Impact of body mass index on clinical outcomes in triple-negative breast cancer

BACKGROUND:

Obesity is associated with poorer outcomes in patients with hormone receptor‐positive breast cancers. This association is not well established for women with triple‐negative breast cancers (TNBC). In this study, the prognostic effects of body mass index on clinical outcome were evaluated in patients with TNBC.

METHODS:

A retrospective study was conducted on 418 patients who were treated between July 1996 and July 2010 for TNBC. Recurrence‐free survival (RFS) and overall survival (OS) were evaluated in relation to body mass index (BMI) after controlling for clinically significant variables.

RESULTS:

One hundred twenty‐four patients (29.7%) were normal/underweight (BMI ≤24.9 kg/m²), 130 patients (31.1%) were overweight (BMI from 25 to 29.9 kg/m²), and 164 patients (39.2%) were obese (BMI ≥30 kg/m²). At a median follow‐up of 37.2 months, there were 105 recurrences (25.1%) and 87 deaths (20.8%). Compared with normal/underweight patients, the multivariate hazard ratio (HR) for RFS was 0.81 (95% confidence interval [CI], 0.49‐1.34) for obese patients. Similarly, OS was not associated with BMI category; obese patients had an HR of death of 0.94 (95% CI, 0.54‐1.64) compared with normal/underweight patients. A Cox regression analysis identified the receipt of chemotherapy (HR, 0.25; 95% CI, 0.12‐0.52), ductal histology (HR, 0.49; 95% CI, 0.25‐0.97), stage III disease (HR, 3.5; 95% CI, 1.35‐9.06), and increasing tumor size (HR, 1.19; 95% CI, 1.09‐1.3) as independent prognostic factors for OS.

CONCLUSIONS:

No significant relation between obesity and RFS or OS emerged in patients with TNBC after controlling for clinically significant factors. Cancer 2011;. © 2011 American Cancer Society.