Effect of smoking on survival from non-small cell lung cancer: a retrospective Veterans' Affairs Central Cancer Registry (VACCR) cohort analysis.

Although a well-established risk factor for lung cancer, the impact of smoking on the survival of non-small cell lung cancer (NSCLC) is not well known. We performed a retrospective analysis of the Veteran's Affairs Comprehensive Cancer Registry of NSCLC patients. Smoking status was categorized as never smoker, past smoker and current smoker based on self-reported history. Multivariate analysis was performed to evaluate the impact of smoking on overall survival (OS) from NSCLC. The study population (n = 61,440) comprised predominantly of males (98 %) and Caucasians (81 %). The median age at diagnosis was 68 years (range 22-108 years). Current smokers were diagnosed with NSCLC at a younger age (65 years) compared to never smokers (71 years) and past smokers (72 years) (p < 0.001). On multivariate analysis, current smokers (n = 34,613) [Hazard ratio (HR) 1.059; 95 % confidence interval (CI) 1.012-1.108], but not past smokers (n = 23,864) (HR 1.008; 95 % CI 0.962-1.056), had worse OS for Stage III and IV NSCLC, compared to never smokers (n = 2,963). Smoking status was not prognostic in stages I and II NSCLC. Current smokers were diagnosed with NSCLC at a younger age than never smokers. Although current smoking was associated with worse prognosis, especially in stages III and IV, the impact of smoking status on OS was modest.