| In managing patients with IPMN, the 2006 Sendai guidelines provided a sense of direction and clarity. Following this guideline, multiple prospective and retrospective series have shown that their application results in resection of a large number of patients with branch-duct IPMN that have low or intermediate-grade dysplasia. This were updated in the international consensus guideline 2012 (Fukuoka guideline), which consisted of high risk stigmata and worrisome features. Patients with HRS should be referred for surgical resection. These worrisome features are cyst size larger than 3 cm, a thickened or enhancing cyst wall, MPD 5-9 mm, non-enhancing mural nodule, abrupt tapering of the pancreatic duct with distal atrophy, and pancreatitis. Patients with any of these features direct to EUS with or without FNA, and dependent on the findings, surgical resection or close surveillance are recommended. Validation of these revised guidelines is ongoing, with some studies showing they do increase specificity, but others showing they may miss cysts of high-grade dysplasia and even invasive cancer. In the prediction of malignancy, the positive predictive value and negative predictive value of high-risk patients according to Sendai and Fukuoka guidelines were 67% and 88% and 88% and 92.5%, respectively. Tanka et al reported that malignant transformation develops more often in the intestinal type IPMN with high frequency of GANS mutation whereas this distinct pancreatic cancer more frequently develops in patients with benign gastric type IPMN without GNAS mutation. We have to think what is the optimal way and interval to identify malignant transformation of pancreatic IPMNs and distinct pancreatic cancer during surveillance. The management strategy for patients with IPMNs of the pancreas has been still controversial, and further studies and discussion will be needed to avoid unnecessary surgery and missing fatal malignancy. |
