What is osteosarcoma?

A sarcoma is a type of cancer that develops in connective tissue, such as bone, cartilage, or muscle. A sarcoma that starts in the bones is called an osteosarcoma, or osteogenic sarcoma.

Osteosarcoma most often affects the long bones, such as those in the arms and legs. It usually occurs near the ends of the bones where the fastest growth is taking place (growth plates). The bones and areas most often affected include:

  • Femur (thigh bone) near the knee.
  • Tibia (shin bone) near the knee.
  • Humerus (upper arm bone) near the shoulder.

Other less common locations for osteosarcoma include the pelvis, skull, and jaw.

Who gets osteosarcoma?

Osteosarcoma most often affects pre-teens and teens; the average age at diagnosis is 15. This may be related to the “growth spurt” most children experience at this age.

Osteosarcoma is slightly more common in African-Americans. Before adolescence, it occurs equally in boys and girls. After adolescence, it occurs slightly more often in boys, possibly because of a longer period of skeletal growth.

How common is osteosarcoma?

Osteosarcoma accounts for about 3% of all childhood cancers. It is the third most common cancer in adolescence (after lymphomas and brain tumors); it is the most common primary bone tumor in children. Between 400 and 1,000 new cases of osteosarcoma are diagnosed in the United States each year.

What causes osteosarcoma?

The causes of osteosarcoma are unknown; however, there are some known risk factors, including:

  • Rapid bone growth: The risk of osteosarcoma increases during a child’s growth spurts.
  • Exposure to radiation: This might have occurred from treatment for another type of cancer. This can take a few or several years to occur.
  • Genetic factors: Osteosarcoma is one of several types of rare cancers in young people. This may be related to the retinoblastoma gene, which can be associated with eye cancers in young children or with other tumors in children and young adults in which a mutation of the p53 gene is involved.

What are the symptoms of osteosarcoma?

The most common symptoms of osteosarcoma include:

  • Bone pain or tenderness.
  • A mass (tumor) that can be felt through the skin.
  • Swelling and redness at the site of the tumor.
  • Increased pain with lifting (if it affects an arm).
  • Limping (if it affects a leg).
  • Limited movement (if it affects a joint).
  • Broken bone (sometimes after a simple movement).

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