Function-preserving gastrectomy for gastric cancer in Japan.

Surgery used to be the only therapy for gastric cancer, and since its ability to cure gastric cancer was the focus of attention, less attention was paid to function-preserving surgery in gastric cancer, though it was studied for gastroduodenal ulcer. Maki et al developed pylorus-preserving gastrectomy for gastric ulcer in 1967. At the same time, the definition of early gastric cancer (EGC) was being considered, histopathological investigations of EGC were carried out, and the validity of modified surgery was sustained. After the development of H2-blockers, the number of operations for gastroduodenal ulcers decreased, and the number of EGC patients increased simultaneously. As a result, the indications for pylorus-preserving gastrectomy for EGC in the middle third of the stomach extended, and various alterations were added. Since then, many kinds of function-preserving gastrectomies have been performed and studied in other fields of gastric cancer, and proximal gastrectomy, jejunal pouch interposition, segmental gastrectomy, and local resection have been performed. On the other hand, from the overall perspective, it can be said that endoscopic resection, which was launched at almost the same time, is the ultimate function-preserving surgery under the current circumstances. The current function-preserving gastrectomies that are often performed and studied are pylorus-preserving gastrectomy and proximal gastrectomy. The reasons for this are that these procedures that can be performed with systemic lymph node dissection, and they include three important elements: (1) reduction of the extent of gastrectomy; (2) preservation of the pylorus; and (3) preservation of the vagal nerve. In addition, these operations are more likely to be performed with a laparoscopic approach as minimally invasive surgery. Of the above-mentioned three elements, reduction of the extent of gastrectomy is the most important in our view. Therefore, we should try to reduce the extent of gastrectomy if curability of the gastric cancer can still be achieved. However, if we preserve a wider residual stomach in function-preserving gastrectomy, we should pay attention to the development of metachronous gastric cancer.