Contralateral prophylactic mastectomy in a rural population: A single-institution experience.

Background: The incidence of contralateral prophylactic mastectomy (CPM) for unilateral breast cancer (UBC) has continued to increase, despite an absent survival benefit except in populations at highest risk for developing contralateral breast cancer (CBC). CPM rates may be higher in rural populations but causes remain unclear. A study performed at our institution previously found that 21.8 % of patients with UBC underwent CPM from 2000 to 2009. This study aimed to evaluate the CPM trend at a single institution serving a rural population and identify the CPM rate in average-risk patients. Methods: Retrospective review of patients who underwent mastectomies for UBC at our institution from 2017 to 2021 was performed. Analysis utilized frequencies and percentages, descriptive statistics, chi-square, and independent sample Results: A total of 438 patients were included, of whom 64.4 % underwent bilateral mastectomy for UBC (CPM). Patients who underwent CPM were significantly younger, underwent genetic testing, had germline pathogenic variants, had a family history of breast cancer, had smaller tumors, underwent reconstruction, and had more wound infections. Of CPM patients, 50.4 % had no identifiable factors for increased risk of developing CBC. Conclusions: The rate of CPM in a rural population at a single institution increased from 21.8 % to 64.4 % over two decades, with an average-risk CPM rate of 50.4 %. Those that undergo CPM are more likely to undergo reconstruction and have more wound infections. Identifying characteristics of patients undergoing CPM in a rural population and the increased associated risks allows for a better understanding of this trend to guide conversations with patients. Key message: This study demonstrates that the rate of contralateral prophylactic mastectomy for unilateral breast cancers performed at a single institution serving a largely rural population has nearly tripled over the last two decades, with half of these patients having no factors that increase the risk for developing contralateral breast cancers. Contralateral prophylactic mastectomy was significantly associated with smaller tumors, younger age, genetic testing, germline pathogenic variants, family history of breast cancer, breast reconstruction, and increased wound infections.