This issue is as old as the field of Oncology. Studies have gone back and forth on this issue. Weighing in now is a group from Oxford. As part of a larger study entitled EPIC (the European Prospective Investigation Into Cancer and Nutrition) Stenger and colleagues looked at a cohort of over 84000 men followed for over fifteen years. Click here for the abstract. If you wish the full article request it from Dr. Stark, using the form on the right. Men were aged 35 to 79, so presumably had they enlarged the group at the high end, many more cases would have been discovered. Nonetheless, during this period 4377 men were diagnosed with prostate cancer, among whom 14.6% had undergone vasectomy. Overall there was no increased risk of prostate cancer in this group. However, among men who had undergone vasectomy at the earliest age (arbitrarily set at a median age of 38) there was a slightly increased risk (HR=1.18). However, there was also a slight tendency for men with vasectomy who got prostate cancer to have a lower-grade disease than average. Overall there was no increased mortality from prostate cancer among the men with vasectomy.
Dr. Stark comments, “This issue has been batted about for a long time. This study is helpful because it is so large. It makes no sense biologically for younger men to get prostate cancer after vasectomy and yet have a lower grade of disease, so I suspect that there really is no link. In any event, the hazard ratio, even for the youngest cohort, is only slightly higher than unity, so any effect if present is tiny.”