Prostate Cancer Caution for Vasectomy Patients

An increased risk of aggressive prostate cancer has been found for men who undergo vasectomy

medwireNews: Vasectomy is associated with a small but significant risk of aggressive prostate cancer, suggest results from a large US population study.

In all, 25% of the 49,405 men in the Health Professionals Follow-up Study underwent vasectomy before or during 24 years of follow-up, say Lorelei Mucci, from Harvard School of Public Health in Boston, Massachusetts, USA, and co-authors.

Men who underwent the contraceptive procedure had a significantly increased risk of high-grade prostate cancer (Gleason score 8–10, relative risk=1.22) and lethal disease (relative risk=1.19), but not low-grade or localised disease, compared with men who had not undergone vasectomy.

And the risk of lethal cancer among men who underwent vasectomy was especially high among the 13,901 patients who regularly underwent prostate-specific Antigen (PSA) screening from 1994, with a relative risk of 1.56 compared with men who did not undergo the surgery.

“[A]lthough detection bias might explain an increased risk of screen-detected localized cancer among men with vasectomy, it cannot explain our findings of the higher risk of lethal or advanced disease among this group”, writes the team in the Journal of Clinical Oncology.

When the researchers examined the impact of sexually transmitted infections (STIs) in the population, they found a significant association between vasectomy and HPV infection, whereas prostate cancer risk has previously been shown to positively correlate with Trichomonas vaginalis and human herpesvirus type-8 infection.

“Thus, confounding by STIs does not seem to explain our findings, although we cannot rule out differences in an unidentified, unmeasured STI”, Lorelei Mucci et al write.

As the cumulative incidence of high-grade and lethal prostate cancer in the study population was just 1.5% and 1.6%, respectively, the researchers emphasise that the increased RRs reported “translate to small increases in absolute risk”.

Nevertheless, they conclude: “The decision to opt for a vasectomy remains a highly personal one in which the potential risks and benefits must be considered.

“The findings of this study warrant continued epidemiologic and experimental research into clarifying the association of vasectomy with prostate cancer.”

Reference

Siddiqui M, Wilson K, Epstein M, et al. Vasectomy and risk of aggressive prostate cancer: A 24-year year follow-up study. J Clin Oncol 2014; Published online before print 7 July. 10.1200/JCO.2013.54.8446

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