What is bone cancer?Bone cancers are rare forms of cancer that can affect any bone in the body. Two types of bone cancer are multiple myeloma and bone sarcomas. Bone cancers can also happen when tumors that start in other organs, such as breasts, lung, and prostate, metastasize (spread) to the bone. Multiple myeloma is the most common type of bone cancer. The two most common bone sarcomas are osteosarcoma, which develops in new tissue in growing bones, and chondrosarcoma, which
develops in cartilage. Osteosarcoma tends to occur more frequently in children and adolescents, while chondrosarcoma occurs more often in adults. Cancers that begin in the bone are quite rare. On the other hand, it is not unusual for cancers to spread to the bones from other parts of the body. When this happens, the disease is not called primary bone cancer. Each type of cancer is named for the organ or the tissue in which it begins. Cancer that spreads is the same disease and has the same name as the original (or primary) cancer. Any kind of cancer can spread to the bone. This bone metastasis usually occurs late in the disease. Breast, prostate, and lung cancer are the most common types of cancers that spread to the bone. The bones of the spine, pelvis, and ribs are the most commonly affected. The bones of the upper arm and upper leg also may be affected. Multiple myeloma, a type of blood cancer, can affect the bones early in the disease.
What causes 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 Pagets 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. The bones support the body and make it possible to move about. Cancers affecting the bone will weaken the bone, and the affected area may break easily. In bone cancer, abnormal cells multiply and spread to form tumors. Healthy bones, nerves, and tissues (including organs) are damaged or destroyed, and the disease can be life threatening. However, successful treatment is often possible, particularly if the cancer is found in its early stages. Chances for successful treatment decrease and the threat to life increases the longer the cancer is untreated. The break can occur for no apparent reason. Or, it may be caused by mild trauma that would not normally be expected to cause a bone to break. There may be a genetic link and bones which have been previously fractured or infected may be more susceptible to bone cancer. Excessive exposure to chemicals or radiation may also increase the risk of bone cancer.
What are the symptoms of bone cancer?Patients may present with persistent pain, swelling, or tenderness of a bone. They may have unexplained fracture of one or more bones, sometimes without noticeable trauma. A fracture in a bone that causes severe pain may be the first sign that cancer has invaded the bone. Sometimes the person will have pain in the area for some time before the fracture occurs. In other cases, there is no pain until the bone breaks. Pain is the most frequent symptom of bone cancer. Sometimes a firm, slightly tender lump on the bone can be felt through the skin. In some cases, bone cancer interferes with normal movements. Bone cancer can also cause bones to break.
How is bone cancer diagnosed?The presenting symptom is usually pain. Pathologic fracture may be present and is more common in the lower than the upper extremity. The presenting radiologic finding on X-ray is often destruction of bone. In a patient with a known primary malignant tumor presenting with a painful, destructive lesion of bone, a diagnosis of metastatic cancer can be made with some assurance. However, there are individuals in whom the primary cancer is not yet recognized at the time when the early metastatic lesion in bone becomes painful. A CAT scan, MRI, radionuclide bone scan or a skeletal survey may be done to pinpoint which bones have been affected.
What is the treatment for bone cancer?The treatment of cancer of the bone, especially metastatic cancer, has two goals: management of the neoplasm and management of the symptoms produced by the local lesion. Prognosis is affected by a patient's age, the size of the primary tumor, grade and stage, degree of lymphatic and blood vessel invasion, the duration of symptoms and the location of the tumor on the arm, leg or trunk.
Treatment options depend on the type, size, location, and stage of the cancer, as well as the persons age and general health. Surgery is often the primary treatment. Although amputation of a limb is sometimes necessary, pre- or post-operative chemotherapy has made limb-sparing surgery possible in many cases. When appropriate, surgeons avoid amputation by removing only the cancerous section of the bone and replacing it with an artificial device called a prosthesis.
Chemotherapy and radiation may also be used alone or in combination. Because of the tendency for Ewings sarcoma to metastasize rapidly, multidrug chemotherapy is often used, in addition to radiation therapy or surgery on the primary tumor. Radiation therapy is used to treat bone pain in a person who has bone metastasis. Radiation to the affected areas can also prevent further weakening of the bones. The total dose of radiation that can be given is limited, however. Chemotherapy is sometimes used to help control the underlying cancer.