Overview of epidemiology of bile duct and gallbladder cancer focusing on the JACC study

BACKGROUND: This review discusses the epidemiologic features of bile duct and gallbladder cancer in Japan, mainly focusing on results of Japan Collaborative Cohort Study (JACC Study) for Evaluation of Cancer Risk Sponsored by the Ministry of Education, Science, Sports and Culture of Japan (Monbusho) in comparison with results of other studies. METHODS: The theses and papers derived from JACC Study on bile duct and gallbladder cancer were all collected for this review. Hirayama's cohort study, which is a representative epidemiologic study, and a large scale case-control study on bile duct and gallbladder cancer in Japan by Kato et al. were also taken into consideration. Small scale cross-sectional studies or ecological studies and the studies conducted outside Japan were collected by the literature reference services on the web net such as Pub Med or Japan Centra Revuo Medicina (Igaku- Chuo- Zasshi) limited to the published after 1980 and use key words bile duct cancer, gallbladder cancer and epidemiology. RESULTS: In the JACC Study, high intake of fried food was regarded as a factor that significantly elevated the risk of the diseases (hazard ratio [HR] = 2.58, 95 % confidence interval [Cl]: 1.08-6.16 in males; HR = 2.98, 95 % Cl: 1.28-6.86 in females). The JACC Study indicated that a high intake of boiled beans had a significant preventive relation to the diseases in females (relative risk [RR] = 0.50, 95 % Cl: 0.26-0.98). High consumption of fish also had a significant preventive relationship to bile duct cancer in males (RR = 0.53, 95 % Cl: 0.26-0.98) and gallbladder cancer in females (RR = 0.43, 95 % Cl: 0.240.79). A history of blood transfusion also had a significant relationship (HR = 2.27, 95 % Cl: 1.29-3.98) as which elevated the risk. The JACC Study determined bowel movement as a risk factor. The group with bowel movements less than once per six days had a significantly elevated hazard ratio (HR = 5.21, 95 % Cl: 1.25-21.68). CONCLUSION: As to recent epidemiologic features of bile duct and gallbladder cancer revealed by the JACC Study, its outline became obvious in comparison with the results of other studies. Evidence for the contribution of the JACC Study is strong because it provides some important findings on the epidemiology of bile duct and gallbladder cancer.