Cancer risk after sterilization with transcervical quinacrine: updated findings from a Chilean cohort.

Background: Dating back to the 1970s, thousands of women worldwide have voluntarily been sterilized with transcervical insertion of quinacrine pellets. The safety and efficacy of the technology are still being assessed today; in particular, better estimates on the incidence of human cancers are now feasible.

Methods: We conducted a cohort study of 1492 women in Santiago and Valdivia, Chile, who received transcervical quinacrine pellets for contraceptive sterilization between 1977 and 1989. We periodically interviewed women with the last interviews in 2006-2007 and reviewed their medical records. We calculated age and site-specific incidence of invasive cancers and compared the observed cases to the number of expected cases based on data from the Cali, Colombia, cancer registry, gathered by the International Agency for Research on Cancer.

Results: During 23,894 person-years of follow-up, 41 invasive cancers were identified, including 16 new cases that had occurred since the previous analysis. Ten cases of cervical cancer were observed, compared with 12.1 expected. Since the initial study's confirmation of a single case of leiomyosarcoma, no other uterine cancers have been diagnosed. We would expect 2.0 uterine cancers during this number of observed women-years. One case of ovarian cancer was diagnosed, compared with 3.1 expected.

Conclusion: Rates of cancer among women exposed to intrauterine quinacrine are similar to population-based rates.