MON-198 Feminizing Regimen Requirements in Transgender Females Following Orchiectomy

Introduction: Transgender females (TF) may undergo orchiectomy as part of their treatment. However, there is no clear recommendation in hormonal transition between pre- and post-orchiectomy (1, 2). Methods: All TF with orchiectomy in the transgender registry at Boston Medical Center (BMC) were reviewed. Feminizing regimens prior to and after orchiectomy were evaluated. The type, form and dose of hormones along with serum estradiol, testosterone, FSH and LH were assessed. Results: 124 TF consented to be included in the transgender registry at BMC. 23 of 124 (18%) TF had orchiectomy. 10/23 TF had the hormonal regimen available pre-orchiectomy and 6 months or more post-orchiectomy. All 10 TF used oral 17-beta estradiol. 6 TF were prescribed less estradiol relative to their pre-orchiectomy regimen, 3 were prescribed the same estradiol dose and 1 was prescribed a higher estradiol dose. An average of adjusted post-orchiectomy estradiol doses was 78% (range 50%-150%) of pre-orchiectomy dose. Among 10 TF with an available hormone regimen pre-and post-orchiectomy, 5 (50%) had serum estradiol at goal (100-200 pg/mL) and FSH in a pre-menopausal cis-female range. Among these 5 TF, the average of the adjusted post-orchiectomy estradiol dose was 96% (range 50%-150%) of the pre-orchiectomy dose. Estradiol doses up to 6 months or more following orchiectomy were available in 17 TF. 15 used oral 17-beta estradiol (average dose of 3.1mg/day with the range of 1-8 mg), 1 used oral conjugated estradiol and 1 used 17-beta estradiol gel. 7/17 had estradiol level at goal (100-200 pg/mL) and FSH in the pre-menopausal female range. All 7 TF used oral 17-beta estradiol. An average of post-orchiectomy estradiol doses was 2.85 mg/day (range 1-5 mg). Conclusion: Most TF who underwent orchiectomy had a lower estradiol dose (approximately 75% of the pre-orchiectomy regimen). However, to achieve the estradiol level at goal and maintain FSH in the the pre-menopausal female range, trans women required estradiol doses closer to the pre-orchiectomy regimen. The dose range of oral 17-beta estradiol in post-orchiectomy TF is 1-5 mg, similar to recommendations for TF who have not undergone orchiectomy (2-6 mg) (1). References: (1) Hembree et al., J Clin Endocrinol Metab. 2017 Nov 1;102(11):3869–903. (2) Coleman et al., International Journal of Transgenderism. 2012;13:4, 165-232.