Osteosarcoma is the uncontrolled growth of abnormal cells in bone. It is the most common type of bone cancer, accounting for more than 50% of bone cancer in adults and children in the United States.

Osteosarcoma typically appears as a mass of abnormal bone or unmineralized bone (osteoid) in an arm or leg, most commonly near the knee (50% of cases) or near the shoulder (25% of cases). Less often, the tumor develops in the pelvic bones, jaw or ribs, but only rarely in the fingers or toes (fewer than 1% of cases). At the time of diagnosis, 10% to 20% of osteosarcomas already have spread (metastasized) to another site, usually to the lungs.

Osteosarcoma is a rare cancer that strikes only two in every 1 million people in the United States each year. About 60% of osteosarcomas develop in people between the ages of 10 and 20, most often during the growth spurt of adolescence. An additional 30% of osteosarcomas strike adults between the ages of 40 and 50, more commonly men than women. Young people have a higher risk of developing an osteosarcoma if they suffer from retinoblastoma or Li-Fraumeni syndrome. Adults are at higher risk if they have a history of Paget's disease or radiation therapy for cancer.

Symptoms include persistent pain and swelling in an arm or leg, especially near the knee or shoulder. This pain may occur at rest, and it may even awaken the person from sleep. It may be mistaken at first for a sprain or other sports injury, particularly in active teenagers.

There also may be a firm lump on an arm or leg, and the lump may be tender.

Because osteosarcoma is very rare, your doctor usually will ask questions that are related to more common causes of pain and swelling in the limbs, such as sports injuries or arthritis. The true cause of your symptoms may not be known until the doctor orders an X-ray of the area.

After reviewing your symptoms, your doctor will examine you, paying special attention to the painful area. Your doctor will check the area for warmth, swelling, tenderness, difficulty moving and any signs of joint swelling or joint fluid. This physical examination will be followed by an X-ray of the area, and, sometimes, blood tests. In most cases, the blood tests will be normal, except for high levels of serum alkaline phosphatase in 45% to 50% of patients. However, the X-ray typically shows characteristic abnormalities suggesting cancer.

Once your doctor has found X-ray evidence of a bone tumor, he or she will refer you to a major medical center that has the facilities, personnel and experience to treat bone cancer. There, you may have a magnetic resonance imaging (MRI) scan of the area to determine how far the tumor has invaded nearby nerves, blood vessels and joints. You also may have X-rays and a radionuclide bone scan to check whether the cancer has spread to your lungs or to other areas, especially other bones. After these tests are complete, you will have a biopsy to confirm the diagnosis of osteosarcoma. In a biopsy, a small piece of bone is removed so it can be examined in a laboratory.

Once it develops, an osteosarcoma will continue to grow until it is treated. If it is not treated, this cancer eventually can spread to the lungs and to other bones.

Osteosarcoma cannot be prevented.

In most cases, an osteosarcoma is treated using a three-step approach that includes chemotherapy and surgery:

• First, the patient is given a preliminary course of chemotherapy to destroy as much of the tumor as possible before surgery.



• Next, limb-sparing surgery is done to remove the cancerous bone without amputating the limb whenever possible. In the area where the cancer was removed, the space is filled with a bone graft or a synthetic prosthesis to allow the limb to remain as functional as possible. If cancer also has spread to the lung, these areas of cancer can be removed through surgery.



• A second course of chemotherapy is given after surgery.

Although most patients can be treated with limb-sparing surgery, this approach may not be possible if the tumor has invaded certain critical blood vessels or portions of a nearby joint. In this case, the limb may need to be amputated.

Call your doctor if you or anyone in your family has persistent or unexplained pain and swelling in a bone or joint.

Between 70% and 90% of osteosarcomas in the limbs can be treated with limb-sparing surgery and chemotherapy so that amputation is not necessary. When osteosarcoma affects only one limb, the long-term survival rate is 60% to 75%. However, this percentage drops to 40% or less if cancer has spread to the lungs.

National Cancer Institute (NCI)
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American Cancer Society (ACS)
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American Academy of Pediatrics (AAP)
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E-Mail: kidsdocs@aap.org
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American Society of Clinical Oncology
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Phone: (703) 299-0150
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American Academy of Orthopaedic Surgeons (AAOS)
6300 North River Road
Rosemont, IL 60018-4262
Phone: (847) 823-7186
Toll-Free: (800) 346-2267
Fax: (847) 823-8125
http://orthoinfo.aaos.org/