Prediction of lymph node status in completely resected IIIa/N2 small cell lung cancer: importance of subcarinal station metastases

BACKGROUND: The aim of this study was to determine the prognostic value of lymph node status in patients with pathologic N2 (pN2) stage IIIA small cell lung cancer (SCLC). METHODS: A total of 163 consecutive pN2 stage IIIA SCLC patients who underwent pulmonary resections and systematic lymphadenectomies at Shanghai Chest Hospital between January 2006 and June 2014 were enrolled. We retrospectively analyzed the potential clinicopathologic factors that influenced survival, including the node levels (single or multiple-station) and the node-spreading patterns (skip N2 or non-skip N2). The prognostic significance was examined by Cox regression analysis. RESULTS: The median overall survival (OS) was 23.7 months. Multiple-station lymph node metastasis indicated a poorer prognosis than single-station involvement (p = 0.003). Skip metastasis did not appear to influence survival (p = 0.099). With respect to the station of lymph node metastasis, the OS was only related to the involvement of the subcarinal node, regardless of tumor location (p < 0.05). Multivariate analysis showed two statistically significant risk factors for survival, including multiple-station lymph node and subcarinal node metastasis (hazard ratio [HR] = 1.76, 95% confidence interval [CI]:1.11–2.78, p = 0.015; HR = 1.61, 95% CI: 1.03–2.50, p = 0.036, respectively). CONCLUSIONS: Multiple-station N2 metastasis and involvement of the subcarinal node predicted poor prognosis in pN2 stage IIIA SCLC patients, which may profoundly influence therapeutic decisions.