What are liver tumors?
Liver tumors are masses occurring in the liver that can be either benign or malignant (cancerous). Tumors that are found at birth or early after delivery are often benign in nature. While these require removal, no additional treatment with chemotherapy or radiotherapy is required. One type of benign tumor is called mesenchymal hamartoma. This tumor represents an abnormal collection of tissues seen in the developing fetus, but not normally occurring in the liver. Surgical removal of the tumor is the only treatment required
There are generally two types of rare malignant tumors and these require more extensive treatment. They are:
Hepatoblastoma is a cancerous liver tumor. The liver, the largest organ in the body, consists of right and left lobes. The disease occurs primarily in younger infants and children. With prompt treatment, hepatoblastoma is remarkably responsive to chemotherapy. Hepatoblastoma cancer cells can spread (metastasize) to other areas of the body. The most common sites of metastasis are the lungs, abdomen and abdominal structures, and rarely to bone, the central nervous system and bone marrow.
Hepatocellular (liver carcinoma):
Hepatocellular carcinoma is a rare disease in which cancerous cells are found in the tissues of the liver. This type of cancer is found in children from birth to 19 years of age, but usually does not occur before the age of 15. The median age is 12 years old.
Hepatocellular carcinoma may occur in multiple sites within the liver, and is much less responsive to chemotherapy than hepatoblastoma. Cancer cells can also spread (metastasize) to other areas of the body. The most common sites of metastasis are the lungs, into the abdomen and abdominal structures, and rarely to bone, the central nervous system, and the bone marrow.
Anatomy of the liver
The liver is located in the upper right-hand portion of the abdominal cavity, beneath the diaphragm and on top of the stomach, right kidney, and intestines. Shaped like a cone, the liver is a dark reddish-brown organ that weighs about three pounds. The liver consists of two main lobes, both of which are made up of thousands of lobules. These lobules are connected to small ducts that connect with larger ducts to ultimately form the hepatic duct. The hepatic duct transports the bile produced by the liver cells to the gallbladder and duodenum (the first part of the small intestine). The liver regulates most chemical levels in the blood and excretes a product called "bile," which helps carry away waste products from the liver.
What causes liver tumors?
Although the exact cause of most liver tumors is unknown, there are a number of genetic conditions that are associated with an increased risk for developing childhood liver cancers. Hepatoblastoma is associated with Beckwith-Wiedemann syndrome, hemihypertrophy, and familial adenomatous polyposis.
Other genetic conditions associated with liver cancers include several inborn errors of metabolism such as tyrosinemia, glycogen storage disease type 1, galactosemia, and alpha-antitrypsin deficiency.
Children who are exposed to hepatitis B infection at an early age or those who have biliary atresia are also at increased risk for developing liver cancer.
Hepatocellular carcinoma may arise in livers with an underlying abnormality such as familial cholestatic cirrhosis, giant cell hepatitis of infancy, Fanconi's anemia, and glycogen storage disease. Children who are exposed to hepatitis B or C infections at an early age are at increased risk for developing hepatocellular carcinoma. Some hepatocellular carcinomas and hepatoblastomas have genetic alterations in tumor suppressor genes, which would explain the uncontrolled cell growth.
What are the symptoms of liver tumors?
The following are the most common symptoms of liver tumors. However, each child may experience symptoms differently. Symptoms may vary depending on the size of the tumor, whether it is benign or malignant and if malignant, the presence and location of metastases. Symptoms may include:
- a large abdominal mass, or swollen abdomen
- pain on the right side that may extend into the back and shoulder
- weight loss, decreased appetite
- abdominal pain
- jaundice (yellowing of the eyes and skin)
- itching skin
- anemia (pale skin and lips from decreased number of red blood cells)
- back pain from compression of the tumor
How are liver tumors diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for hepatocellular carcinoma may include:
- biopsy - a sample of tissue removed from the tumor and examined under a microscope; the surgeon may also look at the liver using an instrument called a laparoscope, a small tube with a light on the end
- complete blood count (CBC) - a measurement of size, number, and maturity of different blood cells in a specific volume of blood
- additional blood tests - may include blood chemistries, evaluation of liver and kidney functions, and genetic studies
- multiple imaging studies, including:
- computerized tomography scan (also called a CT or CAT scan) - a diagnostic imaging procedure that uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- magnetic resonance imaging (MRI) - a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body
- x-ray - a diagnostic test which uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film
- ultrasound (also called sonography) - a diagnostic imaging technique which uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. Ultrasounds are used to view internal organs as they function, and to assess blood flow through various vessels.
- liver scans - pictures or x-rays taken of the liver after a dye has been injected that is absorbed by liver tissue. These are used to detect tumors and liver abnormalities.
- alpha-fetoprotein (AFP) test - alpha-fetoprotein (AFP) levels in the blood can be used to diagnose and follow response to treatment
What are the different stages of childhood liver cancer?
Staging is the process of determining whether cancer has spread and, if so, how far. There are various staging symptoms that are used for hepatocellular carcinoma. Always consult your child's physician for information on staging. One method of staging is the following:
- stage I - usually a tumor that can be completely removed with surgery
- stage II - usually a tumor that can mostly be removed by surgery but very small amounts of the cancer are left in the liver
- stage III - usually a tumor that cannot be completely removed and the cancer cells are found in the lymph nodes
- stage IV - cancer that has spread (metastasized) to other parts of the body
- recurrent - the disease has returned after it has been treated. It may come back in the liver or in another part of the body.
What are the treatments for liver tumors?
Specific treatment for hepatocellular carcinoma will be determined by your child's physician based on:
- your child's age, overall health, and medical history
- extent of the disease
- your child's tolerance for specific medications, procedures, and therapies
- how your child's physician expects the disease to progress
- your opinion or preference
Treatment for benign tumors, such as mesenchymal hamartoma, requires surgical removal of the tumor, and usually, no further therapy.
Treatments for liver cancers require close coordination between the pediatric surgeons and pediatric oncologist who are managing your child's condition. Treatment for liver cancer usually includes a combination of the following:
- Surgery: Whether the tumor can be removed initially in treatment of hepatoblastoma is a decision that must be made by the pediatric surgeon. If it is deemed that removal would be extremely risky or pose a significant risk of leaving the tumor behind, then the child may be treated initially with chemotherapy. After 3 or 4 courses of treatment, surgical removal of the tumor is often much more readily accomplished. Surgery is the key treatment of children with hepatocellular carcinoma. Unfortunately, successful removal of the tumor or tumors is difficult in children with hepatocellular carcinoma for several reasons. One reason is that the disease may be present at multiple sites within the liver. In addition, underlying cirrhosis or scarring within the liver can make tumor removal much more difficult, and underlying metabolic problems with the liver make normal liver function after surgery marginal.
- Chemotherapy - a drug treatment that works by interfering with the cancer cell's ability to grow or reproduce. Different groups of drugs work in different ways to fight cancer cells and shrink tumors. Chemotherapy may be used alone for some types of cancer or in conjunction with other therapy such as radiation or surgery. Often, a combination of chemotherapy drugs is used to fight a specific cancer. Certain chemotherapy drugs may be given in a specific order depending on the type of cancer it is being used to treat. While chemotherapy can be quite effective in treating certain cancers, the agents do not differentiate normal healthy cells from cancer cells. Because of this, there can be many adverse side effects during treatment. Being able to anticipate these side effects can help the care team, parents, and child prepare, and, in some cases, prevent these symptoms from occurring, if possible. Chemotherapy is systemic treatment, meaning it is introduced to the bloodstream and travels throughout the body to kill cancer cells. Chemotherapy can be given:
- as an injection into the muscle or fat tissue
- intravenously (directly to the bloodstream; also called IV)
- intrathecally - chemotherapy given directly into the spinal column with a needle
- radiation therapy - using high-energy rays (radiation) from a specialized machine to damage or kill cancer cells and shrink tumors
- liver transplant - the liver of the child affected with liver cancer may be replaced with a liver from a donor, although this is rare. (See Liver Transplantation.) Your child's physician will provide more information on whether this is an option for your child and the process involved.
- supportive care - any type of treatment to prevent and treat infections, side effects of treatments, and complications, and to keep your child comfortable during treatment
- continuous follow-up care - a schedule of follow-up care determined by your child's physician and other members of your care team to monitor ongoing response to treatment and possible late effects of treatment.
What is the long-term outlook for patients with liver tumors?
Children who have had a benign tumor removed usually have no further problems. Children with hepatoblastoma can often be cured. Studies have shown that after the cancerous tumor is removed, along with the removal of a major segment of the liver, the liver has a remarkable capacity to regenerate or grow towards the normal volume that it had prior to removal. Long-term follow-up studies of children have shown that the liver continues to grow and often remains very close to what would be the predicted normal size of the liver despite removal of up to two-thirds of the liver during infancy. Long-term insufficiency of the liver is rarely seen except in those children who have the significant metabolic abnormalities associated with hepatocellular carcinoma. These children would require liver transplantation.
As with any cancer, prognosis and long-term survival can vary greatly from child to child. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a child diagnosed with a liver cancer. New methods are continually being discovered to improve treatment and to decrease side effects.
What is the latest research on liver cancer?
Children's Hospital and Dana-Farber Cancer Institute are conducting numerous research studies that will help clinicians better understand and treat liver cancers.
Other types of treatment currently being studied include:
- biological therapies - a wide range of substances that may be able to involve the body's own immune system to fight cancer or lessen harmful side effects of some treatments.
- new ways of delivering chemotherapy - researchers are studying new delivery strategies, such as putting chemotherapy directly into the liver.
- cryotherapy - surgeons are studying new ways of using this existing treatment, which uses extreme cold to destroy unwanted tissue) for liver cancer.