Background: 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.
Methods: 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.
Results: Univariate analysis revealed nine significant predictors of both malignant and invasive IPMN: age > or =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.
Conclusions: Our scoring system using five independent factors (age > or =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.