What is Liver Metastases?
A liver metastasis is a cancerous tumor that has spread to the liver from another place in the body. It is also called secondary liver cancer. Primary liver cancer originates in the liver.
Most of the time, liver cancer is secondary.
The cancer cells found in a metastatic liver tumor are not true liver cells. They are the cells from the part of the body where the primary cancer began (for example, cancerous breast, colon, or lung cells).
Other names for this condition include:
- liver metastases
- metastases to the liver
- metastatic liver cancer
Function of the Liver
To understand liver metastasis, it is important to understand the role of the liver in your body. The liver is the largest organ inside the body, and it is vital to life. It is divided into two lobes, and is located under the right ribcage and lung.
The liver’s jobs include:
- cleansing the blood of toxins
- making bile, which helps in digesting fat
- making many types of proteins used throughout the body for fuel and cell regeneration
- making enzymes that initiate and participate in numerous body metabolic functions
- storing glycogen (sugar), which the body uses for energy
The liver is one of the most important organs in the body. It is impossible to live without a functioning liver.
Causes of Liver Metastases
The risk that cancer will spread (metastasize) to the liver depends on the location of the original cancer. Primary cancers that are most likely to spread to the liver are cancers of the:
Even if the primary cancer is removed (or thought to be cured), liver metastasis can still occur years later. If you have had cancer anywhere else, it’s important to learn the signs of liver metastasis and to get regular checkups.
There are six steps in the metastasis process. Not all cancers follow this process, but most do.
- Local invasion: Cancer cells move from the primary site into nearby normal tissue.
- Intravasation: Cancer cells move through the walls of nearby lymph vessels and blood vessels.
- Circulation: Cancer cells migrate through the lymphatic system and the bloodstream to other parts of the body.
- Arrest and extravasation: Cancer cells stop moving when they reach a distant location. They then move through the capillary (small blood vessel) walls, and invade nearby tissue.
- Proliferation: Cancer cells grow at the distant location and create small tumors called micrometastases.
- Angiogenesis: Micrometastases (small tumors created by cancer cells) stimulate the creation of new blood vessels, which supply the nutrients and oxygen needed for tumor growth.
Symptoms of Liver Metastases
Unfortunately, there may be no symptoms in the early stages of liver metastasis. In later stages, cancer can cause the liver to swell. When this happens, the following symptoms may occur:
- loss of appetite
- weight loss
- dark-colored urine
- abdominal swelling or bloating
- jaundice (yellowing of the skin or the whites of the eyes)
- pain in the right shoulder
- pain in the upper right abdomen
- sweats and fever
- lump on the right side of the abdomen below the ribcage
When to Seek Medical Attention
It is important to see your doctor right away if you:
- have severe vomiting
- see bloody vomit
- have recent, unexplained weight loss
- have black bowel movements
- have great difficulty swallowing
You should see your doctor immediately if you develop symptoms of liver metastasis. If you have ever had cancer, you should be seeing your doctor regularly for check-ups.
Tests for and Diagnosis of Liver Metastases
During a physical examination, the doctor may suspect liver cancer if lumps are found, or if any of the symptoms above are reported. Various kinds of testing will be needed to confirm the diagnosis. These tests include:
Liver Function Test
Liver function tests look at blood serum markers, liver enzymes, and certain proteins. Serum markers are substances in the blood that are linked to cancer. When liver cancer is present, there may be higher levels of alpha-fetoprotein (AFP). Liver enzymes are often elevated as well.
CT Scan of the Abdomen
A computed tomography (CT) scan is a special kind of X-ray that takes visual images of soft-tissue organs in detail. Cancerous tissue will have a moth-eaten appearance.
Ultrasound of the Liver
Also called sonography, an ultrasound transmits high-frequency sound waves through the body. These sound waves produce echoes. The echoes are then used to create map-like computerized images of the body’s soft-tissue structures.
Magnetic resonance imaging (MRI) creates extremely clear images of internal organs and soft-tissue structures. It uses radio waves, a large magnet, and a computer.
In an angiogram, dye is injected into an artery. When images are taken of the body along that artery’s pathway, it can produce high-contrast images of internal structures.
The laparascope is a narrow tube with a light and a biopsy (tissue sample) tool. The laparoscope is inserted through a small incision, and biopsies are taken for study under a microscope. Laparoscopy is the most reliable minimally invasive method of diagnosing cancer.
Staging The Cancer
When test results are available, your doctor will go through a process called staging. Staging assigns a number (I through IV) to the diagnosis. Staging ranges from a localized tumor (I) to systemic metastases (spreading of cancer) to the bloodstream, lymphatic system, and other organs (II through IV).
Treatments for Liver Cancer
Several options are currently used for treating metastatic liver cancer. Generally, the choice of treatments will depend on:
- the patient’s age and overall health
- the size, location, and number of metastatic tumors
- location of the primary cancer
- the types of cancer treatment the patient had in the past
Systemic cancer therapies treat the whole body through the bloodstream. These therapies include:
Chemotherapy: a form of treatment that uses drugs to kill cancer cells.
Biological response modifier (BRM) therapy: a treatment that uses certain antibodies, growth factors, and vaccines. These agents are designed to boost or restore the immune system’s ability to fight cancer. BRM therapy can also lessen the side effects of other cancer therapies, and, in some cases, fight tumors directly.
Targeted therapy: uses drugs and other agents such as monoclonal antibodies—which are antibodies made in the laboratory and designed to identify and attach to specific parts of cancer cells—to facilitate targeted treatment with drugs, radiation, or by blocking growth of cancerous cells (Mayo). This therapy can have fewer side effects than some other cancer treatments.
Hormonal therapy: adds, blocks, or removes hormones. In cancer therapy, it is used to slow or to stop the growth of certain types of tumors (such as breast and prostate).
Localized therapies target only tumor cells and nearby tissue. They can be used when cancer is detected early.
Radiation therapy uses high-energy radiation to kill cancer cells and shrink tumors. It may come from:
- radiation machines (external beam radiation)
- radioactive materials placed in the body near cancer cells (internal radiation)
- radioactive substances that travel through the bloodstream
Surgical removal is possible when there are a small number of tumors, affecting only a small area of the liver.
Long-Term Outlook for Liver Metastases
In nearly all cases, there is no cure for liver cancer. However, current treatments can help to improve life expectancy and relieve symptoms. According to the American Cancer Society, the relative 5-year survival rate for liver cancer is about 15 percent. In other words, about 15 percent of those diagnosed with liver cancer can expect to live another five years (ACS, 2012).
The relative success of treatment depends on the location of the primary cancer and how much of it has spread to the liver.
Current research is looking for new ways to fight and kill cancer cells, such as hyperstimulating the immune response and disrupting individual steps in the metastatic process.