(111) PROSTATE SPECIFIC ANTIGEN LEVELS IN TRANSGENDER WOMEN ARE LOWER THAN CISGENDER MEN

Abstract Introduction Little is known about incidence and screening patterns of prostate cancer, a hormone-sensitive malignancy, among transgender and nonbinary (TGNB) individuals assigned male at birth. Objective We sought to evaluate prostate specific antigen (PSA) levels in this population compared to cisgender men and to investigate effect of gender affirming hormonal therapy. Methods We identified TGNB HIV-negative individuals age > 40 from the California Collaborative Treatment Group 603 study aimed at evaluating pre-exposure prophylaxis. We then assembled a 3:1 comparison group of cisgender men age > 40 followed by Urology for a diagnosis other than elevated PSA. Data abstracted included age, sex assigned at birth, gender identity, race/ethnicity, PSA, testosterone and estradiol levels, and use of hormone therapy. Results We identified 31 TGNB individuals (median age 47 years, 77% on estrogen, 48% on antiandrogen) and 94 cisgender men (median age 57 years, 25% on testosterone; Table 1). PSA was significantly lower in TGNB individuals (0.23 vs 0.93 ng/ml, p < 0.01); this remained true after stratifying by age (Table 2). Age and testosterone were significant predictors of increased PSA (p < 0.01) in both cohorts. Estradiol levels significantly predicted decreased PSA (p < 0.01) in both cohorts, whereas antiandrogen and estrogen therapy were predictors of decreased PSA in TGNB individuals (p < 0.01, Table 3). On multivariate analysis, testosterone level remained the only significant predictor of PSA (p < 0.01). Conclusions PSA levels are lower among TGNB individuals assigned male at birth with a retained prostate. Testosterone level is a key determinant of PSA and use of gender affirming hormones is associated with lower PSA. Further studies are needed to establish prostate cancer screening cutoffs in this population. Disclosure No.