IntechOpen is the world's leading publisher of Open Access books, built by scientists for scientists. With 7,200 Open Access books available, 191,000 international authors and editors, and 210 million downloads, IntechOpen delivers content to 154 countries. Its authors are among the top 1% most cited scientists, with 14% contributors from top 500 universities. Books are indexed in the Web of Science™ Book Citation Index (BKCI). Interested in publishing? Contact book.department@intechopen.com. Cholangiocarcinoma (CCA) is a malignant disease of the biliary duct system, divided into intrahepatic (5–10%) and extrahepatic (60–70% proximal, 20–30% distal). The etiology is unknown, but chronic inflammation leads to dysplastic changes and malignancy. Prognosis is poor unless detected early. Treatment includes partial hepatectomy for intrahepatic CCA and radical bile duct resection for extrahepatic. Liver transplantation is considered for advanced disease without extrahepatic lymph node involvement. Palliation via endoscopic drainage or surgical bypass is used for unresectable tumors. Adjuvant therapies like chemotherapy, immunotherapy, and photodynamic therapy are used for advanced disease. Cholangiocarcinoma was first described in 1840 by Durand-Fardel. In 1965, Klatskin described adenocarcinoma of the porta hepatitis, later known as Klatskin tumor. Surgical resection is the only cure, but many patients present with advanced disease. Hilar cholangiocarcinoma is treated with radical bile duct resection and partial hepatectomy. Intrahepatic cholangiocarcinoma is treated with partial hepatectomy, while distal cholangiocarcinoma may require pancreaticoduodenectomy. Surgical outcomes for distal cholangiocarcinoma are better than others. Orthotopic liver transplantation may be viable for some unresectable cases. Incidence of bile duct carcinoma is 0.01–0.5%, with 3,000 new cases annually in the US. Worldwide incidence is 0.5–2.0/100,000. Early-stage tumors can be curative, but prognosis is poor for unresectable cases. Bile duct cancer is rare in Western countries, with higher incidence in Southeast Asia. Risk factors include bile duct cysts, parasitic infections, primary sclerosing cholangitis, hepatolithiasis, and toxins. Genetic factors, such as mutations in p53, APC, and Bcl-2, are implicated. Other risk factors include hepatitis B and C, diabetes, obesity, alcohol, smoking, andIntechOpen is the world's leading publisher of Open Access books, built by scientists for scientists. With 7,200 Open Access books available, 191,000 international authors and editors, and 210 million downloads, IntechOpen delivers content to 154 countries. Its authors are among the top 1% most cited scientists, with 14% contributors from top 500 universities. Books are indexed in the Web of Science™ Book Citation Index (BKCI). Interested in publishing? Contact book.department@intechopen.com. Cholangiocarcinoma (CCA) is a malignant disease of the biliary duct system, divided into intrahepatic (5–10%) and extrahepatic (60–70% proximal, 20–30% distal). The etiology is unknown, but chronic inflammation leads to dysplastic changes and malignancy. Prognosis is poor unless detected early. Treatment includes partial hepatectomy for intrahepatic CCA and radical bile duct resection for extrahepatic. Liver transplantation is considered for advanced disease without extrahepatic lymph node involvement. Palliation via endoscopic drainage or surgical bypass is used for unresectable tumors. Adjuvant therapies like chemotherapy, immunotherapy, and photodynamic therapy are used for advanced disease. Cholangiocarcinoma was first described in 1840 by Durand-Fardel. In 1965, Klatskin described adenocarcinoma of the porta hepatitis, later known as Klatskin tumor. Surgical resection is the only cure, but many patients present with advanced disease. Hilar cholangiocarcinoma is treated with radical bile duct resection and partial hepatectomy. Intrahepatic cholangiocarcinoma is treated with partial hepatectomy, while distal cholangiocarcinoma may require pancreaticoduodenectomy. Surgical outcomes for distal cholangiocarcinoma are better than others. Orthotopic liver transplantation may be viable for some unresectable cases. Incidence of bile duct carcinoma is 0.01–0.5%, with 3,000 new cases annually in the US. Worldwide incidence is 0.5–2.0/100,000. Early-stage tumors can be curative, but prognosis is poor for unresectable cases. Bile duct cancer is rare in Western countries, with higher incidence in Southeast Asia. Risk factors include bile duct cysts, parasitic infections, primary sclerosing cholangitis, hepatolithiasis, and toxins. Genetic factors, such as mutations in p53, APC, and Bcl-2, are implicated. Other risk factors include hepatitis B and C, diabetes, obesity, alcohol, smoking, and