This information is about osteosarcoma (also called osteogenic sarcoma) in children. It is helpful to read it alongside our general information on children's cancer, which contains more information about cancers in children, their diagnosis and treatment, and the support services available.

Around 30 children develop osteosarcomas in the UK each year. These tumours occur more commonly in older children and teenagers, and are very rarely seen in children under five. They are more common in boys than girls.

Osteosarcoma is a cancer that starts in the bone. It often starts at the ends of the bones, where new bone tissue forms as a young person grows. Any bone in the body can be affected, but the most common sites are the arms or legs, particularly around the knee joint.

There are several different types of osteosarcoma. Most occur in the centre of the bone. There are also rare subtypes, such as parosteal, periosteal telangiectatic, and small cell osteosarcoma.

As with most cancers, the cause of osteosarcoma is unknown. Children who have hereditary retinoblastoma (a rare tumour of the eye) have an increased risk of developing osteosarcoma. Children who have had previous radiotherapy and chemotherapy also have an increased risk of developing osteosarcoma.

It is not caused by injuries or damage to the bone, although an injury may draw attention to a bone tumour.

Pain in the affected bone is the most common symptom. This pain may initially come and go, and then gradually become more severe and constant. There may also be swelling around the affected bone.

Primary bone cancer is sometimes discovered when a bone that has been weakened by cancer breaks after the person has had a minor fall or accident.

The symptoms described above can be caused by many things other than cancer. However, any persistent bone pain, particularly at night, should be checked by your child's doctor.

Usually you begin by seeing your family doctor (GP), who will examine your child and may arrange any necessary tests or x‑rays. Your GP will probably refer your child to a specialist surgeon (called an orthopaedic surgeon) who can carry out other investigations and decide if your child needs to be referred to a specialist hospital or bone tumour centre for further tests. Many of the specific tests for diagnosing bone tumours, such as biopsies, require experience and specialist techniques.

The doctor at the hospital will take a full medical history before doing a physical examination. This will include an examination of the painful bone to check for any swelling or tenderness. Your child will probably have a blood test done to check their general health.

A variety of tests and investigations may be needed to diagnose an osteosarcoma. An x-ray of the painful part of the bone will usually identify a tumour, although sometimes they can be difficult to see. A small piece of the tumour will be removed and looked at under a microscope (biopsy). This is done during a small operation, under a general anaesthetic.

Other tests are taken to check whether the cancer has spread elsewhere in the body. These include a chest x-ray, blood tests, a bone scan, a bone marrow aspirate and an MRI or CT scan.

Any tests and investigations that your child needs will be explained to you. Our general information on children’s cancers gives details of what the tests and scans involve.

Grading refers to the appearance of the cancer cells under the microscope, and gives an idea of how quickly the cancer may develop. Low-grade cancer cells look very like normal cells, and are usually slow-growing and less likely to spread. In high-grade tumours, the cells look very abnormal, are likely to grow quickly, and are more likely to spread.

Most osteosarcomas are high-grade, but a type known as parosteal osteosarcoma is usually low-grade. A further subtype (periosteal osteosarcoma) is usually treated as though it was high-grade.

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 stage, of the cancer helps the doctors to decide on the most appropriate treatment.

Most patients are grouped depending on whether cancer is found in only one part of the body (localised disease), or whether the cancer has spread from one part of the body to another (metastatic disease).

A commonly-used staging system for osteosarcomas is described below:

• Stage 1A The cancer is low-grade and is found only within the hard coating of the bone.
• Stage 1B The cancer is low-grade, extending outside the bone and into the soft tissue spaces that contain nerves and blood vessels.
• Stage 2A The cancer is high-grade and is completely contained within the hard coating of the bone.
• Stage 2B The cancer is high-grade and has spread outside the bone and into surrounding soft tissue spaces that contain nerves and blood vessels. Most osteosarcomas are stage 2B. 
• Stage 3 The cancer can be low- or high-grade and it is found either within the bone or extends outside the bone. The cancer has spread to other parts of the body, or to other bones not directly connected to the bone where the tumour started.

If the cancer comes back after initial treatment, this is known as recurrent or relapsed cancer.

Treatment will depend on a number of factors including the size, position, and stage of the tumour.

Surgery is a very important part of treatment for osteosarcoma. Chemotherapy uses anti-cancer (cytotoxic) drugs to destroy cancer cells, and is usually given to shrink the main tumour before surgery. It is also given after the tumour has been removed by surgery, to help reduce the risk of the cancer coming back (recurring). It is common for a combination of drugs to be used.

Radiotherapy may occasionally be given. Radiotherapy treats cancer by using high-energy rays to destroy the cancer cells, while doing as little harm as possible to normal cells.

Surgery

The type and extent of surgery depends on the position and size of the tumour in the body. This surgery may need to be carried out at a specialist orthopaedic centre, and your child may be referred to one.

Surgery may include removing the whole limb (amputation) or part of the affected bone, which is then replaced by some form of false limb (prosthesis). If only part of the affected bone is removed, this is known as limb-sparing surgery.

Amputation of the limb is sometimes unavoidable if the cancer is affecting the surrounding blood vessels and nerves. After amputation, a false limb will be fitted and will be regularly adjusted as your child grows. False limbs can work very well. It should be possible for them to join in with normal activities and even sport.

Limb-sparing surgery preserves the limb. There are two ways in which this may be done:

• replacing the bone with a prosthesis (a specially designed artificial part)
• replacing the affected bone with bone taken from another part of the body.

After this type of surgery, children will usually be able to use their limbs almost normally. However, they are advised not to participate in any contact sports, as, if the bone graft or prosthesis is damaged, another major operation might be needed to repair or replace it. If your child is growing, the limb prosthesis will need to be lengthened as the bone grows. This will mean further short stays in hospital.

Treatment often causes side effects, and your child’s doctor will discuss these with you before treatment starts. Possible side effects will depend upon the particular treatment being used and the part of the body that is being treated. Side effects can include feeling sick (nausea) and being sick (vomiting), hair loss, an 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 later, caused by their treatment for an osteosarcoma. These include reduction in bone growth, infertility, a change in the way the heart and lungs work, and a slight increase in the risk of developing another cancer in later life. Your child’s doctor or nurse will explain more about any possible late side effects. There is more detailed information about these late side effects in the general information on children’s cancers.

Many children have their treatment as part of a clinical research trial. Trials aim to improve our understanding of the best way to treat an illness (usually by comparing the standard treatment with a new or modified version of the standard treatment). Specialist doctors carry out trials for children's cancer. Your child's medical team will talk to you about taking part in a clinical trial (if appropriate) and will answer any questions you may have. Written information is often provided to help explain things. Taking part in a research trial is completely voluntary, and you'll be given plenty of time to decide if it is right for your child. Currently, the main trial for osteosarcoma is the EURAMOS 1 trial. Your child's doctor or specialist nurse can tell you more about this.

Before any trial is allowed to take place it must be approved by an ethics committee, which protects the interests of the patients taking part.

If you decide to take part in a trial, your doctor or a research nurse must discuss the treatment with you so that you have full understanding of the trial and what it means for your child to take part. You may decide not to take part, or you can withdraw from a trial at any stage and will then receive the best standard treatment available.

Many children with osteosarcoma are cured. However, the child may need to have surgery to lengthen the affected limb from time to time. Your child will have regular check-ups, both in the paediatric or adolescent oncology clinic, and at the orthopaedic centre.

If you have specific concerns about your child’s condition and treatment, it is best to discuss them with your child’s doctor, who knows the situation.

As a parent, the fact that your child has cancer is one of the worst situations you can be faced with. You may have many different emotions, such as fear, guilt, sadness, anger and uncertainty. These are all normal reactions, and are part of the process that many parents go through at such a difficult time.

Your child may have a range of powerful emotions throughout their experience of cancer. Our booklet, Peppermint Ward, is a storybook for younger children with cancer. It looks at the issues that they and their family may face, and helps them to explore their feelings. You can order the booklet online.

This section has been compiled using information from a number of reliable sources, including:

• Cancer in Children: Clinical Management (5th ed). Eds PA Voute et al. Oxford University Press, 2005.

For further references, please see the general bibliography.