In a new study, men who underwent vasectomy did not have an increased risk of prostate cancer, nor were they more likely to die from prostate cancer than men who did not receive this procedure. According to the researchers, this is the largest prospective study of vasectomy and fatal prostate cancer to date. They conclude the data provide some reassurance to men who have had a vasectomy or are considering the procedure (Journal of Clinical Oncology, DOI: 10.1200/JCO.2015.66.2361).

Researchers analyzed the association between vasectomy and death from prostate cancer among more than 363,000 men age 40 and older in the Cancer Prevention Study II (CPS-II), including more than 42,000 who were determined to have undergone vasectomy. About 7,400 of the men in the study died of prostate cancer over a 30-year period. In addition, a subgroup of approximately 66,000 men from CPS-II also were tracked for new diagnoses of prostate cancer, and over 9,100 of these men were diagnosed with the disease during the study period. Analyses were adjusted for factors including age, race, education level, body mass index, and smoking status. No link was found between vasectomy and either risk of prostate cancer overall or risk of fatal prostate cancer. The study did report a slight increase in risk of nonaggressive prostate cancer during the past 5 years of the study period, although the authors note this may have been a chance finding.

A previous study on the association between vasectomy and prostate cancer found that vasectomy was associated with about 10 percent higher overall risk of prostate cancer and about 20 percent higher risk of fatal prostate cancer. Researchers noted the previous study included just over 800 prostate cancer deaths, while today's study included more than 7,000, and that differing results could have been a result of chance.

"While a previous study suggested an association, our results show no connection between vasectomies and overall risk of prostate cancer, or of dying from prostate cancer, and should provide some reassurance to men considering vasectomy," said the lead author of the new study, Eric J. Jacobs, PhD, a cancer epidemiologist at the American Cancer Society. "Men concerned about developing a fatal prostate cancer should focus on maintaining a healthy weight and, if they smoke, quitting smoking. Both obesity and smoking have consistently been linked with higher risk of fatal prostate cancer as well as with risk of many other diseases."