Bone Cancer (cont.)

What are possible risk factors for bone cancer?

Although scientists are not certain what causes bone cancer, a number of factors may put a person at increased risk. These cancers occur more frequently in children and young adults, particularly those who have had radiation or chemotherapy treatments for other conditions. Adults with Paget's disease, a noncancerous condition characterized by abnormal development of new bone cells, may be at increased risk for osteosarcoma. A small number of bone cancers are due to heredity. For example, children with hereditary retinoblastoma (an uncommon cancer of the eye) are at a higher risk of developing osteosarcoma.

What are the symptoms of bone cancer?

Pain is the most common symptom of bone cancer. However, symptoms may vary depending on the location and size of the cancer. Tumors that occur in or near joints may cause swelling or tenderness in the affected area. Bone cancer can also interfere with normal movements and can weaken the bones, occasionally leading to a fracture. Other symptoms may include fatigue, fever, weight loss, and anemia. None of these symptoms is a sure sign of cancer. They may also be caused by other, less serious conditions. It is important to check with a doctor.

How is bone cancer diagnosed?

To diagnose bone cancer, the doctor asks about the patient's personal and family medical history and does a complete medical exam. The doctor may suggest a blood test to determine the level of an enzyme called alkaline phosphatase. A large amount of alkaline phosphatase can be found in the blood when the cells that form bone tissue are very active—when children are growing, when a broken bone is mending, or when disease or a tumor causes production of abnormal bone tissue. Because high levels of this enzyme can normally be found in growing children and adolescents, this test is not a completely reliable indicator of bone cancer.

X-rays can show the location, size, and shape of a bone tumor. If x-rays suggest that a tumor may be cancer, the doctor may recommend special imaging tests such as a bone scan, a CT (or CAT) scan, an MRI, or an angiogram. However, a biopsy—the removal of a sample of tissue from the bone tumor—is needed to determine whether cancer is present.

The surgeon may perform a needle biopsy or an incisional biopsy. During a needle biopsy, the surgeon makes a small hole in the bone and removes a sample of tissue from the tumor with a needle-like instrument. In an incisional biopsy, the surgeon cuts into the tumor and removes a sample of tissue. Biopsies are best done by orthopedic oncologists—doctors experienced in the diagnosis of bone cancer. A pathologist—a doctor who identifies disease by studying cells and tissues under a microscope—examines the tissue to determine whether it is cancerous.