aesthetic Symmetry, Surgical Safety, and Oncological Precision

<b>Background:</b> Breast-sharing is an innovative reconstructive approach that combines contralateral reduction mammaplasty with autologous breast reconstruction. This method repurposes tissue typically discarded during reduction mammaplasty to restore post-mastectomy symmetry while minimizing donor site morbidity and preserving oncological safety. <b>Case Presentation:</b> A 46-year-old woman with a significant asymmetry following a left mastectomy for invasive ductal carcinoma (pT2N0M0, ER+, PR+) and adjuvant radiotherapy was treated with a breast-sharing procedure. Preoperative imaging confirmed a robust third intercostal internal mammary artery perforator (IMAP) as the flap's vascular pedicle. The procedure included contralateral reduction mammaplasty, harvest of a glandulocutaneous IMAP flap, and its transposition to the mastectomy site. A subcutaneous tunnel facilitated flap transfer, achieving symmetry and natural contour. In the second case, a 50-year-old female with Stage II invasive ductal carcinoma and significant contralateral breast hypertrophy underwent a breast-sharing procedure utilizing autologous tissue from the contralateral breast, achieving improved symmetry, no disease recurrence, and high patient satisfaction during follow-up. <b>Results:</b> In the first case, postoperative monitoring identified venous congestion at the distal flap tip, successfully managed with medicinal leeches and minor debridement. Over 8 years of follow-up, the patient exhibited no recurrence or contralateral breast cancer. Esthetic outcomes were excellent, with natural projection and texture. In the second case, recovery was uneventful, with no cancer recurrence in the follow-up period of 1 year. <b>Conclusion:</b> Breast-sharing offers a transformative, safe, and effective reconstructive option for select post-mastectomy patients with contralateral hypertrophy, encouraging broader application of this innovative technique.