Estrogen therapy and risk of breast cancer in postmenopausal women: A case-control study and results of a multivariate analysis

Franco Lumachi, Anna Chiara Frigo, Umberto Basso, Valeria Tombolan, Mario Ermani

Research output: Contribution to journalArticle

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.

Original languageEnglish
Pages (from-to)524-528
Number of pages5
JournalMenopause
Volume17
Issue number3
DOIs
Publication statusPublished - May 2010

    Fingerprint

Keywords

  • Estrogen therapy
  • Hormone therapy
  • Menopause
  • Oral contraceptives
  • Risk factors

ASJC Scopus subject areas

  • Obstetrics and Gynaecology

Cite this