Background: Racial minorities exhibit poor survival with nonsmall cell lung cancer (NSCLC) that generally is attributed to low socioeconomic status (SES). In this study, the authors investigated the role of SES in this survival disparity among patients with stage I NSCLC.
Methods: A case-only analysis was performed on California Cancer Registry (CCR) data (1989-2003). Univariate survival analyses were performed using the Kaplan-Meier method. Multivariate survival analyses were performed using Cox proportional hazards ratios.
Results: In total, 19,702 incident cases of stage I NSCLC were analyzed. Low SES was identified more commonly in African-American and Hispanic patients and was associated significantly with men, unmarried status, stage IB disease, squamous cell histology, poorly differentiated tumors, fewer surgical resections performed, and less overall treatment received. Reasons for no surgery were associated strongly with low SES and unmarried status but not with race. In multivariate analysis, each incremental improvement in SES quintile was associated with statistically significant decreases in the hazard ratios (HRs) for death (second SES quintile [SES2] vs SES1: HR, 0.91; 95% confidence interval [95% CI], 0.85-0.98; SES3 vs SES1: HR, 0.90; 95% CI, 0.84-0.97; SES4 vs SES1: HR, 0.83; 95% CI, 0.77-0.89; SES5 vs SES1: HR, 0.78; 95% CI, 0.72-0.84; P(trend) < .0001). African-American or Hispanic race was not an independent poor prognostic factor for survival after adjustment for surgery, SES, and marital status.
Conclusions: Low SES was an independent poor prognostic factor for survival in patients with stage I NSCLC and was independent of surgery, race, and marital status.