[Clinical study of metastasis of thoracic lymph node in resectable lung cancer].

OBJECTIVE

To study the metastatic pattern of thoracic lymph node in resectable lung cancer.

METHODS

From January 1992 to July 1998, the lymph nodes in hilar(N1) and mediastinal(N2) were resected based on their distribution in 160 patiens with resectable lung cancer and were examined by pathology. Number, size and colour of lymph nodes in each regions were recorded. Each lymph node was examined by routine pathology and immunohistochemistry. Quantity of metastatic lymph node was reported according to their regions.

RESULTS

99 cases(61.9%) had thoracic lymph nodes metastasis and 73 cases (45.6%) had mediastinal lymph nodes metastasis. Of those, only N1 metastasis was 16.3%, from N1 to N2 metastasis was 32.5%, only N2 metastasis was 13.1%. The metastatic frequencies in 11, 10, 7, 5 and 4 regions around the hilar or root of lung were 30.0%, 27.5%, 16.9%, 28.8% and 20.0%, respectively. Those were higher than 9, 6, 3, 2 and 1 regions far from the root of lung. The metastatic rate of lymph node in 2.0 cm or greater, 1.0 cm or greater and less than 1.0 cm was 60.7%, 15.5% and 4.3%, respectively (P < 0.001). The smallest metastatic lymph node was only 0.2 cm x 0.2 cm. Statistical analysis revealed that metastatic rate of thoracic lymph nodes was not relevant to different area, size and course of tumors.

CONCLUSIONS

The lymph nodes metastases of most cases were spreading from the near to the distant, from lower to upper, through the hilar to the mediastinal. Lymph nodes metastases occurred easier in SCLC than in NSCLC (P < 0.05). It must be depended on pathologic examination to confirm whether or not the tumor has metastasis to lymph node.