Vasectomy and risk of prostate cancer: population based matched cohort study
Menée au Canada auprès de 326 607 participants âgés de 20 à 65 ans sur la période 1994-2012, cette étude de cohorte évalue l'association entre une vasectomie et le risque de cancer de la prostate (3 462 cas)
Objective : To determine the association between vasectomy and prostate cancer, adjusting for measures of health seeking behaviour. Design : Population based matched cohort study. Setting : Multiple validated healthcare databases in Ontario, Canada, 1994-2012. Participants : 326 607 men aged 20 to 65 who had undergone vasectomy were identified through physician billing codes and matched 1:1 on age (within two years), year of cohort entry, comorbidity score, and geographical region to men who did not undergo a vasectomy. Main outcomes measures : The primary outcome was incident prostate cancer. Secondary outcomes were prostate cancer related grade, stage, and mortality. Results : 3462 incident cases of prostate cancer were identified after a median follow-up of 10.9 years: 1843 (53.2%) in the vasectomy group and 1619 (46.8%) in the non-vasectomy group. In unadjusted analysis, vasectomy was associated with a slightly increased risk of incident prostate cancer (hazard ratio 1.13, 95% confidence interval 1.05 to 1.20). After adjustment for measures of health seeking behaviour, however, no association remained (adjusted hazard ratio 1.02, 95% confidence interval 0.95 to 1.09). Moreover, no association was found between vasectomy and high grade prostate cancer (adjusted odds ratio 1.05, 95% confidence interval 0.67 to 1.66), advanced stage prostate cancer (adjusted odds ratio 1.04, 0.81 to 1.34), or mortality (adjusted hazard ratio 1.06, 0.60 to 1.85). Conclusion : The findings do not support an independent association between vasectomy and prostate cancer