Transgender women keep their prostates even after gender-affirming surgery, but the extent to which they remain at risk of prostate cancer has been unclear.
Now a first-of-its-kind study led by UC San Francisco has estimated the risk at about 14 cases per 10,000 people.
The study drew on 22 years of data from the Veterans Affairs Health System. Although the sample size was necessarily small, it is still the largest study of its kind. The findings were published in the JAMA Network and are timed to the annual meeting of the American Urological Association.
“What we know about prostate cancer to date is almost exclusively based on cisgender men,” said the study’s lead author, Farnoosh Nik-Ahd, MD, a urology resident at UCSF. “This is an important first step in reshaping how clinicians think about prostate cancer in transgender women.”
Transgender people often face discrimination and disparities, and there has been a growing acknowledgement of the complexities involved in their health care.
The study found 155 confirmed transgender women with prostate cancer and stratified them according to whether they had used estrogen: 116 had never used estrogen, 17 had once used estrogen but stopped before they were diagnosed with prostate cancer, and 22 were actively on estrogen.
The median age of diagnosis was 61 years, and 88% of the patients were white. Just 8% were Black, suggesting possible disparities affecting this group. Black cisgender men are at heightened risk of being diagnosed with and dying from prostate cancer.
The authors found that prostate cancer occurs in transgender women more frequently than published accounts might suggest, with about 14 prostate cancer cases per 10,000 transgender women.
While the numbers were small, they suggest that transgender women taking estrogen may have had delayed diagnoses. The authors also said that lower rates of prostate cancer may have been due to less PSA screening, misinterpretation of PSA levels in patients on gender-affirming hormone therapies, stigma, and lack of awareness of prostate cancer risk and the effects of estrogen.
“We still have a lot of work to do to determine optimal prostate cancer screening for transgender women on estrogen and related treatments,” said co-senior author Matthew R. Cooperberg, MD, from the UCSF Department of Urology. “This study should be a reminder to clinicians and patients alike that, regardless of gender, people with prostates are at risk for prostate cancer.”