A Long-term Follow-up Cohort Study in Patients With Intraductal Papillary Mucinous Neoplasm

Baseline assessment will be conducted on IPMN patients who meet the inclusion conditions and are included in the study with informed consent, including: ① demographic characteristics (such as age, gender, etc.); ② Clinical features (such as symptoms, complications, past history, family history, living/eating habits); ③ Characteristics of laboratory indicators (such as pancreatic function, liver enzyme, bile duct enzyme, CA199, CEA in blood; CA199, CEA in cystic fluid, etc.); ④ Imaging features * (such as multiple or single lesions, diameter of cyst, whether there are mural nodules, diameter of main pancreatic duct, etc.); ⑤ Endoscopic ultrasound (EUS) features * (such as: cyst location, echo, maximum diameter, whether the cyst wall is thickened, wall nodules, the connection between the cyst and the main pancreatic duct, laser confocal endoscopy features, etc.); ⑥ Pathological information (cytology of cystic fluid; cytological smear of cystic lesion puncture, histopathology); ⑥ Molecular characteristics of cyst fluid (such as proteomics/mass spectrometry, new biomarkers, next generation sequencing (NGS), flora characteristics, etc.); ⑦ Treatment information (such as current medication, whether to have received endoscopic treatment, etc.).

The follow-up contents include: outpatient follow-up (symptoms, laboratory indicators; keeping peripheral blood samples) every six months;, imaging follow-up (including enhanced pancreatic MR and EUS imaging; the first pancreatic MRI follow-up was conducted 6 months after enrollment to determine the stability of the lesions) at baseline and every 12 months thereafter.

During the follow-up, if the patient died of various causes, the follow-up will be terminated; If enhanced nuclear magnetic resonance imaging or EUS imaging of the pancreas indicates worrisome features (WFs) or high-risk features (High risk stigmata, HRS), EUS-FNA ± nCLE should be performed (when performing EUS, perform contrast-enhanced ultrasonography on cystic lesions with mural nodules, and collect cystic fluid when puncturing some cystic lesions with sufficient volume).

If the cytological/histological pathological results of FNA indicate cancer or high grade dysplasia (HGD), or/and cystic fluid cytological results are positive, surgical treatment is recommended; If the FNA and cyst fluid cytology results are negative, the patients with WF will be followed up 6 months later, while the HRS patients will be followed up 3 months later (whether to accept EUS examination is decided jointly by the follow-up physician and the patient). It is suggested to review EUS-FNA ± nCLE according to the imaging results. If the patient was advised to receive surgical treatment due to IPMN, the follow-up was terminated.

• Endoscopic ultrasound (Device): The EUS follow-up will be conducted at baseline and every 12 months thereafter. For patients with new WF or HRS in the evaluation, the follow-up physician and the patient can jointly decide whether to perform EUS evaluation in the 6 or 3 month intensive follow-up.

Primary outcomes

• The termination of the follow-up of IPMN patients, including death termination and recommended surgery termination. [3 years]: Patient died or was recommended for surgical treatment.

Secondary outcomes

• The new development of worrisome features or high-risk stigmata [3 years]: High-risk stigmata refers to obstructive jaundice, enhancing mural nodules or an associated solid component, and those with an MPD ≥10 mm. Worrisome features refer to acute pancreatitis, cyst size ≥30 mm, thickened/enhancing cyst wall, MPD measuring 5-9.9 mm, nonenhancing mural nodules, and abrupt change in MPD caliber with distal atrophy of the pancreatic gland.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. Age: 18 years old or above;
2. Diagnosis: Imaging examination showed the presence of intraductal papillary mucinous cystic tumor (IPMN) without high-risk features (including WF and HRS);
3. The patient or family members can understand the study protocol, are willing to participate in the study, and provide written informed consent.

Exclusion Criteria:

1. The patient's clinical, imaging and auxiliary examination characteristics conform to the surgical indications of the International Association of Pancreatic Diseases (IAP) 2018 guidelines, and the patient has no surgical contraindication;
2. Previous history of pancreatic malignant tumor;
3. There were the following worrisome features (WF) of IPMN found in the past examination: acute pancreatitis, cyst size ≥ 30mm, cyst wall thickening/strengthening, main pancreatic duct diameter of 5-9.9mm, non enhanced mural nodules, sudden change of main pancreatic duct diameter with distal pancreatic atrophy;
4. The following high risk features of IPMN (HRS) were found in the past: obstructive jaundice, enhanced mural nodules or related solid components, and main pancreatic duct>10mm;
5. The patient or family member could not understand the conditions and objectives of this study.

• Xi Wu, M.D., Study director, Peking Union Medical College Hospital
• Shengyu Zhang, M.D., Principal investigator, Peking Union Medical College Hospital
• Yiran Su, MD candidate, Principal investigator, Peking Union Medical College Hospital