Prognostic Significance of Subcarinal Station in Non-Small Cell Lung Cancer with T1 - 3 N2 Disease

BACKGROUND: Surgical resection may continue to offer the best chance of long-term survival for patients with non-small cell lung cancer (NSCLC). Generally, patients with N2 NSCLC have a poor prognosis. However, the surgical treatment of patients with N2 remains controversial as in these patients, some N2 subgroups have better prognoses than others. The objective of the current study was to evaluate the factors associated with N2, and to determine whether such factors are reliable predictors of survival. METHODS: We retrospectively reviewed 142 non-small cell lung cancer patients with T1-3 N2 in whom a curative approach had been attempted between January 1994 and December 2003. The patients were consequently divided into four groups (NS-1, no subcarinal involvement and without N1; NS-2, no subcarinal involvement and with N1; SI-1, subcarinal involvement and without upper mediastinal site; SI-2, subcarinal involvement and with upper mediastinal site). We also evaluated two groups for N2 stations (single-station N2 versus multiple-station N2). Multivariate analysis by Cox's proportional hazards regression model was performed to identify the prognosis. RESULTS: Lobectomy was carried out in 105 of the patients; bilobectomy in 10, and pneumonectomy in 27. The patients with T1-3 N2 disease showed survival rates of 34.1 % at 3 years and 24.1 % at 5 years. The overall survival rates at 3 years and 5 years were as follows: NS-1, 56.3 % and 43.2 %; NS-2, 35.4 % and 29.5 %; SI-1, 16.7 % and 0 %; SI-2, 15.4 % and 0 %, respectively. The NS-1 group had better prognoses than the other groups. There was a significant difference in survival rates within each group ( p = 0.0005). In univariate analysis, the type of surgery, type of subcarinal involvement, and multiple-station N2 were significantly associated with prognosis. Multivariate analysis showed that NS-1 was only found to be an independent prognostic factor in cases of T1-3 N2 disease ( p = 0.0018). NS-2 was not an independent factor but tended toward significance ( p = 0.0681). But multiple-station N2 was not an independent factor ( p = 0.1549). CONCLUSIONS: Surgery for patients with T1-3 N2 NSCLC might be acceptable if subcarinal lymph node metastasis is predicted to be absent.