Background: A retrospective study was conducted to define the characteristics and the prognosis of N2 disease subgroups according to their patterns of spread.
Methods: From January 1993 to December 2004, 1,329 patients underwent lung resection for bronchogenic carcinoma The records of all patients with positive mediastinal lymph nodes at the surgical specimen (pIIIA/N2) after radical resection were analyzed, and the pattern of mediastinal lymphatic spread was classified according to regional spread, to skip metastasis, and to one or two or more lymph node stations, in relation to primary tumor location. Age, sex, type of resection, right or left lesion, T status, primary tumor location, tumor size, tumor central or peripheral location, histology, and survival were recorded and analyzed. Survival was analyzed according to regional spread or not, number of mediastinal lymph node stations involved, and skip metastasis status.
Results: Among 302 cases (22.7%) with positive mediastinal lymph nodes pIIIA/N2, 66 (22%) were skip metastases, 72 (24%) had a nonregional mode of spread, and 199 (66%) included two or more stations of mediastinal lymph node invasion. Cox regression analysis of all cases disclosed malignant invasion in only one mediastinal lymph node station as the only favorable factor of survival (p < 0.001, odds ratio 0.57, 95% confidence interval: 0.42 to 0.78).
Conclusions: The presence of one-station mediastinal lymph node metastasis in patients with nonsmall-cell lung cancer who underwent major lung resection with complete mediastinal lymph node dissection proved to be a good prognostic factor that should be taken into account in the future.