Which subgroup of patients with pathologic N2 non-small cell lung cancer benefit from surgery?

OBJECTIVE: Patients with pathologic N2 non-small cell lung cancer comprise a heterogeneous group. The objective of this study was to evaluate which subgroup of patients with pathologic N2 benefit from surgery in terms of survival probability.
METHODS: This retrospective study included 141 patients who had undergone major resection with pathologically proven N2 from 1990 to 2006 (103 with adenocarcinoma, 38 with squamous cell carcinoma). Patients undergoing preoperative induction therapy were excluded. Records were examined for age, gender, tumor size, surgical procedure, surgical side, clinical N status, primary tumor lobe, curative resection, and metastatic N2 stations.
RESULTS: In patients with adenocarcinoma, surgical procedure, clinical N status, curative resection, and metastatic N2 stations were significant prognostic factors in univariate analysis. Age and curative resection were significant factors in patients with squamous cell carcinoma. In multivariate analysis, clinical N2 (P = 0.003), incomplete resection (P = 0.04), and multi-station N2 (P = 0.004) were significant adverse prognostic factors in patients with adenocarcinoma, whereas only incomplete resection (P = 0.002) was significant in patients with squamous cell carcinoma. For adenocarcinoma patients with pathologic N2, the 5-year survival rates were 58.8% for clinical N0-1 and single-station N2, 50% for clinical N2 and single-station N2, 23.9% for clinical N0-1 and multi-station N2, and 0% for clinical N2 and multi-station N2.
CONCLUSIONS: Prognosis of patients with pathologic N2 can be grouped according to clinical N status and metastatic N2 stations in adenocarcinoma, but not in squamous cell carcinoma. Only adenocarcinoma patients with pathologic N2 appear to have heterogeneous subgroups with different prognoses.