What is Bone Cancer?
Quite often, bone cancer is the result of metastasis - meaning, a cancer from elsewhere has migrated to the bone. These cancers show the original cancerous cells and not those associated with bone cancer. In these cases, the cancer is treated by following the original course of treatment for the initial tumor.
However, there are primary cancers of the bone-- meaning the cancer starts in the bone -- although they are quite low, composing only around 1% of those diagnosed. Because bones are composed of osteoid (hard or compact), cartilaginous (tough, flexible), fibrous (threadlike) tissue, and bone marrow (soft, spongy tissue in the center of most bones) the types differ.
Risk Factors, Signs & Symptoms
Research is increasing regarding what we know about bone cancer. Scientists are learning more about its causes. Following are common risk factors for the disease:
Bone Marrow Transplantation - Osteosarcoma has been reported in a few patients who have undergone stem cell transplantation.
Genetic Disorders - A small number of bone tumors are believed to be the result of genetic mutations:
- The Li-Fraumeni Syndrome - A mutation of the p53 tumor suppressor gene makes people much more likely to develop several types of cancer, including breast cancer, brain cancer, osteosarcoma, and other types of sarcoma.
- Rothmund-Thomson Syndrome - Children with this syndrome are short, have skeletal problems, and rashes. They also are more likely to develop osteosarcoma.
- Multiple Exostoses Syndrome - Patients with this inherited condition that causes many bumps on a person's bones can have an increased risk of chondrosarcoma.
Radiation - Exposure to large doses of radiation may also increase the risk of developing bone cancer. Also, radioactive materials such as radium and strontium can also cause bone cancer because these minerals build up in bones.
Signs and Symptoms
The most common symptom of bone cancer is pain. Persistent or unusual pain or swelling in or near a bone can be caused by cancer.
If cancer metastasizes and migrates into bones, it makes them weak. Weakened bones are more likely to break. Fractures occur most often in the leg bones near the hip because these bones support most of your weight.
Cancer in the bone may cause severe pain for a while before the bone actually breaks. It is important to consult a doctor if this occurs as an x-ray may show if the bone is likely to break.
Diagnosis & Staging
Pain is the most common symptom of bone cancer. If a patient experiences pain, a doctor will order one of the following tests to diagnose bone cancer:
Biopsy - Removal of tissue through a needle biopsy (surgeon will make a small hole in the bone to remove a sample) or an incisional biopsy (surgeon will cut into the tumor and remove sample) to determine whether cancer is present.
Blood Tests - This test is used to determine the level of an enzyme called alkaline phosphatase. A large amount of this enzyme is present in the blood when the cells that form bone tissue are very active.
Imaging Tests - A variety of tests is available to determine if malignant cells are present. Bone scans, CAT scans, PET scans, and MRI tests are most common.
Bone Scan - A test in which a small amount of radioactive material is injected into a blood vessel and travels through the bloodstream. After the material pools in the bones it is then detected by a scanner.
Computed Tomography (CAT) Scan - A series of detailed images, taken from different angles, are created by a computer linked to an x-ray machine.
Magnetic Resonance Imaging (MRI) Procedure - This uses a powerful magnet linked to a computer to create detailed scans without using x-rays.
Positron Emmision Tomography (PET) Scan - A small amount of radioactive glucose is injected into a vein and a scanner is used to make detailed, computerized images where the glucose is used. Cancer cells often use more glucose than normal cells so the images can be used to find cancer cells in the body.
X-Rays - An x-ray can show the location, size, and shape of a bone tumor.
Your treatment options will depend on the stage of bone cancer, your overall health and your preferences about treatment. You typically have time to make your decision about your treatment. Ask questions if you do not understand any aspect of treatment or the terms your doctors are using. Treatment options for bone cancer include:
Chemotherapy - The use of anticancer drugs to kill cancer cells. Patients who have bone cancer usually receive a combination of anticancer drugs. However, chemotherapy is not currently used to treat chondrosarcoma.
Cryosurgery - The use of liquid nitrogen to freeze and kill cancer cells. This technique can sometimes be used instead of conventional surgery to destroy the tumor.
Radiation Therapy - This involves the use of high-energy x-rays to kill cancer cells. This treatment may be used in combination with surgery. It is often used to treat chondrosarcoma, which cannot be treated with chemotherapy, as well as Ewing sarcoma, where it may be combined with chemotherapy, and possibly surgery as part of multimodality therapy.
Surgery - This is the primary treatment of bone cancer and involves removal of the entire tumor with negative margins (no cancer cells are found at the edge or border of the tissue removed during surgery). Dramatic improvements in surgical techniques and preoperative tumor treatment have made it possible for most patients with bone cancer in an arm or leg to avoid radical surgical procedures (removal of the entire limb).