Background: The purpose of this population-based study is to provide a detailed analysis of survival outcome of patients with stage IIIB and IV non-small cell lung cancer (NSCLC) enrolled in the Surveillance, Epidemiology and End Results (SEER) program.
Methods: We retrieved, from the SEER database, data on demographics, disease extension (size, extent of primary tumor, and nodal status), histology, primary treatment modality, and survival time of NSCLC cases diagnosed between 1998 and 2003 (n = 138,063). Cases were reclassified into separate T4 (satellite, invasive, or pleural effusion) and M1 (ipsilateral, contralateral, or distant) categories based on the extent of the primary tumor and the location of metastatic disease. Univariate and multivariate analyses were performed to assess the effects of each variable on survival.
Results: For stage IIIB NSCLC, T4 satellite had the best prognosis (comparable to T2 lesions), followed by T4 invasive and T4 pleural effusion. For stage IV, M1 ipsilateral had the best prognosis, followed by M1 contralateral and M1 distant. Nodal status remained a powerful determinant of survival, particularly for patients with T4 satellite, T4 invasive, M1 ipsilateral, and, to a less extent, M1 contralateral. Other prognostic variables were identified within each subgroup.
Conclusions: In this report, we present the most comprehensive analysis performed to date of patients with stage IIIB and IV NSCLC enrolled in the SEER program. The survival trends observed here suggest that T4 satellite lung cancer cases should be redefined as T2b, and not T3 as recently proposed for the upcoming TNM classification, seventh edition.