- Clinical science
Biliary tract cancers include cholangiocarcinoma and gallbladder carcinoma, which are both rare diseases with very poor prognoses. Cholangiocarcinoma is classified as either intrahepatic or extrahepatic according to the anatomical site of the tumor. Extrahepatic carcinoma, which is the more common form, can be further classified as perihilar (Klatskin tumor; occurs at the bifurcation of the hepatic duct) and distal extrahepatic carcinoma. Risk factors for cholangiocarcinoma include primary sclerosing cholangitis and chronic biliary tract inflammation. The greatest risk factor for gallbladder carcinoma is cholelithiasis. Patients are often initially asymptomatic or only present with nonspecific symptoms (e.g., abdominal pain, fever, weight loss) until late stages of disease, meaning that most tumors are already advanced at the time of diagnosis. Extrahepatic cholangiocarcinoma may manifest with signs of cholestasis (e.g., jaundice, dark urine, pruritus) and a painless, enlarged gallbladder (Courvoisier sign). If liver transaminases and tumor markers are raised and/or ultrasound imaging suggests bile duct or gallbladder carcinoma, MRCP or MDCT are recommended for diagnosis. Although surgical resection of early-stage tumors is curative, approximately 90% of patients have more advanced, unresectable tumors at the time of diagnosis.
- Cholangiocarcinomas: originate in the bile ducts and are classified based on their anatomical site of origin 
- Gallbladder carcinomas: originate within the mucosal lining of the gallbladder 
- Incidence: ∼ 1/100,000 per year in the US
- Prevalence: < 1% of all cancers
- Peak incidence: 60–70 years of age
- Sex: ♂ > ♀
- Incidence: ∼ 2/100,000 per year in the US but significantly higher in India, Chile, and Eastern Europe
- Sex: ♀ > ♂
Epidemiological data refers to the US, unless otherwise specified.
Risk factors for cholangiocarcinoma 
- Primary sclerosing cholangitis
- Liver fluke infection (e.g., Clonorchis sinensis, Opisthorchis viverrini)
- Choledocholithiasis (both with and without hepatic duct involvement)
- Chronic viral hepatitis (e.g., hepatitis B, hepatitis C)
- Liver cirrhosis
- Environmental toxin exposure (e.g., asbestos, Thorotrast contrast agent)
- Congenital biliary tract abnormalities (e.g., choledochal cysts, congenital hepatic fibrosis)
- Risk factors for gallbladder carcinoma 
Clinical features depend on the location and stage of the tumor.
- Extrahepatic cholangiocarcinoma
- Intrahepatic cholangiocarcinoma
Gallbladder carcinoma 
The diagnostic approach varies depending on the location of the tumor and whether PSC is present. If the patient's presentation, laboratory findings (especially tumor markers), and/or transabdominal ultrasound suggest biliary cancer, then MRCP or MDCT is generally recommended for diagnosis. Biopsy is generally unnecessary.
Laboratory tests 
- Liver function tests: possible ↑ INR, ↑ ALT, and ↑ AST (with chronic biliary obstruction and eventual hepatic dysfunction)
- Parameters of cholestasis (e.g., ALP, GGT, total bilirubin) may initially be normal.
- Tumor markers (to determine the baseline; should not be used to confirm the diagnosis)
Transabdominal ultrasound should be the initial imaging modality for suspected biliary tract carcinoma
- Localization of obstruction and evaluation for gallstones
- Findings: gallbladder and/or bile duct dilatation
- Useful for identifying local metastases and performing ultrasound-guided biopsy
- Recommended for definitive diagnosis
- Findings: bile duct dilatation and/or mass lesion
- Abdominal MDCT is commonly used as an alternative to MRCP
- Endoscopic ultrasound (especially for distal extrahepatic lesions and staging)
- Chest CT for staging
- PET scan: indicated if other diagnostic procedures are inconclusive and for staging
- Transabdominal ultrasound should be the initial imaging modality for suspected biliary tract carcinoma
Cholangiocarcinoma: ERCP with ductal brushings or biopsy is recommended but not always necessary for diagnosis.
- May be indicated if MRCP or MDCT are inconclusive
- Allows for confirmation of tumor type via tissue sampling
- Sometimes preferred by surgeons to assess tumor resectability; allows for immediate placement of a stent if the tumor is inoperable
- Rarely, percutaneous transhepatic cholangiography (PTC) is used for proximal lesions.
- Gallbladder cancer: biopsy is usually unnecessary; typically proceeds directly to surgical exploration/resection if clinical suspicion is high
- Cholangiocarcinoma: ERCP with ductal brushings or biopsy is recommended but not always necessary for diagnosis.
- Surgical exploration: Exploratory laparoscopy is often performed for definitive diagnosis and/or staging prior to resection.
- Gallbladder carcinoma
The differential diagnoses listed here are not exhaustive.
Resectable disease 
- < 10% of cases are resectable.
- Resection is the only curative therapy.
Procedure: radical resection plus lymphadenectomy
- Preoperative biliary drainage is performed in some cases.
- Adjuvant chemotherapy: usually a fluoropyrimidine-based regimen
|Intrahepatic cholangiocarcinoma|| |
|Extrahepatic cholangiocarcinoma|| |
|Gallbladder carcinoma|| |
Unresectable disease 
- Unresectable carcinoma or metastatic disease accounts for > 90% of cases.
- Treatment is palliative
- Transarterial chemoembolization (TACE): local application of chemotherapy and occlusive substance → induces fibrosis and shrinkage of intrahepatic cholangiocarcinoma