BACKGROUNDLymphatic dissemination is the main approach of metastasis in lung cancer, and it is also an important prognostic factor. The aim of this study is to explore the relationship between tumor size and lymph node metastasis in squamous cell carcinoma and adenocarcinoma of the lung.

METHODSA total of 240 patients diagnosed as squamous cell carcinoma and adenocarcinoma were studied. The relationship between tumor size and lymph node metastasis was analyzed.

RESULTSLymph node metastasis rate in maximum diameter (d)≤2cm, 2cm < d≤3cm, 3cm < d≤6cm, 6cm < d≤10cm, and d > 10cm groups was 50.0%, 35.1%, 52.8%, 52.1% and 71.4%, respectively. There was no correlation between tumor size and lymph node metastasis (r=0.10, P > 0.05). Lymph node metastasis occurred more frequently in adenocarcinoma (58.8%) than that in squamous cell carcinoma (42.9%) (P < 0.05). Mediastinal lymph node metastasis was found in 7 patients (16.3%) with d≤3cm, who were all diagnosed as moderate or poor differentiation.

CONCLUSIONSLymph node metastasis is not related to tumor size. Lymph node metastasis occurs more frequently in adenocarcinoma than it does in squamous cell carcinoma. Mediastinal lymph node metastasis can be found in tumor with d≤3cm, and differentiation grade may play an important role in lymph node metastasis.