Lymph node dissection for gastric cancer: Establishment of D2 and the current position of splenectomy in Europe and Japan.

Two European phase III trials comparing D1 and D2 demonstrated that D2 did not improve the overall survival and was associated with a high mortality related to splenectomy. However, a long-term follow-up study showed that the gastric cancer-related death rate was significantly higher in D1 than D2. Based on these findings, the standard surgery in Europe became D2 without pancreatico-splenectomy to prevent mortality. In contrast, the JCOG9501 phase III comparing D2 and D2 plus para-aortic nodal dissection did not showed a survival efficacy of extended lymphadenectomy, but the mortality rate was quite low in both surgeries. Subsequently, the JCOG0110 phase III study comparing D2 and spleen-preserving D2 for upper gastric cancer not invading the greater curvature clearly showed the non-inferiority of spleen preservation. Thus, spleen-preserving D2 was made the standard surgery for these tumors in Japan. However, splenectomy is often selected for complete dissection of the splenic-hilar nodes, a frequent metastatic site for upper gastric tumors invading the greater curvature. Recently, an approach involving splenic hilar nodal dissection without splenectomy has been developed.