Influence of Body Mass Index on Survival of Women with Different Subtypes of Breast Cancer: an Integrative Review

Abstract

Introduction: Obesity is considered a negative prognostic factor for women with breast cancer, however, its influence on the course of the disease can be differentiated in molecular subtypes. Objective: To analyze the influence of the Body Mass Index (BMI) on the survival of women with breast cancer according to the molecular subtype. Method: Integrative review using PICOS strategy for the design of the study, identification of keywords and definition of eligibility criteria. Studies that analyzed the influence of BMI on the survival of women with breast cancer, by tumor subtype, using COX regression and/or Kaplan-Meier published until June 2018 were identified in PubMed, VHL, Scopus and Web of Science databases. Results: There were selected 23 studies from 446 identified. Women with triple negative tumors in higher BMI categories presented worse survival in four of the seventeen studies including this subtype. In cases of luminal tumors, high BMI was a negative prognostic factor in seven of the eleven studies. For HER2 (Human Epidermal growth factor Receptor-type 2) overexpressed, there was worse survival for higher BMI in two of the six studies. Among HER2 positive women regardless of hormone status, it was observed worse survival for women with higher BMI in two of the five studies. Conclusion: The effect of BMI on the survival of women with breast cancer appears to be differentiated according to the tumor subtype, and its effect is apparently greater in those with luminal tumors.