Optimal extent of lymph node dissection for remnant advanced gastric carcinoma after distal gastrectomy: a retrospective analysis of more than 3000 patients from the nationwide registry of the Japanese Gastric Cancer Association

Background No guidelines are available for defining the extent of lymph node (LN) dissection in patients with remnant gastric carcinoma (RGC). Hence, this retrospective study aimed to determine the optimal extent of LN dissection in patients with RGC. Methods We retrospectively evaluated the therapeutic outcomes of node dissection for RGC from a nationwide registry. When the metastatic rate or 5-year survival rate exceeded 10%, dissection was recommended. We calculated the dissection index by multiplying the incidence of metastasis at that nodal station by the 5-year survival rate of patients with metastasis at the station. A dissection index of > 1.0 was considered significant. Results We included 1133 patients with RGC (T2-T4 tumor) who had undergone distal gastrectomy as the primary surgery for the evaluation of the survival benefit of nodal dissection. Any regional node station was considered significant. When the primary surgery was for malignant disease, the index was high for Nos. 3 (10.2), 7 (9.5), 1 (7.1), and 9 (8.0) nodes. For nodes at the splenic hilum, the index value was 4.4, which was higher than that for the perigastric nodes (Nos. 4sa and 4sb). The index for No. 10 nodes was the highest (10.5) when tumors involved a greater curvature. Conclusions The therapeutic strategy for RGC remains the same, regardless of the histology of the primary disease during the initial surgery. Total gastrectomy and dissection of the perigastric LNs (Nos. 1-4), suprapancreatic LNs (Nos. 7-9 and 11), and LNs at the splenic hilum (No. 10) are justified.