Mediastinal Lymph Node Metastasis Pattern in Clinically N0 Non-small-cell Lung Cancer Patients Who Underwent Surgical Resection

The aim of this study was to evaluate the incidence, clinical data and patterns of mediastinal lymph node metastasis (pN2) in non-small-cell lung cancer patients who underwent systematic mediastinal lymph node dissection (SMLND). We retrospectively studied 140 consecutive patients [125 male and 15 female, mean ages 54.61±9.23 years (range, 21-75)], underwent SMLND and major lung resections due to non-small lung cancer (NSCLC), from January 2005 till December 2009. Preoperative clinical staging for mediastinal lymph node metastasis was negative (cN0) in all patients. SMLND was defined as a complete removal of mediastinal lymph nodes. Clinicalpathological data were compared according to the pN stage. Lymph node metastasis to the mediastinum was confirmed in 13 (9.28%) patients. In squamous cell cancer pN2 were in 8 (5.71%) cases out of 82 cases with cN0. On the other side in the adenocarcinomas pN2 were in 5 (3.57%) cases out of 48 with cN0. Unvaried analysis revealed central tumor site as predictive factor for mediastinal lymph node involvement. The upper mediastinal compartment was infiltrated in 12 (8.57%) cases, middle in 8 (5.71%) and lower in 3 (2.14%) cases. Pneumonectomy was the most performed surgical procedure in pN2 patients. We concluded that SMLND improves pTNM staging in lung cancer patients who underwent major lung resections with central location of the tumour.