Introduction: Obesity increases the risk of death from many adverse health outcomes and has also been linked with cancer outcomes. The impact of obesity on outcomes of advanced non-small-cell lung cancer patients is unclear.
Methods: The authors evaluated the association of body mass index (BMI) and outcomes in 2585 eligible patients enrolled in three consecutive first-line trials conducted by the Eastern Cooperative Oncology Group. BMI was categorized as underweight (BMI < 18.5 kg/m), normal weight (BMI: 18.5 to < 25 kg/m), overweight (BMI: 25 to < 30 kg/m), and obese (BMI ≥ 30 kg/m). In addition to analyzing overall and progression-free survival, reasons for treatment discontinuation were also assessed by BMI group.
Results: Of the patients enrolled, 4.6% were underweight, 44.1% were normal weight, 34.3% of patients were classified as overweight, and 16.9% were obese. Nonproportional hazards existed for obese patients relative to the other three groups of patients, with a change in overall survival hazard occurring at approximately 16 months. In multivariable Cox models, obese patients had superior outcomes earlier on study compared with normal/overweight patients 0.86 (HR=0.86, p=0.04; 95% CI: 0.75-0.99), but later experienced increased hazard (HR=1.54, p< 0.001; 95% CI: 1.22-1.94), indicating a time effect while undergoing treatment.
Conclusion: Data from these three trials suggest differential outcomes associated with BMI, and additional studies of the mechanisms underlying this observation, as well as dietary and lifestyle interventions, are warranted to help optimize therapy.