What Causes Cholangiocarcinoma & What are its Symptoms & Pathophysiology?
Cancer is one of the leading deadly diseases that have been spreading all over the world like an epidemic. According to World Health Organization (WHO), in 2012 alone over 8.2 million people have died out of this disease. WHO has also predicted that within next two decades this deadly disease is going to affect near about 25 million people worldwide. There are over 100 different kinds of cancer known to the medical fraternity.
Cholangiocarcinoma or bile duct cancer is one such rare type of cancer that is found in low percentage in different parts of the world, particularly in the Western countries. This form of cancer originates in any or multiple parts of the liver and extrahepatic bile ducts, which terminate at the ampulla of Vater or hepatopancreatic duct. Bile ducts helps in passing bile from the liver to the small intestine which helps in the process of digestion. Precise reason behind the occurrence of cholangiocarcinoma is yet to be detected, however, oncologists are suggesting for healthy and wholesome foods, less smoking and alcohol and regular exercise to stay fit and keep the cancer at bay.
What Causes Cholangiocarcinoma?
Though the precise causes of cholangiocarcinoma are still clearly not known to the researchers and medical fraternity, researchers have found a link between the changes in chemical composition of DNA and cholangiocarcinoma.
Researchers are finding the clue how the inflammation is actively making changes in the DNA of cells, leading to abnormal growth of cells and formation of cancer cells.
Some genes in human cells control the growth, death and formation of cells. Genes that help the cells to grow, divide, and stay active are called oncogenes, while the genes that slow down cell division or lead cells to die are known as tumor suppressor genes. Changes in DNA or mutation hinder the normal activities of oncogenes and suppressor genes thus creating abnormal cells or tumor. There are statics available that show that many persons inherit DNA mutation from their ancestors, though such inherited characteristic of DNA is not yet proved to be responsible for cholangiocarcinoma.
What are the Signs and Symptoms of Cholangiocarcinoma?
At the initial stage of cholangiocarcinoma the symptoms are not very apparent. It's only at the later stages when the tumor starts blocking the free passage of bile to the small intestine that different type of physical signs and symptoms starts appearing. This delayed appearance of the apparent symptoms is one of the main hindrances for the detection of cholangiocarcinoma at the early stage and initiation of treatment at the earliest possible time.
Here are some physical symptoms that may be the signs and symptoms of cholangiocarcinoma or bile duct cancer:
- Jaundice as a Symptom of Cholangiocarcinoma: Jaundice is the most common symptom of cholangiocarcinoma, but it doesn't mean that all types of jaundice are sure indication of cholangiocarcinoma. Bile contains bilirubin, a yellowish type of fluid formed in the liver. If the formed bile is unable to pass to the small intestine from the liver, it starts to mix with the blood and settle in different parts of the body. During this period, skin and eyes look yellowish- an indication of jaundice.
- Abdominal Pain as a Symptom of Cholangiocarcinoma: At the earlier stages, cholangiocarcinoma or bile duct cancer doesn't cause any pain. During the later stages, right abdominal pain is felt by the patient.
- Changes in Excretion Color as a Symptom of Cholangiocarcinoma: Deposition of bile in the kidneys leads to dark colored urine. This changing color of urine, similarly changed color of stools is the other symptoms of cholangiocarcinoma or bile duct cancer.
- Vomiting as a Symptom of Cholangiocarcinoma: Nausea and vomiting sometimes accompany cholangiocarcinoma or bile duct cancer. This happens when a patient develops cholangitis, a type of infection, due to blockage of the bile duct.
- Other Symptoms of Cholangiocarcinoma
- Low fever
- Weight loss
- Courvoisier's sign.
What is the Pathophysiology of Cholangiocarcinoma?
Cholangiocarcinoma or bile duct cancer mostly starts from the intra- or extrahepatic cells of the bile ducts epithelium tissue. In majority of the cases, cholangiocarcinoma have histological characteristics of adenocarcinoma, but the etiology of most of the bile duct cancers are still not clear to the researchers. Recent development in researches has evidenced that cholangiocarcinoma develops through a series of stages, starting from hyperplasia through dysplasia to the ultimate formation of carcinoma.
Cholangiocarcinoma or bile duct cancer grow steadily getting into the walls of the ducts dissecting the layers of the bile duct. With the passage of time local extensions into the liver and adjoining systems such as porta hepatis, and regional lymph nodes etc. occur slowly. Even cholangitis, a life-threatening infection, can occur that requires immediate medical attention, administration of antibiotics and drainage of the bile ducts.
What are the Risk Factors Associated with Cholangiocarcinoma?
Some of the common risk factors that enhance the chance of getting cholangiocarcinoma or bile duct cancer are as follows:
- PSC or Primary Sclerosing Cholangitis: Continuous inflammation of the bile ducts or Cholangitis for a long period leads to the formation of sclerosis. Patients with this typical condition have an increased risk of cholangiocarcinoma.
- Bile Duct Stones: Inflammation of bile duct may also occur due to formation of bile duct stones inside the duct which can lead to cholangiocarcinoma.
- Liver Diseases: Parasitic liver diseases may enhance the risk of cholangiocarcinoma. Patients having chronic liver diseases such as hepatitis B, hepatitis C, alcoholic liver disease, or liver cirrhosis etc. are at significantly increased risk of cholangiocarcinoma. Colonization of the liver fluke Opisthorchis viverrini or Clonorchis sinensis has been found to be closely associated with the growth of Cholangiocarcinoma.
- Abnormalities in Organic Systems: Due to abnormalities in the orientation of bile duct and pancreatic duct, the up-stream flow of digestive juices in the bile duct prevents the bile from being emptied from the duct and liver in time. Though rare, people with these abnormalities are generally at higher risk of getting cholangiocarcinoma or bile duct cancer.
- Liver Abnormalities: Some congenital liver abnormalities such as Caroli's syndrome, Lynch Syndrome II, and Biliary Papilomatosis are also considered some other lifetime risk factors of cholangiocarcinoma.
Although the liver diseases and abnormalities, bile duct stones other organic system problems would pose a risk for cholangiocarcinoma, there is no guarantee that a person with such problems would definitely develop the disease. However, one must take extra care and look at the signs and symptoms to help in the diagnosis of the disease if it has already set in.