Previous oral contraceptive use and breast cancer risk among pre- and postmenopausal women - retrospective study in a cohort of 979 patients

Several randomized trials and observational studies show that the use of oral contraceptives is a weak risk factor (RF) for breast cancer (BC). The aim of this study was to assess the effects on BC risk of use of oral contraceptives (OC) in pre- and postmenopausal women, all residing in the same metropolitan area. Patients and Methods: Data regarding a series of 471 patients with BC, and 508 age-matched healthy controls were reviewed and analyzed. There were 238 premenopausal and 233 postmenopausal women, with a median age of 56 years (range 27−81 years). Odds ratios (OR) estimates was calculated, and the chi-squared test was used to compare categorical variables. Results: The results are reported in the Table. Age at menarche (12.3±1.6 vs. 12.1±2.2 years, p = 0.43), age at first pregnancy (25.3±4.4 vs. 26.03±4.6 years, p = 0.12), parity (1.4±1.1 vs. 1.45±1.15, p = 0.63), months of breastfeeding (10.2±8.6 vs. 9.35±7.23, p = 0.25), and months of OC use (28.4±21.2 vs. 34.4±24.2, p = 0.20) did not differ significantly between groups. Conclusions: In this cohort patients the weight of RFs, enclosed the use and duration of OC therapy, did not differ significantly (p=NS) between pre- and postmenopausal women.