Neuroblastoma.
Fewer than 100 children are diagnosed with neuroblastoma in the UK each year. Most children who get this cancer are younger than five years old. Neuroblastoma is the second most common solid tumour in childhood and makes up two in 25 (8%) of the total number of children's cancers.
Neuroblastoma is a cancer of specialised nerve cells, called neural crest cells. These cells are involved in the development of the nervous system and other tissues.
Neuroblastoma can occur anywhere in the body, but it most often occurs in one of the adrenal glands in the abdomen (tummy). The adrenal glands are specialised glands which are found above the kidneys. They release hormones to maintain blood pressure, and enable us to respond to stress.
In some children, the neuroblastoma can occur in nerve tissue alongside the spinal cord in the neck, chest, abdomen or pelvis.
Causes.
As with most cancers, the cause of neuroblastoma is unknown. Like other cancers, it is not infectious and cannot be passed on to other people.
Symptoms.
The first symptoms are often vague, such as loss of appetite, tiredness and pain in the bones. Other symptoms vary, depending on where the child's 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 is often visible as a lump and occasionally can affect breathing and swallowing.
- Occasionally, there are deposits of neuroblastoma in the skin that appear as small, blue-coloured lumps.
- If the tumour is pressing on the spinal cord, children may have weakness in the legs and walk unsteadily. If the child is not yet walking, there may be noticably reduced leg movements. They may also have constipation or difficulty passing urine.
- Very rarely, children may have jerky eye and muscle movements, and general unsteadiness associated with the neuroblastoma.
Exams and Tests.
A variety of tests and investigations may be needed to diagnose a neuroblastoma. These include: blood tests, urine tests, bone marrow tests, x-rays, CT or MRI scans and mIBG scans. The tests are carried out to find the exact position of the neuroblastoma within the body and to see whether it has spread. This process is known as staging.
A specific type of urine test will also be done. Nearly all (nine 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. Your child will also have their VMA and HVA levels checked during and after treatment. The levels of these substances will fall if the treatment is working. As these chemicals are produced by the tumour cells, and can be used to measure tumour activity, they are sometimes known as tumour markers.
Most children will have an mIBG (meta-iodo-benzyl guanidine) scan. 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 is 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. These tests look at the chromosomes and 'biological markers' in the tumour cells. One of these 'markers' is called MYCN. If a certain amount of MYCN is present in the cells (known as MYCN amplification) then the treatment is usually more intensive.
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:
- Stage 1 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.
- Stage 2A The cancer is localised and has not begun to spread, but cannot be completely removed by surgery.
- Stage 2B The cancer is localised and has begun to spread into nearby lymph nodes.
- Stage 3 The cancer has spread into surrounding organs and structures, but has not spread to distant areas of the body.
- Stage 4 The cancer has spread to distant lymph nodes, bone, bone marrow, liver, skin or other organs.
- Stage 4S The cancer is localised (as in stage 1, 2A or 2B) and has begun to spread to the liver, skin or to some extent the bone marrow. This is found in children under one year old.
A newer staging system is currently being developed by the International Neuroblastoma Risk Group (INRG).
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 (including the MYCN status) and whether the neuroblastoma has spread.
Surgery.
For 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.
Chemotherapy.
If 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 Rescue.
If the neuroblastoma has spread to several parts of the body, or is high-risk with MYCN amplification, 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 over a period of 14–21 days.
Radiotherapy.
If 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.
Immunotherapy.
As Neuroblastoma has a high relapse rate, Immunotherapy is a critical stage in the treatment. New Antibody treatment from the USA has combined 3 drugs, 14.18 (the antibody), IL2 and GM-CSF (cytokines which stimulate the immune system) and this has shown very positive results. A trial in the UK has been opened, without the GM-CSF and with entry criteria that excludes a number of children (including Felix) that would benefit from the treatment.
A paper on the drugs and the case for challenging the trial criteria is shown here.
Felix is fighting stage 4 Neuroblastoma and is undergoing all of the above treatment protocol.
Source http://www.cancerbackup.org.uk/Cancertype/Childrenscancers/Typesofchildrenscancers/Neuroblastoma
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