Cancer occurs when the cells in a certain area of your body divide and multiply too rapidly. This produces a lump of tissue known as a tumour.

The exact reason why this happens is often not known, but certain things can increase your chance of developing bone cancer, including:

• Age
• previous radiotherapy treatment
• other bone conditions, such as Paget’s disease of the bone
• rare genetic conditions, such as Li-Fraumeni syndrome
• a history of certain other conditions, including retinoblastoma and umbilical hernia

Age

Like most cancers, the risk of bone cancer increases with age. But for some types of bone cancer, younger people have a higher risk.

Osteosarcoma is more common in adolescents (10 to 19 years). It seems to be linked to the growth of the bones during puberty. Ewing sarcoma usually develops in children (0 to 14 years) and adolescents. But it can occur in adults. Chondrosarcomas and spindle cell sarcomas tend to occur in adults between the ages of 30 to 60. Chordomas are more common in adults over 50 years of age.

Radiotherapy treatment

Previous exposure to high doses of radiation during radiotherapy may cause cancerous changes in your bone cells at a later stage, although this risk is thought to be small.

Bone conditions

Some non-cancerous (benign) conditions affecting the bones may increase your chances of developing bone cancer, although the risk is still small.

• Enchondroma or osteochondroma: Enchondroma or osteochondroma are non cancerous (benign) bone tumours. If you have these tumours, you are at an increased risk of getting a type of bone cancer called chondrosarcoma. This is very rare.
• Ollier’s disease: Ollier’s disease is a rare condition. It is also called enchondromatosis. People with this condition develop many non cancerous (benign) tumours in their bones. These tumours can become cancerous and can turn into chondrosarcoma.
• Paget disease: People with Paget disease have an increased risk of getting osteosarcoma. Paget disease is a condition where new bone replaces old bones at a faster than normal rate.

Genetic conditions

People with a family history of bone cancer may be at a higher risk of developing the condition.

• Li-Fraumeni syndrome: A condition called Li-Fraumeni syndrome runs in families. It is caused by a gene fault inherited from your parents. If you have Li-Fraumeni syndrome, you have an increased risk of several cancers, including osteosarcoma.
• Hereditary retinoblastoma: There is a type of eye cancer also caused by faulty genes. It is called hereditary retinoblastoma. Children with this gene fault also have an increased risk of osteosarcoma.

Other conditions

• Retinoblastoma: People who had a rare type of eye cancer called retinoblastoma as a child may be more likely to develop bone cancer, because the same inherited faulty gene can be responsible for both conditions.
• Umbilical hernia: Research has also found that babies born with an umbilical hernia are 3 times more likely to develop a type of bone cancer called Ewing sarcoma, although the risk is still very small.
• Werner syndrome
• Rothmund–Thomson syndrome
• Bloom syndrome

Injuries and knocks

People often think that a knock or injury to a bone can cause bone cancer. But research studies do not support this. It’s more likely that an injury causes swelling, which when it’s investigated, shows up a cancer that is already there. Or a bone affected by cancer may be weakened and so is more likely to become broken (fractured) in an accident. Doctors may then spot the tumour when they investigate your fracture.

It’s important to note that most people with these risk factors do not develop bone cancer, and many people who do develop bone cancer do not have any known risk factors. Having any of these risk factors does not mean that you will definitely develop cancer.