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Background; Intraductal papillary mucinous neoplasm (IPMN) of the pancreas often has distinct pancreatic ductal adenocarcinoma (PDAC) in the same pancreas. Roles of endoscopic retrograde pancreatography (ERP) during the management of IPMN in terms of early diagnosis of concomitant PDAC have not been well documented. The aim of this study was to clarify whether ERP would be useful for the early detection of concomitant PDCAs in patients with IPMNs.
Methods: Medical records of 179 patients who were histologically confirmed to have IPMNs by resected specimens at our department between 1987 and 2011 were retrospectively reviewed. The patients having concomitant PDACs were selected, and then the diagnostic abilities to detect concomitant PDACs of computed tomography (CT), magnetic resonance imaging / cholangiopancreatography (MRI/MRCP), endoscopic ultrasonography (EUS), and ERP were compared between early-stage (stage 0 or I according to the Japanese general rules for pancreatic cancer) and advanced PDACs (stage II, III, and IV). Abnormal findings to suspect the presence of PDAC in CT, MRI/MRCP, and EUS included an irregular solid mass lesion and stenosis/dilation of pancreatic duct, distinct from IPMNs. Abnormalities suspicious of the presence of PDAC in ERP were defined as irregularity of pancreatic duct such as stenosis and obstruction, and/or positive results (class IV or V) of pancreatic juice / brushing cytology.
Results: A total of 23 PDACs developed synchronously or metachronously in 20 patients, and the prevalence of PDACs concomitant with IPMNs was 11.2% (20/179). Sensitivities to detect PDACs of CT, MRI, and EUS in early group (16%, 29%, 29%, respectively) were significantly lower than those in advanced group (87%, 93%, 92%, respectively) (p<0.01). On the other hand, sensitivity of ERP in early group was as high as that in advanced group (86% vs. 82%, p>0.99). Among 7 early PDACs, 3 were diagnosed only by ERP.
Conclusion: ERP has an important role in the early diagnosis of distinct PDACs in patients with IPMNs. Further investigation is necessary to clarify the indication and timing of ERP during the management of IPMNs in term of early detection of concomitant PDACs.