152 Background: Natural history studies suggest that intraductal papillary mucinous neoplasm (IPMN) is a field defect of pancreatic ductal instability. The risk of malignancy is well known, but it is unclear if the radiographic abnormality is the predominant site at which this progression occurs. This study analyzes the prevalence and site of pancreatic ductal adenocarcinoma (PDAC) progression in patients initially selected for radiographic surveillance. Methods: Patients evaluated for pancreatic cystic lesions between 1995-2010 were reviewed. Patients were included if they were followed for > 6 months for a cystic lesion with either a documented cyst fluid CEA >/= 200 ng/mL or pathologic confirmation of an IPMN. Results: Of the 157 patients initially selected for surveillance, 97 (62%) eventually underwent resection. The median length of surveillance prior to operation was 15 mo (range: 6-193 mo). Pathologically confirmed carcinoma in situ (high grade dysplasia, n=22) or invasive carcinoma (n=18) was identified in 40 patients. Of the 18 patients who were found to have invasive carcinoma, 10 had main duct IPMN (56%), 5 had branch duct (28%), and 3 had combined (17%). Four of the 18 patients who developed invasive cancer during surveillance (22% of those resected for carcinoma and 3% of those followed) developed PDAC in a region of the gland distinct from the radiographically identified lesion for which surveillance was recommended. Invasive carcinoma was diagnosed a median of 24 mo after the original IPMN diagnosis. During follow-up (median = 8 months from the cancer diagnosis), 1 patient died of disease, 2 are cancer-free, and 1 patient is alive with recurrence. Conclusions: In this study, 11% of patients with IPMN initially selected for surveillance developed invasive disease; 22% of those tumors arose in an area of the gland distinct from the initially identified lesion. Diagnostic and operative strategies for IPMN should consider the cancer risk in the entire gland. [Table: see text]
Long-term Risk of Malignancy in Branch-Duct Intraductal Papillary Mucinous Neoplasms
