When the impact of obesity on outcomes was studied among patients with advanced non–small cell lung cancer (NSCLC), obese patients had superior outcomes early on but had increased hazards later.

From 1993 to 2004, the Eastern Cooperative Oncology Group enrolled 2,684 patients in three phase III trials of first-line systemic chemotherapy for advanced NSCLC. The body mass index (BMI) of 2,585 eligible patients was calculated. The median follow-up was 64.9 months. As with the general population, 4.6% of the patients were underweight, 44.1% were normal weight, 34.3% were overweight, and 16.9% were obese.

Median overall survival rates varied based on patient weights. Among underweight patients, the median overall survival was 7.0 months, among normal weight patients it was 8.6 months, among overweight patients it was 9.3 months, and among obese patients it was 11.0 months. Multivariable models found that obese patients had significantly different overall survival compared with normal-weight and overweight patients. However, the risk for death from any cause for obese patients increased dramatically once they had been on a study longer than 16 months.

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The researchers said, “This indicates that the protective effect of obesity in lung cancer patients is for a limited time, after which the ultimate impact of obesity on survival from all causes supersedes.”

The authors stated that outcomes differ depending on BMI and that therapy may be optimized through additional studies of the mechanisms underlying this observation, along with dietary and lifestyle interventions. The study was published in the Journal of Thoracic Oncology (2013; doi: 10.1097/JTO.0b013e31829cf942).