The liver, the largest gland in the body, plays a vital role in keeping us alive. Its many functions include storing vitamins and nutrients, producing proteins used for blood clotting, and creating bile used for digestion. It also breaks down and filters out toxins from the blood.
Two types of cancer affect the liver:
- Primary cancer first begins in the liver and may spread to other organs. The most common primary cancer is hepatocellular carcinoma.
- Metastasized cancer of the liver comes originally from another part of the body. Cancer cells can easily travel from another affected organ to the liver because of the role the liver plays in filtering the blood. Some of the most common cancers that spread to the liver are from the colon, pancreas, stomach, lung, and breast.
The average person diagnosed with liver cancer is over 60 years old. In Canada, about 2,000 people are diagnosed every year with liver cancer, and more men than women are affected.
The causes of liver cancer are still unknown, but some risk factors have been identified. They include:
- chronic hepatitis B and C infection
- cirrhosis of the liver
- diabetes mellitus
- exposure to toxins, such as certain types of fungi (aflatoxin), vinyl chloride, anabolic steroids, and arsenic
Symptoms and Complications
Liver cancer can go undetected for quite a while before there are any indications that something might be wrong. Most of the symptoms are a result of liver damage. They include:
- ascites (an accumulation of fluid around the liver and intestines)
- jaundice (yellowing of the skin and whites of the eye)
- abdominal pain
- loss of appetite
- weight loss
- pain in the back or abdomen or around the right shoulder blade
- a hard lump just below the rib cage
- dark-coloured urine
- clay-coloured bowel movements
- internal bleeding
Making the Diagnosis
To make the diagnosis, a thorough medical history must be taken, followed by a physical examination. Your doctor may then recommend some of the following tests:
- blood tests to check liver enzyme levels
- abdominal ultrasound to check liver size and to look for any tumours or abnormalities
- magnetic resonance imaging (MRI) of the abdomen
- computed tomography (CT) scan of the abdomen
- laparoscopy – through a small incision, the doctor inserts a small, thin tube called a laparoscope, which allows viewing of the liver and surrounding organs
- biopsy – using a laparoscope, a small piece of tissue is taken from the liver for microscopic examination
- angiography – a dye is injected into the veins and its progress through the liver is tracked by X-ray
- chest X-rays to see if the cancer has spread
Once cancer has been diagnosed, your doctor will need to "stage" or classify the cancer in order to recommend the proper treatment.
The classifications are done by the TNM system:
- T refers to the size of the tumour and can be listed anywhere from T1 to T4 according to its size and the extent of spread to surrounding tissue. (T1 is the smallest.) TX is used to classify a tumour that cannot be observed well enough to categorize.
- N refers to whether or not the cancer has spread to the lymph nodes. N1 means that the tumour has spread and NX means that the doctors can't access the lymph nodes to check.
- M refers to whether or not the cancer has spread to other organs in the body. M0 means that the tumour hasn't spread, and M1 means it has. MX indicates that it can't be determined whether it has spread or not.
Some doctors stage liver cancer according to the following categories:
- localized resectable: the cancer is contained to a limited number of spots in the liver, and because it hasn't spread, it can be removed (generally T1-T2, N0, M0 tumours)
- localized unresectable: the cancer is still confined to one part of the liver but can't be completely removed by surgery
- advanced: the cancer has spread through the liver and perhaps to other parts of the body
- recurrent: the cancer has returned some time after treatment
A variety of other classifications are used in some centres to help predict overall prognosis as well as to determine the ability to undergo surgery.
Treatment and Prevention
As with most cancers, there are three forms of treatment available for liver cancer: surgery, chemotherapy, and radiotherapy. The treatments can be combined with one another.
For localized resectable cancer (small T number, N0, M0), the treatment is usually surgery. This involves removing the tumour and, perhaps, some surrounding tissue. The liver is a unique organ in that it can regenerate its cells and continue to function as before. Chemotherapy may be offered after surgery to kill cancer cells that may have been left behind.
The cancer can also be destroyed in place through cryosurgery or ethanol ablation. For cryosurgery, the surgeon uses a metal probe to freeze the cancer cells. A small incision is made and the probe, which has liquid nitrogen circulating in the tip, does the freezing. In ethanol ablation, the surgeon injects alcohol directly into the tumour, either through the skin or during a surgical procedure.
Removal of the entire liver isn't an option, as the liver is essential to survival. In the past, those with cancer weren't candidates for liver transplants; however, surgeons are now learning that some people with early liver cancer can benefit from a transplant. With a successful transplant and proper medical care, the recipient can go on to lead a healthy life.
For localized unresectable cancer (higher T number, N0, M0), the location of the tumour doesn't allow for surgical removal. This may be because it's situated in a very sensitive area or because it is affecting too much of the liver. The treatment options include cryosurgery, chemotherapy, targeted therapy (medication to reduce tumour blood supply and block tumour growth and spread), liver transplant, radiation therapy, radiofrequency ablation, or ethanol ablation.
Chemotherapy uses medications to kill the cancer cells. The medications are usually given intravenously (injected directly into the blood), but some are available in a pill form to be taken orally. One difficulty with treating liver cancer is that many medications are metabolized (broken down) in the liver, so the options may be limited.
Chemotherapy medications circulate throughout the body, so the side effects, although temporary, can affect many different areas of the body. They include:
- nausea and vomiting
- hair loss
- shortness of breath
- mouth sores
Another form of chemotherapy, called hepatic artery infusion, allows the medications to go directly to the liver. A small pump is placed directly under the skin and delivers the medications directly into the artery leading to the liver. This type of treatment decreases the side effects, since the medications are delivered in a more focused manner and don't spread as much through the rest of the body. Researchers haven't found that this type of treatment is more effective in treating liver cancer than the normal way of giving chemotherapy, but it does seem to increase the quality of life among those with liver cancer.
A procedure called chemoembolization might be considered for a tumour that can't be removed surgically. Material that has been saturated with chemotherapy medications is injected into the blood vessels that supply nutrients to the tumours. By cutting off their fuel, it kills the cancer cells.
Radiation therapy (radiotherapy) is an external treatment that kills the cancer cells. It's aimed directly at the tumours in an effort to shrink them. In some cases, radiotherapy might be done before surgery to shrink the tumours, making them easier to remove. Radiotherapy isn't used very often to treat liver cancer, as the tumours tend not to respond to radiation and the liver itself is very sensitive to it.
For people treated with radiotherapy, there are several possible side effects. They include:
- red, dry skin at the radiation site
- nausea and vomiting
- decreased appetite
Advanced liver cancer (N1 and/or M1) is more difficult to treat, as it has spread to other parts of the body. In these cases, chemotherapy and radiotherapy might be options. "Targeted therapy" medications, such as sorafenib, may help certain patients live longer.
People who have recurrent liver cancer will have their treatment based on what has already been done and how far the cancer has developed.
Liver cancer can't be prevented, but with understanding of the risk factors involved, it might be easier to detect in its early stages. People who fall in the high-risk groups, such as those who have hepatitis or cirrhosis, should be screened regularly with either ultrasounds or blood tests. Blood tests can show the level of liver enzymes, which tells doctors how well the liver is working.