Improving pancreatic cancer prognosis with standardized surgery

  Standardized surgical resection is the key and foundation. The anatomical location of the pancreas is deep and adjacent to important organs and large blood vessels, which makes surgery difficult and the complication rate is high. With the maturity of surgical techniques, pancreatic cancer surgery is gradually carried out in hospitals at all levels in China, but most of the patients are already in advanced stage when they are first diagnosed, and only 10-20% of them have the chance of surgical resection. Therefore, early diagnosis and improvement of surgical resection rate are the first and foremost problems faced by surgeons. Clinically, we can strengthen scientific education, raise awareness, and collaborate with related departments such as radiology, gastroenterology and pathology to improve the early diagnosis rate of pancreatic cancer through screening of high-risk groups and imaging examinations such as abdominal CT and ultrasound endoscopy, and make these patients undergo surgery as early as possible through the green channel, so as to improve their prognosis.  Preoperative resectability assessment is the basis for standardized and rationalized treatment of pancreatic cancer patients, through which resectability assessment can reduce unnecessary “dissection”, save medical costs, and help to develop a personalized and comprehensive treatment plan. The core content is to assess the degree of tumor invasion to the surrounding large blood vessels, and abdominal CT + vascular 3D reconstruction can show the degree of vascular invasion more intuitively, so surgeons can take this as a routine preoperative examination and combine it with the general conditions of patients’ age, cardiopulmonary function, nutritional status and their own unit experience. It is important to emphasize that Borderline resectable is a special type of pancreatic cancer, which is between resectable and unresectable. The M.D. Anderson Cancer Center has conducted systematic clinical studies on it and proposed CT-based anatomical criteria, including: no distant metastasis, involvement of superior mesenteric artery less than 180°, small segment of hepatic The criteria include: no distant metastasis, involvement of the superior mesenteric artery less than 180°, small segment of the common hepatic artery, no involvement of the abdominal trunk, and small segment of the SMV/PV involved but resectable for reconstruction. The determination of these patients also relies on multi-row spiral CT + 3D revascularization. There is no uniform treatment plan for these patients, but preoperative neoadjuvant radiotherapy can give these patients an opportunity for surgery and improve the chances of R0 resection.  Standard pancreaticoduodenectomy is the classical procedure for pancreatic cancer surgery. However, there is still a gap between the standardized implementation of this procedure in clinical practice, especially for less experienced units and physicians who only take the successful completion of surgery as the standard, or blindly pursue the shortening of surgery time while ignoring R0 resection, which cannot achieve the purpose of radical resection and is prone to local recurrence and metastasis after surgery. This type of surgery cannot achieve radical resection and is prone to local recurrence and metastasis after surgery . In addition, because there is no uniform standard for pathological specimen processing and sampling of pancreaticoduodenectomy, surgeons neglect to mark the margins of each specimen during surgery, which makes it difficult to make accurate and standard judgment of each margin during pathological diagnosis, resulting in a wide variation of R1 resection rate reported in the literature, fluctuating from 10-85%, and many R0 resections relying on the naked eye or subjective judgment of surgeons. In fact, a large proportion of R1 resections are actually R1 resections. This affects the objective evaluation of surgical resection on the survival prognosis of patients, resulting in similar prognosis between R1 resection and R0 resection as reported in some literature. Therefore, it is necessary to standardize and standardize the marking of surgical margins, especially the “superior mesenteric artery margins”. The surgeon can try to ensure the integrity of the specimen after surgical resection and mark each margin with ink. In Europe, the “1 mm rule” is mainly used, while in the United States and Canada, the presence of tumor cells on the surface of the cut edge is the standard. Multicenter prospective studies can help to develop specific norms and standards suitable for China.  Whether to expand lymph node dissection and combined vascular resection has been the most hotly debated area in the surgical treatment of pancreatic cancer. Surgeons, represented by Japanese scholars, advocate expanding lymph node dissection, skeletonizing the superior mesenteric and abdominal trunk arteries, and completely removing peripancreatic and retroperitoneal fatty soft tissues and nerve plexus, with the aim of minimizing micrometastases and avoiding postoperative recurrence, but a number of prospective studies suggest that expanding lymph node dissection compared with standard lymph node dissection is not effective in prolonging patient survival and improving prognosis, but rather makes Pawlik et al. developed a mathematical model to evaluate the efficacy of expanded radical treatment and showed that only 1 in 250 patients could benefit from expanded lymph node dissection treatment. Therefore, the implementation of expanded lymph node dissection is not advocated at this time, but surgeons should still thoroughly remove peritumor lymph nodes according to the criteria to maximize the number of lymph node dissections and reduce the incidence of R1 resection. The maturity of surgical techniques has greatly improved the safety and effectiveness of combined vascular resection in whipple surgery. The purpose of combined vascular resection is to completely remove the tumor radically, reduce residual lesions, and ensure negative retroperitoneal margins. For experienced physicians and centers, this procedure can be performed selectively, but physicians who are unable to guarantee negative margins after PV/SMV resection and reconstruction or who have less surgical experience should choose this procedure with caution. In addition, there are various pancreatic-intestinal anastomoses, and the use of pancreaticogastric anastomosis has gradually increased in recent years and has shown some advantages. However, no matter what kind of anastomosis is used, it has its technical characteristics and shortcomings, and cannot be generalized. Operators can choose the most familiar and reliable anastomosis according to their own experience and texture of the pancreas, and should not follow blindly. For tumors that can be resected by preoperative assessment but cannot be removed by surgical exploration, palliative resection is generally not advocated, and short-circuit surgery such as biliary-intestinal anastomosis and gastrointestinal anastomosis is feasible, but some studies suggest that the prognosis of pancreaticoduodenectomy with positive margins is still better than short-circuit surgery, which is mainly for R1 resection, because pancreaticoduodenectomy is traumatic and has a high incidence of perioperative complications and affects the quality of life of patients. Therefore, the pros and cons of this type of surgery should be weighed and carefully chosen.