A Cohort Study on Screening and Follow-up of High-risk Population of PDAC Based on EUS

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.