Prognosis of Stage II non-small cell lung cancer according to tumor and nodal status at diagnosis

Abstract

To evaluate the prognostic significance of tumor and node status among patients with Stage II non-small cell lung cancer using a population-based national database. We identified all primary cases of Stage II non-small cell lung cancer diagnosed prior to autopsy from the Surveillance, Epidemiology and End Results (SEER) registry. Lung cancer-specific survival curves were obtained for the 5254 patients who had curative surgical resection, stratifying for tumor and node status (T1-2N1M0, T3N0M0). The 12.5-year Kaplan-Meier estimator of survival was used as a measure of lung cancer cure rate. The influence of gender, age, cell type, pathologic tumor status, nodal metastasis, surgical method, and post-operative radiation therapy were evaluated using Cox regression. Survival was better for T1N1 cases during the first 3--4 years after diagnosis. Five-year survival for T1N1 and T3N0 cases however, was not significantly different (46% versus 48%, p=0.4) and the cure rate was somewhat higher for T3N0 cases (33% versus to 27%, p=0.10). T2N1 cases had the worst overall survival. Multivariate analysis revealed that gender, age, tumor and nodal status, and histology were independent prognostic factors. Among Stage II cancers, T3N0 cases have the highest cure rate and an overall survival pattern that more closely resembles T1N1 tumors. Several clinico-pathologic characteristics are significantly associated with survival and may explain some of the heterogeneity in outcomes among Stage II patients. These results suggest that T3N0 cases may be better classified as Stage IIA disease.