Slight dilatation of the main pancreatic duct and presence of pancreatic cysts as predictive signs of pancreatic cancer: a prospective study

Abstract

Purpose: To prospectively determine whether slight dilatation of the main pancreatic duct and pancreatic cysts detected at ultrasonography (US) are predictive signs of pancreatic cancer.

Materials and methods: The research protocol was approved by the institutional review board, and written informed consent was obtained from all participants. One thousand fifty-eight subjects (age range, 36-80 years; mean, 61.8 years) with various kinds of abnormal US findings in the pancreas were enrolled from 1999 to 2002, after exclusion of pancreatic neoplasm and other malignant diseases. The endpoint was the subsequent development of pancreatic cancer, and the outcome was determined at the end of December 2007. To identify independent predictive variables for the subsequent development of pancreatic cancer, various baseline characteristics were examined by using a Cox regression model and a Cox proportional hazards model. The cumulative incidence of pancreatic cancer was estimated by using the Kaplan-Meyer method.

Results: During the mean follow-up of 75.5 months (+/- 17.3[standard deviation]), pancreatic cancer subsequently developed in 12 of 1058 subjects. The risk of pancreatic cancer was significantly elevated in subjects with slight dilatation (> or = 2.5 mm) of the main pancreatic duct or presence of cyst (s) (> or = 5 mm). The respective hazard ratios were 6.38 (P = .018) and 6.23 (P = .003). For subjects with both findings, the 5-year cumulative risk of pancreatic cancer was 5.62% (95% confidence interval: .37%, 13.03%), and the age-and sex-adjusted hazard ratio compared with the risk in the absence of these findings was 27.50 (P = .002).

Conclusion: Main pancreatic duct dilatation (> or = 2.5 mm) and presence of a pancreatic cyst (> or = 5 mm) were both strong independent predictors of the subsequent development of pancreatic cancer. (c) RSNA, 2010.