Study Links Vasectomy to Aggressive Prostate Cancer
But the finding doesn't prove cause-and-effect; urologists call for more research
By Robert Preidt
THURSDAY, July 10, 2014 (HealthDay News) -- Men who have a vasectomy may be at increased risk for aggressive prostate cancer, a new study suggests.
But the risk is comparatively small, the researchers acknowledged. And several urologists not involved with the study said more research is needed to determine if the study findings are truly accurate.
For the study, Harvard researchers analyzed data from more than 49,400 American men who were followed for 24 years, starting in 1986. During that time, 6,023 cases of prostate cancer were diagnosed among the men, including 811 fatal cases.
The 25 percent of the men in the study who'd had a vasectomy had a 10 percent increased risk of developing prostate cancer, according to the study published online July 7 in the Journal of Clinical Oncology.
Vasectomy was not linked with an increased risk of low-grade prostate cancer. But it was associated with a 20 percent higher risk of advanced prostate cancer and a 19 percent greater risk of fatal prostate cancer, respectively, the study authors said.
Even among men who had regular prostate-specific antigen (PSA) screening tests for prostate cancer, those who had a vasectomy were 56 percent more likely to develop fatal prostate cancer. This link was strongest among men who had a vasectomy at a younger age.
However, the absolute risk of developing deadly prostate cancer was small, the study authors noted -- 16 of every 1,000 men.
"This study follows our initial publication on vasectomy and prostate cancer in 1993, with 19 additional years of follow-up and tenfold greater number of cases. The results support the hypothesis that vasectomy is associated with an increased risk of advanced or lethal prostate cancer," study co-author Lorelei Mucci, associate professor of epidemiology at the Harvard School of Public Health, said in a university news release.
About 15 percent of men in the United States have a vasectomy. Prostate cancer is the second leading cause of death among American men, although most men diagnosed with the disease don't die from it.
"The decision to opt for a vasectomy as a form of birth control is a highly personal one and a man should discuss the risks and benefits with his physician," study co-author Kathryn Wilson, a research associate in the department of epidemiology, said in the university news release.
Dr. Louis Kavoussi is chairman of urology at North Shore-LIJ Health System in New Hyde Park, N.Y. He said: "I would be cautious about applying these findings to clinical practice right now. This is not like cigarette smoking causing a large number of people to develop lung cancer. This is a small increase in the risk of prostate cancer. I think further studies really need to be mandated in a better controlled fashion.