Staging of gastric cancer: correlation of lymph node size and metastatic infiltration.

OBJECTIVE: The assessment of lymphatic metastases is an important factor in the staging of gastric cancer. Lymph node size has been used as one criterion for possible nodal metastasis. Although enlarged regional lymph nodes are generally interpreted as metastases, few data are available that correlate lymph node size with metastatic infiltration. MATERIALS AND METHODS: In a prospective morphometric study, the regional lymph nodes from 31 gastrectomy specimens of consecutive patients with primary gastric adenocarcinoma were analyzed. The lymph nodes were counted, the largest diameter of each node was measured, and each node was analyzed for metastatic involvement by histologic examination. The frequency of metastatic involvement was calculated and correlated to lymph node size. RESULTS: A total of 1253 lymph nodes were present in the 31 specimens examined for this study. A mean number of 40 lymph nodes (range, 20-53) were found in each specimen. Of these 1253 nodes, 922 (74%) were tumor-free and 331 (26%) contained metastases. The mean diameter of the lymph nodes free of metastases was 4.1 mm, whereas that of nodes infiltrated by metastases was 6.0 mm (p < .0001). Of the tumor-free lymph nodes, 735 (80%) were less than 5 mm in diameter, whereas 182 (55%) nodes containing metastases were less than 5 mm in diameter. Of the 10 patients without lymph node metastases, seven had at least one node that was 10 mm or greater in diameter; similarly, 15 (71%) of the 21 patients with node metastases had at least one node that was 10 mm or greater in diameter. CONCLUSION: Lymph node size is not a reliable indicator for lymph node metastasis in patients with gastric cancer.