What is Neuroblastoma?

Neuroblastoma is a type of cancer that particularly affects children under 5 years old. It is the second most common ‘solid’ tumour in this age group after brain tumours and the most common cause of death from cancer in this age group. Neuroblastomas develop from cells called pluripotent stem cells that migrate within the developing foetus to form the sympathetic nervous system. They develop in areas of the body where sympathetic nerves are found with the commonest site being the abdomen, as it has two structures, which contain a lot of sympathetic nerves. Abdominal neuroblastomas most commonly occur in -:

• Adrenal glands - a pair of glands, one on top of each kidney – 40%.
• Para-spinal sympathetic chain – a chain of sympathetic nerve bodies running down the back wall of the abdominal cavity – 25%. Para-spinal tumours grow near and may affect the spinal cord.

Many other sites in the body contain sympathetic nerves and these can give rise to neuroblastoma tumours. These sites include -:

• Thorax (chest cavity) – 15%.
• Pelvis – 5%.
• Neck – 3%.
• Other sites – 12 %.

Neuroblastomas usually produce neurotransmitter substances (also known as catecholamines) in greater than normal quantities. The breakdown products of these can be measured in the urine and is one way of testing for neuroblastoma. In the majority of cases of neuroblastoma, the cause is unknown. In very rare cases, other family members have been affected by neuroblastoma and these families have a genetic condition predisposing children to develop neuroblastoma.

Children may not have symptoms from their tumour or they may simply feel generally unwell. The parent may notice a lump or swelling, abdominal swelling is a common reason for the child to have been taken to the doctor in neuroblastoma.

Age, stage and biological features of the tumour strongly influence survival. Children under 18 months with early stage disease do best. Children with low risk and intermediate risk neuroblastoma have an excellent prognosis and outcome, with 3 year survival rates of 88% to 96% reported in one study. Children with high risk neuroblastoma do not do well.

There are several staging systems for this type of tumour. The stage and other information about the child and the tumour are used to stratify individual children into very low, low, intermediate or high risk groups. The risk classification is used as the basis for treatment decisions. For example, a child in the low risk group may have their neuroblastoma removed surgically and recover completely within 3 months developing no care or mobility needs. A child in the intermediate group may need surgery followed by 4-8 cycles of chemotherapy with treatment related needs throughout the period, making a complete recovery. A child in the high risk group may undergo high dose chemotherapy and a stem cell transplant taking two years to recover. Stratification in to risk groups is complex and based on multiple factors.

Most recent data from the National Registry of Childhood Tumours shows 5 year survival rates for all risk groups together are 53%, being much improved from 18% survival rate reported for the period 1962-66. There is no screening programme for neuroblastoma in the UK.

What is the incidence/prevalence?

Around 80 children develop neuroblastoma in the UK each year. 40% of these children will be under 1 year, 35% aged 1 to 2 years and 25% over 2 years when diagnosed. Neuroblastoma is very rare beyond age 10 years.