Purpose: In order to examine the significance of a sentinel lymph node for gastric cancer, we investigated single node metastases that were hypothesized to represent the sentinel lymph node.
Methods: Of 2,265 primary gastric cancers patients we experienced from 1994 to 2003, 140 patients having gastric carcinoma with a single node metastasis were enrolled in this study. The factors we studied including age, gender, tumor size, location, cellular differentiation, stage, and the patients´ survival rate.
Results: Single node metastases were found in 30.7% of T1, 35.0% of T2, 29.3% of T3 and 5.0% of T4 staged tumor. Metastatic lymph nodes were mainly located near the tumor in 122 of 140 patients (87.1%). Skip metastases, which were defined as metastases that were found at more distant locations, were found in 18 patients (12.7%), and they were mainly located around the left gastric artery, the common hepatic artery, the proper hepatic artery and the splenic artery. The frequency of skip metastases significantly increased when the tumor was located upper part of the stomach, the tumor size was more than 5 cm in diameter and depth of tumor invasion was deeper (P<0.05). We found more frequent skip metastases in lymph nodes for the diffuse type of tumor infiltration than the macronodular type (P<0.05). The patients´ overall 5 year survival was 76.9%, and skip metastasis did not affect on the survival rate.
Conclusion: Our study supports the understanding of the biology of sentinel nodes. During gastrectomy in gastric cancer patients, great attention should be paid to remove the sentinel nodes and D2 dissection should be done when skip metastasis is suspected.