Prediction of ipsilateral mediastinal lymph node metastasis (N2 disease) in patients with lung cancer

Background: To determine the relation between the clinical pathophysiological characteristics and mediastinal lymph node metastasis (N2 disease) in patients with non-small cell lung cancer(NSCLC).

Methods: A retrospective study was carried out. Between January, 1996, and October, 1999, 378 patients with NSCLC underwent mediastinal lymph nodes dissection, and 105 of them were proved to be N2 disease through pathological examination. A clinical lymph node staging (c-N) was determined on the basis of findings of preoperative CT scan in each patient: mediastinal or hilar lymph nodes 1.0cm or larger in the shortest axis were diagnosed as metastasis (c-N1-2). Univariate and multivariate analysis were performed to determine the relationship between clinical predictors and pathologically proven N2 disease.

Results: Among all of the 378 cases, N2 disease accounted for 27.8%(105/378). c-N2 disease, adenocarcinoma and c-T3 tumor were the significant clinical predictors of pathological N2 disease on the basis of multivariate analysis (P<0.001). Among 316 patients with c-N0-1 disease, N2 disease accounted for 23.4%(74/316). Adenocarcinoma and c-T2-3 tumor were significant clinical predictors of pathologic N2 disease according to multivariate analysis procedure (P<0.05). When these predictors were combined, more than 50% of adenocarcinoma with c-T3 tumor and about 40% of adenocarcinoma with c-T2 tumor had N2 disease (P<0.01).

Conclusions: In the patients with adenocarcinoma and c-T2 or c-T3 tumor, probability of pathological N2 disease should be considered.