Vasectomy Associated With Modestly Increased Risk of High-Grade and Lethal Prostate Cancer
An analysis of data from the Health Professionals Follow-Up Study reported by Siddiqui et al in the Journal of Clinical Oncology indicates that vasectomy is associated with a modestly but significantly increased risk of high-grade and lethal prostate cancer.
The study involved data from 49,405 U.S. men in the Health Professionals Follow-up Study aged 40 to 75 years at baseline in 1986. During the 24-year follow-up through 2010, 6,023 patients were diagnosed with prostate cancer, including 811 lethal cases, and 12,321 men had vasectomies.
Increased Risks
On multivariate analysis adjusting for age, race, height, body mass index, vigorous physical activity, smoking, type 2 diabetes, family history of prostate cancer, history of prostate-specific antigen (PSA) testing, multivitamin use, and intakes of supplemental vitamin E and alcohol, vasectomy was associated with a small but significantly increased risk of prostate cancer overall (relative risk [RR] = 1.10, 95% confidence interval [CI] = 1.04–1.17) and increased risk for high-grade (RR = 1.22, 95% CI = 1.03–1.45, for Gleason score 8–10), advanced (RR = 1.20, 95% CI = 1.03–1.40), and lethal disease (RR = 1.19, 95% CI = 1.00–1.43). Vasectomy was not associated with increased risk of low-grade or localized disease.
PSA-Screened Subgroup
Among the subgroup of men receiving regular PSA screening, the association of vasectomy with lethal prostate cancer was stronger (RR = 1.56, 95% CI =1.03–2.36) and there was a significant increase in risk of grade 7 cancer (RR =1.22, 95% CI = 1.02–1.47) and a nonsignificant increase in risk for high-grade cancer (RR =1.28, 95% CI = 0.91–1.81). Vasectomy was not associated with increased risk of overall, low-grade, or localized cancer.
The associations between vasectomy and prostate cancer did not differ according to time since vasectomy or age at vasectomy and additional analyses indicate that the associations were not affected by differences in sex hormone levels, sexually transmitted infections, or cancer treatment.
The investigators concluded, “Our data support the hypothesis that vasectomy is associated with a modest increased incidence of lethal prostate cancer. The results do not appear to be due to detection bias, and confounding by infections or cancer treatment is unlikely.”
Lorelei A. Mucci, ScD, of Harvard School of Public Health, is the corresponding author for the Journal of Clinical Oncology article.
The study was supported by grants from the National Cancer Institute. The study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
