The liver is the largest internal organ in the body and is situated in the upper abdomen, on the right side of the body. It has many functions, including the production of bile, which is passed into the intestines, via a tube known as the bile duct. The liver filters toxins from the body. It is an essential organ in the conversion of food into energy and body tissue.
What is liver cancer?
Liver cancer can either start within the liver itself (a primary cancer) or start elsewhere in the body and then spread to the liver (a secondary cancer or metastatid). The majority of cancers seen in the liver are of a secondary type. Generally, cancers within the liver can be very difficult to cure. However, clinicians and scientists are finding more ways in which both primary and secondary cancers may be treated.
What is primary liver cancer?
The liver is a complex organ consisting of very many different types of cells. However, only the two principal cell types tend to form cancers. The cells, which perform the fundamental tasks of the liver, are called hepatocytes; the cancers these form are called hepatomas. The cells lining the bile ducts of the liver can also change into cancers; these are termed cholangiocarcinomas. Hepatomas almost always occur in the livers of people who have conditions that have damaged the liver over a long period of time. This damage causes scarring of the liver, known as cirrhosis. Any disease that causes cirrhosis of the liver can lead to a hepatoma. Fortunately, only a small number of people with cirrhosis actually get a hepatoma. Certain causes of cirrhosis have a higher chance of developing hepatomas. These are the viral infections hepatitis B and hepatitis C, the cirrhosis linked to excessive alcohol, and the cirrhosis of hemochromatosis (a condition wherein an excessive amount of iron is stored in liver cells).
Currently we do not understand why cholangiocarcinomas develop. So, in most people there is no obvious reason why the cancer should form. It does occur more frequently in people who suffer from a rare condition called sclerosing cholangitis, which causes slow and progressive damage to the bile ducts.
What is secondary liver cancer?
Nearly any cancer in the body can spread to the liver. Cancers more likely to have secondary growths in the liver are those from the stomach, pancreas, and large bowel (colon). This is because the blood stream away from these digestive organs flows directly to the liver. Hence, all cancer cells that break away from the original growth are carried to the liver where they can embed and grow. Breast and lung cancers are relatively common cancers that can also form secondary growths within the liver.
What are the symptoms of liver cancer?
Early on in their growth, liver cancers often produce no symptoms. Secondary cancers tend to be found only after the original cancer elsewhere in the body is diagnosed. A liver cancer may produce jaundice (a yellow coloring of the skin and eyes), often with a darkening of urine and a pale color to the stool (bowel motion). This is because the growth of the cancer blocks the drainage of bile from the liver and the bile’s yellow pigment cannot get into the bowel to color the stool. Because of the blocked drainage, the bile’s yellow pigment is subsequently eliminated through the kidneys, hence the dark urine. Other symptoms that may occur are liver pain (especially if the cancer is stretching the fibrous coating that surrounds the liver) and weight loss. Very occasionally a liver cancer causes vomiting. This is because the cancer grows out from the liver and pushes on the stomach, blocking the passage of food and liquids.
What tests confirm a diagnosis of liver cancer?
Apart from hepatomas, there are no specific blood tests for the detection of liver cancer. However, a cancer in the liver might be suspected when an abnormality is seen in Lefts, or liver function tests. These blood tests merely detect that there is something wrong and an abnormality can show up for many other reasons besides cancer. In the case of hepatomas, a doctor may find an unusually high concentration of a substance produced by the hepatoma, called alpha-fetoprotein. However, this blood test is only an indication of the presence of a hepatoma and will not detect other cancers.
The best method of diagnosing a cancer is to detect it visually. This can be done using ultrasound, a CT scan X-ray, or magnetic resonance imaging (MRI). Sometimes it is necessary to have pictures of the blood supply to the cancer, in which case an angiogram is performed. This entails putting X-ray dye into the blood vessels that supply the liver via a fine tube inserted into an artery, normally at the top of the leg.
If liver cancer is detected, specialists need to know what type of cell is forming the cancer. This means that a sample of the cancer is required. This involves introducing a needle into the cancer and then taking a small sample (biopsy), which is examined under a microscope.