Identifying Breast Cancer Risk in Patients Undergoing Gender-Affirming Chest Masculinization Surgery.

BACKGROUND AND

OBJECTIVES

Breast cancer risk among transgender and gender-diverse individuals undergoing gender-affirming chest masculinization ("top") surgery remains poorly defined. This study aimed to characterize breast cancer risk and management in this population.

METHODS

We conducted retrospective chart review of patients undergoing top surgery within an academic plastic surgery practice. Variables included family and reproductive history, genetic testing, International Breast Intervention Study (IBIS) scores, and final pathology. The primary outcome was elevated breast cancer risk, defined as IBIS ≥ 20% (high risk) or 15%-19% (intermediate). Significance was set at p < 0.05.

RESULTS

From April 2019 to December 2024, 284 individuals underwent top surgery. One-third reported a family history of breast cancer, and two of fifteen genetically tested patients carried pathogenic variants. IBIS scores were calculable in 79 patients, with 43% demonstrating intermediate or high risk (IBIS ≥ 15%). Seven patients were referred to breast surgical oncology and fifteen to genetics; four high-risk individuals elected risk-reducing mastectomy. One case of ductal carcinoma in situ was identified during risk-reducing mastectomy.

CONCLUSION

A subset of top surgery patients exhibit elevated familial, genetic, or IBIS-based breast cancer risk. Although incidental malignancy was rare, structured risk assessment and selective referral may improve screening and management in this population.