Estrogen Therapy and Risk of Breast Cancer in Postmenopausal Women
Estrogen Therapy and Risk of Breast Cancer in Postmenopausal Women
Objective: 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.
Breast cancer (BC) is the most common cancer among women and is a significant global health problem, even though several advances in the diagnosis, staging, and therapeutic approach of BC have been achieved over the past few years. The relationship between BC and various risk factors (RFs) has been investigated for almost half a century, and significant geographical variations in BC incidence have also been observed. Several randomized trials and observational studies show that hormone therapy (HT) increases the risk of BC, especially when estrogen-progestin combinations are chosen, whereas oral contraceptives (OCs) are usually considered as a weak RF. Few studies consider HT and OCs together. The aim of this study was to assess the effects of exposure to both HT and OCs on BC risk in postmenopausal women, all residing in the same metropolitan area, and the cumulative risk in the presence of other RFs.
Abstract and Introduction
Abstract
Objective: 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.
Introduction
Breast cancer (BC) is the most common cancer among women and is a significant global health problem, even though several advances in the diagnosis, staging, and therapeutic approach of BC have been achieved over the past few years. The relationship between BC and various risk factors (RFs) has been investigated for almost half a century, and significant geographical variations in BC incidence have also been observed. Several randomized trials and observational studies show that hormone therapy (HT) increases the risk of BC, especially when estrogen-progestin combinations are chosen, whereas oral contraceptives (OCs) are usually considered as a weak RF. Few studies consider HT and OCs together. The aim of this study was to assess the effects of exposure to both HT and OCs on BC risk in postmenopausal women, all residing in the same metropolitan area, and the cumulative risk in the presence of other RFs.