Several randomized trials and observational studies show that the use of hormone therapy (HT) increases the risk of breast cancer (BC). The aim of this study was to assess the effects of exposure to both HT and oral contraceptives (OCs) on BC risk in postmenopausal women, all residing in the same metropolitan area.
Methods
Data regarding a series of 238 consecutive postmenopausal women with infiltrating ductal carcinoma (cases) and 255 randomly selected age-matched healthy women (controls) were reviewed. Odds ratios for no breast-feeding and HT and OC use were 1.82 (95% CI, 1.20-2.77), 2.49 (95% CI, 1.73-3.58), and 2.06 (95% CI 1.14-3.70), respectively.
Results
Four independent variables (years between menarche and menopause, breast-feeding, OC use, and HT use) were included in the final multivariate analysis using logistic regression. The cumulative odds ratio calculated from the observed versus predicted values, obtained using the logistic regression function, was 4.55 (95% CI, 2.13-9.71), whereas the cumulative risk of common exposure to both OCs and HT was 2.77 (95% CI, 1.44-5.32). The logistic model correctly classified 67.5% (95% CI, 63.2-71.5) of cases. The receiver operating characteristic (ROC) curve of the complete logistic function showed a fair area of accuracy (0.77; 95% CI, 0.72-0.81).
Conclusions
Our results show that the risk of common exposure to both OCs and HT increases in women with other risk factors. However, several parameters traditionally considered in epidemiological studies do not have the same weight in each local community, suggesting the need to create different models to correctly select the high-risk population.
estrogen therapy breast cancer risk postmenopausal case-control study, hormone therapy oral contraceptive breast cancer cumulative risk, combined exposure oral contraceptives hormone therapy breast cancer odds ratio, estrogen replacement therapy infiltrating ductal carcinoma postmenopausal, menarche menopause interval breast cancer risk multivariate analysis, breastfeeding protective factor breast cancer postmenopausal women, oral contraceptive use breast cancer risk case-control, logistic regression breast cancer risk factors hormonal exposure, HRT OC combined exposure breast cancer risk assessment, postmenopausal hormone therapy breast cancer epidemiological study
PMID 20130492 20130492 DOI 10.1097/gme.0b013e3181ca0c74 10.1097/gme.0b013e3181ca0c74
Cite this article
Lumachi, F., Frigo, A. C., Basso, U., Tombolan, V., & Ermani, M. (2010). Estrogen therapy and risk of breast cancer in postmenopausal women: a case-control study and results of a multivariate analysis. Menopause (New York, N.Y.), 17(3), 524-528. https://doi.org/10.1097/gme.0b013e3181ca0c74
Lumachi F, Frigo AC, Basso U, Tombolan V, Ermani M. Estrogen therapy and risk of breast cancer in postmenopausal women: a case-control study and results of a multivariate analysis. Menopause. 2010;17(3):524-528. doi:10.1097/gme.0b013e3181ca0c74
Lumachi, Franco, et al. "Estrogen therapy and risk of breast cancer in postmenopausal women: a case-control study and results of a multivariate analysis." Menopause (New York, N.Y.), vol. 17, no. 3, 2010, pp. 524-528.
Keywords
Contraceptives, Oral, Hormonal
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