In the largest and most comprehensive study of its kind, researchers from Harvard School of Public Health (HSPH), found that vasectomy is associated with a small increased risk of prostate cancer, and a larger increased risk for advanced or lethal prostate cancer. The results of the study were reported by Medical News Today.
Prostate cancer is the second leading cause of death among American men. Around 15 percent of American men have had a vasectomy.
The New York Times wrote that earlier studies hinted at a link between vasectomies and prostate cancer. Yet many experts dismissed this idea saying that men who have vasectomies may receive more medical care and therefore may be more likely to be diagnosed.
Published in the Journal of Clinical Oncology, the new study sought to account for that possibility and other variables.
“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 HSPH told the Harvard Gazette.
Researchers analyzed data from the Health Professionals Follow-Up Study, which observed 49,405 American men for up to 24 years between 1986 and 2010. During that time, 6,023 cases of prostate cancer were diagnosed, including 811 lethal cases. One in four men reported having a vasectomy.
In this study, 16 out of every 1,000 men developed lethal prostate cancer over 24 years of follow-up which is equivalent to roughly 20 percent of raised risk of lethal prostate cancer. The incidence was 19 in 1,000 cases, compared with 16 in 1,000, over the 24-year period.
The team found a 10 percent overall increased risk of prostate cancer in those men who had a vasectomy.
No association between a vasectomy and low-grade cancers was found.
Among men who received regular PSA screening, the relative increase in risk of lethal prostate cancer was 56 percent. The effect appeared to be stronger among men who had a vasectomy at a younger age.
The reason for the increase is unclear, but some experts speculate that immunological changes, abnormal cell growth or hormonal imbalances following a vasectomy may also affect prostate cancer risk.
In this study, researchers had access to diverse information and ruled out potential biases, including the possibilities that men who have vasectomies seek more medical care in general or have higher rates of PSA screening, The association may also be driven by differences in sex hormone levels, sexually transmitted infections or cancer treatment.
Mucci emphasized that a vasectomy does not increase the risk for prostate cancer over all. “We’re really seeing the association only for advanced state and lethal cancers,” she told the New York Times.
Several urologists have said that much more research is necessary to determine the accuracy of the findings.
Sources:
Bakalar , Nicholas . "A Vasectomy May Increase Prostate Cancer Risk." Well A Vasectomy May Increase Prostate Cancer Risk Comments. N.p., n.d. Web. 4 Aug. 2014.
http://well.blogs.nytimes.com/2014/07/17/a-vasectomy-may-increase-prostate-cancer-risk/?_php=true&_type=blogs&_r=0
Datz, Todd. "Vasectomy may increase risk of aggressive prostate cancer." Harvard Gazette. N.p., n.d. Web. 4 Aug. 2014.
http://news.harvard.edu/gazette/story/2014/07/vasectomy-may-increase-risk-of-aggressive-prostate-cancer
Paddock PhD, Catharine. "Vasectomy linked with aggressive prostate cancer risk." Medical News Today. MediLexicon International, n.d. Web. 4 Aug. 2014.
http://www.medicalnewstoday.com/articles/279410.php
Preidt, Robert. "Study Links Vasectomy to Aggressive Prostate Cancer." Consumer HealthDay. N.p., n.d. Web. 4 Aug. 2014.
http://consumer.healthday.com/men-s-health-information-24/men-s-problems-health-news-469/study-links-vasectomy-to-aggressive-prostate-cancer-689653.html
Reviewed August 26, 2014
by Michele Blacksberg RN
Edited by Jody Smith