RISK OF TESTICULAR CANCER AFTER VASECTOMY - COHORT STUDY OF OVER 73000 MEN

Objective-To confirm or refute reports that vasectomy may increase the risk of cancers of the testis and prostate. Design-Computerised record linkage study of cohort of men with vasectomy and comparison of cancer rates with those in the whole Danish population; manual check of all records of patients with testicular and prostate cancer diagnosed within the first year of follow up. Setting-Denmark 1977-89. Subjects-Cohort of 73 917 men identified in hospital discharge and pathology registers as having had a vasectomy for any reason during 1977-89. Main outcome measures-Observed incidences of testicular, prostate, and other cancers up to the end of 1989. Results-The overall pattern of cancer incidence in the study cohort was similar to that expected nationally. No increased incidence in testicular cancer was observed (70 cases; standardised morbidity ratio 1.01 (95% confidence interval 0.79 to 1.28)). The incidence during the first year of follow up was also close to that expected (nine cases; standardised morbidity ratio 0.80 (0.36 to 1.51)). The incidence of prostate cancer was not increased (165 cases; standardised morbidity ratio 0.98 (0.84 to 1.14)). Conclusions-The incidence of testicular cancer in men with vasectomy is no higher than in other men. Vasectomy does not cause testicular cancer and does not accelerate the growth or diagnosis of pre-existing testicular neoplasms. Data concerning a causal relation between vasectomy and prostate cancer were inconclusive.