Abstract
Background: Infertility treatments may be associated with increased breast cancer risk. Results so far have been inconclusive. Objective: To evaluate the association between infertility, infertility treatments and breast cancer risk. Methods: A historical prospective cohort with 5,788 women who attended 5 Israeli infertility centers between 1964 and 1984. Their medical charts were abstracted. Breast cancer incidence was determined through linkage with the National Cancer Registry. Standardized incidence ratios (SIRs) and 95% confidence intervals were computed by comparing observed cancer rates to those expected in the general population. Additionally, in order to control for known risk factors, a casecontrol study nested within the cohort was carried out as well based on telephone interviews with breast cancer cases and controls matched by 1:2 ratio. Results: Compared to 115.2 expected breast cancer cases, 131 were observed (SIR = 1.1;non-significant). Risk for breast cancer was higher for women treated with clomiphene citrate (SIR = 1.4; 95% CI 1.0–1.8). Similar results were noted when treated and untreated women were compared, and when multivariate models were applied. In the nested case-control study, higher cycle index and treatment with clomiphene citrate were associated with significantly higher risk for breast cancer. Conclusions: Clomiphene citrate may be associated with higher breast cancer risk.
Original language | English |
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Pages (from-to) | 43-44 |
Number of pages | 2 |
Journal | European Journal of Epidemiology |
Volume | 21 |
Issue number | 1 (Supplement) |
DOIs | |
State | Published - Jun 2006 |