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Medline ® Abstract for Reference 26

of 'Intraductal papillary mucinous neoplasm of the pancreas (IPMN): Pathophysiology and clinical manifestations'

Natural history of intraductal papillary mucinous tumors of the pancreas: actuarial risk of malignancy.
Lévy P, Jouannaud V, O'Toole D, Couvelard A, Vullierme MP, Palazzo L, Aubert A, Ponsot P, Sauvanet A, Maire F, Hentic O, Hammel P, Ruszniewski P
Clin Gastroenterol Hepatol. 2006;4(4):460.
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 confinedto 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.
Pôle des Maladies de L'Appareil Digestif, Service de Gastroentérologie-Pancrétologie, Hôpital Beaujon, Clichy, France. philippe.levy@bjn.aphp.fr