Risk factors and causes of primary bone cancer

The exact causes of primary bone cancer are unknown. For most people with bone cancer, it’s not clear why it has developed.

Research into possible causes is going on all the time. Because a lot of bone cancers occur in teenagers and young people, it’s thought that it may be related in some way to changes that happen when bones are growing.

There are some factors that are known to increase a person’s risk of developing primary bone cancer, which we discuss here.

Previous radiotherapy or chemotherapy

People who’ve had high doses of radiotherapy to an area that includes the bones have a slightly increased risk of developing cancer in one of these bones. This is a very small risk, and most people who have radiotherapy never develop primary bone cancer. If it does occur, it’s usually about 10–20 years after having the radiotherapy.

People who have previously been treated with certain chemotherapy drugs can have an increased risk of developing osteosarcoma.

Non-cancerous (benign) bone conditions

Having certain benign bone conditions can increase your risk of developing particular types of bone cancer.

Paget’s disease of the bone is a non-cancerous condition that causes painful and deformed bones. It can increase the risk of developing osteosarcoma. It mainly affects people over 60. A non-cancerous bone tumour called osteochondroma (or chondroma) can sometimes develop into chondrosarcoma.

People with hereditary multiple exostoses (HME) have an increased risk of developing chondrosarcoma. HME is a rare condition that causes bony lumps to grow, most commonly in the arm or leg bones. It often starts in childhood and is usually, but not always, inherited.

Inheriting a faulty gene

Most bone cancers are not caused by an inherited faulty gene, but people with certain genetic conditions have an increased risk of developing bone cancer.

People who have an inherited condition called Li-Fraumeni syndrome have an increased risk of developing osteosarcoma.

Children who have retinoblastoma, a rare type of eye cancer caused by an inherited faulty gene, also have an increased risk of developing osteosarcoma.

We have more detailed information about inheriting faulty genes and conditions that can run in families.


Sometimes people discover they have primary bone cancer after a knock to their bone. They may think the injury caused the cancer to develop.

There isn’t clear evidence that injury to a bone can cause bone cancer, but an injury may draw attention to a bone cancer that’s already there.