Is splenic hilar lymph node dissection necessary for proximal gastric cancer surgery?

Advanced proximal gastric cancer sometimes metastasizes to the splenic hilar lymph nodes (No. 10 LN). Total gastrectomy combined with splenectomy is performed for complete removal of the No. 10 LN and was historically a standard procedure in Japan. However, splenectomy is associated with several disadvantages for patients, such as increased postoperative morbidity, risk of thrombogenic disease, fatal infection from encapsulated bacteria, and the development of other types of cancer in the long term because of loss of immune function. Therefore, splenectomy should only be performed when its estimated oncological effect exceeds such disadvantages. A Japanese randomized controlled trial (JCOG0110) clearly demonstrated that prophylactic splenectomy is not necessary unless the tumor has invaded the greater curvature; thus, splenectomy is no longer routinely performed in Japan. However, several retrospective studies have shown a comparatively high incidence of No. 10 LN metastasis and therapeutic value from LN dissection at that station in the tumors invading the greater curvature. Similar tendencies have also been reported in type 4 or remnant gastric cancer involving the greater curvature. In view of these facts, No. 10 LN dissection is presently recommended for such patients; however, robust evidence is lacking. In recent years, laparoscopic/robotic spleen-preserving splenic hilar dissection utilizing augmented visualization without pancreatic mobilization has been developed. This procedure is expected to replace prophylactic splenectomy and provide an equal oncological effect with lower morbidity. In Japan, a prospective phase-II study (JCOG1809) is currently ongoing to investigate the safety and feasibility of this procedure.