Clinical study on the metastatic patterns of lymph node in lung cancer

Abstract

To investigate the relationship between the size of primary tumor, pathologic classification, cell differentiation or location of tumor and lymph node metastasis in lung cancer. Three hundred and thirty-two patients with lung cancer underwent pulmonectomy plus extensive dissection of hilar and mediastinal nodes. The law of lymph node metastasis was analyzed. A total of 3 280 lymph nodes were removed. Metastatic rates of N1 and N2 were 29.9% and 22.4% respectively. The total lymph node metastatic rates of T1, T2, and T3 diseases were 8.5%, 27.4% and 61.2% respectively ( P < 0.005). No lymphatic metastasis was observed in well-differentiated squamous cell carcinoma, however, the lymph node metastatic rates in moderate- and poor-differentiated squamous cell carcinoma were 16.8% and 19.6% respectively. The lymph node metastatic rates were 27.5% and 71.6% in moderate- and poor-differentiated adenocarcinoma respectively ( P < 0.005). The total lymph node metastatic rates in central and peripheral squamous cell carcinoma were 19.6% and 11.7% respectively ( P < 0.005), while in adenocarcinoma, the rates were 57.9% and 24.0% respectively ( P < 0.005). The N2 metastatic rates in central and peripheral squamous cell carcinoma were 10.9% and 2.9% respectively ( P < 0.005), while in adenocarcinoma, the rates were 47.5% and 17.8% respectively ( P < 0.005 ). Under the same T status, cell differentiation or location of tumor, the metastatic rate of adenocarcinoma was much higher than that of squamous cell carcinoma ( P < 0.005 ). The frequency of lymph node metastasis significantly correlate with size of primary tumor, pathological classification, cell differentiation and location of tumor.