Breast Cancer Occurrence After Risk-reducing Mastectomies in 274 Cases: A Single Center With More Than 42 Years of Experience.

Introduction: Carriers of genetic mutations with a high risk of developing breast cancer have a lifetime risk of this cancer of up to 70%. To reduce the risk, patients have the option of a risk-reducing mastectomy. There is limited data with only short follow-ups on its safety. The aim of the study was to determine the long-term incidence of breast cancer in healthy patients with no previous surgery, who underwent bilateral risk-reducing mastectomies (BRRMs).

Methods: We retrospectively reviewed 274 patients from our facility with no previous breast surgery, who underwent BRRM from 1981 to 2022, due to genetic mutations, a strong family history, or having very dense mammary glands. We approached these patients during their checkups, by phone call or email, and we asked them if they had developed breast cancer after their procedures. We recorded the patients' demographic factors, their genetic mutation types, and the mastectomy methods carried out.

Results: A total of 274 patients had BRRMs with a mean follow-up after 76 months; 208 patients had undergone nipple-sparing mastectomies, 39 patients had undergone skin-sparing mastectomies, and 27 patients had skin-reducing mastectomies. One BRCA1+ patient developed breast cancer 21 months after undergoing the risk-reducing skin-sparing mastectomy procedure. None of the patients died of breast cancer.

Conclusions: The incidence of breast cancer in the monitored patients is comparable to the results of the other related studies. The study result confirms that risk-reducing mastectomies reduce the risk of breast cancer in high-risk populations, regardless of the type of mastectomy performed.