The Minimal Range of a Lymphadenectomy in Gastric Cancer according to an Analysis of Sentinel Lymph Node and Solitary Lymph Node Metastasis

Purpose: The incidence of nodal metastases is as low as 2 to $20\%$ in early gastric cancer, so there is a trend to lessen the extent of surgery. In addition, the adequate range for a lymphadenectomy is controversial, especially in early gastric cancer. In this study, we tried to find the minimal range for a lymphadenectomy by analyzing sentinel-node and solitary lymph-node metastases in gastric cancer. Materials and Methods: The total of 78 patients who underwent a curative gastrectomy with a D2 lymphadenectomy for early gastric cancer between 2000 and 2002 in the Department of Surgery, Yonsei University, Seoul, Korea, were included for the evaluation of sentinel-node metastases.. After a laparotomy, 25 mg of indocyanine green was mixed in 5 ml of normal saline, and all the dye was injected into the subserosal layer around the primary tumor. All nodes stained within 5 minutes were marked. In addition, a total of 141 patients, who underwent a curative gastrectomy between 1997 and 2001 at the Department of Surgery, Yonsei University, Seoul, Korea, were analyzed for solitary lymph- node metastases. Results: Among the 78 patients, sentinel nodes were detected in 69 patients ($88.5\%$). The sentinel nodes in 60 cases ($87.0\%$) were located in the perigastric area. However, 9 cases ($13.0\%$) had sentinel nodes in the N2 group. In the 141 cases that had a solitary metastatic node, 125 cases ($88.6\%$) demonstrated the metastatic lymph node in the perigastric area, and 16 cases ($11.4\%$) showed that the metastatic node in the N2 group. Conclusion: Taken together, removal of a perigastric lymph node could miss early metastases in gastric cancer, so a D1 lymphadenectomy should not be the minimal range of dissection if a lymphadenectomy is necessary.ope