Cancer risk among women sterilized with transcervical quinacrine hydrochloride pellets, 1977 to 1991.

OBJECTIVE To determine whether a cluster of eight cancers among 572 women who had received transcervical quinacrine hydrochloride was a random occurrence or evidence of an increased risk of cancer. DESIGN Retrospective cohort study using interviews and reviews of medical records. Cancer cases were evaluated using cohort analyses and space-time cluster methods. SETTING Santiago and Valdivia, Chile. SUBJECTS Fourteen hundred ninety-two women who received transcervical quinacrine pellets for sterilization between 1977 and 1989. MAIN OUTCOME MEASURE Age- and site-specific incidence of invasive cancers. RESULTS Eight hundred two women were interviewed. From 1 to 14 years of data were available on 600 of the noninterviewed women from clinic records. During 7,852 women-years of follow-up, 17 invasive cancers were identified, compared with 11.8 expected, based on age-specific rates from the Cali, Colombia cancer registry. Five cases of cervical cancer were observed, compared with 3.96 expected. Only one other uterine cancer was observed, a leiomyosarcoma, compared with 0.2 or 0.3 other uterine cancers expected. CONCLUSIONS The occurrence of an unusual cluster was confirmed, but no evidence was found of excess cancer risk associated with quinacrine pellet sterilization. However there was a single provocative observation (the leiomyosarcoma), and surveillance of the cohort is continuing.