Intra-operative diagnosis of N2 lymph node metastasis of gastric cancer

Abstract

Background/aims: Limited lymph node dissection for gastric cancer, which is prevalent in Western countries, leaves cancer cells in the second tier of nodes in patients who have metastasis in those nodes. It is, however, difficult to correctly diagnose nodal status during surgery. The present study was, therefore, designed to examine how to detect N2 metastasis intra-operatively.

Methodology: Five hundred and eight patients undergoing extended lymph node dissections for gastric cancer were retrospectively analyzed. Accuracy of the intraoperative diagnosis of node involvement based on macroscopic findings was investigated, according to the N stage and histological type of the tumor. Furthermore, the distributions of N2 metastasis were clarified, according to tumor site.

Results: Intra-operative macroscopic findings were frequently assessed as being less severe than histological findings in cases with N2 metastasis (61.9%, 39/63). Intra-operative recognition of N2 metastasis was significantly lower in the cases with undifferentiated adenocarcinoma (28.2%, 11/39) than in those with differentiated adenocarcinoma (56.5%, 13/23). The distributions of N2 metastasis revealed nodes along the left gastric and common hepatic arteries to be the key junctions for lymphatic flow from the middle and lower thirds of the stomach, respectively.

Conclusions: Intra-operative diagnosis of N2 metastasis is difficult to make based on macroscopic findings, especially in undifferentiated tumors. To detect N2 metastasis intra-operatively, the nodes along the left gastric or common hepatic artery should be submitted to frozen section examination for primary tumors located in the middle or lower third of the stomach, respectively.