Definition
Primary liver cancer is a condition that happens when normal cells in the liver become abnormal in appearance and behavior. The cancer cells can then become destructive to adjacent normal tissues, and can spread both to other areas of the liver and to organs outside the liver.
Malignant or cancerous cells that develop in the normal cells of the liver (hepatocytes) are called hepatocellular carcinoma. A cancer that arises in the ducts of the liver is called cholangiocarcinoma.
Epidemiology
Hepatocellular carcinoma is the fifth most common cancer in men and the eighth most common cancer in women worldwide. An estimated 560,000 new cases are diagnosed annually. The incidence of hepatocellular carcinoma worldwide varies according to the prevalence of hepatitis B and C infections. Areas such as Asia and sub-Saharan Africa with high rates of infectious hepatitis have incidences as high as 120 cases per 100,000.
Types
There are several types of liver cancer or cancers that start in the liver.
Hepatocellular Carcinoma (HCC)
The most common type of primary liver cancer is called Hepatocellular Carcinoma (HCC), or malignant hepatoma. This type of cancer starts in cells called hepatocytes, the main type of liver cells.
Cholangiocarcinoma
Cholangiocarcinoma is bile duct cancer. The cancers start in the bile ducts, which are small tubes that carry bile to the gallbladder.
Angiosarcoma
Cancers that start in the blood vessels of the liver are called angiosarcomas and hemangiosarcomas. These cancers are very rare, but grow very quickly. They have often spread so far by the time they are found that surgery is not an option.
Hepatoblastoma
The last type of liver cancer is usually found in children younger than 4 years old and is called hepatoblastoma. Cancers that arises from other organs and travel (metastasize) to the liver
Risk factors
Some factors that increase the risk of liver cancer are:
Cirrhosis is a disease of the liver that is caused by liver cells being damaged and replaced by scar tissue. It can be caused by alcohol abuse, chronic infection via hepatitis B and C, fatty liver, primary sclerosing cholangitis and other causes of liver disease. This is the most important factor.
- Aflatoxin is a harmful substance made by certain types of mold. This is not a problem in the United States, but is still found in Asia and Africa.
- Family history
- Environmental – alcohol and tobacco are important toxins that are important for the development of liver cancer.
Causes of Liver Cancer
Anabolic steroids – Used by athletes and weight lifters. These male hormones, if used regularly and for long enough, can raise the risk of developing liver cancer, as well as some other cancers.
Aflatoxins – A substance made by a fungus and may be found in moldy wheat, groundnuts, corn, nuts, soybeans and peanuts. For liver cancer risk to increase there needs to be long-term exposure. This is more of a problem in less wealthy countries.
Cirrhosis – When liver cells are damaged and replaced with scar tissue. People with cirrhosis of the liver have a higher risk of developing liver cancer.
Diabetes – Patients with diabetes, especially if they also have hepatitis, or regularly consume a lot of alcohol, are more likely to develop liver cancer.
Family history – People whose mother, father, brother, or sister had liver cancer are at a higher risk of developing it themselves, compared to others.
L-carnitine deficiency – Studies suggest that an L-carnitine deficiency increases the risk of developing liver cancer.
Liver disease and inherited liver disease – people with hepatitis B or C have a significantly higher risk of developing liver cancer, compared to other healthy individuals. According to the American Cancer Society, hepatitis C is the most common cause of liver cancer in the USA. The Society mentions that some inherited liver diseases also increase the risk of liver cancer.
Low immunity – People with weakened immune systems, such as those with HIV/AIDS have a risk of liver cancer that is five times greater than other healthy individuals.
Obesity – Obesity raises the risk of developing many cancers, including liver cancer.
Gender – A higher percentage of males get liver cancer compared to females. Some experts believe this is not due to gender, but to lifestyle characteristics. On average, males tend to smoke and abuse alcohol more than females.
Smoking – individuals with hepatitis B or C have a higher risk of liver cancer if they smoke. Water wells with arsenic – people who rely on water wells that contain arsenic may eventually have a significantly higher risk of developing several conditions or diseases, including liver cancer.
Symptoms of Liver Cancer
In its early stage many people with liver cancer will have no symptoms. As the cancer grows it may start to cause symptoms, including:
- Pain in the upper right part of the abdomen, which may extend to your back and shoulder
- Swollen or bloated stomach
- Unexplained weight loss
- Loss of appetite or feeling full without eating
- Feeling weak or very tired
- Nausea and vomiting
- Unexplained fever
- Jaundice, yellow discoloration of the eyes and skin
Healthy and cancer liver
Diagnosis and test
Serum alpha feto-protein (AFP) test shows if there is an increased level of this protein in the blood, which may indicate the presence of a tumor. However, AFP may also be elevated by a different cancer or non-cancerous condition, so other tests are offered.
Blood tests are done to assess liver function, kidney function, and measure a complete blood cell count.
Laparoscopy is a surgical procedure which allows the physician to view the abdominal organs through a laparoscope (a small camera).
Biopsy involves the removal of cells or tissues from the suspected tumor. A biopsy can be taken during a laparoscopy or with a thin needle inserted into the liver during an ultrasound or CT scan. A doctor looks at the tissue under a microscope to determine if cancer cells are present.
Computerized Tomography scan (CT or CAT scan) is an x-ray taken from various angles with the help of a computer. A dye (for contrast) may be swallowed as a liquid or injected through a vein to make the organs show up more clearly.
Ultrasound takes a picture called a sonogram created by bouncing sound waves off organs in the abdominal cavity, to see if anything abnormal exists.
Magnetic Resonance Imaging (MRI) is a detailed picture of the organs in the body, created using a magnet, radio waves and a computer.
Chest X-ray and Bone Scan tests determine if cancer has spread to the lungs or bones.
Treatment and medications
Surgery
Standard surgery or hepatectomy is the surgical removal of the part of the liver affected by cancer. This procedure can only be performed in people who do not have severe liver damage and whose cancer has not spread to the blood vessels of the liver or other parts of the body.
Liver transplants are done most often in people whose tumors are very small, few in number, do not involve blood vessels and have not spread outside the liver. These tumors usually cannot be removed by surgery because of advanced cirrhosis. To receive a transplant, a suitable donor with a healthy liver must be found.
Treating the Liver Directly
Embolization or chemoembolization may be used as options to treat liver tumors that cannot be removed by surgery. In these cases, doctors may use a procedure called transarterial embolization (TAE, without chemotherapy) or transarterial chemoembolization (TACE, with chemotherapy). In these procedures, a catheter (a small plastic tube) is placed into the liver’s artery. An inactive substance, with or without chemotherapy, is injected directly into the liver tumor to control and kill the cancer cells. Although TAE and TACE may not destroy all the cancer cells, they can slow the growth of the tumor and perhaps stop it from growing.
Radiofrequency ablation (RFA) kills cancer cells with heat. An imaging technique such as ultrasound or CT scan is used to help guide a needle into the liver tumor. High-frequency electrical currents are then passed through the needle, creating heat, which destroys the cancer cells.
Cryoablation is similar to RFA, but this technique uses cold instead of heat to freeze tumors and kill them.
Radiation is sometimes used when a liver cancer cannot be removed by surgery. Although radiation kills liver cancer cells, very high doses can damage healthy liver tissue as well. So now, doctors use devices that deliver radiation beams more directly to the tumor, helping to spare healthy tissue.
Intensity-modulated radiation therapy (IMRT) is a technique that uses advanced computer technologies to map and plan a precise dose of radiation to the liver. The dose is based on the tumor’s size, shape and location. IMRT modulates, or controls, very thin beams of radiation at different intensities and angles. This allows the radiation beams to conform to, or fit, the three-dimensional shape of the tumor for a custom-tailored dose.
Radioembolization is a technique used by the radiation specialist to inject small radioactive beads into the main artery of the liver. This allows concentrated amounts of radiation to attack the tumor. Radioembolization delivers an intense dose of radiation to the cancer cells with less damage to healthy tissue. Patients remain awake during this procedure, which is usually performed in a hospital’s radiology suite.
Prevention of Liver Cancer
Alcohol: long-term, regular high alcohol intake significantly increases the risk of cirrhosis of the liver, which in turn makes the likelihood of developing liver cancer much greater. It stands to reason, therefore, that moderating one’s alcohol intake (or giving up completely) can significantly reduce the risk of developing liver cancer.
Hepatitis B: The following individuals should seriously consider receiving the hepatitis vaccine: drug addicts who share needles, individuals who engage in unprotected sex with partners who may be at risk of having hepatitis B, nurses, doctors, dentists and other individuals whose occupations raise their risk of becoming infected. Frequent travelers, especially those who go to parts of the world where hepatitis B is common should also consider being vaccinated.
Hepatitis C: Although there is no sure way of protecting oneself from hepatitis C, using a condom during sex may help reduce the risk of infection. There is no hepatitis C vaccination (July 2010).
Body pierceings and tattoos : Make sure the establishment is reputable and new or very well sterilized needles are being used. If you have any doubt about the place, go somewhere else.