Clinical impact of micrometastasis of the lymph node in gastric cancer

Micrometastasis in regional lymph nodes has been observed immunohistochemically, but the biological and clinical roles of minute nodal invasion of carcinoma in gastric cancer remain unclear. We used the anti-cytokeratin (AE1/AE3) antibody to immunohistochemically detect nodal micrometastatic lesions that could not be identified by routine pathological examination. A total of 4203 lymph nodes were examined in 180 gastric cancer patients. Lymph node metastasis was found in 36 of the 180 patients by routine pathological evaluation. Immunohistochemically micrometastasis was detected in the lymph nodes of 19 node-negative patients. Micrometastasis was not detected in any of the mucosal gastric cancer patients who underwent lymph node dissection. Gastric cancer patients with more than six metastatic lymph nodes all had nodal micrometastasis. Patients with micrometastasis had a significantly poorer survival rate than those without micrometastasis (P < 0.05). Based on the present results the presence of lymph node micrometastasis may provide a more accurate indication for surgical outcome in gastric cancer patients at the same clinical stage.