Prognostic factors for survival of stage I nonsmall cell lung cancer patients - A population-based analysis of 19,702 stage I patients in the California Cancer Registry from 1989 to 2003

BACKGROUND. Platinum-based adjuvant chemotherapy in randomized trials has failed to provide a survival benefit in patients with resected stage I nonsmall cell lung cancer (NSCLC). Using data from the California Cancer Registry (CCR), we explored factors that had detrimental effects on survival in patients with stage I NSCLC to identify a subset of patients at high risk for disease recurrence and subsequent mortality. METHODS. Between 1989 and 2003, 19,702 incident cases of stage I NSCLC in the CCR were identified and subgrouped into stage IA and IB disease. Patient demographic factors, tumor characteristics, and treatment delivered were examined. Kaplan-Meier survival curves were calculated to estimate survival rates. Cox proportional-hazards ratios were used to identify independent prognostic factors for survival. RESULTS. Advanced age at diagnosis, male sex, low socioeconomic status (SES), nonsurgical treatment, and poor histologic grade (stage IA NSCLC: hazards ratio [HR], 1.13; 95% confidence interval [95% CI], 1.08-1.19; stage IB NSCLC: HR, 1.11; 95% CI, 1.07-1.16) were associated with increased mortality risk on multivariate analysis. Nonupper lobe tumor location (right middle lobe, right and left lower lobes) and tumor size >= 4 cm (vs <4 cm: HR, 1.23; 95% CI, 1.15-1.30) were additional factors that increased the risk of mortality among patients with stage IB disease. Bronchioloalveolar carcinoma and Asian ethnicity were associated with decreased mortality risk in stage I NSCLC. CONCLUSIONS. Stage I NSCLC with poorly differentiated histology and stage IB NSCLC with nonupper lobar tumor location or tumor size >= 4 cm carried an increased mortality risk.