Pancreatic surgery has made tremendous progress in the last 100 years or so, both in terms of diagnosis, surgical techniques and comprehensive treatment. However, the treatment for pancreatic cancer has not achieved significant improvement in its long-term survival rate, even after a considerable period of time on the road to expanded surgery. Today, as we enter the new century, there is an urgent need for new thinking and new technologies to be injected into this cross-century challenge of pancreatic cancer treatment. Radical surgical resection of pancreatic cancer is the only hope for long-term survival of pancreatic cancer patients and the main means to improve the survival rate of patients. Patients’ quality of life is often significantly improved after surgical resection of pancreatic cancer, and obtaining surgical resection for a few low-grade malignancies is even more significant. However, surgical resection of pancreatic cancer has long been a high-risk and difficult abdominal surgery, with problems of low resection rate, high operative mortality, high complication rate and short postoperative survival. Therefore, the indications for surgery should be strictly mastered, the perioperative treatment should be strengthened, and the surgical method should be reasonably selected to improve the safety of pancreatic cancer surgery and reduce the incidence of complications. Reasonable selection of preoperative patients Preoperatively, on the premise of excluding obvious distant metastases, a comprehensive judgment should be made by combining the patient’s age, general condition, combined diseases and resectability of surgery. The preoperative tumor resectability is mainly based on imaging performance. Multilayer spiral CT is considered to be the best means to determine the resectability of pancreatic cancer, and its correctness and sensitivity are superior to other methods. The extent of invasion of the surrounding area by pancreatic cancer determines the resectability of the tumor. The loss of the superior mesenteric artery and vein and the fatty layer around the peri-abdominal trunk often indicates vascular involvement. If there is an enlarged nodal shadow around the celiac trunk, superior mesenteric artery, or a chain shadow around the abdominal aorta, it indicates the possibility of lymph node involvement. The current CT signs of unresectable pancreatic cancer include: (1) liver or peritoneal metastasis; (2) interruption and occlusion of the major peripancreatic vessels (including the main portal vein and its branches, the celiac trunk and its branches, the superior mesenteric artery, the inferior vena cava, and the abdominal aorta), and semi-annular to annular encapsulation. The tumor is considered resectable if there is no other unresectable sign of portal vein involvement alone; the tumor diameter is greater than 125px; (3) the regional or distant lymph nodes of the pancreas are enlarged and fused into a mass, encapsulating the adjacent large vessels. However, none of the current examination methods can absolutely and correctly determine whether a pancreatic tumor can be surgically resected. If there is no obvious displacement and invasion of portal vein, superior mesenteric vein and hepatic artery, and the perivascular space is clearly visible, it is generally considered that it can be surgically resected. It has been proved that palliative pancreatic cancer resection is helpful to improve the quality of life of some patients after surgery. With the continuous improvement of surgical techniques and surgical safety, some cases that were previously considered to have no chance of surgical resection, such as combined with obvious invasion of blood vessels or regional lymph node metastasis, can be considered for surgical resection under the premise of ensuring surgical safety. With the current level of surgical technology, the surgical safety of resection of pancreatic cancer with combined portal/superior mesenteric vein resection and reconstruction is no longer a major issue. The resection length is <125px, and direct end-to-end anastomosis is usually possible. Broeck et al. reported that the incidence of intra-abdominal recurrence after radical resection of pancreatic cancer was as high as 93.6%, and positive margins or tumor invasion within 1 mm from the margins were important factors affecting the prognosis of pancreatic cancer. The common sites of positive margins for pancreatic cancer are pancreatic hook tract, posterior peritoneum, pancreatic neck margin, peripancreatic lymph nodes and peripancreatic nerve plexus. According to the staging criteria of UICC, posterior peritoneal, vascular and lymph node invasion are important indicators of pancreatic cancer prognosis. Many studies have reported that lymphovascular invasion and lymph node metastasis are important factors affecting the prognosis of pancreatic cancer. Therefore, achieving R0 resection is the key to improve the long-term survival rate after pancreaticoduodenectomy. The pancreas is a retroperitoneal organ and is surrounded by many important organs and large blood vessels. The perivascular nerve plexus and lymph are densely distributed. Pancreatic cancer has a strong aggressiveness to surrounding organs, large blood vessels and many nearby lymph nodes. These histological features are responsible for the local residual of pancreatic cancer after surgery and the high rate of tumor recurrence. However, most studies have shown that extended lymph node dissection for progressive pancreatic cancer is not effective in improving survival. Only for early stage (I and II) pancreatic cancer, enlarged lymph node and soft tissue debulking can improve the long-term survival rate to some extent. Therefore, we advocate the classic Whipple procedure plus first-stage (6, 8, 12apb, 13ab, 14bcd, 17ab) lymph node dissection for progressive pancreatic cancer, and it is required to achieve negative specimen margins (including bile duct, pancreatic neck, leptomeningeal and retroperitoneal soft tissues). Intraoperative frozen sections of the cut margins were performed to confirm if necessary. The incisional end of the pancreatic neck is usually to the left of the portal vein/superior mesenteric vein and should be more than 50px from the tumor. For cases of stage I or II pancreatic cancer judged intraoperatively, a second station (9, 11, 12a1, 14a, 15, 16a2b1, 18) lymph node contouring can be added on top of this, focusing on clearing the soft tissues, lymph nodes and nerve tissues between the inferior vena cava and the abdominal aorta and anteriorly, next to the superior mesenteric artery and next to the hepatic artery, so that the superior mesenteric vein, portal vein, hepatic artery and superior mesenteric artery can be Skeletonization. 2. Plexus clearance There is a rich plexus around the pancreas. Studies have shown that pancreatic ductal adenocarcinoma is neurophilic and will progress along the nerve bundle. The survival rate of patients with pancreatic cancer without peripheral nerve invasion (ne0) is relatively high, while the survival rate of patients with nerve invasion decreases significantly as the degree of nerve invasion increases. Therefore, one of the reasons for the persistently high recurrence rate of pancreatic cancer after surgery may be the residual tumor cells in the peripancreatic ganglion and superior mesenteric plexus. This leads to the possibility of positive cut margins of the peripancreatic plexus despite the performance of expanded lymph node contouring. Studies have shown that even in stage I pancreatic cancer cases, nerve invasion is found in approximately 75% of cases. This suggests that invasion and spread of pancreatic cancer to the peripheral nerves may be an early event. Although it remains unclear whether there is a direct correlation between resection of the superior mesenteric artery perineural plexus and improved patient prognosis, because of the high incidence of plexus infiltration in pancreatic cancer, resection of the peripancreatic plexus may help reduce the rate of positive margins and the incidence of local recurrence after surgery. Resection of the peripancreatic ganglion generally does not cause serious complications. However, some patients may develop recalcitrant diarrhea after performing total peripheral superior mesenteric artery perineural plexus resection, which can seriously affect the quality of life and nutritional status of patients. Therefore, we advocate complete resection of the affected abdominal ganglion and preservation of the contralateral 1/3 or half circumference of the SMA plexus. The plexus resection during radical surgery for pancreatic head cancer includes the right abdominal ganglion, hepatic paraganglionic plexus, abdominal trunk paraganglionic plexus, and the right hemithoracic plexus of superior mesenteric artery (parts 1 and 2). In contrast, plexus resection should also be routinely performed when radical pancreatic body caudal carcinoma is performed, including the left celiac ganglion, the parietal hepatic artery plexus, the parietal trunk plexus, and the left hemithoracic plexus of the SMA. Our experience is that the incidence of recalcitrant postoperative diarrhea in patients can be controlled at a low level even if only about 1/3 of the contralateral slender nerve tissue is preserved. Pylorus-preserving pancreaticoduodenectomy (PPPD) can slow down the rate of food advancement and reduce the incidence of intractable diarrhea. If a patient develops intractable diarrhea after surgery, oral phenylephrine or emmenagogue can be used to control the symptoms, and most of them can be treated with good results. Generally, patients can gradually stop the drug after six months due to the compensation of intestinal function. 3.Cancellation of leptomeningeal carcinoma and tumor invading the mesenteric root Pancreatic leptomeningeal carcinoma is adjacent to mesenteric vessels and the mesenteric root, and it is easy to invade the mesenteric root and vessels through the lymphatic system and plexus infiltration at an early stage, which makes surgical resection difficult and R0 resection is difficult. Therefore, the local recurrence rate of pancreatic leptomeningeal carcinoma after conventional pancreaticoduodenectomy is very high. To address this problem, Japanese scholars have proposed whole SMA and SMV resection and reconstruction in order to achieve R0 resection and improve the long-term survival rate. However, the difficulty and risk of the procedure limit its application. For cases in which the SMA is not surrounded by the whole circumference of the tumor, the vascular outline is still normal, and the length does not exceed 125 px, we use a transverse colonic mesenteric path to free the SMA and SMV first, and then resect the tumor after separating the SMA from the tumor tissue completely. On the one hand, we avoided the damage to SMA during the conventional surgical dissection of the leptomeningeal tract, and improved the resection of the tumor tissue behind SMA or even on the left side. The incidence of recalcitrant diarrhea after surgery is not high because a small amount of thin plexus tissue around SMA is preserved. Even if part of SMA or SMV needs to be removed, the difficulty of performing vascular anastomosis is reduced. How to reduce intraoperative risks Preoperatively, through imaging (mainly spiral CT), the operator should have a correct understanding of the tumor size, location, adjacent relationship with surrounding vessels and possible intraoperative risks. In conventional pancreaticoduodenectomy, no tumor distant organ metastasis was explored, there was no tumor invasion and fixation at the root of the transverse colon mesentery, and the tumor diameter was less than 125 px. the head of the pancreas was free of the duodenum and there was no tumor invasion of the inferior vena cava. Part of the gastrocolic ligament was dissected, and the superior mesenteric vein and superior mesenteric artery at the lower margin of the pancreas were dissected out. The hepatoduodenal ligament was dissected, the common hepatic duct, part of the common bile duct and the hepatic artery were dissected and released, and the gastroduodenal artery was dissected. The portal vein at the superior margin of the pancreas is then dissected out. If these steps can be done, it is generally considered that the tumor can be removed surgically. However, if the tumor is larger than 5 cm in diameter and has severely pushed or invaded some vessels such as PV/SMV, SMA and hepatic artery, intraoperative vascular laceration injury may occur, resulting in uncontrollable hemorrhage. If the superior mesenteric vein has been controlled for too long, the small intestine is prone to reperfusion injury and postoperative colony translocation if it is bruised for a long time. If there is concurrent hepatic artery involvement, it may lead to a bloodless state in the liver for a longer period of time. The larger tumor in the leptomeningeal region lifts the SMV and SMA anteriorly, making it difficult to disconnect the leptomeningeal tract and prone to damage the tract vessels. If the larger tumor compresses and invades the inferior vena cava, it is difficult to dissect and separate the pancreas before dissection, and it is difficult to control hemostasis when vascular injury occurs. In this regard, the traditional pancreaticoduodenectomy is difficult to ensure intraoperative safety. With the deepening of the understanding of local anatomy, the gradual improvement of surgical techniques, and the improvement of separation steps and surgical paths, the safety of surgery can be significantly improved. Before separating and dissecting the vessels of the involved segment, adequate dissection of the portal vein and superior mesenteric vein at the upper and lower margins of the tumor is the key to controlling bleeding and shortening the time of blood flow blockage. Simultaneous blockage of the superior mesenteric vein and the hepatic artery should be avoided as much as possible to prevent the liver from being in a state of non-perfusion leading to serious impairment of liver function. For these complex pancreatic head tumors that were difficult to handle by conventional pancreaticoduodenectomy in the past and have high surgical risk, our countermeasures are 1. Huge tumors with PV/SMV are difficult to separate anatomically: if preoperative imaging determines that there is a chance of surgical resection, intraoperative Kocher's maneuver is used to separate the pancreatic head and duodenum, and the retroperitoneal separation ranges from the left side to the left margin of the abdominal aorta, and The right hemicolectomy was fully freed. Firstly, the gallbladder was resected, the bile duct was separated, the superior pancreatic portal vein and hepatic artery were isolated, the gastroduodenal artery was separated, the stomach or duodenum was separated (PPPD), the neck of the pancreas was separated on the left side of the PV, the SMV was separated anteriorly along the portal vein downward, and the branch vessels with the head of the pancreas and the hooks were separated respectively. Depending on the tumor invasion, it is decided whether to perform partial vascular resection and reconstruction. The advantage of this procedure is to avoid the risk of hemorrhage and difficulty in hemostasis at the beginning of dissection and freeing the SMV, and to fully free the SMV from the surrounding low-risk area first, so as to change the complexity into simplicity. 2.Difficult separation of the giant pancreatic head tumor due to compression and invasion of the inferior vena cava: instead of Kocher's separation at the beginning of surgery, the gallbladder is first removed, the bile duct is separated, the superior pancreatic portal vein and hepatic artery are separated, the gastroduodenal artery is separated, the SMV is separated at the lower edge of the pancreas, the stomach or duodenum is separated (PPPD), the neck of the pancreas is separated, the head of the pancreas and the branch vessels of the hooks are separated, and the beginning of the jejunum is separated. The advantage of this procedure is that the most difficult step is left to the end, which improves the space for anatomical operation and makes it easy to control and repair even vascular damage. 3. Tumor invasion of SMV/SMA in the leptomeningeal region: Starting from the root of the transverse colonic mesentery, the SMA and SMV are freed respectively, the middle colonic artery and vein are severed, the gallbladder is cut, the bile duct is severed, the pancreatic neck is cut, and the SMA is separated along the whole circumference of the separated SMA towards the root until the root of the SMA, and the leptomeningeal mesentery is separated here. If the tumor invasion is obvious, partial vascular resection and reconstruction will be performed. The advantage is that the anterior transcatheter freeing of the SMA and dissection of the hooked tract avoid the blindness of separation and improve the safety and radicality. 4. Huge tumor invades PV and hepatic artery at the same time, or tumor invades a long section of PV/SMV: first dissect the mesenteric root to free the SMV or SMV trunk, dissect the hepatic portal, free the portal vein above the pancreatic neck, cut off the SMV, perform end-to-end anastomosis of the artificial vessel-superior mesenteric vein with ePTFE material of 8-10 mm in diameter and 8-10 cm in length with a ring, and then cut off the portal vein and perform end-to-end anastomosis of the artificial vessel-superior mesenteric vein. The portal vein is then dissected and the end-to-end anastomosis between the artificial vessel and the portal vein is performed to complete the portal- mesenteric artificial vessel reconstruction, followed by pancreaticoduodenectomy. The advantage of this procedure is that the establishment of a smooth portal venous system can avoid the simultaneous battle between two fronts (PV and hepatic artery), ensure the main blood flow to the liver, and reduce the complications of severe intestinal stasis and liver ischemia. Blocking and reconstruction of the portal vein is completed in situ before resection of the tumor, which theoretically reduces the possibility of compression of the tumor and resulting in dissemination of tumor cells to the portal venous system. Expanded pancreatic tumor resection with prior portal-superior mesenteric vein can significantly improve surgical resection rate and surgical safety. The biological behavior of pancreatic cancer is different from other tumors, showing significant high aggressiveness and metastasis. Expanded surgical resection alone is not sufficient. The importance of multidisciplinary participation should be emphasized to enhance the comprehensive treatment of pancreatic cancer after surgery. With the development of targeted tumor therapy technology, molecular targeted therapy has become a new hope to improve survival rate. However, facing the century-old persistent disease of pancreatic cancer, pancreatic surgery still needs to make efforts to improve the technical level and enhance the scientific nature of treatment through evidence-based medical research. It is the common responsibility of every pancreatic surgeon to continuously challenge the technical limits of pancreatic surgery, to provide the most suitable surgical and therapeutic methods for each patient, and to improve the outcome of pancreatic cancer treatment as soon as possible.