Liver cancer at a glance
- Liver cancer is the out-of-control growth of cells in the liver, the internal organ under the right lung that plays a role in several vital bodily functions.
- “Primary” liver cancer starts in the liver and “secondary” liver cancer begins elsewhere in the body before spreading to the liver.
- Treatment for primary liver cancer depends on the type, with hepatocellular carcinoma the most common followed by cancers of the bile ducts.
What is liver cancer?
Liver cancer is the unregulated growth of cells in the liver forming a malignant tumor that can continue to spread throughout the liver and to other areas. Approximately 35,000 new cases of liver cancer will be diagnosed this year, and about 24,000 people will die of liver cancers. Men have liver cancers about twice as frequently as do women.
“Primary” liver cancer originates in the liver. Cancer that begins somewhere else in the body (colon, lung, breast, etc.) then spreads to the liver is called “secondary,” or metastatic, liver cancer. Cancer cells that break away from a tumor can travel to other areas of the body through the lymphatic system or bloodstream.
Liver cancer treatment depends on whether it is secondary or primary; and if it is primary, it depends upon the specific liver cells where the cancer began. So it is vital to identify the type of cancer before treatment can begin.
The main type of liver cell is the hepatocyte, and the most common form of liver cancer is hepatocellular carcinoma (HCC). Other types of liver cells, such as those in the bile ducts, can also become primary liver cancers.
For example, there are three types of primary liver cancers of the bile ducts each requiring different treatments. These bile duct cancers, called intrahepatic cholangiocarcinomas, account for 10-20 percent of primary liver cancers.
The liver is the largest internal organ in the body and is located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. The liver processes nutrients, aids in blood clotting, breaks down toxins in the blood and assists the body in other vital ways. One cannot live without a liver.
Aside from categorizing liver cancers into primary and secondary, liver cancer, as with all cancers, is classified by the stage of its growth. To determine the stage, a doctor factors in the size of the tumor, whether it has grown into blood vessels (spreads easier), and if it has spread to lymph nodes.
Stages for primary liver cancer are:
- Stage 1, hasn’t spread outside the liver or into the blood vessels or lymph nodes
- Stage 2, either a tumor only spread into the blood vessels or multiple small tumors not in the blood vessels
- Stage 3, further divided into 3A, 3B, 3C, which relate to tumor size and cancers that have not spread to lymph nodes
- Stage 4, with 4A being present in the lymph nodes but not other parts of the body and 4B, having spread to other parts of the body.
What are the causes of liver cancer?
Liver cells that grow uncontrollably begin with mutations in the DNA (deoxyribonucleic acid), the material that provides instructions for every chemical process in the body. DNA mutations cause changes in these instructions. One result is that cells may begin to grow out of control and eventually form a malignant tumor, which is a mass of cancerous cells. Cells may also form benign tumors that are not cancerous.
Primary liver cancer can be caused by:
- Alcohol abuse
- Birth defects
- Chronic infections from diseases
- Hepatitis B and C
- Hemochromatosis (hereditary, associated with too much iron in the liver).
What are the symptoms of liver cancer and methods of diagnosis?
In most cases, people don’t show signs or symptoms in early stages of liver cancer. Once symptoms appear, they can include:
- Loss of appetite
- Upper abdominal pain
- Abdominal swelling
- Loss of weight
- Dark urine
- Yellow discoloration of the skin and the whites of the eyes.
Patients who experience and are concerned about any of these symptoms should seek medical evaluation.
Physicians generally use tests and imaging procedures to diagnose liver cancer. These include blood tests, imaging (CT scan, MRI) and biopsy of sample liver tissue.
What are the risk factors?
Several factors increase the risk of developing cancer of the liver, both bile duct cancers and the more common form, hepatocellular carcinoma (HCC).
Risk factors for HCC include:
- Chronic hepatitis — the most common risk factor is chronic (long-term) infection with hepatitis B virus (HBV) or hepatitis C virus (HVC)
- Cirrhosis — a disease in which liver cells become damaged and are replaced by scar tissue
- Aflatoxins — cancer-causing poisons in fungus grown on poorly stored crops, such as corn, peanuts and wheat.
- Alcohol consumption — heavy alcohol abuse is a leading cause of cirrhosis and increases the risk of liver cancer.
- Inherited diseases
- Hemochromatosis — a hereditary disease in which the liver absorbs too much iron and can lead to cirrhosis and liver cancer
- Wilson’s disease — causes copper to accumulate in the liver and isn’t eliminated properly and can lead to liver cancer or liver failure.
Risk factors for bile duct cancers include:
- Lifestyle — excessive smoking, alcohol drinking, cirrhosis, toxic chemical exposure)
- Age (60 percent of cases in patients older than 64)