Patterns of recurrence and long-term outcomes in patients who underwent pancreatectomy for intraductal papillary mucinous neoplasms with high grade dysplasia: implications for surveillance and future management guidelines.

Background: While intraductal papillary mucinous neoplasms (IPMNs) with high-grade dysplasia (HGD) are thought to represent non-invasive, high-risk lesions, its natural history following resection is unknown.

Methods: A retrospective review of HGD-IPMN patients (1999-2015) was performed. Recurrence patterns and clinical outcomes following pancreatectomy were analyzed and the indications for surgery were explored based on current guidelines.

Results: HGD was diagnosed in 100 of 314 patients (32%) following pancreatectomy for IPMN. IPMNs were classified as main duct, branch duct, or mixed in 15, 58 and 27 patients, respectively. Following resection, 25 patients had low-risk residual disease in the remnant pancreas. With a median follow-up of 35 months (range 1-129), 9 patients developed progressive or recurrent disease, 4 of whom underwent additional pancreatectomy. Three patients developed invasive adenocarcinoma. Median time to recurrence was 15 months (range 7-72). Based on the management algorithm from the international consensus guidelines, resection was indicated in 76 patients (76%). Other indications for surgery included mixed-duct IPMN(13), increased cyst size(7) and other(4).

Conclusion: The prognosis of HGD-IPMN following resection is good; however, HGD may be a marker for developing IPMN recurrence or adenocarcinoma. Current guidelines regarding surgical indications for IPMN can miss a significant number of patients with HGD.