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. Non-upper lobe tumor location (right middle lobe, right and left lower lobes) and tumor size > or =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 non-upper lobar tumor location or tumor size > or =4 cm carried an increased mortality risk.