Epidemiology study of never-smokers with non-small cell lung cancer (NSCLC): High percentages of Asian and Hispanic female never-smokers and the significance of Asian ethnicity

Abstract

8004 Background: Never-smokers with non-small cell lung cancer (NSCLC) have unique epidemiologic features and survival outcome. Methods: This retrospective population-based study of never-smokers with NSCLC involves analysis of NSCLC cases from the Cancer Surveillance Programs of three Southern California counties from 1991 to 2005. Results: 25,204 NSCLC patients with known smoking status were analyzed. 2240 patients (8.9%) were never-smokers. More females, more adenocarcinoma, approximately 3-fold more bronchioloalveolar carcinoma (BAC), and more distant disease were found among never-smokers. Median age of presentation was higher for never-smokers (vs. smokers; 71 vs. 69 years; P < .0001). Overall survival (OS) (P < .0001) and lung cancer-specific survival (LCSS) (P < .0001) in never-smokers were significantly improved over smokers. Never-smokers with distant disease (8 months OS improvement) benefited more from chemotherapy than smokers (6 months OS improvement). By multivariate analysis smoking status remained a significant poor prognostic factor for OS (vs. never-smokers, HR = 1.140, 95% CI: 1.080–1.203) and LCSS (vs. never-smoker, HR = 1.159, 95% CI: 1.090–1.233). Asian ethnicity was a favorable prognostic factor for OS among smokers (vs. Caucasian, HR = 0.847, 95% CI: 0.794–0.904) and never-smokers (vs. Caucasian, HR = 0.861, 95% CI: 0.750–0.988). Conclusions: Ever-smoking status is a poor prognostic factor in NSCLC. Among female NSCLC patients, Asians (45.6%) has the highest percentage of never-smokers followed by Hispanics (25.0%), Caucasians (12.6%) and African-Americans (10.8%). Asian ethnicity is a favorable prognostic factor among smokers and never-smokers. No significant financial relationships to disclose.