Incidence of High Risk and Malignant Pathological Findings in Transgender and Gender Diverse Individuals Undergoing Gender-Affirming Mastectomy.

[BACKGROUND] Concrete, data-driven guidelines for breast cancer screening among the transgender and gender diverse (TGD) population is lacking. The present study evaluates possible associations of gender-affirming hormone therapy (GAHT) on incidental breast pathology findings in trans-masculine patients to inform decision making about breast cancer screening.

[PATIENTS AND METHODS] This was a retrospective cohort study of patients who had gender-affirming mastectomy or breast reduction at a single center from July 2019 to February 2024. A total of 865 patients met the inclusion criteria. Gender-affirming testosterone therapy and length of exposure were evaluated to seek differences in post-operative pathology findings.

[RESULTS] The median age at the time of surgery was 27 years [interquartile range (IQR) 21-30]. Most participants identified as female to male (658, 75.6%). A significant portion of the participants (688, 79.2%) were undergoing testosterone therapy at the time of surgery, with the median duration of testosterone use prior to surgery being 14 months (IQR 4-29). High risk or malignant findings were noted in pathology results for 12 of 1730 breasts (0.7%). Ordered logistic regression found that duration of testosterone therapy was not associated with increasing severity of incidental breast pathology. Additionally, patients under 25 years of age were 70% less likely to have any incidental finding on pathological evaluation than older patients [odds ratio (OR) 0.3, p < 0.01, confidence interval (CI) 0.18-0.50].

[CONCLUSIONS] The present study found that patients undergoing GAHT should not be screened for breast cancer with increased frequency compared with cis-gender women. Additionally, it may be appropriate for trans women under the age of 25 with normal breast cancer risk to forego pathological breast tissue examination.