The Basics of Bone Cancer

Healthy bones support and protect internal organs, act as levers and braces for muscle-driven movement, and produce and store a wide variety of blood cells crucial for fighting infections and supplying the body with oxygen and nutrients.

If bones become unhealthy because of a tumor, there is a greater risk for fractures, anemia, significant pain and, left undiagnosed, possibly a preventable death.

Bone tumors are a lump or mass of tissue in the bone(s) that may be malignant (cancerous) or benign (non-cancerous). Benign bone tumors are more common than malignant tumors. Unlike cancerous tumors, benign tumors neither spread to other parts of the body, nor are they a life-threatening condition. However, both types may grow and squash healthy bone tissue and replace it with abnormal, nonfunctioning tissue.

Cancer that begins inside or on the surface of the bone (primary bone cancer), as opposed to cancer that spreads to the bone (metastases), is a relatively rare disease. It primarily affects about 2,500 new patients in the United States each year, according to the National Cancer Institute (NCI). Primary bone cancer affects more men than women.

What are the main types of bone cancer?

The three most common primary bone cancers are:

• Osteosarcoma, also known as osteogenic sarcoma, primarily affects children whose bones are still growing. The most common body sites for an osteosarcoma are the knees, upper legs, and upper arms in people between 10 and 25 years.

• Ewing's sarcoma usually forms in the nerve tissue of bone marrow. The most commonly affected sites are the pelvis, upper legs, and shoulders in people between 10 and 20 years.

• Chrondrosarcoma typically develops in the cartilage. The most common locations of this tumor are the pelvis, upper legs, and shoulders in people between 50 and 60 years.

What are the symptoms?

The most common symptom of bone cancer is pain, which can vary in intensity depending on the location and size of the tumor. For example, tumors that occur close to joints may cause local swelling or tenderness. Additionally, bone cancer can hinder both normal movement and weaken bones, sometimes leading to fractures.

Other symptoms may include:

• Fatigue



• Anemia



• Fever



• Unexplained weight loss

While these developments do not necessarily signal the presence of cancer, they should be reported to your doctor so that the precise source of your symptoms can be adequately identified, diagnosed, and treated.

Who is at risk?

Scientists aren't sure what causes bone cancer. Bone cancer occurs more often in children and growing adults, particularly in those who have had radiation treatment or chemotherapy to treat another disease. There are certain other risk factors:

• Adults with Paget's disease, a non-cancerous condition hallmarked by abnormal bone development, may be at increased risk for developing osteosarcoma.

• Children with hereditary retinoblastoma (a rare type of eye cancer) are at a higher risk of developing osteosarcoma.

• Heredity may be responsible for a small number of bone cancers.

How is it diagnosed?

The doctor will ask for a personal and family history and perform a physical examination. To obtain information about the patient's current medical status, the doctor may suggest a number of tests, including:

1. A blood chemistry test known as alkaline phosphatase. Alkaline phosphatase (Alk Phos) is an enzyme (a protein that speeds up chemical reactions) that increases in the blood when bone activity is increased. Because high levels of this enzyme can normally be found in growing children and adolescents, this test in not a completely reliable indicator of bone cancer. The test is, however, a good indicator of increased bone activity such as the mending of a broken bone or the development of bone cancer. Additionally, an Alk Phos determination is required to provide an accurate overview of the patient's overall bone functioning and may also be used to monitor the patient's progress with therapy.

Another helpful blood test is a complete blood count (CBC) to test for anemia and immature blood cells.

2. Radiology testing. X-rays can show the location, size, and shape of a bone tumor. If an X-ray suggests that a tumor may be cancerous, the primary doctor will most likely send the patient to a tumor treatment specialist, who will explain and schedule further imaging tests, such as:



• A bone scan: A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner. Bone scans are used to detect arthritis, osteoporosis, fractures, sports injuries, and tumors. Based on these findings, other procedures may be required to determine the precise status of a patient's bones.



• A computed tomography (CT, CAT) Scan: A CT scan is a series of detailed pictures of areas inside the body, taken from different angles. These pictures are created by a computer linked to an X-ray machine. This test is also known as a computerized axial tomography scan. Special pictures called bone windows can help.



• Magnetic resonance imaging (MRI): An MRI is a procedure in which a magnet linked to a computer is used to create a detailed picture of specific areas inside the body.



• Angiogram: This test is an X-ray of a patient's blood vessels after receiving an injection of dye that outlines the blood vessels.

3. Biopsies



• Incisional biopsy: A surgical procedure in which a portion of a lump or suspicious tissue is removed. The tissue is then examined under the microscope for abnormalities.



• Needle biopsy: The removal of tissue or fluid with a needle for examination under a microscope. This test is also known as a fine-needle aspiration.



• Core needle biopsy: Similar to needle biopsy, core needle biopsy is done with a bigger needle to get a small biopsy.

What are the stages of bone cancer?

Treatment options for cancer depend on the size, type, location, and stage of the tumor. Osteosarcoma is divided into two stages: localized and metastatic.

How is bone cancer treated?

Initial treatments will most likely include a combination of surgery, radiation and/or chemotherapy, depending on the site and the size of the tumor.

• Limb "salvage" surgery removes the cancerous section of bone, while protecting nearby tendons, nerves, and blood vessels. The excised bone is replaced with a bone transplant or a prosthesis (a metallic replacement).

• Amputation removes all or part of an arm or leg when the tumor is large and/or nerves and/or blood vessels are involved.

• Radiation therapy uses high-dose X-rays to kill cancer cells and shrink tumors.

• Additional treatment, known as chemotherapy, will be required to kill the tumor if it has already spread from the bone. Chemotherapy is a technique that uses anti-cancer drugs, administered by mouth or intravenous needle, to destroy cancer cells.

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External Sources American Academy of Orthopedics Surgeons National Institutes of Health Osteoporosis and Bone Diseases - National Resource Center National Cancer Institute Dollinger M, Rosenbaum, EH, Tempero M., et al. Everyone's Guide to Cancer Therapy, Fourth Edition, Kansas City, Missouri: Andrews McMeel Publishing, 2002

This article was reviewed and updated June 2007.

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