Radical antegrade modular pancreatosplenectomy (RAMPS) includes the following aspects. Firstly, the surgical approach is "antegrade", which means from the right to the left, the pancreatic neck will be transected at first and the spleen will be seperated at last. Secondly, lymph nodes dissection includes not only the regional lymph nodes(No.10,11,18 lymph nodes), but also N1 station lymph nodes (N1: 6, 8a, 8p, 12a2/b2/p2, 13a/b, 14b/c/d, 14v, 17a/b), No.7, 9 lymph nodes, the lymph nodes anterior and left of superior mesenteric artery, as well as the peripheral nerve of celiac trunk. Thirdly, the transection platform is in the pancreatic neck, which is mandatory. At last, left prerenal fascia will be resected. When the tumor abuts or infiltrates the left adrenal gland, left adrenalectomy will be performed, which is also called "posterior approach RAMPS". While in normal cases, left adrenal gland will be preserved.

Standard retrograde pancreatosplenectomy(SRPS) includes several key points. Firstly, the surgical approach is "retrograde", which means from the left to the right, spleen will be seperated at first and the pancreas will be transected later on. Secondly, only the regional lymph nodes will be dissected, which include No.10, No.11, No.18 lymph nodes, and No.9 lymph nodes should be dissected only when the lesion is in pancreatic neck. Thirdly, the transection platform is in the left side of the lesion, but transection at pancreatic neck is not mandatory. At last, the surgical plane is anterior to the left renal fascia, prerenal fascia will be preserved.

Radical antegrade modular pancreatosplenectomy (RAMPS) includes the following aspects. Firstly, the surgical approach is "antegrade", which means from the right to the left, the pancreatic neck will be transected at first and the spleen will be seperated at last. Secondly, lymph nodes dissection includes not only the regional lymph nodes(No.10,11,18 lymph nodes), but also N1 station lymph nodes (N1: 6, 8a, 8p, 12a2/b2/p2, 13a/b, 14b/c/d, 14v, 17a/b), No.7, 9 lymph nodes, the lymph nodes anterior and left of superior mesenteric artery, as well as the peripheral nerve of celiac trunk. Thirdly, the transection platform is in the pancreatic neck, which is mandatory. At last, left prerenal fascia will be resected. When the tumor abuts or infiltrates the left adrenal gland, left adrenalectomy will be performed, which is also called "posterior approach RAMPS". While in normal cases, left adrenal gland will be preserved.

Overall survival was defined as the time from surgery to either death or last follow-up. Patients will be observed or contacted every 2 months in the first 2 years after surgery and then every 3 months thereafter. Overall survival measurement will be based on patient's survival status and what is the date of death if the patient is not alive.

DFS was calculated from the date of surgery to the date of recurrence or last follow-up if recurrence did not occur. Recurrence was diagnosed by imaging examination like CT, MRI, PET-CT and PET-MRI.

Operation time means "skin to skin"time (from the surgeon start to incise the skin to the last suture of the skin)

Estimated blood loss will be evaluated based on the vacuum amount, gauze weight and liquid intake