Cholangiocarcinoma (Bile Duct Cancer)

The bile ducts carry bile from the liver to the gallbladder and small intestine. Cholangiocarcinoma is classified according to where the tumor develops:

• Intrahepatic cholangiocarcinoma (iCCA) arises from bile ducts within the liver.

• Perihilar cholangiocarcinoma (pCCA) develops near the junction of the right and left hepatic ducts.

• Distal cholangiocarcinoma (dCCA) develops in the lower portion of the bile duct near the pancreas and small intestine.

Perihilar and distal tumors are collectively referred to as extrahepatic cholangiocarcinoma.

Although all are bile duct cancers, these subtypes differ in clinical presentation, imaging findings, surgical approach, and molecular features, making accurate classification important.

Most people with cholangiocarcinoma do not have a single identifiable cause. Factors associated with an increased risk include:

• Primary sclerosing cholangitis (PSC)

• Congenital bile duct abnormalities such as choledochal cysts

• Hepatolithiasis, or stones within the intrahepatic bile ducts

• Infection with liver flukes such as Clonorchis sinensis or Opisthorchis viverrini

• Certain chronic inflammatory disorders of the bile ducts

• Chronic hepatitis B or C and cirrhosis, particularly in relation to intrahepatic cholangiocarcinoma

• Certain inherited conditions or genetic susceptibility

Patterns of cholangiocarcinoma in parts of East and Southeast Asia are influenced by several factors, including liver fluke infection, chronic biliary disease, and chronic liver disease.

Symptoms depend strongly on where the tumor is located.

Perihilar and distal cholangiocarcinomas are more likely to block the flow of bile and may cause:

• Yellowing of the skin or eyes

• Dark urine

• Pale stools

• Itching

• Loss of appetite

• Unexplained weight loss

• Abdominal discomfort or pain

• Fatigue

When bile duct obstruction is complicated by infection, fever, chills, and abdominal pain may occur and can indicate cholangitis.

Intrahepatic cholangiocarcinoma may cause no symptoms at an early stage and does not usually cause jaundice until more advanced. Possible symptoms include upper abdominal discomfort, fatigue, loss of appetite, and weight loss. Some tumors are found incidentally on imaging.

Diagnosis usually involves imaging, blood tests, pathology, and staging.

Contrast-enhanced CT and MRI are important imaging studies. Magnetic resonance cholangiopancreatography (MRCP) provides detailed images of the bile ducts and can help determine the location and extent of an obstruction.

Imaging is used to assess:

• The location and extent of the tumor

• Involvement of the liver or nearby organs

• Involvement of major blood vessels

• Lymph node or distant metastases

• Whether complete surgical removal may be possible

CA19-9 is a commonly used blood tumor marker, but it cannot diagnose cholangiocarcinoma on its own. Benign conditions such as bile duct obstruction or cholangitis can also cause high CA19-9 levels, while some patients with cholangiocarcinoma have normal levels.

Tissue or cell samples may be obtained through different approaches, including image-guided biopsy, ERCP-based sampling, cholangioscopy, or endoscopic ultrasound-guided procedures.

However, a percutaneous biopsy is not automatically recommended before surgery for every patient. In some potentially resectable perihilar or distal tumors, the decision about whether and how to obtain tissue should be made by an experienced multidisciplinary team.

Molecular Testing

Molecular profiling has become an important part of treatment planning for unresectable, recurrent, or metastatic cholangiocarcinoma.

Current guidelines recommend broad molecular testing before or during first-line treatment. Relevant biomarkers may include:

• FGFR2 fusions or rearrangements

• IDH1 mutations

• BRAF V600E mutations

• HER2 amplification or overexpression

• NTRK fusions

• RET fusions

• MSI-H or dMMR

FGFR2 fusions and IDH1 mutations are particularly associated with subsets of intrahepatic cholangiocarcinoma. Molecular profiles can differ substantially among cholangiocarcinoma subtypes.

Treatment begins with determining whether the tumor can be completely removed and then takes into account its location, stage, the patient's overall health, and molecular findings.

Surgery

For localized cholangiocarcinoma that can be completely removed, surgery remains the main potentially curative treatment.

The operation varies according to tumor location. Intrahepatic tumors generally require liver resection. Perihilar tumors may require removal of the extrahepatic bile ducts together with part of the liver. Distal tumors may require a pancreaticoduodenectomy.

Because these procedures can be complex, evaluation at a center experienced in hepatobiliary surgery is important.

Adjuvant Treatment

After complete surgical resection, the risk of recurrence is assessed and additional treatment may be recommended.

Capecitabine is an important standard adjuvant chemotherapy option following resection of biliary tract cancer. Radiation or chemoradiation may be considered in selected patients based on factors such as surgical margins, lymph node involvement, and tumor location.

Routine postoperative immunotherapy is not currently appropriate for every patient.

Unresectable or Metastatic Disease

For unresectable, recurrent, or metastatic cholangiocarcinoma, gemcitabine plus cisplatin remains an important chemotherapy backbone.

Immune checkpoint inhibitors are now part of standard first-line treatment. Major options include gemcitabine and cisplatin combined with either durvalumab or pembrolizumab.

Targeted Therapy

Molecularly targeted therapy may be available when a specific actionable alteration is identified.

Examples include FGFR inhibitors for FGFR2 fusions or rearrangements and IDH1 inhibitors for IDH1-mutated tumors. Targeted treatments may also be available for selected tumors with BRAF V600E, HER2, NTRK, or RET alterations.

The exact indication and availability of these therapies vary by country and treatment setting.

Radiation and Local Therapies

Radiation therapy may be used for selected locally advanced tumors, postoperative high-risk disease, or metastatic lesions.

Some intrahepatic tumors may also be treated with ablation, transarterial therapy, or other liver-directed approaches.

In selected patients whose initially unresectable tumors respond well to systemic or local treatment, surgery may be reconsidered.