Vasectomy and Increased Risk of Prostate Cancer

Abstract

To the Editor. —In their studies of the relationship of vasectomy to prostate cancer, Giovannucci et al 1,2 relied on self-report by cohort members or their wives to identify incident prostate cancers and confirmed as many of these cases as possible by request for and review of medical records. Self-report of prostate cancer may potentially result in significant underascertainment of cases. The Kaiser Permanente Study 3 of vasectomy and prostate cancer afforded an opportunity to assess the potential for underascertainment. In the Kaiser Permanente Study, incident prostate cases were identified in a cohort of multiphasic health checkup (MHC) examinees by linking the medical record number of the MHC examinee to computerized tumor registry and hospitalization records, a method that does not rely on self-report. Of the 38 MHC cohort members who had a second MHC after an incident prostate cancer, 17 (45%) did not report a history of any cancer