What is osteosarcoma?

Osteosarcoma is a disease in which cancer (malignant) cells are found in the bone. It is the most common type of bone cancer. Osteosarcoma most often occurs in adolescents and young adults. In children and adolescents, tumors appear most often in the bones around the knee. Rarely, osteosarcoma may be found in soft tissue or organs in the chest or abdomen. The symptoms and chance for recovery in children and adolescents appear to be the same.

Malignant fibrous histiocytoma (MFH) of bone is a rare tumor of the bone. It may occur following radiation treatments. MFH is generally treated the same as osteosarcoma and appears to have a similar response to treatment.

Ewing sarcoma is another kind of bone cancer, but the cancer cells look different under a microscope than osteosarcoma cancer cells. (See the PDQ summary on Ewing Family of Tumors Treatment for more information.)

If a patient has symptoms (such as pain and swelling of a bone or a bone region), a doctor may order x-rays and blood tests. If it is suspected that the problem is osteosarcoma, your doctor may recommend seeing a specialist called an orthopedic oncologist. The orthopedic oncologist may cut out a piece of tissue from the affected area. This is called a biopsy. The tissue will be looked at under a microscope to see if there are any cancer cells. This test may be done in the hospital.

The prognosis (chance of recovery) is affected by certain factors before and after treatment.

The prognosis of untreated osteosarcoma depends on the following:

• The location of the tumor.
• The size of the tumor.
• The stage of the cancer (whether it spread from where it started to other places in the body).
• The age of the patient.
• The results of blood tests and other tests.
• The type of tumor (based on how the cancer cells look under a microscope).

After osteosarcoma is treated, prognosis also depends on the following:

• How much of the cancer was killed by chemotherapy ; and/or
• How much of the tumor was taken out by surgery.

Treatment options depend on the following:

• The location of the tumor.
• The stage of the cancer.
• Whether the cancer has recurred (come back) after treatment.
• The patient’s age and general health.
• Having certain genetic diseases such as Rothmund-Thomson syndrome.