Research Article BodyMass Index and Prognosis of Metastatic Breast Cancer Patients Receiving First-Line Chemotherapy

Background:The effect of bodymass index (BMI) on the prognosis ofmetastatic breast cancer (MBC) has not been explored so far. Methods: The relationship between BMI (kg/m2) and progression-free survival (PFS) or overall survival (OS) was assessed in 489 patients with MBC enrolled in three clinical trials of first-line chemotherapy. World Health Organization BMI categories were used: normal, 18.5–24.9 kg/m2; overweight, 25–29.9 kg/m2; and obese, 30þ kg/m2. Univariate PFS and OS curves were estimated; multivariate Cox analysis was conducted adjusting for age, menopausal status, performance status (PS), hormonal status and site, and number of metastases. Results:Overall, 39.9%of thepatientswere normal or underweight, 37.8%were overweight, and 22.3%were obese. Median age was 57 years (range 25–73); median PS was 0. Median PFS was 10.9 months [interquartile range (IQR) 5.5 to 19.9] in normalweightwomen, 13.0months (IQR 7.8 to 23.7) in overweight, and 12.2 (IQR 7.1 to 23.0) in obese women, P 0.17.Median OSwas 32.0months [95 % confidence interval (CI), 14.5–88.3] versus 33.2 months (95 % CI, 19.4–81.1) and 30.7 (95 % CI, 17.6–50.8), respectively. In multivariate analyses, no statistically significant association between BMI category and PFS or OS was observed. Conclusions: In this study, BMIwasnot associatedwith the outcome of patientswithMBC treatedwith first-line chemotherapy. Impact: In the absence of any evidence in support of a prognostic role of obesity in patients with MBC treated with chemotherapy, dietary restrictions, medical interventions aimed at reducing BMI/insulin resistance, or specific anticancer treatment strategies do not seem to be appropriate. Cancer Epidemiol Biomarkers Prev; 22(10); 1862–7. 2013 AACR