Several studies from groups that systematically perform mediastinal lymph node dissection in conjunction with pulmonary metastasectomy have been published and in all studies the presence of lymph node metastasis emerges as an ominous prognostic factor. Ercan and colleagues found a 3-year survival of 69% for patients without lymph node involvement versus 38% in patients with positive lymph nodes. Saito and colleagues reported a 5-year survival of 53,6 for patients without hilar or mediastinal node involvement versus 6,2% at 4 years for patients with positive nodes. Bölükbas and colleagues reported a 5-year survival of 59% for patients without lymph node involvement in contrast to 23% for patients with lymph node involvement.