Cancers Affecting The Bone
Cancer of the bone occurs when cells in the bone undergo changes that make theml grow and divide uncontrollably. This is called primary bone cancer. Cancer can also affect the bone when a cancer spreads from another part of the body to the bones. This is called bone metastasis. A bone metastasis is much more common than a primary bone cancer.
What is going on in the body?
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 and sometimes for no apparent reason. Or, it may be caused by mild trauma that would not normally be expected to cause a bone to break.
The most common bone cancer is osteosarcoma. It can spread from the bone to other parts of the body if untreated. Osteosarcoma is a rare cancer. It occurs most often in children but can occur in adults. Ewing's sarcoma is another type of bone cancer in children.
Other types of cancer, most commonly breast, prostate, and lung cancers, can spread to the bone. These bone metastases usually occurs late in the disease. 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 involved. Multiple myeloma, a type of blood cancer, can spread to the bones earlier in its course than other cancers.
What are the causes and risks of the disease?
Osteosarcoma and other primary bone tumors are rare. A person who has been exposed to radiation may be more at risk for primary bone cancer. A person who has uncontrolled cancer of the breast, lung, or prostate is at high risk for developing bone metastases.
What can be done to prevent the disease?
There is no known way to prevent primary bone cancer. Early detection and treatment of other cancers can help prevent bone metastasis. Cancer detection methods are designed to diagnose cancers before they can spread to the bone. These methods include:
- colorectal cancer screening
- rectal exams and PSA blood tests
- routine physical exams
How is the disease diagnosed?
Primary bone cancer is often diagnosed after there has been an unexplained bone fracture. Or, an individual may complain of long-term bone pain. An X-ray will show a tumor of the bone. A bone biopsy is done to remove a piece of tissue for examination under a microscope.
If a bone metastasis is suspected, a bone scan can show damage to a bone before a fracture occurs. It is not always necessary to take a sample of suspected bone metastasis to prove it is cancer. This is especially true if a person has active cancer that has spread to other areas of the body.
Long Term Effects
What are the long-term effects of the disease?
Osteosarcoma and other primary bone cancers that are localized may be controlled with treatment. However if the tumor has spread to other parts of the body they are usually fatal. In bone metastasis, cancer has spread to the bone from another part of the body. This means that the primary cancer is at an advanced stage. Treatment is aimed at reducing pain and keeping the cancer from spreading further. It may not be possible to cure the cancer at that point.
What are the risks to others?
Cancers affecting the bone are not contagious and pose no risk to others.
What are the treatments for the disease?
Removing a small tumor may offer long-term control of primary bone cancer. Radiation therapy may be offered once a small tumor is removed. This may help slow the return of the tumor.
Primary bone cancer that has spread to other parts of the body may be treated with chemotherapy and radiation therapy. 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. Some bone metastases cause calcium to leave the bone. This weakens the bone even more. Medicines known as bisphosphonates (a family of drugs used in the treatment of osteoporosis) can be given to help keep the calcium in the bone. Some recent studies indicate that bisphosphonates may slow the spread of bone cancers. Bisphosphonates may also help strengthen bones. This approach is commonly used in advanced breast cancer and multiple myeloma.
Other therapy, such as pain medicines, will be given to help improve a person's quality of life. Surgery may be done to support weakened bones and make them stronger.
What are the side effects of the treatments?
The side effects experienced by a person with primary bone cancer depend on the treatment given. Surgery to remove a bone cancer may affect the strength and stability of the bone. The side effects of chemotherapy depend on the particular medicines given but may be significant.
Radiation therapy also has several side effects, including short- and long-term damage of healthy tissue. Bisphosphonates can cause stomach upset, but they are usually well tolerated. Pain medicines can cause allergic reactions and stomach upset.
What happens after treatment for the disease?
The person who has primary bone cancer will need to be followed closely to watch for any signs that the disease has come back or gotten worse. A person with a bone metastasis will be monitored for bone fractures or further spread of the cancer.
How is the disease monitored?
Regular CT scans may be done to monitor the cancer. Bone scans will generally be used to monitor a person with known or suspected bone metastases. Regular X-rays may be used to monitor suspected progression of multiple myeloma. Any new or worsening symptoms should be reported to the healthcare provider.
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Rubens, R.D. and Coleman, R.E.( ). Bone metastasis in Clinical Oncology. Abelhoff, M.d et al (Eds), Churchill, Livingstone: New York. Pp. 643-666.