Risk of limited lymph node dissection in patients with clinically early gastric cancer: Indications of extended lymph node dissection for early gastric Cancer

Background: Laparoscopic gastrectomy is usually indicated in T1 N0-1 early gastric cancer (EGC). Limited lymph node dissection, such as D1+, is applied in these cases. However, preoperative staging is not always correct, and the risk of undertreatment thus exists. Methods: Patients with clinically early gastric cancer (cEGC) who underwent gastrectomy with lymph node dissection of D2 and over were selected from 4,021 patients with gastric cancer. The station numbers of all metastatic lymph nodes (MLNs) were identified, and MLNs were classified into groups 1 and 2 (including lymph nodes of second tier and over) on the basis of the system of the Japanese Gastric Cancer Association, irrespective of the number of MLNs. Clinicopathological data were compared according to the existence of lymph node metastasis and the classification of MLNs. Results: Of 1,308 patients with cEGC who fulfilled the inclusion criteria, 1,184 (90.5 %) were diagnosed pathologically with EGC. Among 126 patients with cEGC who were diagnosed with lymph node metastasis, 93 patients had only group 1 MLNs and 33 patients had group 2 MLNs. Tumor location in the proximal third of the stomach (odds ratio 5.450) and ulceration (odds ratio 11.928) were significant factors for group 2 metastasis. Conclusions: Extended lymph node dissection is recommended in cEGC with ulceration or disease located in the proximal third of the stomach.