PP105-SUN: Body Mass Index and Breast Cancer Subtype in Pre-Postmenopausal Women

Abstract

Rationale: Obesity has a complex relationship to breast cancer risk that differs in premenopausal and postmenopausal women. Methods: This study aims to determine the association between Body Mass Index (BMI) and the distribution of breast cancer subtypes defined by Estrogen Receptor (ER), Progesterone Receptor (PR) and in preand postmenopausal breast cancers. A total of 105 female breast cancer patients were included in the analyses. The histological type of the tumor, ER and PR expression, age, body weight, height and menopausal status at diagnosis were investigated retrospectively. The patients with normal body weight had BMI 24.9 kg/m2, overweight had BMI between 25.0 and 29.9 kg/m2, and obese patients had BMI 30.0 kg/m2. Results: Median BMI was 27.098 kg/m2 (11.72 35.55) in the postmenopausal and 25.781 kg/m2 (14.84 40.60) in the premenopausal group (P< 0.065). BMI at diagnosis did not differ significantly between the menopausal age groups (P= 1.636). BMI was similar between the menopausal age both in preand postmenopausal and subtype breast cancer (P= 1.556 and P= 0.831, respectively). Premenopausal women with a BMI of 25.0 kg/m2 showed a propensity towards negative Estrogen Receptor and Progesterone Receptor (ER /PR ) tumors when compared to premenopausal women with a BMI of <25.0 kg/m2 (P= 0.648). Conclusion: The risk of breast cancer may be not associated with BMI in preand postmenopausal breast cancer patients in our study. However, obesity might be related to an increased risk of premenopausal hormone receptor-negative breast cancer. Further studies, with large figures, are needed for explanation of the credible mechanisms in the pathogenesis of premenopausal hormone receptor-negative breast cancer.