Current screening standards could miss early-stage prostate cancer in transgender women, a new study warns.
Prostate cancer tests look for prostate-specific antigen (PSA), a protein produced by the small gland. Blood levels of PSA tend to be elevated in people with prostate cancer.
But the estrogen that many transgender women take as part of their gender-affirming care "drastically lowers PSA levels, which could mean the threshold we are using as 'normal' is too high to detect early-stage cancer in these patients,"said senior researcher Dr. Stephen Freedland, chair of prostate cancer at Cedars-Sinai Medical Center in Los Angeles.
Current guidelines hold that PSA levels above 4 nanograms per milliliter of blood suggest cancer could be present. At those levels, a prostate biopsy can be ordered to check for cancer.
For this study, published June 26 in the Journal of the American Medical Association, researchers analyzed the Veterans Health Administration medical records of 210 transgender women without prostate cancer who were taking estrogen.
"We found that the median PSA value, the midpoint in the range of participants, was 0.02 ng/mL, which is fiftyfold lower than PSA values reported in similar-aged cisgender men,"said lead researcher Dr. Farnoosh Nik-Ahd, a urology resident at the University of California, San Francisco.
This means transgender women taking estrogen who develop prostate cancer aren't likely to see their PSA increase enough to trigger a biopsy -- at least, not until the cancer is at a later stage, Nik-Ahd explained.
At that point, the prostate cancer will be more life-threatening and difficult to treat.
Additional research is needed to pinpoint specific PSA levels that indicate a transgender woman on estrogen is at higher risk for developing prostate cancer, Freedland said.
Freedland noted that the study is not a call for all transgender women to be screened, however.
"We know that PSA screening reduces the risk that cisgender men ages 55 to 69 will die of prostate cancer, but we don't know that it does the same thing for transgender women taking estrogen,"Freedland said in a Cedars SInai news release. "However, because some of these women are being screened, we want to raise awareness that their typical PSA levels are different."
In the meantime, Freedland advises transgender women taking estrogen to consult with their doctors.
"Don't forget that you have a prostate and that prostates can become cancerous,"Freedland said. "The best way we know to find those cancers early and reduce the risk of death is a PSA test. And if you choose to do that, keep in mind that the test values are not calibrated for you."
"Bring your results -- and possibly this study -- to your urologist so that your results will be interpreted by someone who understands what to do with that information,"Freedland said.
More information
The Cleveland Clinic has more about transgender women and prostate cancer.
SOURCE: Cedars-Sinai Medical Center, news release, June 26, 2024