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Osteosarcoma

What Is Osteosarcoma?

Osteosarcoma is a cancerous bone tumor. It happens most often in the arms and legs but can affect other bones too. Treatments can help most children who have osteosarcoma (ah-stee-oh-sar-KOH-muh).

What Are the Signs & Symptoms of Osteosarcoma?

Osteosarcoma usually develops during the adolescent growth spurt (usually ages 13 to 16 in boys but a little younger in girls). It causes pain in the bone, which may be worse during exercise or at night. A lump or swelling may form.

Less often, osteosarcoma causes a limp or a broken bone (when the cancer has weakened the bone).

What Causes Osteosarcoma?

Osteosarcoma happens when bone cells (called osteoblasts) start to grow abnormally. Doctors don’t know why this happens, but different types of gene changes (mutations) may play a role. Most kids who get osteosarcoma don’t have any risk factors for it. But it is more likely in kids who:

have had radiation therapy for cancer or chemotherapy
have some types of genetic conditions including retinoblastoma and Li-Fraumeni syndrome (where kids can develop many types of cancer)

How Is Osteosarcoma Diagnosed?

Doctors diagnose osteosarcoma by doing an exam and ordering tests such as:

X-rays
an MRI or CT scan of the bone tumor
MRIs, CT scans, or bone scans of areas near the bone tumor and other organs to see if it has spread to other parts of the body
blood tests
a biopsy of the tumor
genetic testing

How Is Osteosarcoma Treated?

Orthopedic surgeons and pediatric oncologists work together to treat children with osteosarcoma. Treatment includes:

chemotherapy: to shrink the tumor and kill cancer cells
then, surgery: The surgeon usually takes out the tumor and surrounding tissues but saves the limb (called limb-salvaging surgery). Rarely, the limb needs to be removed (amputation).
more chemo: to kill any remaining cancer cells and lower the chances of the cancer coming back

Physical therapy can help kids recover. Sometimes other treatments (such as radiation therapy) or more surgeries are needed.

What Else Should I Know?

If your child has osteosarcoma, it can be a stressful time. Although every child is different, many children recover from osteosarcoma. Doctors and scientists are researching treatments that will help even more.

To find support, talk to your doctor, a hospital social worker, a counselor, or a Child Life specialist. Many resources are available to help your child and the whole family. You also can find more information and support online at:

Medically reviewed by: Amy W. Anzilotti, MD

Date reviewed: November 2022