BACKGROUNDTo study the metastatic pattern of thoracic lymph nodes in patients with resectable lung cancer.

METHODSFrom January 1992 to December 2000, radical lobectomy or pneumonectomy and systemic lymphadenectomy were performed in 306 patients with lung cancer. Number, size, colour and hardness of lymph nodes in each region were recorded and neoplastic metastasis was examined by pathology.

RESULTSOut of 4 614 resected lymph nodes from 2 456 regions, 954 lymph nodes from 521 regions were confirmed to have metastasis. The metastatic rates of thoracic lymph nodes and mediastinal lymph nodes were 61.8% and 43.5% , respectively. The metastatic frequencies in regions around the hilar or root of lung (11,10,7,5,4) were higher than those of regions far from the root of lung (9,6,3,2,1). There was a remarkably higher metastatic rate of lymph nodes in small cell lung cancer than that in non small cell lung cancer (P < 0.01 ). The metastatic rate was closely related to size, colour and hardness of lymph nodes (P < 0.001, P < 0.001 , P < 0.001 ).

CONCLUSIONSMost of neoplastic metastasis of lymph nodes spreads from proximal to distal areas, lower to upper regions, and from the hilar to the mediastinal. A few mediastinal lymph nodes show a skipping pattern. It is necessary to perform systemic lymphadenectomy during pulmonary resection.