Infertile men may have an increased risk of developing high-grade prostate cancer, according to a study led by Dr. Thomas Walsh, UW Medicine assistant professor of urology, and colleagues from the University of California, San Francisco, and Kaiser Permanente of northern California.
The study findings—published online this month in Cancer — suggest that because infertility may be an identifiable risk factor for prostate cancer, early screening may be warranted in some infertile men. Cancer is a peer-reviewed journal of the American Cancer Society.
Walsh said researchers have not yet found an ideal way to identify men who will develop clinically aggressive prostate cancer, and that this study is a starting point. “We examine whether reproductive failure early in a man’s life should be a red flag for what comes later in life,” he said.
The unexpected findings gave him and colleagues a lot of pause, said Walsh. “I’m not trying to raise any alarms,” he said. “But the greatest opportunity to move forward in science is when we find unique and unexpected findings.”
Researchers identified 168 cases of prostate cancer that developed in a group of 22,562 men evaluated for infertility in California. The figure was not significantly different from the expected rate (185 cases). But among this group, men who were evaluated and found to be infertile were 2.6 times more likely to be diagnosed with high-grade prostate cancer than men who were evaluated but not found to be infertile.
“What puts men at risk for infertility is difficult to study,” said Walsh. There are no state registries, it’s not a reportable disease and it is difficult to identify because it’s not often covered by insurance, he said. But the findings warrant more research on possible common biological pathways underlying infertility and prostate cancer.
One question Walsh said he would like to explore is whether or not a hormonal link exists between infertility and prostate cancer. Researchers at Baylor College of Medicine in Houston are looking at possible genetic links.
If the results from this study are confirmed in other data sets, Walsh said it may be appropriate for infertile men to undergo regular physical exams and PSA (prostate-specific antigen) testing at an earlier age, instead of the typical yearly recommendation for men over age 50. “The findings prompt me to tell my patients of these risks,” he said. “It should also prompt other physicians to do the same, and to be very attune to risks of screening for prostate cancer.”
Walsh said the next big step in his work will be to identify a group of men who have equal access to infertility diagnosis and treatment, regardless of socioeconomic, racial or ethnic factors. “We might then begin to have a better understanding of the risk factors for infertility.”