Key Terms: Calcitonin, Cognitive distraction and reframing, Hypercalcemia, Magnetic resonance imaging, Metastases, Multiple myeloma, Nociceptors, Opioid, Osteoclast, Radionuclide scintigraphy.
Description
Bone pain represents one of the most debilitating side effects of the metastases (distant spread) of many 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 cancer, but from bone- and skeletal-related complications. When a patient complains of bone pain, it require confirmation, usually by imaging. Plain-film radiography may detect typical lesions, 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 pushes against or enters the bone. The tumor may compress surrounding blood vessels, nerves, and soft tissue, or may activate nociceptors (pain receptors) located at the site. Pain also may result from tissue compression caused by fibrosis (a condition caused by an increase in tissue) after the patient has undergone radiation therapy. A major source of bone pain in the cancer patient is pathologic fracture and 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
There are several options for pain management for bone metastases. The primary treatment for the majority of patients is external beam radiation therapy. These treatments provide excellent pain relief. Localized radiation treatments target specific sites for pain relief, promote healing, and help prevent 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 bone pain in 55%–100% of patients. A 2003 study reported that external beam radiation therapy treatments provided significant pain relief for two-thirds of patients with bone mestastases from breast and prostate cancer.
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 medications prescribed range from over-the-counter pain medicine 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 on 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.
"External Beam Radiation Effective in Providing Bone Metasteses Pain Relief. "Medical Devices & Surgical Technology Week November 16, 2003: 137.
—Jane Taylor-Jones, M.S., Research Associate; Teresa G. Odle
