Cholangiocarcinoma is a type of cancer caused by bile ducts in the liver. The tumor may originate from the gallbladder, the small bile ducts inside the liver, the large bile ducts at the entrance of the liver, the main bile duct (choledochus), and the area where the bile duct is joined into the intestine (Ampulla Vateri). According to their origin, cholangiocarcinomas are divided into 3 groups:
1. Intrahepatic cholangiocarcinoma (derived from small bile ducts in the liver)
2. Perihilar cholangiocarcinoma (originating from the large bile duct at the entrance of the liver)
3. Extrahepatic cholangiocarcinoma (originating from bile ducts outside liver)
Cholangiocarcinoma is the most common primary tumor of the liver after HCC. The frequency of intrahepatic cholangiocarcinoma has been increasing in all over the world, especially in middle east. Although primary sclerosing cholangitis and certain parasitic diseases may cause cholangiocarcinoma, there is no underlying cause in most cases.
How is it diagnosed?
Cholangiocarcinoma may cause symptoms such as abdominal pain, jaundice, malaise, and urine color changes. In some patients, it may be seen on ultrasound, CT and MRI, although cholangiocarcinoma is more difficult to differentiate from the normal liver tissue compared to other tumors in the liver. Sometimes cholangioma is suspected by the enlargement of the bile ducts, although the mass itself is not seen. If ultrasound, CT or MRI shows a mass suspicious for cholangiocarcinoma, ultrasound or CT-guided needle biopsy should confirm the diagnosis.
How is it treated?
In cholangiocarcinoma, it should first be investigated whether surgery is possible. For this purpose, the age of the patient, heart-lung problems that may interfere with the operation, as well as the location, size of the tumor and the presence of extra-liver metastases are examined. If the patient's clinical condition and the structure of the tumor are appropriate, the cholangiocarcinoma should be removed by surgical operation. If the patient is not eligible for surgery, the classical treatment methods are chemotherapy and radiotherapy. If the tumor has obstructed the bile ducts and is causing jaundice and itching , the obstruction should be eliminated by placing a plastic or metal stent in the bile ducts.
New treatment methods
In cholangiocarcinoma, surgical resection is possible only in 30% of the patients, and in the rest, surgical operation cannot be performed because of the size, number or location of the tumor or the condition of the patient. Although chemotherapy and radiotherapy are applied in such patients, survival rates are not very high.
In recent years, there has been an increasing use of minimally invasive interventions such as percutaneous ablation and transarterial treatments. Intrahepatic cholangiocarcinomas can sometimes be treated with thermal ablation methods such as cryoablation, radiofrequency and microwave, especially if they are less than 5 cm in diameter. Thermal ablation methods in hilar cholangiocarcinoma can only be performed by special techniques that protect bile ducts, because they are likely to damage bile ducts. In these tumors, the irreversible electroporation (Nanoknife) method, which does not damage the bile ducts, may be useful, but there is not enough evidence.
Other promising treatments for cholangiocarcinoma are angiographic treatments such as chemoembolization (TACE) and radioembolization (TARE). The efficacy of these treatments has been well demonstrated in liver metastases of colon cancer HCC, which is the most common primary tumor of the liver. Recent studies have also shown that chemoembolization and radioembolization may significantly improve treatment response rates and patient survival in cholangiocarcinoma. Both treatments can be used not only in tumors that do not respond to chemoradiotherapy, but also in combination with chemotherapy.
Studies in the literature show that both chemoembolization and radioembolization are similarly successful in cholangiocarcinoma. An advantage of radioembolization is that if administered at high doses, it will reduce the size of the diseased lobe of the liver allowing the healthy lobe to grow, and kill the tumor by giving high dose radiation at the same time. This may allow some patients who could not be operated before, to become suitable for operation after some months. For this purpose, portal vein embolization may also be used or may be administered sequentially with radioembolization.