The treatment of pancreatic cancer is an internationally recognized challenge, characterized by low early diagnosis rate and radical resection rate, poor clinical outcome and low 5-year survival rate. Early diagnosis of pancreatic cancer has an important value for prognosis. There are many data showing that the 5-year survival rate of small pancreatic cancer with diameter ≤2cm is 42%, while the 5-year survival rate of pancreatic cancer with diameter >2cm is less than 5%. In recent years, with the advancement of gastrointestinal endoscopy technology, the early diagnosis rate of pancreatic cancer has been gradually improved, and at the same time, for patients with advanced inoperable disease, endoscopic treatment has shown certain advantages, which are reviewed here. The value of endoscopy in the diagnosis of pancreatic cancer Endoscopy ultrasound (EUS) is difficult for the diagnosis of pancreatic cancer due to the interference of gastrointestinal gas; EUS combines ultrasound and endoscopy, so that the high-frequency probe can pass through the endoscopic orifice close to the gastroduodenal wall, avoiding echo attenuation and intestinal gas interference, and improving the diagnosis rate of early pancreatic cancer. EUS has a positive rate of 73.7% to 100% for small pancreatic cancers ≤2 cm in diameter, and Habr et al. also reported that EUS is more accurate than CT and MRI in the detection of small pancreatic cancers, and can detect pancreatic masses as small as 5 mm in diameter that are undetectable by other methods. EUS can detect the depth and extent of tumor infiltration and lymph node metastasis, which is useful for determining the stage of pancreatic cancer. The application of intraductal ultrasonography (IDUS) with a small probe has further improved the accuracy of pancreatic cancer diagnosis. A study by Wei Lu et al. in China showed that the accuracy of IDUS in diagnosing pancreatic cancer could reach 100%. It is difficult to describe the lesion quantitatively by ordinary EUS. A new study found that quantitative endoscopic ultrasound elastography (QEES), by calculating the elasticity quotient (B/A, where B and A represent the ultrasound elasticity values of control and pancreatic lesions, respectively), showed that the value was significantly higher in pancreatic cancer than in inflammatory masses, and the sensitivity and specificity for the diagnosis of pancreatic cancer were 100% and 92%, respectively, which is beneficial to Identification of solid pancreatic masses and evaluation of hardness. Endoscopic ultrasound guided fine needle aspiration (EUS-FNA) The development of EUS-FNA technique has further improved the accuracy of pancreatic cancer diagnosis. Recent data showed that the sensitivity, specificity and accuracy of EUS-FNA for the diagnosis of pancreatic cancer were 92.6% (95% CI: 87.20-95.96), 88.6% (95% CI: 74.64-95.64) and 91.8% (95% CI: 87.24-94.81), respectively, while the incidence of less severe complications was less than 2% and no serious complications occurred. Endoscopic retrograde cholangiopancreatography (ERCP) has been widely used in the diagnosis of pancreatic cancer since 1968 when McCune et al. applied ERCP to diagnose pancreatic and biliary diseases, and has made great progress with the gradual popularization of ERCP and the increasing proficiency of the technique. ERCP can be used to diagnose pancreatic cancer, but it is of great value in cases of obstruction or abnormal changes of the lower bile duct and pancreatic duct. In addition, pancreatic cancer also has some special ERCP signs, such as “double duct sign” and “soft vine sign”, which have specific diagnostic value for pancreatic cancer. “ERCP combined with endoscopic biopsy is decisive for the qualitative diagnosis of pancreatic cancer, especially for pancreatic cancer with papillary involvement. The accuracy of diagnosis can reach 100%. The limitations of ERCP are that it cannot reveal the tumor itself and has limited diagnostic value for early pancreatic cancer, and it is an invasive test. Nakaizumi et al. reported that 76% (19/25) of pancreatic cancers were diagnosed cytologically by cannula aspiration of pancreatic fluid during ERCP. cytologic diagnosis.