A propensity-matched comparison of survival after lung resection in patients with a high versus low body mass index†

An inverse relationship between body mass index (BMI) and the risk of lung cancer has been reported in several studies. In this study, we aimed to assess whether BMI can affect survival after lung resection for cancer. We reviewed patient data for a 10-year period; 337 patients with BMI >= 30 who underwent lung resection for non-small cell lung cancer were identified. This group of patients was matched at a ratio of 1:1 to a group with BMI < 30 and with similar characteristics such as sex, age, lung function test, history of smoking, diabetes, peripheral vascular disease, stroke, myocardial infarction, chronic obstructive pulmonary disease (COPD), procedure type, histology and stage of tumour. We also used the Kaplan-Meier survival curves before and after matching for the above mentioned patient characteristics. Before adjusting for the preoperative and operative characteristics, despite more history of diabetes, hypertension and renal impairment in patients with BMI >= 30 compared to those with BMI < 30 (BMI = 18.5-30 and < 8.5), the survival rate was found to be significantly higher when analysed univariately (P = 0.02). This difference remained significant after adjusting for all the characteristics, suggesting a significantly higher survival rate in the group with BMI >= 30 (P = 0.04). Unlike in breast cancer, a high BMI in lung cancer patients after resection has protective effects. This may be due to the better nutritional status of the patient, a less aggressive cancer type that has not resulted in weight loss at the time of presentation or it may be due to certain hormones released from the adipose tissue. BMI can be a predictor of outcome after lung resection in cancer patients.