The Prognostic Value of Body Fat Percentage in Early-Stage Breast Cancer Patients Receiving Adjuvant Aromatase Inhibitors

Objective: In obese breast cancer patients, aromatase inhibitors may be less effective, possibly because of increased aromatase enzyme activity in peripheral adipose tissue and higher estradiol levels. The aim of this study was to evaluate the effect of body composition on prognosis in patients with early-stage breast cancer receiving aromatase inhibitors in adjuvant endocrine therapy.Methods: Our study included patients with radiologically and histopathologically confirmed early-stage breast cancer who were admitted to Dicle University Faculty of Medicine, Department of Medical Oncology, between January 2001 and March 2017. We included postmenopausal women who had body fat percentage data and received adjuvant aromatase inhibitor therapy for hormone receptor-positive breast cancer.Results: Prognostic factors’ effects on DFS were evaluated by multivariate analysis. The analysis showed that age (p=0.637), BMI (p=0.336), lymph node positivity (p=0.114), stage (p=0.216), grade (p=0.201), lymphatic invasion (p=0.819), ER positivity (p=0.608), and Her-2 positivity (p=0.941) had no effect on prognosis. In multivariable Cox regression analysis, comorbidity status (HR: 0.70, 95% CI: 0.42–0.91, p=0.03) and body fat percentage ≥45% versus <45% (HR: 3.15, 95% CI: 1.23–8.07, p=0.01) were independently associated with DFS.Conclusion: In early-stage aromatase inhibitor-treated breast cancer patients, body fat percentage was shown to be a more valuable measure than BMI and an independent prognostic factor.