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Symptoms and Treatment of Bone Metastasis
When cancer spreads from a different part of the body to a bone, it is called bone metastasis. For example, if a person has prostate cancer and it spreads to the bones, the primary cancer is prostate cancer even though the bones become affected — it is not bone cancer, as often believed.
While cancer can spread anywhere in the body, people who have certain cancers are more likely than others to experience metastasis to bony tissues. Approximately 80 percent of metastatic bone disease is due to prostate, breast and lung cancers.
Other cancers that metastasize to bones include lymphomas, sarcomas, and tumors of the thyroid, bladder and kidney.
How Does Cancer Spread to the Bones?
Most of the time cancer cells travel through the blood stream and lodge in bony tissues, where they multiply and cause damage to the bones. Sometimes metastatic bone disease occurs when soft tissues next to a bone become cancerous.
The cancer may invade the bone tissue locally, at least initially. For example, a tumor of the breast may spread into the underlying chest muscle, soft connective tissues, and eventually into a rib.
The most common site of bone metastasis is into the vertebrae. Other areas likely to be affected include the upper thigh bone, pelvis, ribs, breastbone, upper arm and skull.
Metastasis may arise in a completely different location from the site of the primary cancer, and multiple areas of metastasis are common.
Signs and Symptoms of Bone Metastasis
Metastatic bone cancer may be present without any obvious signs or symptoms.
The most common symptom is pain, which may be mild or severe. Pain is usually localized to the affected bone and surrounding tissues and usually develops over a period of several weeks. There may also be some swelling in the affected areas.
Fractures may occur with little or no provocation. For example, if a rib has been invaded with metastatic cancer, simply turning over in bed may result in a fracture of the affected rib. Pain from a fracture occurs suddenly and can be severe.
When metastasis occurs in the spine, pressure may develop along the spinal cord. This is called spinal cord compression and is a very serious condition.
Symptoms vary depending upon the progression of the cancer, as well as the quality and location of the bone metastasis. Some metastatic lesions cause paralysis; others result in severe pain or a loss of bowel or bladder control.
The cancer may take over the bone marrow. Since bone marrow produces red blood cells, anemia may occur.
Other blood and electrolyte disorders may arise when bone metastases are present. Too much calcium may be present in the blood stream, which is called hypercalcemia, due to bone damage and other processes related to cancer. Signs of hypercalcemia include fatigue, rash, weakness and weight loss.
How Are Metastatic Bone Lesions Found?
They may be discovered as a result of an investigation into a new onset of pain, paralysis or other symptoms. Some lesions are discovered by screening tests. If bone metastasis is suspected or if a person is at risk for developing them, specific testing protocols are implemented.
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X-rays can show some lesions and are particularly useful if a lesion is large or if a fracture has occurred.
A bone scan may also be performed, where special radioactive materials are administered via intravenous infusion. This material helps health care experts visualize healthy and unhealthy areas of bony tissue.
Both X-ray and bone scans are relatively painless and noninvasive procedures. Discomfort is usually only present if a person is uncomfortable in the position the tests require or at the injection site if an intravenous infusion is needed.
Blood tests show the presence of abnormalities in calcium levels and red blood cell counts. Other laboratory tests are used depending upon the type and stage of cancer, as well as presenting symptoms.
Treatment of Bone Metastases
The prognosis and treatment of bone metastases is determined by multiple factors. Lesions that result from lymphoma and Hodgkin’s diseases may be treated and cured; however most metastatic lesions are not curable.
Treatment is geared toward reducing discomfort, slowing down the rate of bone destruction, and promoting an optimal quality of life. The primary type of cancer, location of the lesion, symptoms present, and overall progression of the cancer are considerations that impact the course of treatment.
A combination of therapies is employed for the treatment of bone metastases. The use of pillows, modified transferring and positioning techniques, and adaptive equipment can help protect bones from injury and immobilize areas of fracture.
Radiation therapy can help to relieve localized pain due to bone metastasis. It is delivered via various means.
A wide array of medications may be employed: hormonal therapy is used to treat bone lesions that have arisen as a result of prostate or breast cancer; bisphosphonates relieve pain and enhance bone strength; and narcotics and acetaminophen are often employed to manage discomfort.
Surgery may be required, sometimes used as a means to relieve pressure and pain. Hardware may be inserted in order to reduce pain and promote independence. It is performed when the lesion is pressing on a nerve, causing severe pain, paralysis or other serious symptoms.
Hypercalcemia may or may not be treated, depending upon the progression of the cancer and the origin of the elevated blood calcium levels.
Spinal cord compression is treated by radiation and medications classified as glucocorticoids. Chemotherapy may be implemented, too.
Managing Bone Pain at End of Life
As the cancer progresses, it is extremely important to provide an adequate analgesic. A wide array of medications in multiple delivery forms are available to promote comfort at end of life.
If a person has less than a six-month life expectancy a hospice referral should be made, as hospice care providers are the experts when it comes to providing pain relief and ensuring the best quality of life when advanced cancers are present. Bone metastasis can be disabling and painful, however help is available.