Natural history of intraductal papillary mucinous tumors of the pancreas: actuarial risk of malignancy

Clin Gastroenterol Hepatol. 2006 Apr;4(4):460-8. doi: 10.1016/j.cgh.2006.01.018.


Background & aims: Natural history of intraductal papillary mucinous tumors of the pancreas (IPMTs) is unknown. Cross-sectional studies suggest that exclusive branch duct (BD) involvement is associated with a lower risk of carcinoma than main pancreatic duct (MPD) involvement. The aim of our study was to calculate longitudinal risk of malignant transformation of IPMT since the first sign.

Methods: All the patients with a diagnosis of highly probable or histologically proven IPMT were included. Actuarial risks of occurrence of at least low-grade dysplasia (>or=LGD), high-grade dysplasia (>or=HGD), or invasive carcinoma (IC) were calculated by Kaplan-Meier method from the first sign attributable to IPMT. The risks according to sex, acute pancreatitis, tumor size, and involvement of MPD were compared by log-rank test.

Results: One hundred six patients were included with a proven (n = 76) or probable (n = 30) IPMT. The tumor was confined to BD in 53 cases. Median duration since the onset of the first sign to the end of follow-up was 21 months (range, 0-241). Ten-year actuarial risk that IPMT grade was >or=LGD, >or=HGD, or IC was 67%, 49%, and 29%, respectively. The only morphologic risk factor of malignant transformation was involvement of MPD, with a 5-year actuarial risk of >or=HGD of 63% in the MPD group compared with 15% in the BD group (P < .001).

Conclusions: Longitudinal risk of at least HGD or IC is time-dependent. Patients with BD IPMT present a much lower risk, justifying a nonoperative surveillance.

MeSH terms

  • Actuarial Analysis
  • Adult
  • Aged
  • Aged, 80 and over
  • Cell Transformation, Neoplastic
  • Cystadenoma, Papillary / diagnostic imaging
  • Cystadenoma, Papillary / pathology*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Pancreatic Ducts*
  • Pancreatic Neoplasms / diagnostic imaging
  • Pancreatic Neoplasms / pathology*
  • Radiography
  • Risk Assessment
  • Risk Factors