Contrary to some earlier studies, a new study funded in part by the National Institute of Child Health and Human Development (NICHD) found that men who undergo vasectomies are no more likely to develop prostate cancer than are men who do not.
"About one out of six American men over the age of 35 has had a vasectomy," said Duane Alexander, M.D., director of the NICHD. "The results of this study are reassuring since they indicate that these men are no more likely than other men to get prostate cancer."
The study, by Brian Cox, M.B., Ph.D. and colleagues, appears in the current issue of the Journal of the American Medical Association.
Prostate cancer is a leading form of cancer among men in the United States, second only to skin cancer. Although there is no biological explanation why vasectomy might be associated with an increased prostate cancer risk, a few studies conducted in the United States in the early 1990s reported a moderately increased risk of prostate cancer among men who underwent vasectomy. Several other studies have found no increased risk of prostate cancer among vasectomized men. However, despite this conflicting evidence, urologists have been concerned enough to increase prostate cancer screening of vasectomized men and to discourage vasectomies in men with a family history of prostate cancer.
The current study was conducted in New Zealand, a country considered ideal to examine any possible connection between vasectomy and prostate cancer because, according to the authors, it has both the highest vasectomy prevalence in the world and mandatory reporting of all new cancer cases. The researchers interviewed over 2,200 men. Almost half of the participants were newly diagnosed prostate cancer patients. The remaining participants were randomly selected from the adult male population and did not have prostate cancer. All participants were between the ages of 40 and 74 and had been married at some time. The men were interviewed by telephone and asked about previous illnesses, vasectomy, smoking and alcohol consumption, prostate specific antigen (PSA) testing, rectal examination, previous urological symptoms, family history of cancer, and socio-demographic characteristics.
Vasectomized men were no more likely to have prostate cancer than those who had not had a vasectomy. Furthermore, according to the study's authors, "Adjustment for social class, geographic region, religious affiliation, and a family history of prostate cancer, had little effect on the relative risk of prostate cancer from vasectomy." The study also found that there was no increased risk of prostate cancer among men who had vasectomies 25 or more years before they were interviewed.
"Since vasectomy is so common in New Zealand and all new prostate cancers there must be reported to its National Cancer Registry, that's where you would expect to find a link between the two, if one exists" said Steven Kaufman, M.D., of NICHD's Contraception and Reproductive Health Branch. "Also, although the study was more than large enough to detect an increased prostate cancer risk associated with vasectomy, none was found."
The NICHD is part of the National Institutes of Health, the biomedical research arm of the federal government. The Institute sponsors research on development, before and after birth; maternal, child, and family health; reproductive biology and population issues; and medical rehabilitation. NICHD publications, as well as information about the Institute, are available from the NICHD Web site, http://www.nichd.nih.gov, or from the NICHD Information Resource Center, 1-800-370-2943; e-mail NICHDInformationResourceCenter@mail.nih.gov.