Bone tumours

09 March 2012

Around 65 children are diagnosed with bone tumours ever year in Britain, 4% of all childhood cancers.

smiling child in wheel chair

There are two main types of bone tumour that affect children - osteosarcoma and Ewing sarcoma of bone.

Osteosarcoma in children usually affects the long bones of the limbs, most often the legs.

Ewing sarcoma has a lower incidence than osteosarcoma. Again, the most common site is the long bones of the leg, but substantial numbers of these sarcomas occur in other bones including the pelvis, the arm, the ribs, sternum and clavicle and the spine.

Incidence

Bone tumours are very rare in children under five years, increase in incidence with age and peak in adolescence. This is probably because this is the peak time of bone growth.

More than two-thirds of childhood bone tumours are diagnosed at 10-14 years.

Overall, in the 0 to 14 year age group, incidence rates are similar between the two sexes although osteosarcoma is slightly more common in girls than in boys and Ewing sarcoma has a male excess at age 10-14 years.

A pronounced male excess of osteosarcoma starts at the age of 15-16 years.

Ewing sarcoma is almost unknown in African and Chinese populations.

Causes

The cause of most cases of bone cancer in children is unknown.

Children who have had previous radiotherapy and/or chemotherapy are at increased risk of osteosarcoma. Incidence of osteosarcoma is also increased in children with various hereditary disorders including heritable retinoblastoma (eye cancer). As a result, osteosarcoma is one of the most frequent second solid malignancies following treatment for childhood cancer.

Bone cancers have been suggested to be caused by injuries or damage to the bone, but there is little evidence to support this. It is more likely that an injury simply draws attention to a bone tumour.

Survival

Bone tumours have amongst the lowest survival rates for childhood cancers. The overall rate for all bone tumours is 61 per cent. Within this, the rate for osteosarcoma is considerably worse, at 54 per cent , and the rate for Ewing sarcoma, slightly better at 64 per cent .

Symptoms and diagnosis

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

A variety of tests and investigations may be needed to diagnose a bone tumour. An x-ray of the painful bone will usually identify a tumour, although they can sometimes be difficult to see.

A biopsy will be carried out to determine the type of tumour.

Other tests will be carried out to check whether the cancer has spread to other parts of the body. These include:

a chest x-ray
a bone scan
blood tests
a bone marrow aspirate and
an MRI or CT scan.

Treatment

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

Surgery is the main treatment for bone tumours. The type and extent of surgery depends on the position and size of the tumour:

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 the child grows. False limbs can work very well and it should be possible for the child to join in with normal activities.

Limb-sparing surgery preserves the limb by removing only a part of the affected bone. This is then replaced with either an artificial part (prosthesis) or with bone taken from another part of the body. Normal activities should then be possible although some care needs to be taken not to damage the prosthesis. The prosthesis may need to be lengthened as the child grows.

Chemotherapy is usually given before surgery to shrink the main tumour and after surgery to reduce the risk of the cancer recurring.

Radiotherapy may also be given in some cases, either pre- or post-surgery, or both.

Side effects of treatment

Possible side effects depend upon the particular treatment being used and the part of the body being treated. Side effects can include nausea and vomiting, hair loss, reduced resistance to infection, bruising and bleeding, tiredness and diarrhoea.

Read more: Side effects of treatment

Late effects of treatment

A small number of children may develop late side effects, sometimes many years later, that are caused by their treatment for bone cancer.

The main risks arise from the use of radiotherapy, which may impair growth and cause infertility. The risk of infertility is greater among boys and the risk is increased if both radiotherapy and chemotherapy are used.

Both radiotherapy and chemotherapy have been associated with heart and lung complications.

There is an increased risk of second cancers in those who survive childhood cancer, thought to be associated with the treatments used.

The possible risks of any treatment given will be explained by the child’s doctor before treatment begins. Every effort will be made to minimise the risk of these kinds of complications.

Read more: Long-term and late effects of treatment

References:
Cancer in Children: Clinical Management (5th edition). Eds: P A Voute, Ann Barrett, Michael C G Stevens and Hubert N Caron. Oxford University Press, 2005.
Childhood Cancer in Britain: incidence, survival, mortality. Ed by Charles Stiller. Oxford University Press, 2007.

Related Topics types of childhood cancer, bone tumours