Prognostic signi cance of body mass index in breast cancer patients with hormone receptor-positive tumours a er curative surgery

Purpose: Obesity has been recognized as a signi cant risk factor for postmenopausal breast cancer. e aim of this study is to investigate the prognostic signi cance of body mass index (BMI) in hormone receptor-positive, operable breast cancer. Methods: In this retrospective cohort study, 1,192 consecutive patients with curative resection of primary breast cancer were enrolled. Patients were assigned to two groups according to BMI: normal or underweight (BMI < 23.0 kg/m2) and overweight or obese (BMI ≥23.0 kg/m2). Associations among BMI and clinicopathological characteristics and prognosis of patients were assessed. Results: A high BMI was signi cantly (P < 0.01) correlated with age, nodal stage, ALNR, ER positivity, PR positivity and menopausal status at diagnosis. Univariate analysis revealed that BMI, pathologic T stage, nodal stage, axillary lymph node ratio (ALNR) and adjuvant radiotherapy history were signi cantly (P < 0.05) associated with disease-free survival and overall survival, irrespective of tumour hormone receptor status. Multivariate analysis revealed BMI as an independent prognostic factor in all cases and in hormone receptor-positive cases. Conclusion: A high BMI (≥23.0 kg/m2) is independently associated with poor prognosis in hormone receptor-positive breast cancer. ORIGINAL RESEARCH © 2013 CIM Clin Invest Med • Vol 36, no 6, December 2013 E297 Correspondence to: Dr. Peng Xing Department of Surgical Oncology, General Surgery, First A liated Hospital of China Medical University, 92 Beima Road, Heping District, Shenyang, China e-mail: [email protected] Manuscript submitted 3rd July, 2013 Manuscript accepted 22nd October, 2013 Clin Invest Med 2013; 36 (6): E297-E305. Breast cancer is one of the most common malignancies among women, a ecting about 1.4 million women worldwide in 2008 and leading to approximately 459,000 deaths each year [1]. ere have been substantial improvements in the treatment of breast cancer during the last decades, with ve-year and 10-year overall survival rates of 89.3% and 78.8%, respectively, in Chinese patients [2]. Clinically, breast cancer represents a heterogeneous and complex disease. Based on the expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2), breast cancer is classi ed into several histological subtypes that have important clinical implications. e presence of ER or PR is a powerful predictive factor for bene t from adjuvant tamoxifen therapy in breast cancer [3,4]. In contrast, HER-2-overexpressing and ER/PR-negative luminal breast cancers fail to respond to hormonal therapy. Hormone receptor-positive breast cancer patients generally have a better outcome than hormone receptornegative patients [5]; however, the prognostic value of ER and PR is limited [6]. Several other prognostic factors, such as tumour size, axillary lymph node status, histological tumour grade, HER2 status and vascular invasion, have previously been identi ed for breast cancer [7,8]. Obesity has been recognized as a signi cant risk factor of breast cancer among postmenopausal women and is associated with poor prognosis [9,10]. Body mass index (BMI) is widely used as a measure of obesity. Dignam et al. [11] investigated the relationship between obesity (BMI ≥30.0 kg/m2) and outcomes in women with lymph node-negative, ER-positive earlystage breast cancer. ey found that compared with normalweight women, obese women had greater all-cause mortality. Obesity also has an adverse prognostic e ect in women with lymph node-negative, ER-negative breast cancer [12]; however, this prognostic e ect has not been consistent and may be in uenced by several factors such as menopausal status, extent of disease, and receptor status [13]. Dawood et al. [14] reported that, among women with early stage triple-negative breast cancer, ve-year distant disease-free survival times were comparable, regardless of BMI category. Mousa et al. [15] demonstrated that a lower BMI is associated with a shorter disease-free survival (DFS) in patients with early stage breast cancer. Similarly, Borgquist et al. [16] showed that overweight may be protective in breast cancer patients with certain ERbeta genotypes. In the present study, the clinical signi cance of BMI in operable breast cancer was determined and the e ect of tumour hormone receptor status on its prognostic signi cance was investigated. Materials and Methods