DNA-mutation Analysis in Cyst Fluid of Suspected Intraductal Papillary Mucinous Neoplasia of the Pancreas

DNA-mutation Analysis in Cyst Fluid of Suspected Intraductal Papillary Mucinous Neoplasia of the Pancreas

DNA-mutation Analysis by Next Generation Sequencing in Cyst Fluid of Suspected Intraductal Papillary Mucinous Neoplasia of the Pancreas Obtained by Endoscopic Ultrasound-guided Fine Needle Aspiration (ZYSTEUS-Study)

Diagnostic tools are needed to identify mucinous cysts for further evaluation or follow-up respectively to identify cysts with HGD or invasive cancer at an early stage for surgical resection. Molecular genetic analysis of pancreatic cyst fluid is a new but rapidly evolving method to identify KRAS/GNAS oncogenic driver mutations in mucinous cysts and to identify tumour suppressor gene mutations which are involved in advanced cysts with HGD or carcinoma. The ongoing ZYSTEUS-study tries to implement DNA mutation analysis by Next Generation Sequencing in the diagnostic algorithm of pancreas cyst evaluation. The first aim is to distinguish mucinous from non-mucinous cysts. The second aim is to define relevant tumour suppressor gene mutations which are relevant to distinguish between LGD and HGD/carcinoma in mucinous cysts.

Intraductal papillary mucinous neoplasm (IPMN) with low grade dysplasia (LGD) can progress to high grade dysplasia (HGD) or invasive cancer. Main duct IPMN, mixed type IPMN or branch duct IPMN with high risk stigmata are highly predictive for malignancy. Therefore, patients in good general state should be considered for surgical resection. Guidelines like the International Fukuoka Consensus Guidelines from 2017 or the European evidence-based Guidelines on Pancreatic cyst neoplasms from 2018 provide detailed recommendations on the management of IPMNs by focusing on clinical characteristics, image morphology, cytology and laboratory parameters. However, these applied guidelines still lead to surgical overtreatment of pancreas cysts based on the pathologic outcomes as neither HGD nor carcinoma is found in up to 82.1 % of the resected cysts. Cyst fluid sent for cytology usually provides adequate cellular material for analysis in only 31% of the cases and Endoscopic Ultrasound-guided forceps biopsy has not yet shown to be better than fine needle aspiration. Hence, further diagnostic tools are needed to identify mucinous cysts for further evaluation or follow-up respectively to identify cysts with HGD or invasive cancer at an early stage for surgical resection. Molecular genetic analysis of pancreatic cyst fluid is possibly able to identify KRAS/GNAS oncogenic driver mutations in mucinous cysts and to identify tumour suppressor gene mutations which are involved in advanced cysts with HGD or carcinoma. This workgroup described a high sensitive method of targeted Next Generation Sequencing in pancreas cyst fluid with a limit of detection of allele frequency down to 0.01 %. Further investigations of the ongoing ZYSTEUS-study are focused on the implementation of DNA mutation analysis by NGS in the diagnostic algorithm of pancreas cyst evaluation. The first aim is to reliably distinguish mucinous from non-mucinous cysts respectively main duct IPMN from chronic pancreatitis with main duct dilatation as the absence of KRAS/GNAS-mutations is highly predictive for non-mucinous diseases. The second aim is to define relevant tumour suppressor gene mutations which are relevant to differentiate LGD from HGD/carcinoma in mucinous cysts. DNA mutation analysis will be compared with already established peroperative diagnostic tests of pancreas cyst fluid: Measurement of CEA and lipase as well as cytology.

DNA-mutation analysis by Next Generation Sequencing is performed to identify IPMN pancreas cysts with LGD versus HGD/Carcinoma. Controls: non-neoplastic pancreas cysts and chronic pancreatitis with main duct dilation

In all pancreas cysts > 15mm and/or pancreas duct dilatation > 5mm in patients who are fit for surgery EUS-guided pancreas cyst fluid aspiration is conducted. In cyst fluid CEA and lipase examination, cytology and Next Generation Sequencing is performed. After that, the pancreas cyst will be resected and histopathologically analysed.

DNA Mutational Analysis in pancreas cyst fluid concerning KRAS/GNAS-mutations and mutations in tumor supressor genes

Measuring CEA and lipase level in pancreas cyst fluid: CEA > 192 ng/ml and lipase > 200 U/l = mucinous cyst

Histology of resected pancreas cyst concerning mucinous versus non-mucinous cyst, IPMN versus non-IPMN and LGD versus HGD/Carcinoma

Number of patients with the preoperative diagnosis of a mucinous pancreas cyst (numerator) in correlation with the number of patients with a mucinous pancreas cyst confirmed by surgery (denominator)

Number of patients with the preoperative diagnosis of a HGD/carcinoma pancreas cyst (numerator) in correlation with the number of patients with a HGD/carcinoma pancreas cyst confirmed by surgery (denominator)

Inclusion Criteria: pancreas cysts with cyst size > 15mm pancreas with main duct dilation > 5mm Exclusion Criteria: patients who are not fit for surgery

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