gms | German Medical Science

Introduction: Lung cancer is the leading cause of cancer-related deaths in the United States, but lung cancer survival differs across race and ethnic groups, sex, and histology. For instance, prior studies utilizing Surveillance, Epidemiology, and End Results (SEER) data found that, for early-stage non-small cell lung cancer, women have a better overall survival than men and that Asian/Pacific Islanders have a better survival than Whites. These studies utilize registry data and have not accounted for other factors that may influence survival, such as education and smoking status. Here, we investigated lung cancer survival in a multiethnic population accounting for education and smoking status at baseline.

Methods: This analysis utilized data from the Multiethnic Cohort (MEC) study. A total of 6,888 incident lung cancer cases were identified from linked data with Hawaii and California SEER cancer registries from 1993-2019. Cox proportional hazards models were performed to estimate hazards ratios (HR) and their 95% confidence intervals (95% CI) for all-cause mortality. Follow-up time was calculated from age at lung cancer diagnosis to age of the following end points: death or end of follow-up (December 31, 2019). Lung cancer cases alive at the end of the follow-up were censored. The model included stage (localized, regional, distant, and unknown), as a strata variable, and was adjusted for age at diagnosis, age at cohort entry (to account for birth cohort), race and ethnicity (African American, Native Hawaiian, Japanese American, Latino, and White), sex, education (≤ high school graduate, some college/vocational, and ≥ college graduate), smoking status at baseline (ever and never), and histologic cell-types (adenocarcinoma, squamous cell carcinoma, large cell carcinoma, and small cell carcinoma).

Results: After a mean follow-up period of 2.2 ± 3.7 years, a total of 6,228 deaths were observed. In a multivariable analysis, lower overall mortality was observed in women compared to men (HR=0.85; 95% CI: 0.81-0.90) and for those who never smoked compared to those who smoked (HR=1.37; 95% CI: 1.25-1.49). Higher overall mortality was also found for those who had an educational attainment level of high school or less compared to those with a college education or higher (HR=1.28; 95% CI: 1.19-1.37). Compared to adenocarcinoma, squamous cell carcinoma (HR=1.22; 95% CI: 1.14-1.31) and small cell carcinoma (HR=1.49; 95% CI: 1.36-1.63) were associated with higher overall mortality. Survival differences across races and ethnicities were not detected in the fully adjusted multivariable model. These findings were consistent across subgroup analyses by stage at diagnosis and the five race and ethnic groups in the MEC.

Conclusion: In a multiethnic population, overall survival following lung cancer diagnosis was better for females, non-smokers, individuals with a college education or higher, and adenocarcinoma subtype. Future directions include adjusting for additional lifestyle and socioeconomic factors to improve our understanding of factors that contribute to survival after lung cancer.

The authors declare that they have no competing interests.

The authors declare that an ethics committee vote is not required.