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A risk factor is anything that increases your chances of getting a disease such as cancer. Different cancers have different risk factors.

Lifestyle-related risk factors such as body weight, physical activity, diet, and tobacco use play a major role in many adult cancers. But these factors usually take many years to influence cancer risk, and they are not thought to play much of a role in cancers that are more common in children, including childhood osteosarcomas. So far, lifestyle-related factors have not been linked to osteosarcomas in adults, either. Still, there are some factors that affect osteosarcoma risk.

Age

The risk of osteosarcoma is highest for those between the ages of 10 and 30, especially during the teenage growth spurt. This suggests there may be a link between rapid bone growth and risk of tumor formation. The risk goes down in middle age, but rises again in older adults (usually over the age of 60). Osteosarcoma in older adults is often linked to another cause, such as a long-standing bone disease (see below).

Height

Children with osteosarcoma are usually tall for their age. This also suggests that osteosarcoma may be related to rapid bone growth.

Sex

Osteosarcoma is more common in males than in females. Females tend to develop it slightly earlier, possibly because they tend to have their growth spurts earlier.

Race/ethnicity

In the United States, osteosarcoma is slightly more common in African American, Hispanics, and Latino children than in White children.

Radiation to bones

People who were treated with radiation therapy for another cancer appear to have a higher risk of later developing osteosarcoma in the area that was exposed to radiation. Being treated at a younger age and being treated with higher doses of radiation both increase this risk.

It's not clear if imaging tests that use radiation, such as x-rays, CT scans, and nuclear medicine scans (such as PET scans or bone scans), raise the risk of developing osteosarcoma. The amount of radiation used for these tests is many times lower than that used for radiation therapy. If there is any increased risk it is likely to be very small, but doctors try to limit the use of these types of tests whenever possible, especially in children, just in case.

Certain bone diseases

People with certain non-cancerous bone diseases have an increased risk of developing osteosarcoma.

Paget disease of the bone: In this condition, abnormal bone tissue forms in one or more bones. It mostly affects people older than 50. The affected bones are heavy and thick but are weaker than normal bones and are more likely to break. Usually this condition by itself is not life-threatening. But bone sarcomas (mostly osteosarcomas) develop in about 1% of people with Paget disease, usually when many bones are affected.

Hereditary multiple osteochondromas: Osteochondromas are benign tumors formed of bone and cartilage. Each osteochondroma has a very small risk of developing into a bone sarcoma (most often a chondrosarcoma, but less often it can be an osteosarcoma).

Most osteochondromas can be removed completely by surgery. However, some people inherit a tendency to develop many osteochondromas starting when they are young, and it may not be possible to remove them all. The more osteochondromas a person has, the greater the risk of developing a bone sarcoma.

Fibrous dysplasia: This is an uncommon condition in which cells in a certain part of a bone make too much fibrous (scar-like) tissue, which replaces the normal bone in the area. In some people this happens in only one bone, while in others it affects more than one. It is sometimes seen as part of a condition called McCune-Albright syndrome. There is a small risk that each area of fibrous dysplasia might transform into an osteosarcoma.

Inherited cancer syndromes

People with certain rare, inherited cancer syndromes have an increased risk of developing osteosarcoma.

• Retinoblastoma is a rare eye cancer in children. Some children have the inherited form of retinoblastoma (hereditary retinoblastoma), in which all the cells of the body have a mutation (change) in the RB1 gene. These children also have an increased risk of developing bone or soft tissue sarcomas, including osteosarcoma. If radiation therapy is used to treat retinoblastoma, the risk of osteosarcoma in the bones around the eye is even higher.
• People with Li-Fraumeni syndrome are much more likely to develop certain types of cancer, including breast cancer, brain tumors, osteosarcoma, and other types of sarcoma. This syndrome is usually caused by a mutation of the TP53 gene.
• Children with Rothmund-Thomson syndrome tend to be short and to have skin and skeletal problems. They also are more likely to develop osteosarcoma. This syndrome is usually caused by abnormal changes in the REQL4 gene.
• Other rare inherited conditions, including Bloom syndrome, Werner syndrome, and Diamond-Blackfan anemia, have also been linked to an increased risk of osteosarcoma.

The way in which inherited gene changes make some people more likely to develop osteosarcoma is discussed in What Causes Osteosarcoma?