What is hepatoblastoma?
Hepatoblastoma is a very rare cancerous tumor that originates in the liver. The liver is one of the largest organs in the body. The primary functions of the liver include filtering and storing blood. The liver consists of right and left lobes. Most hepatoblastoma tumors originate in the right lobe.
This disease primarily affects children from infancy to about 5 years of age. Most cases appear during the first 18 months of life. Hepatoblastoma cancer cells can 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 hepatoblastoma?
Although the exact cause of liver cancer is unknown, there are a number of genetic conditions that are associated with an increased risk for developing hepatoblastoma, including Beckwith-Wiedemann syndrome, hemihypertrophy, and familial adenomatous polyposis. Other genetic conditions associated with liver cancer include several inborn errors of metabolism such as tyrosinemia, glycogen storage disease type I, galactosemia, and alpha1-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 hepatocellular carcinoma. Some hepatoblastomas have genetic alterations in tumor suppressor genes, which would explain the uncontrolled cell growth.
What are the symptoms of hepatoblastoma?
The following are the most common symptoms of hepatoblastoma. However, each child may experience symptoms differently. Symptoms may vary depending on the size of the tumor and the presence and location of metastases. Symptoms may include:
- a large abdominal mass, or swollen abdomen
- 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
The symptoms of hepatoblastoma may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
How is hepatoblastoma diagnosed?
In addition to a complete medical history and physical examination, diagnostic procedures for hepatoblastoma may include:
- biopsy - a sample of tissue is removed from the tumor and examined under a microscope.
- 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:
- computed 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.
- bone scans - pictures or x-rays taken of the bone after a dye has been injected that is absorbed by bone tissue. These are used to detect tumors and bone 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 hepatoblastoma. Always consult your child's physician for information on staging. One method of staging hepatoblastoma 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.
Treatment for hepatoblastoma:
Specific treatment for hepatoblastoma 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
- expectations for the course of the disease
- your opinion or preference
Treatment for hepatoblastoma is generally aimed at resecting (removing) as much of the tumor as possible while maintaining adequate liver function. Liver tissue can regenerate when removed.
Surgery may be used to take out the cancer and part of the liver where the cancer is found. Sometimes the entire liver may be surgically removed and replaced by a liver transplant from a donor. Surgery may also be used to remove cancer that may spread to other parts of the body, such as to the tissues surrounding the liver, to the lungs, or to the brain.
Chemotherapy uses drugs to kill cancer cells. Chemotherapy may be given to the patient before surgery to help reduce the size of the liver cancer. The child may be given chemotherapy after surgery to kill any remaining cells. Chemotherapy given after an operation to remove the tumor is called “adjuvant therapy.”
Chemotherapy for childhood liver cancer is usually put into the body through a needle in a vein or artery. This type of chemotherapy is called a “systemic treatment” because the drug enters the bloodstream, travels through the body, and can kill cancer cells outside the liver. In another type of chemotherapy called direct infusion chemotherapy, drugs are injected directly into the blood vessels that go into the liver. Sometimes a special treatment called chemo-embolization is used to treat childhood liver cancer. Chemotherapy drugs are injected into the main artery of the liver with substances that block or slow the flow of blood into the cancer. This lengthens the time the drugs have to kill the cancer cells and it also prevents the cancer cells from getting oxygen or other materials that they need to grow.
If surgery to remove the tumor is not possible, the child may be a candidate to undergo liver transplantation to replace the diseased liver with a healthy one from a donor.
The child’s chance of recovery and choice of treatment depend on the stage of the child’s cancer, how the cancer cells look under a microscope, and the child’s general state of health.
Other forms of treatment may include (alone or in combination):
- supportive care (for the side effects of treatment)
- antibiotics (to prevent and treat infections)
- continuous follow-up care (to determine response to treatment, detect recurrent disease and manage late effects of treatment)
Long-term outlook for a child with hepatoblastoma:
Prognosis greatly depends on:
- the extent of the disease.
- the size and location of the tumor.
- presence or absence of metastasis.
- the tumor's response to therapy.
- the age and overall health of your child.
- your child's tolerance of specific medications, procedures, or therapies.
- new developments in treatment.
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 hepatoblastoma. New methods are continually being discovered to improve treatment and to decrease side effects.
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