Metastasis to subsegmental and segmental lymph nodes in patients resected for non-small cell lung cancer: Prognostic impact

Background We investigated the prognostic significance of segmental and subsegmental (level 13 and 14) lymph nodes metastasis in patients with resected non-small cell lung cancer (NSCLC). Methods The pattern of lymph nodal metastasis was analyzed in 124 patients with pN1 NSCLC. Long-term outcomes were compared for 390 pN0, 124 pN1, and 82 pN2 consecutive patients submitted to planned pulmonary resection for NSCLC between 2000 and 2006. The pN1 status was stratified into 3 groups according to the highest level of lymph node involvement: level 10 (hilar); level 11+12 (lobar + interlobar); and level 13+14 (segmental + subsegmental). Results The 5-year overall survival (OS) rates for pN0, pN1, and pN2 patients were 93%, 66%, and 25%, respectively. The highest level of lymph node involvement was a significant prognostic indicator; the 5-year OS rate for level 13+14, level 11+12, level 10 pN1, and pN2 was 81%, 58%, 48%, and 25%, respectively. Significant differences were recorded in long-term outcome when pN0 and pN1 level 13+14, pN1 level 13+14, and pN1 level 11+12, pN1 level 11+12 and pN1 level 10 were compared (p < 0.05). The median number of examined level 13+14 lymph nodes was 2 (range 0 to 6) and 57% pN1 patients had metastasis at level 13+14 lymph nodes. Conclusions The highest level of lymph node metastases may be used to stratify outcome of patients with pN1 disease. Routine examination of level 13+14 lymph nodes is to be recommended to correctly identify patients at risk of relapse and predict long-term prognosis.