Quinacrine sterilization and gynecologic cancers: a case-control study in northern Vietnam.

Background: Over 100,000 women worldwide have been sterilized by insertion of quinacrine into the uterus to induce tubal scarring. Concern has been expressed about possible carcinogenicity, and specifically the risk of uterine cancer. Methods: From 2001 through 2006, we conducted a population-based, case-control study of gynecologic cancers in 12 provinces in northern Vietnam, where relatively large numbers of women had received quinacrine. Cases of incident cervical, ovarian, and uterine cancer were identified at provincial hospitals or at referral hospitals in Hanoi. For each case, 3 age- and residence-matched controls were randomly selected from the population registries of the case's home community. Results: The prevalence of quinacrine exposure was 1.2% among cases and 1.1% among controls. For cervical cancer, analysis of 606 cases (9 exposed) and their 1774 matched controls (18 exposed) produced an odds ratio of 1.44 (95% confidence interval = 0.59-3.48) ( adjusted for several covariates including human papillomavirus risk score). For ovarian cancer, based on 262 cases (3 exposed) and 755 controls (8 exposed) and adjusted for age and number of years of ovulation, the odds ratio was 1.26 (0.21-5.45). For uterine cancer, none of the cases-including 23 cases of leiomyosarcoma- was exposed to quinacrine. The 95% confidence interval, based on 161 cases (none exposed) and 470 controls (7 exposed) and adjusted only for age, was 0-1.85. Conclusion: We found no evidence of a relationship between quinacrine sterilization and gynecologic cancer.