Abstracts
2000 Digestive Disease Week

# 2222 Trends in the Prevalence of Cholecystectomy and the Incidence of Cancers of the Pancreas, Extrahepatic Bile Duct, and Ampulla of Vater in the United States: 1980-1996.
David R. Urbach, Lee L. Swanstrom, Yashodan Khajanchee, Paul D. Hansen, Portland, OR

Background: Several epidemiologic studies have implicated cholecystectomy as a risk factor for subsequent cancer of the pancreas, bile duct and ampulla of Vater. In the United States, the cholecystectomy rate increased by approximately 30% following the rapid adoption of a laparoscopic procedure around 1991. We used a population-based approach to analyze trends in the incidence of pancreatic, bile duct and ampullary cancers before and after the dissemination of laparoscopic cholecystectomy, in order to determine whether there was an association between increased cholecystectomy prevalence and cancer risk. Methods: We estimated the annual rates of cholecystectomy in the United States from the National Hospital Discharge Survey for the years between 1980 and 1996 for which reliable data were available. Cancer incidence data were obtained from the Surveillance, Epidemiology and End Results (SEER) database. Results: The rate of cholecystectomy increased 30.5% from 203 per 100,000 population (95% CI 184-222) before 1991, to 292 per 100,000 (95% CI 271-312) in 1996. For the diagnosis years 1980-1996, the SEER database contains histologically confirmed records of 30,113 incident cases of pancreatic cancer, 2,397 incident cases of cancer of the bile duct, and 1,573 incident cases of ampullary cancer. Comparing the period 1980-1991 to 1992-1996, the age-adjusted incidence rate of pancreatic cancer (per 100,000 population) decreased from 7.83 (95% CI 7.72-7.93) to 7.45 (95% CI 7.30- 7.61), the rate of bile duct cancer decreased from 0.65 (95% CI 0.62-0.68) to 0.52 (95% CI 0.48-0.57), and the rate of cancer of the ampulla of Vater increased slightly from 0.38 (95% CI 0.35-0.40) to 0.44 (95% CI 0.40-0.48). The trend towards an increase in the rate of ampullary cancer preceded the advent of laparoscopic cholecystectomy (estimated annual percent change (EAPC) 1980-1991: +2.18%, p=0.05; EAPC 1992-1996: -4.96%, p=0.33). Conclusions: This population-based study does not support the hypothesis that there is an increased short-term risk of developing cancers of the pancreas, extrahepatic bile duct or ampulla of Vater following cholecystectomy. While longer follow up is necessary to rule out long-term cancer risks, the previously reported association between cholecystectomy and short-term cancer risk is probably due to bias.