The impact of baseline body mass index on clinical outcomes in metastatic breast cancer: a prospective study

OBJECTIVE: The prognostic value of body mass index (BMI) in metastatic breast cancer (MBC) has not been fully elucidated. In a prospective study to investigate the chemo-sensitizing effect of statins on clinical outcomes in MBC patients who were scheduled to receive palliative chemotherapy (Carboplatin and Vinorelbine), we sought to investigate the relationship between baseline BMI and clinical outcomes; response, overall survival (OS) and progression free survival (PFS), over a median follow-up of 40-months. RESULTS: Eighty-Two MBC patients were enrolled and categorized using baseline BMI as underweight (BMI, < 18.5 kg/m(2), n = 1), normal-weight (BMI, 18.5–24.9 kg/m(2), n = 20), overweight (BMI, 25–29.9 kg/m(2), n = 34), and obese (BMI, ≥ 30 kg/m(2), n = 27). Median OS was 10 months in normal/underweight, 19 months in overweight, and 16 months in obese (P = 0.083). Univariate Cox model revealed that overweight patients were significantly less likely to die of MBC as normal BMI patients (hazard ratio [HR] = 0.54, 95% confidence interval [CI], (0.29–0.98), P = 0.044). Similarly, multivariate Cox model, after adjusting for age, number of metastatic sites, chemotherapy line’s grade, HER2 and hormone receptors status, confirmed longer survivorship of overweight in comparison with normal BMI patients (HR = 0.51, 95% CI (0.26–0.99), P = 0.047). Our data suggest that being overweight could improve OS in MBC patients. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13104-017-2876-2) contains supplementary material, which is available to authorized users.