Neuroblastoma often begins in the nerve tissue of the adrenal glands. There are two adrenal glands, one on top of each kidney in the back of the upper abdomen. The adrenal glands produce important hormones that help control heart rate, blood pressure, blood sugar, and the way the body reacts to stress. Neuroblastoma may also begin in the chest, in nerve tissue near the spine in the neck, or in the spinal cord.
Fewer than 100 children are diagnosed with neuroblastoma in the UK each year. Neuroblastoma most often begins during early childhood, usually in children younger than 5 years. It sometimes forms before birth but is usually found later, when the tumor begins to grow and cause symptoms. In rare cases, neuroblastoma may be found before birth by fetal ultrasound.
By the time neuroblastoma is diagnosed, the cancer has usually metastasized (spread), most often to the lymph nodes, bones, bone marrow, liver, and skin.
Causes of Neuroblastoma
As with most cancers, the cause of neuroblastoma is unknown. As with other cancers, it is not infectious and cannot be passed on to other people.
The first symptoms are often vague, such as loss of appetite, tiredness and pain in the bones. Other symptoms vary, depending on where the neuroblastoma starts:
If the tumour is in the abdomen, the child’s tummy may be swollen and they may complain of constipation or have difficulty passing urine. Sometimes the child's blood pressure is found to be high.
If the tumour affects the chest area, the child may be breathless and have difficulty swallowing.
If the tumour occurs in the neck, it may be visible as a lump as well as affecting breathing and swallowing.
Less often, children may have weakness in the legs and walk unsteadily if the tumour is pressing on the spinal cord.
Very rarely, children may have jerky eye and muscle movements associated with the neuroblastoma.
A variety of tests and investigations may be needed to diagnose a neuroblastoma. Tests such as x-rays, CT or MRI scans, bone marrow tests and blood tests are carried out to find the exact position of the neuroblastoma within the body and to see whether it has spread. This is known as staging.
A specific type of urine test will also be done. Nearly all (9 out of 10) children with neuroblastoma will have substances called vanillylmandelic acid (VMA), or homovanillic acid (HVA), in their urine. Measuring the VMA and HVA in the urine can help to confirm the diagnosis.
An mIBG (meta-iodo-benzyl guanidine) scan may also be done. mIBG is a substance that is taken up by neuroblastoma cells. It is given by injection. Attaching a small amount of radioactive iodine to the mIBG enables the tumours to be seen by a radiation scanner. mIBG may also be used as a treatment.A small sample of cells are usually taken from the tumour (biopsy) during an operation under a general anaesthetic. The cells are then examined under a microscope. Other tests, collectively referred to as tumour biology are also carried out on these cells in the laboratory.Staging
The 'stage' of a cancer is a term used to describe its size and whether it has spread beyond its original site. Knowing the particular type, and the stage, of the cancer helps the doctors to decide on the best treatment for the child.
A commonly used staging system for neuroblastoma is described below:
The cancer is contained within one area of the body (localised) and there is no evidence of it having spread. It can be completely removed by surgery, or there may be very small (microscopic) amounts of tumour left
The cancer is localised and has not begun to spread, but cannot be completely removed by surgery
The cancer is localised and has begun to spread into nearby lymph nodes
The cancer has spread into surrounding organs and structures, but has not spread to distant areas of the body
The cancer has spread to distant lymph nodes, bone, bone marrow, liver, skin or other organs
If the cancer has spread to distant parts of the body, this is known as secondary, or metastatic cancer.
If the cancer comes back after initial treatment, this is known as recurrent cancer.Treatment
The treatment of neuroblastoma depends on the age of the child, the size and position of the tumour, the tumour biology, and whether the neuroblastoma has spread.
SurgeryFor Neuroblastoma tumours that have not spread (localised tumours), the treatment is usually surgery. If the tumour is at an early stage and there is no evidence that it has spread to the lymph nodes or other parts of the body, an operation to remove the tumour, or as much of it as possible, will be done. In children with localised tumours, a cure is usually possible. However, if, due to the tumour biology results, the tumour is classed as 'high risk', further treatment will be needed. If the tumour is initially too large to remove safely, then chemotherapy will be given to shrink it down before surgery.
ChemotherapyIf the tumour has already spread by the time of diagnosis, or is indicated as being high risk by the tumour biology result, intensive chemotherapy is needed. Chemotherapy is the use of anti-cancer (cytotoxic) drugs to destroy cancer cells. It is usually given as injections and drips (infusions) into a vein.
High dose chemotherapy with stem-cell rescueIf the neuroblastoma has spread to several parts of the body, or is high risk, high-dose chemotherapy with stem cell rescue is used (after the initial courses of chemotherapy).High doses of chemotherapy 'wipe out' the body's bone marrow (where blood cells are made). To prevent the problems that this causes, stem cells (blood cells at their earliest stages of development) are collected from the child through a drip, before the chemotherapy is given. They are then frozen and stored. After the chemotherapy, the stem cells are given back to the child (again through a drip). The stem cells make their way into the bone marrow where they grow and develop into mature blood cells.
RadiotherapyIf the neuroblastoma has spread to several parts of the body or is high risk, external radiotherapy may be given. This uses high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells. External radiotherapy is given from a machine outside of the body. Internal radiotherapy may sometimes be given using radioactive mIBG. Radioactive mIBG is similar to the investigation used to diagnose a neuroblastoma, but uses higher doses of radioactivity to kill the cancer cells.Younger Children
Neuroblastoma is an unusual type of cancer because younger children (under the age of 12 months) can get 'good risk' tumours. Stage 4S disease can often get better on its own. For these very young children, minimal, or even no treatment may be required. The child will just be carefully monitored for the next few years. The tumour will very often either disappear completely on its own, or it may develop into a non-cancerous (benign) tumour called a ganglioneuroma.Ganglioneuromas are usually harmless and will not cause any problems or need any treatment.Most children under the age of 12 months with neuroblastoma are cured.
Treatment often causes side effects. Any possible side effects will depend upon the actual treatment being given and the part of the body that is being treated. Side effects can include: feeling sick (nausea) and vomiting, hair loss, increased risk of infection, bruising and bleeding, tiredness and diarrhoea.
Late side effects
A small number of children may develop late side effects, sometimes many years after treatment. These include possible reduction in bone growth, fertility problems, a change in the way the heart and the kidneys work, hearing problems and a slightly increased risk of developing another cancer in later life.