Breast Cancer Incidence Among Patients Undergoing Chest Masculinization Surgery: A Scoping Review.

Background: The incidence of breast cancer (BC) cases among transgender males undergoing gender-affirming mastectomy (GAM) and the future BC risk for this population are not well established. This scoping review aimed to explore breast cancer incidence rates before and after GAM in the United States.

Methods: Following the Arskey and O'Malley framework, the search was conducted in Embase and PubMed using keywords "gender-affirming surgery" and "breast cancer." The initial search resulted in 405 articles, with 36 articles imported to Covidence for the screening and selection phase. The articles were limited to the United States alone and within the last 10 years.

Results: For final inclusion, 13 articles were identified (11 observational/retrospective cohort studies and 2 case studies). Across all the studies, 42 cases of atypia, 6 cases of ductal carcinoma in situ (DCIS), 1 case of Paget's disease, and 10 cases of invasive ductal carcinoma (IDC) were reported. Nine studies reviewed routine GAM surgical specimens (3869 cases), identifying 42 cases of atypia, 5 cases of DCIS, 1 case of Paget's disease, and 3 cases of IDC. Seven invasive carcinomas and one DCIS case were detected pre-GAM during screening and involved concurrent treatment from breast and plastic surgery teams.

Conclusions: Standardization and best-practice screening protocols, including breast imaging before GAM and pathology performed on specimens collected during GAM, are needed. A shared decision-making approach and clinical coordination, including breast and plastic surgery for patients who receive a breast cancer diagnosis while pursuing GAM, can help achieve oncologic and cosmetic goals.