Hepatoblastoma is the most common liver tumor in children, with a higher incidence between 0 and 4 years of age, being rare after 5 years of age. Hepatoblastoma cells are similar to fetal liver cells. About two out of three children with these tumors are successfully treated with surgery and chemotherapy.
In recent decades, great advances have been made in the management of hepatoblastoma thanks to the improvement in diagnostic imaging methods, the use of effective chemotherapy regimens, the best surgical approach and the possibility of performing liver transplantation.
Symptoms of Hepatoblastoma
Signs may vary in each child and depend on the extent of the tumor and the presence or absence of distant metastases. Some patients experience precocious puberty associated with an increase in human chorionic gonadotropin (BetaHCG). Overall, the symptoms are:
- Enlarged abdomen (which can be painful)
- Weight loss for no known reason;
- loss of appetite;
Diagnosis of hepatoblastoma
Diagnosis and treatment are based on risk stratification of patients, with an assessment of serum tumor biomarkers, imaging (to study the extent of disease) and histopathology.
To reach the diagnosis of hepatoblastoma it is necessary to perform:
- Laboratory tests – alpha-fetoprotein is a tumor marker that is elevated in patients with hepatoblastoma. This marker, measured in blood tests, also helps in evaluating the response to chemotherapy and surgery. Other blood tests should be ordered, such as a complete blood count, liver function tests, and hepatitis and Epstein-Barr virus (EBV) tests;
- Imaging tests – abdominal ultrasound with Doppler is the test requested for the identification of liver tumors. Computed tomography with contrast and MRI of the abdomen are also essential to evaluate the liver tumor. Computed tomography of the chest is used to assess the presence of lung metastases;
- Angiography – is an X-ray examination that examines the blood vessels. A dye (or dye) is injected into an artery to outline the blood vessels while X-ray images are taken. Angiography can be used to show the arteries that supply blood to liver cancer, which can help doctors decide whether the cancer can be removed, and to help plan the operation. It can also guide some types of non-surgical treatment, such as embolization; and
- Biopsy – is the removal of a tissue sample to check for cancer cells. Often, imaging and blood tests can confirm this type of cancer. Even so, in some cases a biopsy may be necessary to confirm the neoplasm.
The proposed treatment of hepatoblastoma by the SIOP (International Society of Pediatric Oncology) protocol involves a multimodal approach, including preoperative chemotherapy (with the aim of reducing the primary tumor), followed by surgical resection of the residual tumor. Patients with unresectable tumors after preoperative chemotherapy are referred for liver transplantation evaluation.
The prognosis depends on the resectability, size and location of the tumor, the extent of the disease, and the presence or absence of metastases.
Next, we will go through the main treatment approaches for hepatoblastoma.
Surgical resection (removal of the tumor with surgery) is the best option for curing hepatoblastoma. A partial hepatectomy may be done, removing the part of the liver where the cancer is, along with a small amount of healthy tissue around it. If it is a total hepatectomy, in addition to removing the entire liver, transplantation is indicated.
Another possibility is ablation, a treatment that destroys liver tumors without removing them. This technique can be used in patients with some small tumors and when surgery is not a good alternative (usually due to health issues). It is also sometimes used in patients awaiting a liver transplant. There are different types of ablation, such as radiofrequency, microwave or cryoablation (destroys the tumor by freezing it).
Embolization is a procedure that injects substances directly into an artery in the liver to block or reduce blood flow to the tumor. Blocking the part of the hepatic artery that feeds the tumor helps kill cancer cells.
In the treatment of tumors that cannot be removed by surgery, treated with ablation or embolization, or that have not responded well to these treatments, radiotherapy is a commonly used option.
Finally, chemotherapy is indicated in all cases of hepatoblastoma in children. It is usually given before surgery to shrink the tumor and make it easier to remove.
The exact cause of liver cancer in children is unknown – it is known, however, that prematurity and low birth weight are associated with the risk of developing the disease. However, as these factors are not controllable by patients, there is no way to prevent hepatoblastoma.