Multicenter cohort study of gender-diverse patients with breast cancer

Limited data exist on breast cancer in transgender, nonbinary, and/or gender-diverse (TGD) individuals. A cohort study of patients treated from 1990 to 2023 in 22 US academic medical centers investigated patient demographic and tumor clinicopathologic variables, clinically relevant risk factors, method of breast cancer detection, treatment characteristics, locoregional outcomes, and 5-year breast cancer-specific survival (BCSS) in TGD breast cancer patients. Included participants were TGD individuals aged 18 years or older with stage 0 to IC breast cancer. A comparative breast cancer cohort was selected from the 2016 to 2021 SEER breast cancer dataset (n=480 915). A total of 112 TGD persons (median age at diagnosis 42.5 years; IQR 36.5-51.0; 92.9% were assigned female at birth) with breast cancer and one with bilateral disease were included in the analysis. Forty-three patients (38.4%) used gender-affirming hormone therapy before diagnosis. Among the entire cohort, 58 patients (51.8%) detected their own breast cancer, 68 (60.7%) had a familial breast cancer history, and 16 (14.3%) had a pathogenic germline variant. The TGD cohort, compared with the SEER dataset, was younger at diagnosis, had a higher proportion of persons assigned male at birth, more often ahd progesterone receptor-positive disease, and presented with earlier-stage disease. With a median follow-up of 38 months, the estimated 5-year BCSS was 96.2%. The authors conclude that, although short-term BCSS was favorable, the cohort’s young age at diagnosis underscores the value of identifying individuals at elevated risk who may benefit from risk-reducing strategies and earliers breast cancer screening.