A Comprehensive Analysis of Breast Malignancies in Transgender Patients: A Systematic Review of Breast Cancer Incidence and Pathology with Provider Survey Results on Long-Term Screening

Abstract

Background:

Lifetime risk of breast cancer varies based on gender; however, there is no defined incidence among transgendered patients. We present the first systematic review of breast cancer incidence and pooled surgical specimen pathology of transpatients, along with results from a provider survey to highlight the need for long-term cancer screening.

Methods:

Three large-scale population studies (11,736 patients) were included to measure incidence. A PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) review was additionally performed to delineate variance in pathology and further characterize the spectrum of benign conditions in transpatients. Finally, WPATH providers were queried regarding practice patterns and recommendations for breast cancer screening in transpatients.

Results:

Systematic review of histopathological analysis of breast specimen of 1064 patients (2044 samples) was included. Majority of findings were benign (apocrine metaplasia, columnar changes, and usual ducal hyperplasia; n=345, 33%); 1.79% (n=19) had risk-elevating (e.g., atypical ductal hyperplasia [ADH]), pre-cancerous (e.g., ductal carcinoma in situ [DCIS]), or invasive cancer. Review of 11,736 transpatients yielded a pooled invasive breast cancer incidence of 0.27% (n=32), although there is notable discordance in reported rates. Finally, of 46 providers polled on implementing definitive screening guidelines, 98% advocated for standardized screening protocols for breast cancer.

Conclusion:

Our results underscore three issues: (1) transgender breast histopathology occurs on a spectrum of finding and should therefore be regularly evaluated and reported, (2) these patients have unique screening demands, given breast cancer incidence due to unforeseen effects of hormone therapy and top surgery practices, and (3) is the need and anticipation for breast cancer screening guidelines in transpatients among providers. Central databases, in conjunction with studies on the role of hormone therapy on tumor biology, are warranted to improve catchment to delineate incidence and prevalence.