Cholangiocarcinoma is a type of cancer that forms in the bile ducts, which are small tubes that carry bile from the liver to the small intestine. This cancer can occur in any part of the bile ducts, including the intrahepatic bile ducts inside the liver, the perihilar bile ducts at the junction of the liver and the bile ducts outside the liver. Cholangiocarcinoma is a rare but aggressive form of cancer that is often diagnosed at an advanced stage when treatment options are limited. Risk factors for cholangiocarcinoma include chronic inflammation of the bile ducts, infections with certain parasites, liver diseases such as cirrhosis, and genetic conditions. Treatment for cholangiocarcinoma may include surgery, chemotherapy, radiation therapy, targeted therapy, and immunotherapy. Research in this area is focused on developing new and more effective treatments, understanding the genetic and molecular mechanisms underlying the disease, improving early detection methods, and finding ways to prevent cholangiocarcinoma.