In the conventional procedure group, first, the pancreatic body and tail and spleen are mobilized (mandatory procedure), and the regional lymph nodes of the body and tail of the pancreas, such as the hepatoduodenal mesentery (No12 lymph node) and the common hepatic artery perimeter (No8), are removed. (Recommended procedure) and dissection of lymph nodes (No14p) around SMA (Recommended procedure), and after dissection of the gastro-splenic ligament and pancreas, transection of the splenic vein at the end of the resection procedure (required procedure) . However, in order to prevent bleeding and secure a safe field of view, early pancreatotomy is allowed.

In the Isolation procedure group, the transection of the root of the splenic artery and the pancreatic transection are performed first, followed by the transection of the splenic vein (mandatory procedure). At that time, the branch from the splenic artery (dorsal pancreatic artery), the branch to the splenic vein (left gastric vein, inferior mesenteric vein), and short gastric arteriovenous are also disconnected as soon as possible (recommended procedure). An operation to lift up the pancreatic neck from the dorsal portal vein or superior mesenteric artery to expose the splenic vein (so-called tunneling) is allowed. After that, lymph node dissection such as hepatoduodenal mesentery (No12), common hepatic artery perimeter (No8), lymph node dissection around SMA (No14p) was performed (recommended procedure), and at the end of the resection operation, the pancreas body/tail and spleen are mobilized and removed (required procedure).

In the Isolation procedure group, the transection of the root of the splenic artery and the pancreatic transection are performed first, followed by the transection of the splenic vein (mandatory procedure). At that time, the branch from the splenic artery (dorsal pancreatic artery), the branch to the splenic vein (left gastric vein, inferior mesenteric vein), and short gastric arteriovenous are also disconnected as soon as possible (recommended procedure). An operation to lift up the pancreatic neck from the dorsal portal vein or superior mesenteric artery to expose the splenic vein (so-called tunneling) is allowed. After that, lymph node dissection such as hepatoduodenal mesentery (No12), common hepatic artery perimeter (No8), lymph node dissection around SMA (No14p) was performed (recommended procedure), and at the end of the resection operation, the pancreas body/tail and spleen are mobilized and removed (required procedure).

Until 2 years after last entry case undergo surgery