Liver Cancer & Tumours

Childhood liver cancer is a disease in which malignant tumours form in the liver. There are two main types of liver tumours in children: hepatoblastoma (an embryonal cancer) and Hepatocellular carcinoma. Liver cancer account for 1% of childhood cancers. Five-year survival rate for childhood liver cancer is 73%.

The most common type of liver tumours are hepatoblastomas, a type of embryonal tumour. The remainder are hepatic carcinomas.

In addition to hepatoblastoma and hepatic carcinoma, other types of childhood cancer can occur with the liver as the primary site. These include soft tissue sarcomas, lymphomas, neuroblastoma and germ-cell tumours. Inclusion of these tumours increases the total incidence of liver cancer in childhood by about a quarter.

Hepatoblastoma and hepatic carcinomas are primary tumours. The liver is a common site for the development of secondary tumours that spread (metastasise) from another site. These secondary tumours are not classified as hepatic tumours.

The causes of primary cancers of the liver are not fully understood. Some reports suggest associations between environmental exposures and hepatoblastoma, including parental occupational exposure to metals, petroleum products and paints or pigments.

There also appears to be an association between hepatoblastoma and low birth weight. A very small number of cases of hepatoblastoma occur in association with congenital anomalies and familial conditions.

Hepatic carcinomas are more common in countries that have a high incidence of hepatitis B. Children who are infected with hepatitis B have a higher risk of developing hepatic carcinoma than uninfected children.

Incidence

In Great Britain, liver cancer (hepatic tumours) are quite rare, accounting for 1% of childhood cancers, with up to 20 new cases diagnosed every year in the UK. This group is broadly divided into hepatoblastoma and hepatic carcinoma, which account for around four-fifths (81%) and one-fifth (18%) of cases, respectively.

Younger children aged under 4 years are at a higher risk than older children from hepatic tumours in general. In children in the UK there are around 12 cases a year in girls and 16 cases in boys. In teenagers and young adults in the UK there are around 4 cases in females and 5 cases in males each year

Hepatoblastoma is the rarest of the four principal embryonal tumours, and is most likely to be diagnosed in children under two years of age.

Incidence of hepatoblastoma is highest in the under-3 age group, declining steeply thereafter. Hepatoblastoma is more common in boys.

Incidence of hepatic carcinoma increases with age, with the majority of cases diagnosed at 10-14 years. Boys and girls are affected equally.

Liver tumours need to be removed surgically. A system called PRETEXT (the ‘pre-treatment extent of disease’) uses MRI scanning to establish the extent of the tumour in the liver and to determine whether it has spread to other parts of the body.

• PRETEXT 1: one liver sector is affected and the tumour can be removed by straight-forward surgery
• PRETEXT 2: two sectors are affected and the tumour can be removed with more extensive surgery
• PRETEXT 3: three sectors are affected and the tumour can be removed with major surgery
• PRETEXT 4: all four sectors of the liver are affected and a liver transplant is required

PRETEXT 1, 2 and 3 tumours are classed as ‘standard risk’. PRETEXT 4 is ‘high risk’ and includes tumours which have spread (metastasised) to other parts of the body.

For hepatoblastoma, chemotherapy is given first – to shrink the tumour and eradicate metastatic tumours. Surgery to remove the remaining tumour will take place a few weeks after chemotherapy. Further chemotherapy is usually given after surgery to make sure all remaining traces of the disease are destroyed.

The role of chemotherapy in the treatment of hepatic carcinomas is less certain. If the tumour is not too large, surgery usually takes place straight away and chemotherapy may be given afterwards. If the tumour is too large to remove straight away, chemotherapy will be used to shrink it before surgery.

If there is cancer in the lungs – and this is not completely destroyed by chemotherapy – the lungs will be operated on first. If the liver tumour can be surgically removed, that operation will usually follow a week or two later.

A liver transplant will be necessary if the tumour involves all four sectors of the liver (PRETEXT 4). This is only possible if all the cancer outside the liver has gone. A liver transplant involves removal of the whole liver and replacement with a liver from a donor. It may be possible for a parent to donate half of their liver.

Hepatic carcinomas may respond less well to chemotherapy. For this reason other treatments such as chemoembolisation and targeted treatments may be considered.

Chemoembolisation involves giving drugs directly into the artery going into the liver.

Targeted drugs are a new group of treatments that work in a different way to conventional chemotherapy. Some drugs may cause cancer cells to die directly. Others act to cut off the blood supply to the tumour cells (antiangiogenesis). Some drugs, called multi-targeted agents, work in both ways.

Overall, children’s five-year survival rates in England from liver tumours is 73%.

Within this, the rate for hepatoblastoma is better at around 80%.

The outlook for children with hepatic carcinoma, however, is very poor – less than 30 per cent of children survive.