Biliary tract cancer cases at printing plants in Japan

1. Background Three former and current employees of a printing plant in Osaka were reported having developed biliary tract cancer, announced the Ministry of Health, Labour and Welfare in May 2012. Those workers at the printing room used to handle chlorinated hydrocarbons as ink cleaner all day, according to their claims for workers’ compensation filed on 30 March 2012. The Ministry started to investigate the cause of the cancer through technical team in April. A total of 17 claims of biliary tract cancer cases at the plant were filed to a local inspectors’ office of the Ministry. They are all male and under age of 50 and seven (7) of them were dead at the time of claims as shown in table 1. The incidence of biliary tract cancer in the plant is unusually high, considering the number of employees at the plant and the age groups: the plant has around 70 employees and 30 of them regularly work in the printing room. Their histologic features are shown in Table 2. Workers compensation panel started to consider 16 cases first and reviewed 13 pathology specimens available. All 13 cases have adenocarcinoma with various differentiations. No hepatocarcinoma or primary malignant tumour was observed. The medical records showed no remarkable non-occupational risk factors such as liver fluke, liver cirrhosis and viral hepatitis.