Liver cancer causes destruction of liver cells and interferes with the ability of the liver to function normally. There are several types of liver cancer. In general, liver cancer is classified as being primary or secondary.
Primary liver cancer begins its growth inside the liver.
Secondary liver cancer occurs when cancer cells from other parts of the body spread to the liver.
This article focuses on primary liver cancer.
The most common primary liver cancer is hepatocellular carcinoma. This is also known as primary liver cell carcinoma or hepatoma. It can spread from the liver to other parts of the body, such as the pancreas, intestines, stomach, lungs, brain, and bones.
The liver is the largest organ in the body. It is located in the upper right section of the abdomen, right below the ribs. The liver makes enzymes and bile. These substances help you digest fats, vitamins, and other nutrients. It produces proteins that are important for your health, such as blood clotting factors. It stores nutrients such as glucose, so that you remain nourished at times when you are not eating. It also breaks down medications and toxins.
Doctors don’t know exactly why one person gets liver cancer and another does not. However, the National Cancer Institute (NCI) has identified the following risk factors for liver cancer:
- Age: Liver cancer is more common in people over the age of 50
- Hepatitis B & C: Chronic infection with hepatitis damages the liver. Hepatitis is spread from person to person during sex or exposure to blood. Transmission can also occur from mother to child. Although hepatitis C and B are contagious, liver cancer is not. You cannot catch liver cancer from another person. There is a vaccine that can protect you against hepatitis B.
- Heavy alcohol intake: Having two or more drinks of alcohol daily for many years increases the risk of liver cancer. Risk increases as the amount of alcohol you drink increases.
- Cirrhosis: This is a form of liver damage where healthy tissue is replaced by scar tissue. Alcohol and hepatitis C infection are the most common causes of cirrhosis in the United States. Drugs, parasites, and excess iron in the body can also cause cirrhosis. Most people with liver cancer in the United States had cirrhosis before they developed liver cancer.
- Aflatoxin: This is a toxic substance produced by a type of mold that can grow on peanuts, grains, and corn. In the United States, food handling laws prevent widespread exposure to aflatoxin. Outside of the country, aflatoxin exposure can be high.
- Diabetes and Obesity: Research has shown that obesity and diabetes increase the risk of liver cancer.
The National Cancer Institute (NCI) estimates that there will be close to 29,000 new cases and over 20,000 deaths from liver and intrahepatic bile duct cancer in the United States in 2012:
The types of primary liver cancer come from the different kinds of cells that make-up the liver. Primary liver cancer can start as a single lump growing in the liver, or it can start in many places within the liver at the same time. People with severe liver damage are more likely to have multiple cancer growth sites. Types of primary liver cancer are:
- Hepatocellular carcinoma (HCC): This is the most common type of primary liver cancer. Three out of four people with liver cancer have this type. It can start as a single tumor or as multiple tumors throughout the liver. Multiple sites are more common than single tumors.
- Cholangiosarcoma: This type of liver cancer starts in the bile ducts of the liver. The bile ducts carry bile from the liver to the gallbladder. One or two out of every 10 people with liver cancer have this type.
- Hemangiosarcoma: This type of liver cancer is rare. It begins in the blood vessels of the liver. Hemangiosarcoma grows quickly. This type of cancer can be advanced at the time of diagnosis.
- Hepatoblastoma: This is a very rare type of liver cancer. It is usually seen in children under the age of 4. With surgery and chemotherapy, the outlook for this type of cancer can be very good. With early treatment, the survival rate can be 90 percent.
Symptoms of liver cancer include:
The diagnosis of liver cancer begins with a medical history and physical examination. A history of long term alcohol intake and chronic infection with hepatitis C or B are important clues.
Tests for liver cancer include:
- Liver enzymes: This blood test shows doctors how well the liver is functioning.
- Alpha fetoprotein (AFP): The presence of AFP in the blood can be a sign of liver cancer. This protein is usually only produced in the liver and yolk sac of babies before they are born. AFP production normally stops after birth.
- Liver biopsy: This test involves obtaining a small piece of liver tissue. This is done by inserting a needle into the liver (with local anesthesia). The tissue specimen is then examined under a microscope to look for cancer. Doctors can also perform a liver biopsy using a thin tube called a laparoscope. It uses a camera, so the doctor can see what liver looks like. This allows for more precise biopsies. If samples from other organs are needed, doctors may use a larger incision. This is called a laparotomy.
- Abdominal CT scan: This test takes multiple images of the liver and other organs in the abdomen. It tells doctors where a tumor is located in the liver, and whether it has spread to other organs.
- MRI: This test shows the areas of the liver where there are tumors. Like the CT scan, it also detects when cancer has spread to other organs.
Treatment of liver cancer is determined by:
- the number, size, and location of tumors in the liver
- how well the liver is functioning
- whether cirrhosis is present
- whether the tumor has spread outside of the liver
Depending on these factors, there are a number of treatment options.
Surgery can be used to remove either a portion of the liver or the entire liver. This is usually done when the disease is limited. As much as 80 percent of the liver can be removed safely. Over time, the remaining healthy tissue will regrow and replace the missing part
Liver transplant replaces the entire diseased liver with a healthy liver from a suitable donor. This is an option if the cancer is small and has not spread outside the liver. Medicines to prevent rejection are given after liver transplants.
Ablation destroys cancer cells directly. This treatment involves the use of heat or ethanol injections to destroy the cancer cells. Ablation can help people with liver cancer who are not candidates for surgery or a transplant. It is performed using local anesthesia.
Chemotherapy for liver cancer involves the use of intravenous medications. It kills tumor cells, but it can also injure normal cells. Side effects like nausea and vomiting, decreased appetite, headache, weakness, chills, and fever can occur. Chemotherapy can also increase the risk on infection. Most of the time, chemotherapy can be given as an outpatient treatment.
Radiation therapy uses high-energy rays to kill cancer cells. It can be delivered by external beam or by internal radiation. In external beam radiation, the radiation is aimed at the abdomen and chest. Internal radiation involves the use of a catheter to inject tiny radioactive spheres into the hepatic artery. The radiation then destroys the hepatic artery. This decreases the blood supply to the cancer.
Targeted therapy uses medications that are designed to hit cancer cells where they are vulnerable. They decrease tumor growth and help to shut down the blood supply to the tumor. Sorafenib (Nexavar) has been approved as targeted therapy for people with liver cancer. Targeted therapy can be useful for people who are not candidates for surgery or a transplant. However, targeted therapy can have significant side effects.
Embolization and chemoembolization can also be used for people who are not candidates for surgery or transplant. These are techniques for blocking off the hepatic artery using small sponges or other particles. This cuts off the blood supply to the cancer. Embolization can be temporary or permanent. When the hepatic artery is closed off, the portal vein continues to nourish the liver.
In chemembolization, chemotherapy is injected into the hepatic artery before the particles are injected. The blockage then keeps the chemotherapy in the liver for a longer period of time.
Avoiding alcohol and being vaccinated against hepatitis B infection eliminate two major risk factors for liver cancer. Lifestyle changes can also help you control your weight and diabetes.