Bile duct cancer is an uncommon disease. The exact causes of bile duct cancer are not known with any certainty, states the American Cancer Society, but changes in the genetic makeup of the cancer cells are being studied for clues to the actual causes. There are, however, certain associated conditions known as risk factors that increase the chances of bile duct in individuals.
Liver and Bile Duct Disease
The ACS states that conditions that cause chronic or long-term inflammation in the bile duct increase the chances of the development of bile duct cancer. Conditions mentioned by the ACS are primary sclerosing cholangitis, bile duct stones, choledochal cysts, liver cirrhosis and ulcerative colitis. Pancreaticobiliary maljunction, a condition from birth that causes pancreatic fluid to reflux into the bile duct, is also mentioned as a risk factor. Other anomalies mentioned are Caroli syndrome and polycystic disease of the liver.
Age
Bile duct cancer is not common in younger age groups. The ACS states that more than 60 percent of those with bile duct cancer are over 65 years of age.
Liver Flukes
Clonorchis sinensis and Opisthorchis viverrini are two types of liver flukes seen in developing countries. These are food and waterborne diseases. According to the ACS, the infestation with these parasites increases the chances of developing bile duct cancer.
Obesity
Bile duct cancer occurs more in the obese and overweight. The ACS attributes this finding to the fact that the incidence of gallstones and bile duct stones are increased in obesity. Some hormonal changes seen in obesity appear to be involved in increasing the risk of bile duct cancer.
Exposure to Thorium Dioxide
The radiological dye thorium dioxide is believed to increase the risk of bile duct cancer. This fact, reports the ACS, has led to the withdrawal of thorium dioxide from the market.
Other Possible Risk Factors
The American Society of Clinical Oncology lists certain chemicals found in automotive and rubber plants as potential agents in the development of bile duct cancer. These chemicals are nitrosamines, dioxins and polychlorinated biphenyls, or PCBs. Other chemicals mentioned by the ACS are asbestos, radon and other radioactive chemicals.
Family history, infection with hepatitis B and hepatitis C, diabetes, pancreatitis and tobacco use are all factors considered important in the development of bile duct cancer, according to the ACS.
