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There are different types of primary bone cancers (cancers that start in the bones), and while they might have some things in common, these different cancers do not all have the same risk factors.

Many bone cancers are not linked with any known risk factors and have no obvious cause. But there are a few factors that can raise the risk of some types of bone cancers.

The information here focuses on primary bone cancers (cancers that start in bones) that most often are seen in adults. Information on Osteosarcoma, Ewing Tumors (Ewing sarcomas), and Bone Metastases is covered separately.

What is a risk factor?

A risk factor is anything that raises your chances of getting a disease such as cancer. Different cancers have different risk factors. Some risk factors, like smoking, can be changed. Others, like a person’s age or family history, can’t be changed.

But having a risk factor, or even several risk factors, does not mean that you will get the disease. Many people with one or more risk factors never get cancer, while others who get cancer may have had few or no known risk factors.

Chondrosarcoma risk factors

Older age: Most chondrosarcomas occur in older adults, although they can develop in younger people as well.

Benign bone tumors: Having certain types of benign (non-cancerous) bone tumors can increase a person’s risk of chondrosarcoma. 

For example, an enchondroma is a benign cartilage tumor that can develop in the middle of a bone. These tumors rarely transform into chondrosarcomas, but people with many of these tumors (a condition called multiple enchondromatosis) have an increased risk of chondrosarcoma. Sometimes this condition is linked with inherited changes in the IDH1 or IDH2 genes.

Multiple exostoses (also known as multiple osteochondromas) is an inherited condition in which a person has many benign bone tumors called osteochondromas, which are made mostly of cartilage. These tumors can sometimes be painful and can lead to deformed or fractured bones. Each tumor also has a small chance of transforming into a chondrosarcoma. This disorder is most often caused by  inherited changes (mutations) in either the EXT1 or EXT2 gene.

Chordoma risk factors

Most chordomas do not have a known cause. But a small number of chordomas seem to run in families (known as familial chordoma). This is often linked to a mutation (change) in the TBXT gene that a person inherits from a parent.

Patients with tuberous sclerosis, an inherited syndrome caused by a defect (mutation) in either the TSC1 or TSC2 gene, seem to have a high risk of chordoma during childhood, although this seems to be rare overall.

Other risk factors for bone cancer

There are few known risk factors for other, less common types of bone cancer, although there are some factors that increase the risk for several types of bone cancer.

Paget disease of bone: This is a benign condition that occurs mostly in older people, in which an area (or areas) of bone becomes more active than normal. This can result in abnormal bone that is more likely to fracture (break). People with this condition have a small chance of developing bone tumors in these areas. Most often this is an osteosarcoma, but it can also be a less common type of bone tumor, such as a giant cell tumor of bone.

Previous radiation therapy: People who have received radiation therapy (usually to treat another type of cancer) have a slightly increased risk of developing bone cancer in the area that was treated. This risk is higher in people who were treated when they were younger (especially as children) and those who were treated with higher doses of radiation.

These cancers tend to develop many years (often decades) after the radiation therapy was given. Most often these are osteosarcomas, but they also can be less common types of bone cancer, such as fibrosarcoma of bone or undifferentiated pleomorphic sarcoma (UPS) of bone.