Liver metastases are malignant (cancerous) tumors that originated at sites remote from the liver and spread to the liver via the bloodstream.

Common primary tumors that may spread to the liver include gastrointestinal cancers (such as colorectal, pancreatic, stomach and esophageal), as well as breast cancer, lung cancer, melanoma, and a number of other cancers. The reasons for such spread vary, and depend both on blood flow and on the characteristics of the different cancer cells. For example, cancers of the gastrointestinal tract often spread to the liver because blood flows directly from these organs to the liver. Cancer cells, therefore, have a direct path to the liver. Alternatively, melanoma usually spreads through the body's arteries to the liver.

The risk of cancer spreading to the liver depends on the primary cancer site. Liver metastases may be present at the time the primary cancer is diagnosed, or they may occur months or years after the primary tumor is removed.

Symptoms vary, and many times liver metastasis is asymptomatic. When symptoms occur, they may include:

• Weight loss
• Pain, usually in the right upper quadrant of the abdomen
• Jaundice
• Fevers
• Sweats

• Elevated bilirubin
• Abnormal liver function tests
• Elevated tumor markers
• Abdominal CT scan or MRI revealing liver masses
• PET scan revealing liver masses
• Ultrasound of the liver that reveals masses

Treatment depends on the primary cancer site, extent of spread to the liver (for example, only one tumor in the liver versus many tumors in the liver), whether it has spread to other organs, and the condition of the patient.

In situations where cancer has spread not only to the liver but to other organs as well, systemic chemotherapy (directed at treating the entire body) is usually used.

In situations in which spread is limited to the liver, systemic chemotherapy may be used, although other treatment methods may be effective. When the tumor is localized to only a few areas of the liver, the cancer may be removed surgically.

Use of radiofrequency waves or injection of toxic substances may also be used to kill tumors. When larger areas of the liver are involved, liver-directed chemotherapy (infusing chemotherapy directly into the liver), or embolization (blockage of blood flow to parts of the liver) may be used.

Prognosis depends primarily on the site of the original cancer and on the extent of spread to the liver. In a minority of cases, surgical removal of liver metastases may result in cure. This, however, is usually only possible in patients with certain tumor types (for example, colorectal cancer), and when there are limited tumors in the liver.

In most cases, cancer that has spread to the liver is not curable, although the various treatments discussed above may help to shrink tumors, improve life expectancy, and relieve symptoms. However, patients with metastatic cancer to the liver usually die of their disease.

Complications are generally the result of tumors spreading to a large area of the liver. This can result in fever, pain, obstruction of bile, decreased appetite and weight loss. Liver failure may result, but usually only in the late stages of disease.

Call your health care provider if you have cancer and suspect that it has spread to the liver. Anyone who has had a type of cancer that can spread to the liver should be aware of the signs and symptoms listed above, and call a physician should any of these develop.

Early detection of some types of cancer may prevent the spread of these cancers to the liver.