UC San Diego

Background

Population studies suggest that high body mass index (BMI) correlates with a reduced risk for death from lung cancer. The aim of our study was to evaluate definitively the influence of BMI on long-term overall survival (OS) in surgical patients with NSCLC.

Methods

The study population consisted of 1935 patients who underwent surgical resection for lung cancer at M. D. Anderson Cancer Center (2000-2014). Study variables included both patient- and treatment-related characteristics. Univariate and multivariate Cox regression analyses were performed to identify variables associated with OS.

Results

On univariate analysis, significant predictors of improved survival were higher BMI, pathologic tumor stage (stage I versus stage II, III, or IV), type of surgical procedure (lobectomy/pneumonectomy versus wedge resection/segmentectomy), younger age, female sex, and adenocarcinoma histologic subtype (versus squamous) (all p < 0.05). Morbidly obese patients (BMI ≥ 35) demonstrated a trend toward better outcomes than those classified as obese (BMI ≥30 and <35 kg/m²) (p = 0.05), overweight (BMI ≥ 25 and <30 kg/m²) (p = 0.13), or healthy weight (BMI <25 kg/m²) (p = 0.37) (hazard ratio = 0.727, 0.848, 0.926, and 1, respectively). On multivariate analysis, BMI remained an independent predictor of survival (p = 0.02). Propensity matching analysis demonstrated significantly better OS (p = 0.003) in patients with a BMI of 30 kg/m² or higher as compared with a BMI of 25 kg/m².

Conclusions

In this large, retrospective, single-center series, after control for disease stage and other variables, higher BMI was associated with improved OS after surgical resection of NSCLC. Further studies are necessary to elucidate the precise relationship between BMI and treatment outcomes.