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Ovarian Stimulation for In Vitro Fertilization and Long-term Risk of Breast Cancer

Alexandra W. van den Belt‐Dusebout, Mandy Spaan, Cornelis Bavo Lambalk, Marian Kortman, Joop S.E. Laven, Evert J. P. van Santbrink, Lucette A. J. van der Westerlaken, Ben J Cohlen et al.

JAMA, 2016

25,108 participants · 89 citations

Abstract

IMPORTANCE: Previous studies of breast cancer risk after in vitro fertilization (IVF) treatment were inconclusive due to limited follow-up. OBJECTIVE: To assess long-term risk of breast cancer after ovarian stimulation for IVF. DESIGN, SETTING, AND PARTICIPANTS: Historical cohort (OMEGA study) with complete follow-up through December 2013 for 96% of the cohort. The cohort included 19,158 women who started IVF treatment between 1983 and 1995 (IVF group) and 5950 women starting other fertility treatments between 1980 and 1995 (non-IVF group) from all 12 IVF clinics in the Netherlands. The median age at end of follow-up was 53.8 years for the IVF group and 55.3 years for the non-IVF group. EXPOSURES: Information on ovarian stimulation for IVF, other fertility treatments, and potential confounders was collected from medical records and through mailed questionnaires. MAIN OUTCOMES AND MEASURES: Incidence of invasive and in situ breast cancers in women who underwent fertility treatments was obtained through linkage with the Netherlands Cancer Registry (1989-2013). Breast cancer risk in the IVF group was compared with risks in the general population (standardized incidence ratios [SIRs]) and the non-IVF group (hazard ratios [HRs]). RESULTS: Among 25,108 women (mean age at baseline, 32.8 years; mean number of IVF cycles, 3.6), 839 cases of invasive breast cancer and 109 cases of in situ breast cancer occurred after a median follow-up of 21.1 years. Breast cancer risk in IVF-treated…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 25,108 participants or records.

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