Breast cancer classified mostly into 4 major molecular subtypes based on the expression of receptors for estrogen (ER), progesterone (PR), and human epidermal growth factor (HER-2) and ki-67 staining. Triple-negative breast cancer (TNBC) refers to a subgroup of patients with no expression of ER, PR or HER-2, and accounts for 10-20% of all newly diagnosed breast cancer cases. Although obesity is known to be an important risk factor for development of breast cancer and affects the prognosis unfavorably especially in luminal type tumors the effect of obesity in TNBC was not known exactly. In this trial we aimed to investigate the effect of body mass index (BMI) on the outcome of TNBC.
Between 1998-2015 years from 4584 patients with invasive breast cancer patients who had non-metastatic TNBC with baseline BMI at the time of diagnosis were enrolled to this study (n = 371). Patient's demographics, including survival data and tumor characteristics were obtained from medical charts. Patients with BMI ranging between 18.5 and 24.9 kg/m2 were considered as normal weight patients (Arm A, n = 122), and patients with a BMI ranging ≥ 25 kg/m2 were grouped as overweight and obese patients (Arm B, n = 249). Kaplan–Meier survival analysis was carried out for disease free survival (DFS) and overall survival (OS).
The median follow up of patients was 44.1 months. Median age of patients was 43 (23-81) and 49 (20-82) in group A and B, respectively (P
In our study, like luminal A and B tumors, obesity is associated with poorer DFS and OS in stage 1-3 TNBC patients.
Legal entity responsible for the study
All authors have declared no conflicts of interest.