Lung cancer is the leading cause of cancer death in the United States. 1 Although it is well known that lung cancer is associated with tobacco use, it is also apparent that never smokers are susceptible to the disease. Comparisons of genetic and epigenetic aberrations in non-small cell lung cancer (NSCLC) among smokers and never smokers have revealed marked differences in tumor biology that have resulted in clinicopathologic distinctions between smokers and never smokers. Data have established that mutational differences in the active kinase domain of the epidermal growth factor receptor confer increased sensitivities of a subset of never smokers with lung cancer to tyrosine kinase inhibitors. 2,3 Less well established is the actual natural history of NSCLC in never smokers compared with smokers. Emerging tumor biology data, especially recent reports highlighting fewer genomic alterations in never smokers, such as gene Results: Never smokers were signifi cantly more likely than current smokers to be women ( P , .01), older ( P , .01), and to have adenocarcinoma ( P , .01) and bronchioloalveolar carcinoma ( P , .01). No statistically signifi cant differences existed in stage distribution at presentation for the analytic cohort ( P 5 .35) or for the subgroup undergoing surgery ( P 5 .24). The strongest risk factors of mortality among patients with NSCLC who underwent surgery were advanced stage (adjusted hazard ratio, 3.43; 95% CI, 2.32-5.07; P , .01) and elevated American Society of Anesthesiologists classifi cation (adjusted hazard ratio, 2.18; 95% CI, 1.40-3.40; P , .01). The minor trend toward an elevated risk of death on univariate analysis for current vs never smokers in the surgically treated group (hazard ratio, 1.20; 95% CI, 0.98-1.46; P 5 .07) was completely eliminated when the model was adjusted for covariates ( P 5 .97). Conclusions: Our fi ndings suggest that smoking status at time of lung cancer diagnosis has little impact on the long-term survival of patients with NSCLC, especially after curative surgery. Despite different etiologies between lung cancer in never and current smokers the prognosis is equally dismal.CHEST 2010; 138(3):500-509Abbreviations: aHR 5 adjusted hazard ratio; AJCC 5 American Joint Commission on Cancer; ASA 5 American Society of Anesthesiologists; BAC 5 bronchioloalveolar carcinoma; HR 5 hazard ratio; NSCLC 5 non-small cell lung cancer