Study objective: The purpose of this study is to establish a prospective follow-up cohort of high-risk groups of pancreatic cancer, screen early pancreatic cancer through EUS and other means according to the existing clinical process, and evaluate each risk factors. And to prospectively collect biological samples to find molecular markers for early diagnosis of pancreatic cancer.

Study design: This is a real world, multicenter, prospective, observational cohort study.

This study intends to conduct pancreatic MR screening for the high-risk population of pancreatic cancer who meet the requirements and voluntarily participate in this study (see eligibility criteria), and retain baseline information and peripheral blood, dental plaque and stool samples.

I. For patients with solid mass of the pancreas, continue diagnosis and treatment according to the routine clinical path.

II. For patients with MPD dilatation but no clear solid pancreatic mass, EUS examination should be performed after excluding contraindications. During EUS, duodenal fluid samples were collected.

III. If solid mass is found in EUS, FNA shall be performed. If the pathological examination is positive, the patient shall be diagnosed with PDAC and treated according to the clinical routine path of PDAC. If the pathological biopsy sample is negative, repeat FNA after an appropriate interval (1 to 3 months later).

IV. If no solid mass is found in EUS, follow up the patient every 6-12 months for EUS and/or MR examination.

V. For patients with cystic lesions, EUS examination is performed after contraindications are excluded. During EUS, duodenal fluid samples were collected. If solid components such as mural nodules or "worrisome features" are found, FNA will be performed. In order to make a clear diagnosis of some cases, FNA+nCLE will be performed at the same time, and cystic fluid samples will be taken to continue diagnosis and treatment according to the clinical guidelines. If no solid lesions and "worrisome features" are found, follow up the patient every 6-12 months and perform EUS and/or MR examinations.

VI. Follow up and perform pancreatic MR examination every 12 months for those with no clear pancreatic lesions found on pancreatic MR.

The main outcome of this study was the discovery of pancreatic T1 PDAC (tumor diameter < 2cm), or no pancreatic disease was found during the 5-year follow-up period.

The secondary outcome of this study was the discovery of other levels of PDAC, IPMN, chronic pancreatitis, autoimmune pancreatitis and other pancreatic diseases.

The samples involved in this study include baseline and follow-up samples (peripheral blood, dental plaque, stool samples), EUS-FNA solid mass aspiration tissue samples or cystic fluid samples of cystic lesions, and duodenal fluid samples collected during EUS examination. The collected samples were analyzed by transcriptomics, proteomics and next generation sequencing to study the clinical characteristics, molecular, flora markers and gene sequences related to the diagnosis of early pancreatic cancer.

Inclusion Criteria:

• From the beginning of the study to the end of the study, the 18-80 year old patients who were admitted to Peking Union Medical College Hospital and related research centers and who met the high-risk population of pancreatic cancer understood and were willing to participate in the study and signed the informed consent form.
• In this study, the high-risk population of pancreatic cancer is defined as patients who meet any of the following conditions:
• A. Patients with previous history of pancreatitis (acute or chronic).
• B. Patients with pancreatic cancer related genetic background, including immediate relatives with a family history of pancreatic cancer. Or genetic syndrome related to pancreatic cancer. [including hereditary breast cancer ovarian cancer syndrome (HBOCS), carney complex (CNC), familial adenomatous polyps (FAP), hereditary diffuse gastric cancer syndrome (HDGC), juvenile polyposis (JPS), cutaneous malignant melanoma (CMM), hereditary papillary renal cell carcinoma (HPRCC) and Lynch syndrome]
• C. Patients with continuous or progressive increase of CA19-9 and CEA.
• D. Patients with potential malignant pancreatic tumors, including mucinous cystic tumor (MCN) and intraductal papillary myxoma of the pancreas (IPMN).
• E. Newly diagnosed patients with diabetes (within 3 years after diagnosis of diabetes).
• F. Other patients who are considered as having high risk factors for pancreatic cancer.

Exclusion Criteria:

• A. Those who are not suitable for endoscopic examination, including but not limited to: poor general condition, serious heart and lung disease, and difficult to tolerate the examination; coagulation disorders; platelets <50 × 10^9/L；those who are not suitable for endoscopic examination after interview by an endoscopic physician.
• B. The patient or family member could not understand the conditions and objectives of this study.

Patients with high risks for pancreas cancer in Peking Union Medical College Hospital and other related research centers in China.