Oncologic Considerations for Safe Gender-Affirming Mastectomy: Preoperative Imaging, Pathologic Evaluation, Counseling, and Long-Term Screening.

SUMMARY: There remain significant gaps in the evidence-based care of patients undergoing gender-affirming mastectomy with regard to implications for breast cancer development and screening. The current clinical evidence does not demonstrate an increased risk of breast cancer secondary to testosterone therapy in transgender patients. Gender-affirmation mastectomy techniques vary significantly with regard to the amount of residual breast tissue left behind, which has unknown implications for the incidence of postoperative breast cancer and need for screening. Subcutaneous mastectomy should aim to remove all gross breast parenchyma, although this is limited in certain techniques. Tissue specimens should also be routinely sent for pathologic analysis. Several cases of incidental breast cancer after subcutaneous mastectomy have been described. There is little evidence on the need for or types of postoperative cancer screening. Chest awareness is an important concept for patients that have undergone subcutaneous mastectomies, as clinical examination remains the most common reported method of postmastectomy malignancy detection. In patients with greater known retained breast tissue, such as those with circumareolar or pedicled techniques, consideration may be given to alternative imaging modalities, although the efficacy and cost-utility of these techniques must still be proven. Preoperative patient counseling on the risk of breast cancer after gender-affirming mastectomy in addition to the unknown implications of residual breast tissue and long-term androgen exposure is critical. Patient awareness and education play an important role in shared decision-making, as further research is needed to define standards of medical and oncologic care in this population.