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Evidence summaries

The Association Between Vasectomy and Prostate Cancer

There appears to be no association between vasectomy and high-grade, advanced-stage, or fatal prostate cancer. A weak association of vasectomy and any prostate cancer cannot be excluded, but the association is probably caused by several sources of bias and disappears with more robust study design. Level of evidence: "B"

The level of evidence is upgraded by consistent findings in better quality studies, although no randomized studies are included.

A systematic review 1 included fifty-three studies (16 cohort studies including 2563519 participants, 33 case-control studies including 44536 participants, and 4 cross-sectional studies including 12098221 participants). Of these, 7 cohort studies (44%), 26 case-control studies (79%), and all 4 cross-sectional studies were deemed to have a moderate to high risk of bias. Among studies deemed to have a low risk of bias, a weak association was found among cohort studies (7 studies; adjusted rate ratio, 1.05; 95% CI, 1.02 to 1.09; P < .001) and a similar but nonsignificant association was found among case-control studies (6 studies; adjusted odds ratio, 1.06; 95% CI, 0.88 to1.29; P = .54). Effect estimates were further from the null when studies with a moderate to high risk of bias were included. Associations between vasectomy and high-grade prostate cancer (6 studies; adjusted rate ratio, 1.03; 95% CI 0.89 to1.21; P = .67), advanced prostate cancer (6 studies; adjusted rate ratio, 1.08; 95% CI, 0.98 to 1.20; P = .11), and fatal prostate cancer (5 studies; adjusted rate ratio, 1.02; 95% CI, 0.92 to 1.14; P = .68;) were not significant (all cohort studies). Based on these data, a 0.6% (95% CI 0.3% to 1.2%) absolute increase in lifetime risk of prostate cancer associated with vasectomy and a population-attributable fraction of 0.5% (95% CI 0.2%-0.9%) were calculated.

    References

    • Bhindi B, Wallis CJD, Nayan M et al. The Association Between Vasectomy and Prostate Cancer: A Systematic Review and Meta-analysis. JAMA Intern Med 2017;Jul 17; [Epub ahead of print] [PubMed]

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