Validating a Simple Scoring System to Predict Malignancy and Invasiveness of Intraductal Papillary Mucinous Neoplasms of the Pancreas

Abstract

The objective of the present study was to identify reliable preoperative factors predicting malignancy or invasiveness of intraductal papillary mucinous neoplasm (IPMN) of the pancreas and the effectiveness of a diagnostic scoring system based on these factors. Between August 1994 and December 2007, 204 patients underwent pancreatic resection for IPMN at a single institute. Medical records were reviewed retrospectively, and a new diagnostic scoring system for predicting malignant IPMN preoperatively was designed. Univariate analysis revealed nine significant predictors of both malignant and invasive IPMN: age ≥60 years, history of pancreatitis, presence of mural nodule(s), diameter of main pancreatic duct (MPD) >6 mm, main duct or mixed type, total bilirubin >1.2 mg/dl, CA-19-9 >37 U/ml, tumor location in the pancreatic head, and tumor size >30 mm. Multivariate analysis showed that age, pancreatitis, mural nodule(s), and MPD diameter were independent predictors of invasive IPMN, and that all these parameters, plus elevated carbohydrate antigen-19-9 (CA-19-9), were independent predictors of malignant IPMN. A scoring system based on these five factors, each assigned 1 point, and with a cut-off of 3 points, could predict malignant IPMN with a sensitivity of 50.7% and a specificity of 90.1%. The 5-year survival rates of patients with benign and malignant IPMN were 95.0% and 64.0%, respectively. Our scoring system using five independent factors (age ≥60 years, history of pancreatitis, presence of mural nodule(s), elevated level of CA-19-9, and MPD diameter >6 mm) may be helpful for predicting malignancy and postoperative survival.