Asian Ethnicity Is a Favorable Prognostic Factor for Overall Survival in Non-small Cell Lung Cancer (NSCLC) and Is Independent of Smoking Status

BackgroundWe previously showed that Asian ethnicity was an independent favorable prognostic factor in non-small cell lung cancer (NSCLC). Many Asian NSCLC patients were never-smokers, and never-smokers had improved survival than ever-smokers. We investigated whether Asian ethnicity is a favorable prognostic factor independent of smoking status.MethodsRetrospective population-based study of NSCLC cases from the cancer surveillance programs of three Southern California counties from 1991 to 2005.ResultsA total of 20,140 NSCLC patients with known smoking status were analyzed of which 9.1% were never-smokers and 6.5% were Asians. There was a threefold increase in the percentage of Asian never-smokers as compared with ever-smokers. Asians had the highest overall survival (OS) among the 4 major ethnicities (p < 0.0001) and never-smokers had improved OS over ever-smokers (p = 0.0183) by univariate analyses. By multivariate analyses, Asian ethnicity was an independent and favorable prognostic factor for OS (versus non-Asian; hazard ratio [HR] = 0.861, 95% confidence interval [CI]: 0.808–0.918, p < 0.0001), among smokers (versus non-Asian; HR = 0.867, 95% CI: 0.807–0.931, p < 0.0001), and among never-smokers (versus non-Asian; HR = 0.841, 95% CI: 0.728–0.971, p = 0.0180). Never-smoker was a favorable prognostic factor if ethnicity was not accounted for (versus ever-smoker; HR = 0.936, 95% CI: 0.886–0.988, p = 0.0169) but was no longer an independent favorable prognostic factor (versus ever-smoker; HR = 0.953, 95% CI: 0.902–1.007, p = 0.0861) after accounting for ethnicity.ConclusionsAsian ethnicity is an independent favorable prognostic factor for OS in NSCLC regardless of smoking status.