Bone pain represents one of the most debilitating side effects of the metastases of high-incidence cancers such as breast, prostate, lung, and multiple myeloma (myelomatosis). Severe bone pain is frequent, reported by greater than 65% of patients suffering with bone metastases. The most common sites affected include the pelvis, femur,
skull, and vertebra. The patient often describes the pain as dull and aching, localized at the site affected; however, some patients experience short, shooting pain that radiates out from the torso to the extremities. Movement typically aggravates the pain. Bone pain can signal disease progression, a new infection, or a complication from treatment. Pain is a reliable early indicator of complications from metastases-osteoporosis, hypercalcemia, fractures, and spinal cord compression. These conditions not only adversely affect the patient's quality of life, but in some cases may create such a decline that death results not from the metastases, but solely from bone-and skeletal-related complications. Patient complaints of bone pain require diagnostic confirmation, usually by radiographic techniques. Plain-film radiography may adequately detect typical lesions from metastatic causes, but may not be sensitive enough to detect certain complications. In these cases, radionuclide scintigraphy and magnetic resonance imaging (MRI) are the preferred diagnostic tools.
Causes
Bone pain may be the result of direct tumor involvement. Pain is produced when the tumor infiltrates the skeletal structures. The tumor may compress surrounding blood vessels, nerves, and soft tissue, or may be activating nociceptors (pain receptors) located at the site. Pain may also be a result of tissue compression caused by fibrosis (a condition caused by an increase in tissue) after the patient has undergone radiation therapy; this type of bone pain tends to be tolerable. A predominant source of bone pain in the cancer patient is due to pathologic fracture and to osteoclast-induced bone resorption by the tumor. This condition promotes bone loss and, at the same time, provides growth factors for the tumor to increase in size.
Treatments
Pain management for bone metastases has multiple options for the health care team to draw upon. The primary treatment for the majority of patients is external beam radiotherapy, either localized or wide field. These treatments provide excellent relief of the bone pain. Localized radiation treatments target specific sites for pain relief and the promotion of healing and prevention of fractures. Spinal cord compression from vertebral collapse requires immediate and localized radiation therapy, possibly in conjunction with surgical intervention to prevent paralysis or loss of life. Wide-field radiation therapy treats multiple disease sites and is appropriate for more diffuse bone pain. One half of the body receives radiation in a single treatment. Studies report relief of the bone pain in 55-100% of patients. Analgesics (pain relievers) are typically given in conjunction with radiotherapy. Severity of the bone pain and general health of the patient will determine the prescribed medication. The spectrum of medications prescribed range from over-the-counter pain medication to opioids for extreme bone pain management.
Radiopharmaceuticals may be an effective choice for bone pain management. Iodine-131 is used in the treatment of multiple bone metastases from thyroid cancer. Phosphorus-32 orthophosphate has a success rate of about 80% in bone pain management in patients suffering with breast and prostate cancer. Strontium-89 provides partial or complete pain relief in approximately 65% of patients. Other radiopharmaceuticals are being
tested internationally but have not yet received FDA approval for use in the United States. In treatments for bone resorption-induced pain, a group of chemical agents, known as bisphosphonates and calcitonin, acts to strongly block the bone resorption process. These agents are used in the management of hypercalcemia and have the added effect of reducing the prescribed amount of analgesics and shortening the duration of bone pain.
Alternative and complementary therapies
Comprehensive management of bone pain includes non-clinical choices. Patients should be encouraged to participate in complementary therapies, and some patients may choose to investigate more alternative therapies. More conventional complementary therapies may include relaxation and imagery therapy, cognitive distraction and reframing, support group and pastoral counseling, skin stimulation, biofeedback, nerve blocks, immobilization and stabilization techniques, and surgical intervention. Less well-defined alternative therapies may include acupuncture, body massage with pressure and vibration techniques, hypnosis, menthol preparations, and holistic or herbal medical practices. No conclusive data exist of the effectiveness of these therapies used alone; however, in conjunction with conventional methods of bone pain management, they do not appear to hinder therapy and may provide the patient with increased goodwill and a positive outlook.
Resources
PERIODICALS
Coleman, Robert E. "Management of Bone Metastases." The Oncologist 5 (September 2000): 463-470.
Jane Taylor-Jones, M.S., Research Associate
Calcitonin
—A hormone produced by the thyroid that causes a reduction of calcium ions in the blood.
Cognitive distraction and reframing
—Techniques to teach the patient to focus on things not associated with pain.
Hypercalcemia
—The presence of abnormally high concentrations of calcium compounds in the bloodstream.
Magnetic resonance imaging (MRI)
—A diagnostic technique that makes images of internal structures of the body, often superior to a normal x ray.
Metastases
—Cancer that starts from cancer cells that originate in a different location in the body.
Multiple myeloma
—Multiplying plasma cells that often replace all other cell types found in the bone marrow and frequently cause the loss of the bone cortex.
Nociceptors
—Peripheral pain receptors that are sensitive to movement, extreme heat and cold, and chemical stimuli.
Opioid
—Any morphine-like compound producing bodily effects that may include relief from severe pain, respiratory depression, or sedation.
Osteoclast
—Cells responsible for the breakdown of bone tissue.
Radionuclide scintography
—The process of injecting a radionuclide to capture an image of a particular area of the body for diagnostic purposes.
Radiopharmaceuticals
—Compounds used as radiation sources for radiotherapy and for diagnostic procedures.
