Purpose: Vasectomy has been associated with an increased risk of prostate cancer in some previous studies but not in others. We evaluated the association in a population based, case control study in Massachusetts.
Materials and methods: Included in our study were 1,216 patients younger than 70 years with newly diagnosed prostate cancer and 1,400 controls with no history of prostate cancer who were matched to patients by age and town of residence. Data on vasectomy and potential confounding factors were obtained by telephone interview, and confounding was controlled by conditional logistic regression analysis.
Results: Overall 16% of patients and 15% of controls had undergone vasectomy. Compared with no vasectomy the odds ratio for ever having undergone vasectomy was 1.0 (95% confidence interval [CI] 0.8 to 1.3), which did not vary significantly by age at or interval since vasectomy. In men who reported urological symptoms and those without symptoms the odds ratio was 0.9 (95% CI 0.7 to 1.2) and 1.4 (1.0 to 1.9), respectively. In men younger than 55 years and those 55 years old or older at diagnosis of prostate cancer the odds ratio was 1.9 (95% CI 1.2 to 3.2) and 1.0 (0.8 to 1.3), respectively [corrected]. In the younger men with stages A or B and C or D disease the odds ratio was 2.3 (95% CI 1.2 to 4.3) and 1.3 (0.5 to 3.5), respectively.
Conclusions: Our findings do not support the hypothesis that vasectomy increases the risk of prostate cancer in men older than 55 years. Further study is needed to determine whether the observed association between vasectomy and prostate cancer in men younger than 55 years is due to chance, detection bias or a causal effect.