Effect of Body Mass Index on Survival in Breast Cancer Patients According to Subtype, Metabolic Syndrome, and Treatment

Purpose To investigate the effect of body mass index (BMI) on survival in patients with breast cancer according to tumor subtype, metabolic syndrome, and systemic treatment. Patients and Methods We identified 5668 patients who underwent curative surgery for breast cancer between 1996 and 2013 from the clinical data of a single institution. Disease-free survival (DFS) and overall survival (OS) were calculated and compared between the patients with BMI ≥ 25 kg/m2 and Results In all patients, BMI ≥ 25 kg/m2 was an unfavorable factor for OS (P = .030) but not for DFS. In the HR+/HER2− subgroup, DFS and OS were longer in patients with BMI Conclusion BMI ≥ 25 kg/m2 was an unfavorable survival factor, particularly in patients with HR+/HER2− breast cancer.