Obesity and breast cancer

Abstract

Introduction: Adult obesity rates have tripled since 1975 and continue to rise, worldwide. In recent years, the consequences of the physiological effects of obesity have evolved into major health concerns. On the other hand, breast cancer is the second most common cancer, globally. Obesity implies an increased risk of breast cancer, posing challenges to understanding the underlying mechanisms linking this relationship. The purpose of this study was to explore the relationship between obesity and breast cancer.

Methodology: It was performed a bibliographic search of articles in the electronic databases Medline (PubMed) and Scopus, during the last 25 years. For this study, the following key words were used: obesity, breast cancer, women as well as synonyms and combinations of these terms.

Results: According to the literature review, the main factors associated with obesity and the occurrence of breast cancer were an increase in adipose tissue and Body Mass Index (BMI), the postmenopausal period as well as central obesity. Breast cancer risk has been with endogenous estrogen levels which are elevated in obese women, possibly due to the activity of aromatase in adipose tissue. For postmenopausal women, obesity is associated with an increased risk of hormone receptor-positive breast cancer, while for every 5-point increase in BMI greater than 25 kg/m2, the risk of breast cancer increases by 10%. Black women have a lower incidence of breast cancer, but a higher mortality rate. Weight loss combined with physical activity reduces total body weight, adipose tissue, and biomarkers associated with breast cancer risk. Conclusions: Targeting modifiable obesity risk factors, such as diet and physical activity, is a strategy to reduce breast cancer risk and improve survival.