Relationship between body mass index and the expression of hormone receptors or human epidermal growth factor receptor 2 with respect to breast cancer survival.

Ye Won Jeon,Young Jin Suh,Woosung Lim,Se Heun Cho,Min Ho Park,Su Hwan Kang

doi:10.1186/s12885-015-1879-4

Abstract

BackgroundThe association between body mass index (BMI) at the time of breast cancer diagnosis and the prognosis of breast cancer patients remains controversial. Furthermore, the association between BMI and prognosis with respect to different breast cancer subtypes is not clearly defined.MethodsWe analyzed data from 41,021 invasive breast cancer patients between January 1988 and February 2008 from the Korean Breast Cancer Registry (KBCR) database. Overall survival (OS) and breast cancer-specific survival (BCSS) were analyzed using the Kaplan-Meier method and Cox’s proportional hazard regression model among all patients and specific breast cancer subtypes with respect to BMI categories.ResultsA U-shaped association between BMI and mortality was observed in the total cohort. Underweight and obese individuals exhibited worse OS (hazard ratio, 1.23 [95 % confidence interval {CI}, 1.05 to 1.44] and 1.29 [1.13 to 1.48], respectively) and BCSS (1.26 [1.03 to 1.54] and 1.21 [1.02 to 1.43], respectively) than normal-weight individuals. In the estrogen receptor (ER) and/or progesterone receptor (PR)+/human epidermal growth factor receptor 2 (HER2) - subgroup, obese individuals exhibited worse OS (1.48 [1.18 to 1.85]) and BCSS (1.31 [1.13 to 1.52]) than normal-weight individuals. Conversely, in the ER and PR-/HER2+ subgroup, underweight individuals exhibited worse OS (1.68 [1.12 to 2.47]) and BCSS (1.79 [1.11 to 2.90]) than normal-weight individuals.ConclusionsWe observed a U-shaped relationship between BMI at diagnosis and poor OS and BCSS among all breast cancer patients. However, obesity in the ER and/or PR+/HER2- subgroup and underweight in the ER and PR-/HER2+ subgroup were poor prognostic factors. Therefore, BMI at diagnosis and breast cancer subtype should be considered simultaneously in various treatment decision processes and surveillance schedules.

Highlights

The association between body mass index (BMI) at the time of breast cancer diagnosis and the prognosis of breast cancer patients remains controversial
The aim of this study was to investigate the prognostic significance of BMI at the time of breast cancer diagnosis in all breast cancer patients and in each breast cancer subtype by analyzing overall survival (OS) and breast cancerspecific survival (BCSS) using population-based data from the Korean Breast Cancer Registry (KBCR) database
Breast cancer subgroups categorized according to the expression of estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) exhibited a significant association with BMI categories (p < 0.001)

Summary

Introduction

The association between body mass index (BMI) at the time of breast cancer diagnosis and the prognosis of breast cancer patients remains controversial. The association between BMI and prognosis with respect to different breast cancer subtypes is not clearly defined. The association between body mass index (BMI) at the time of breast cancer diagnosis and the prognosis of breast cancer patients remains controversial despite many studies, including single institution, multi-center, and population-based studies, meta-analyses, and randomized. Recent advances in our understanding of breast cancer biology based on molecular techniques allow us to divide breast cancer into at least four subtypes [25, 26]. It is important to understand the association between BMI and prognosis in the different breast cancer subtypes. An analysis of a large population-based cohort is needed to understand the prognostic significance of obesity in Asian breast cancer patients

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