Prognostic implication of metastasis limited to segmental (level 13) and/or subsegmental (level 14) lymph nodes in patients with surgically resected nonsmall cell lung carcinoma and pathologic N1 lymph node status

Abstract

In patients with nonsmall cell lung carcinoma (NSCLC) who have with pathologic N1 (pN1) lymph node status, the prognostic significance of segmental lymph node (level 13) metastasis and/or subsegmental lymph node (level 14) metastasis is unknown. Lymph node metastasis patterns were analyzed in 230 patients with NSCLC who had pN1 status. Clinical outcomes were examined for 230 patients with pN1 status and 700 patients with pN0 status. The pN1 group was stratified into 4 subgroups according to the highest level of lymph node involvement. The 5-year disease-free survival (5DFS) rates for pN1 and pN0 patients were 50.1% and 90.5%, respectively. The highest level of lymph node involvement was a significant prognostic indicator; the 5DFS rates for patients with pN1 status who had level 13/14, lobar (level 12), interlobar (level 11), and hilar (level 10) lymph node metastasis were 69.4%, 46.4%, 46.7%, and 37%, respectively. Patient outcomes were significantly worse for those with pN1 status who had only level 13/14 lymph node metastasis than for patients with pN0 status (P = .0034), and outcomes were significantly worse for patients with pN1 status who had level 11/12 lymph node metastasis than for patients who had only level 13/14 lymph node metastasis (P = .021). The median number of level 13/14 lymph nodes examined was 3 (range, 0-22 level 13/14 lymph nodes), and metastases to these lymph nodes were detected in 61% of patients who had pN1 status. A single lymph node pN1 disease, single-level pN1 status, and squamous cell carcinoma histopathology also were indicators of a better patient outcome. The current results indicated that the highest level of lymph node involvement may be used to stratify the outcome of patients who have NSCLC with pN1 status. Patients with pN1 status who had only level 13/14 lymph node metastasis had an intermediate 5DFS rate between that of patients with pN0 status and other patients with pN1 status. Routine examination of level 13/14 lymph nodes is important for accurate pathologic staging and for the predicting clinical outcome of patients with NSCLC.