Body mass index (BMI), BMI change, and overall survival in small cell and non-small cell lung cancer patients: a pooled analysis of the International Lung Cancer Consortium

Abstract Background The relationships between morbid obesity, changes in body mass index (BMI) prior to cancer diagnosis, and lung cancer outcomes by histology (small-cell lung cancer (SCLC) and non-SCLC (NSCLC)) have not been well studied. Methods Individual level data analysis was performed on 25,430 NSCLC and 2,787 SCLC patients from sixteen studies of the International Lung Cancer Consortium (ILCCO) evaluating the association between various BMI variables and lung cancer overall survival (OS), reported as adjusted hazard ratios (aHR) from Cox proportional hazard models and adjusted penalized smoothing spline plots. Results OS of NSCLC had putative U-shaped hazard ratio relationships with BMI, based on spline plots: being underweight (BMI 2 ; aHR=1.56; 95%CI:1.43-1.70) or morbidly overweight (BMI>40; aHR=1.09; 95%CI:0.95-1.26) at the time of diagnosis was associated with worse stage-specific prognosis, while being overweight (25≤BMI Conclusions Both being underweight or morbidly obese at time of diagnosis is associated with lower stage-specific survival in independent assessments of NSCLC and SCLC patients. In addition, a decrease in BMI at lung cancer diagnosis relative to early adulthood is a consistent marker of poor survival.