Clinical study of lymph node metastasis in lung cancer

Objective To investigate the frequency,distribution and feature of lymph nodes metastasis in lung cancer as to provide evidence for extensive dissection of lymph nodes. Method 386 patients with lung cancer underwent surgery plus extensive dissection of hilar,inter lobor and mediastinal noodes according to the grouping system proposed by Naruke. Results A total of 2?603 groups of lymph nodes were removed.Metastatic rates of N 1 and N 2 nodes were 20.1% and 16 2%. Significant difference of lymph node metastasis existed among T 1,T 2 and T 3 patients(P0 01). No cancer metastasized to mediastinum in T 1 squamous carcinoma. N 2 metastatic rates for squamous carcinoma,adenocarcinoma,small cell carcinoma and large cell carcinoma were 30 1%,44 1%,48 0% and 50 0%,respectively. 64 2% of N 2 nodes in squamous carcinoma localized to one single group. 46 2% of N 2 nodes in adenocarcinoma spread to more than 3 groups. Sloitary metastatic nodes accounted for 53 7% of N 2 nodes. 15 1% of N 2 positive cancer in upper lobes metastasized to lower mediastinum,while 53 1% of N 2 positive cancer in lower lobes spread to upper mediastinum. Conclusion Solitary and multiple metastasis are the characteristic of lymph nodes metastasis in lung cancer. The frequency of metastasis increases with the growth and invasion of tumor. Metastasis in adenocarcinoma occurs more frequently than in squamous carcinoma. Tumor at any site can metastasize to distant mediastinum.Except for T 1 squamous carcinoma,radical surgery can be achieved only by extensive dissection of intrapulmonary and ipsilateral mediastinal lymph nodes.