Prostate cancer more likely in infertile men
■ Other risk factors for the most commonly diagnosed cancer among U.S. men include age, race and family history.
Infertility may increase men's risk for aggressive prostate cancer, according to a study published online March 22 in Cancer. But more research is needed before fertility problems can be used to help determine when early screening should be conducted, the study's authors said.
The study analyzed the risk of prostate cancer in 22,562 men who were evaluated for infertility between 1967 and 1998 in 15 California infertility centers. The incidence of cancer in this group was compared with incidence in a similar group of men in the general population.
Researchers found that infertile men were 2.6 times more likely to be diagnosed with aggressive prostate cancer than those who were fertile, when controlling for age, and duration and location of infertility treatment. The study found that different infertility centers had different patterns of prostate cancer screening (link).
Infertile men were also 1.6 times more likely to be diagnosed with slow-growing prostate cancer.
Reasons for the link between reproductive problems and high-grade prostate cancer are not clear, said study lead author Thomas Walsh, MD, a Seattle urologist. But he said researchers believe one possibility could be faulty DNA repair among infertile men, which can increase sensitivity to carcinogens and raise cancer risk. About 7.3 million men and women are infertile in the U.S., according to the American Society for Reproductive Medicine.
The study findings "generate new questions about [whether male infertility] could be somehow translated into a tool to help identify young men at greatest risk for the most aggressive [prostate] cancer," said Dr. Walsh, assistant professor of urology and director of male reproductive and sexual medicine at the University of Washington School of Medicine in Seattle.
He said if the findings are confirmed by additional research, physicians might consider early cancer screening for male patients with fertility problems.
"We know we're at risk for identifying too many [cases of prostate] cancer that may not have an aggressive course," Dr. Walsh said, referring to overdiagnosis due largely to the prostate-specific antigen test.
A leading cause of cancer
Prostate cancer is the most commonly diagnosed cancer among U.S. men and remains the second leading cause of cancer death in males, after lung cancer, according to the American Cancer Society. In 2009, about 192,000 men were diagnosed with prostate cancer, with 27,000 expected to die from the disease.
Dr. Walsh's study identified 168 cases of prostate cancer. Cancer developed in 1.2% of the infertile men compared with 0.4% of fertile men.
Aggressive tumors, which were defined as those diagnosed with a Gleason score of 8 to 10, were identified in 19 infertile men. Sixteen cases were found in fertile men.
Otis Brawley, MD, chief medical officer of the American Cancer Society, said the findings were intriguing. But, he said, "there are bigger risk factors than infertility for prostate cancer."
Those risk factors include being older, being black and having a father or brother diagnosed with the disease before age 65. The ACS recommends that screening discussions begin for these at-risk men at age 45. For men at average risk for the disease, the society suggests screening discussions start at age 50.
The American Urological Assn. advises that all men with at least a 10-year life expectancy be screened starting at age 40.