Prognostic impact of bulky swollen lymph nodes in cN1 non-small cell lung cancer patients

Objective: The aim of this study was to analyze clinicopathological backgrounds and prognosis of clinical N1 non-small cell lung cancer and clarify the difference between bulky and non-bulky cN1 diseases. Methods: We reviewed 110 patients with completely resected cN1 non-small cell lung cancer and examined the prognostic impact of lymph node size. We classified the swollen lymph nodes into two groups based on their size on chest computed tomography: short-axis diameter >= 20 mm (=bulky group) or <20 mm (= non-bulky group). Results: The bulky group consisted of 10 patients, and the non-bulky group comprised 100 patients. There was no significant difference in the upstaging rate to pathological N2 between the bulky and non-bulky groups (31% vs. 30%; P = 0.63). The 5-year recurrence-free survival rate and 5-year overall survival rate of both groups did not differ significantly (P = 0.36, P = 0.30, respectively). Our results suggested the possibility that the size of the swollen lymph nodes had no impact on the prognosis in cN1 non-small cell lung cancer patients. In comparison of surgical procedure, pneumonectomy was performed in the bulky group more frequently than the non-bulky group (70% vs. 19%; P < 0.01). Conclusions: Bulky cN1 disease was not different from non-bulky disease in the prognosis and the upstaging rate to pN2. Curative resection should be indicated to resectable bulky cN1 disease as with non-bulky disease, with careful pre-operative evaluation and preparation considering the possibility of pneumonectomy.