Introduction
Children's cancers are rare and are quite different from the cancers that affect adults in that they occur in different parts of the body, the cells look different when examined under a microscope and they respond differently to treatment.
Leukaemia and brain tumours are the most common childhood cancers, making up 75% of the total number of cases. Medulloblastoma, neuroblastoma, lymphoma, Wilms’ tumour, rhabdomyosarcoma, retinoblastoma, germ cell tumour, osteosarcoma and Ewing’s sarcoma account for the remainder, but they are all rare.
Knowing that a child has cancer is devastating, but in most cases the results of treatment are good. Cure rates for childhood cancers are much higher than for most adult cancers, with over 70% of all children being completely cured - a figure which is increasing all the time.
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Childhood Leukaemia
Leukaemia is a form of cancer affecting the blood’s white cells, which are a part of the body’s defence system against infections. There are different types of leukaemia, but it is usually Acute Lymphoblastic Leukaemia (ALL) that affects children.
An overproduction of immature lymphocytes clogs up the bone marrow stopping the production of normal blood cells and platelets. A lack of these two important blood elements causes the symptoms of leukaemia.
Some syndromes, such as Down's syndrome and Fanconi’s syndrome, are known to be associated with a higher risk of developing leukaemia. However, in the majority of cases, there is no known cause.
In acute lymphoblastic leukaemia, a reduced production of normal cells in the bone marrow results in a range of non-specific symptoms including:
- generalised weakness and fatigue
- infections
- bruising and bleeding
- bone and joint pain
- an enlarged spleen and lymph nodes
The onset of these symptoms is rapid and the bruising, bleeding and joint pains are sometimes mistakenly thought to be due to injury.
Chemotherapy (the use of drugs to destroy abnormal cells) is the main treatment for acute lymphoblastic leukaemia, with a combination of drugs given in a series of treatment blocks.
In addition, radiotherapy is sometimes given to the brain if leukaemia cells are found in the fluid around the spine (or to prevent recurrence of the disease in the meninges in high risk patients). In boys, in very particular cases, radiotherapy is given to the testicles, as leukaemia cells can survive there even after chemotherapy.
Stem cell (bone marrow) transplants may be used in a small number of cases where it proves impossible to eradicate the disease using drug treatment alone. Before a transplant can take place, a session of high-dose chemotherapy and/or radiotherapy is given to destroy the patient’s existing bone marrow. Transplants work best early in the course of the disease.
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Central Nervous System Tumours - (Brain and Spinal Cord Tumours)
The central nervous system (CNS) consists of the brain and spinal cord. While spinal tumours are rare, brain tumours are, as a group, the most common type of childhood solid tumours, accounting for 20-25% of all paediatric malignancies. Their incidence is 1 per 25,000 children every year. Childhood brain tumours are different from adult brain tumours, as they usually develop in the lower part of the brain. Medulloblastoma and low-grade glioma are the most common tumour types.
The cause of most childhood brain and spinal cord tumours is not known.
The symptoms of childhood brain and spinal tumours are not the same in every child but often include:
- Headache, which is worse in the morning
- Nausea and vomiting
- Problems with vision, hearing, and speech
- Loss of balance, being clumsy and unsteady, especially as a new symptom
- Sleepiness
- Personality or behavioural change
- Convulsions (seizures)
- Movement or sensation changes
- In very young children (infants) an increase in head size (this only occurs before the bones of the skull fuse together)
In spinal cord tumours, common symptoms are:
- Pain in the back
- Incontinence or difficulty in going to the toilet
- Weakness in the legs, stumbling and falling over
- Difficulty in walking
There are many different types of brain and spinal cord tumours.
Clinical symptoms and signs will usually help doctors decide where the tumour is likely to be and the precise location is usually detected using various forms of brain scans (CT scan and/or MRI scan). Diagnosing the exact type of central nervous system tumour usually involves taking a sample (biopsy) for examination under a microscope.
Surgical removal of the tumour is, as far as is reasonably possible, the main treatment. In addition, some brain tumours are also treated with radiotherapy and/or chemotherapy to destroy any cells that have not been removed during surgery – this is called adjuvant therapy.
The most common childhood brain tumour treated by radiotherapy is medulloblastoma, which makes up 20-25% of all paediatric brain tumours.
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Medulloblastoma
Medulloblastoma is the most common form of primitive neuroectodermal tumour (PNET). Characteristically, it causes raised pressure inside the head giving rise to headaches, nausea and vomiting. The tumour grows locally and tends to spread within the central nervous system (CNS). Treatment involves surgery to remove the tumour, with radiotherapy to treat potentially microscopic disease in the whole CNS, and a larger dose to the site of the original tumour.
The majority of children with medulloblastoma are cured, with long-term survival rates of 70-80%.
To reduce long term effects on healthy tissues, lower radiotherapy doses are often used with chemotherapy.
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Neuroblastoma
Neuroblastoma usually affects children under 5 years old. It originates most often in the nerve tissue of the adrenal glands, but it can also develop from nerve tissue near the spine, in the abdomen, chest, neck, or in the spinal cord.
Neuroblastomas grow and spread quickly, affecting nearby lymph nodes, bones, bone marrow, liver and skin. Often the first sign that there is anything wrong is pain or a lump in the abdomen, neck or chest.
A variety of tests will help establish that a neuroblastoma is present. In order to find out exactly what type of neuroblastoma it is, cells from the tumour are examined under a microscope.
The treatment depends on the particular type of cells that are found but it is likely to include surgery to remove the tumour, followed by chemotherapy, and then very careful monitoring once the treatment has finished.
Radiotherapy is used very rarely after surgery to kill any cancer cells that have not been removed during surgery.
Bone marrow transplantation is used in some specific clinical circumstances.
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Lymphoma
Lymphomas are cancers that develop from cells of the lymphatic system. The lymphatic system drains fluid away from the body tissues through a network of tiny vessels and lymph nodes. It helps to protect the body against infections and foreign material. There are two main groups of lymphomas - Hodgkin's and non-Hodgkin's lymphomas.
Up to three children per 100,000 will develop lymphoma in childhood, making up about 10% of childhood cancers. Non-Hodgkin's lymphoma is more common than Hodgkin's lymphoma.
Lymphomas usually occur in children over 3 years old and boys tend to be affected more often than girls.
Common symptoms include:
- Painless swellings in the neck, chest, underarm, or groin (due to enlargement of the lymph nodes)
- Fever
- Night sweats
- Unexplained weight loss
- An itchy skin
Taking a sample of tissue, for examination under the microscope, from the enlarged lymph nodes, bone marrow or from the fluid around the spinal cord is the only way to tell the various forms of lymphoma apart in order to make a diagnosis.
Treatment options will depend on the exact type of tumour as well as on the extent of the disease, but generally include radiotherapy, chemotherapy and in some cases a bone marrow transplant. Radiotherapy can be combined with chemotherapy in the treatment of lymphoma.
Radiotherapy, normally given as a series of short regular treatments in a radiotherapy department (each treatment may be referred to as a fraction), is delivered to an area that follows the shape of the cancer. A higher dose of radiation can be more precisely targeted at the cancer, therefore avoiding neighbouring healthy tissue and resulting in fewer side effects.
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Wilms' Tumour
Wilms’ tumour is a rare childhood form of kidney (renal) cancer. It affects approximately 10 children and adolescents under the age of 15 per 1 million of the population - about 6% of all childhood cancers. The average age at diagnosis is three and a half. Symptoms can include:
- Painless swelling in the abdomen
- Bleeding with pain in the loin
- Blood in the urine
- Fever
- Upset stomach
- Weight loss
- Loss of appetite
Treatment with surgery and chemotherapy, and sometimes radiotherapy, is very successful in 80-90% of children.
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Rhabdomyosarcoma
Rhabdomyosarcomas are tumours arising from primitive muscle cells that would normally develop into striated muscle cells – the type found in the muscles used for movement in the arms, legs, back and all over the body. They account for 5-8% of childhood cancer, usually affecting children aged 2 to 6, and 15 to 19 years old. The most common sites for rhabdomyosarcoma are:
Rhabdomyosarcomas are treated with a combination of surgery to remove the tumour, chemotherapy and/or radiotherapy to shrink the tumour before surgery or to reduce the risk of the cancer returning after surgery.
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Retinoblastoma
Retinoblastomas develop from cells in the retina in the eye, and contain very primitive cells. These tumours usually affect children under 5 and can affect one or both eyes. 40% of retinoblastomas are hereditary.
The treatment for retinoblastoma depends on how early the diagnosis is made, and how far it has spread before treatment starts. Treatment usually involves surgery, chemotherapy, cryotherapy (a way of destroying cancer cells by freezing them), light coagulation and radiotherapy. Whenever possible, the eye is not removed.
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Germ Cell Tumour - (excluding Brain and Spinal Cord)
Germ cell tumours are rare. Some are malignant tumours, but others are benign. Germ cells are cells that develop in the foetus to become the reproductive system in males and females - the ovaries and testes. Sometimes these cells travel to other areas of the body, such as the chest, abdomen, or brain, and develop into a germ cell tumour. Most of these tumours are benign and are very rare in children younger than 15 years.
Cancerous germ cell tumours can spread to other parts of the body, usually the lungs, liver, regional lymph nodes and central nervous system.
In most germ cell tumours there is no obvious cause but there is a higher risk of testicular germ cell tumours in males with undescended testes.
Symptoms vary according to the site where the tumour develops but may include:
- a swelling that can be felt or seen
- constipation
- incontinence
- weakness in the legs
In order to establish the exact type of germ cell tumour a biopsy is usually taken so that cells from the tumour can be examined under a microscope.
Treatment may include surgery to remove the tumour, chemotherapy, radiotherapy and less commonly, bone marrow transplantation. In the long term, hormone replacement therapy (HRT) may also be necessary. Some specific issues related to the conservation of fertility may be very different according to the disease presentation.
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Osteosarcoma
Osteosarcomas are malignant tumours arising from the bones. Usually they develop at the growing point (metaphysis) of the long bones in the arms and legs, and most commonly in the knee. They can also occur in the shoulder, pelvis, and skull. They typically affect teenagers and are twice as common in males.
There are different types of osteosarcoma and the treatment and long-term outcome depends on the exact type of osteosarcoma. Therapy is usually a combination of surgery (removing the tumour and replacing the bone with a bone graft or metal rod), and chemotherapy (usually ifosfamide, cisplatin, methotrexate, and doxorubicin). Radiotherapy is rarely used in osteosarcoma.
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Ewing's Sarcoma
Ewing's sarcoma accounts for 10-15% of childhood bone cancers and 1% of all childhood cancers, and is most common in 10 to 20 year-olds. It is made up of small round blue cells, and usually occurs in the pelvis, thigh, lower leg, upper arm, and ribs.
The first symptom is usually a lump where the tumour is growing, which may be noticed for the first time after a fall or some other injury. Often it is assumed that the tumour is a result of the injury but in fact it has only drawn attention to a lump that is already there.
Ewing’s sarcomas are highly responsive to radiotherapy (unlike osteosarcomas) and so are treated with radiotherapy, as well as surgery and chemotherapy.
The exact treatment and prognosis depend on where in the body the tumour started and whether it has spread to other areas.
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Childhood Liver Tumours
Childhood liver tumours are very rare and are more common in boys than girls. There are two main types of cancer developing from liver cells: hepatoblastoma, which usually occurs in children under 5 years of age, and HepatoCellular Carcinoma (HCC), which is exceptionally rare and usually occurs in older children.
Treatment usually includes chemotherapy, followed by surgery. In very selected cases a specialised form of radiotherapy (stereotactic radiotherapy) can be used as an alternative to surgery. In some cases, a liver transplant will be necessary.
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Looking after Yourself
Radiotherapy, either on its own or in combination with other treatments, is highly effective for many children with cancer, but all treatments can cause some side effects. Some children will not experience any side effects, whilst others may have several that are troublesome. Fortunately many of these side effects disappear soon after the treatment ends and the symptoms can usually be treated, so it is important to mention any symptoms to the doctor or nurse, so they can give the treatment that is needed.
Whatever the problem do not assume that nothing can be done about it – ask your doctor or nurse: side effects can be worrying and often understanding why it has happened and how long it is likely to last will be more helpful than medication to relieve the symptom.
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Questions for your Doctor
Before making up your mind about the best treatment option for your child, you will need information about your child’s cancer, the treatments available in your area, what this will involve, what to expect from the treatment, what side effects your child might experience and how these may change over time as well as what your doctors believe would be most effective in fighting the cancer.
For different patients the answers will be different, so it is important to discuss all these issues with your doctor so that you are able to make the right choice for your child or help your child to decide if they can understand all the issues.
You will have your own questions but some issues that you might want to discuss are:
- What does the treatment involve?
- What are the benefits that my child might get from the treatment?
- How good are my child’s chances of getting those benefits?
- Could having treatment make my child feel worse? If so, in what way?
- Are there alternative treatments?
- What are the risks of the treatment?
- Are the risks minor or serious? How likely are they to happen?
- What care will my child need after treatment?
- What happens if something goes wrong?
- What may happen if my child does not have the treatment?
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Conclusion
There are a large number of childhood cancers, and most have a number of different types, which will require different approaches to treatment. All these cancers are rare, but through multinational research and cooperation treatments are improving all the time and clinical results in terms of cure are better than in adulthood. All the health professionals involved in your child’s care will be able to discuss the best approaches to treatment and answer your questions.
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