Adjuvant medications Neuropathic pain may be less responsive to standard analgesics alone. Adjuvants, such as antidepressants, anticonvulsants, benzodiazepines, local anesthetics, neuroleptics, psychostimulants, antihistamines, corticosteroids, levodopa(Drug information on levodopa), calcitonin, and bisphosphonates, are useful for particular indications (Table 6). These agents may be administered via oral and other routes. Administration of topical local anesthetics, NSAIDs and other preparations (Table 7), and neurolytic blocks (Table 8) should also be considered.
Surgery for bone metastasis
Surgical intervention is warranted for bone metastases to stabilize a pathologic fracture or preempt an impending fracture. The objectives of surgery are to palliate pain, reduce patient anxiety, improve patient mobility and function, facilitate nursing care, and control local tumors when nonsurgical therapies fail. In general, surgery involves excision of all gross tumor followed by stabilization of the bone before or after fracture by means of an internal fixation or prosthetic device.
Indications No strict criteria have been established for surgical treatment. Clinical parameters, such as the patient’s general medical condition, performance status, nature of the primary tumor, effectiveness of other therapies, extent of extraskeletal disease, and degree of osseous involvement, as well as the patient’s life expectancy, must be considered before surgery.
Fracture and long bone pain In general, the presence of a pathologic fracture, an impending fracture, or a painful lesion in a long bone despite radiotherapy should be considered to be indications for surgery. A pathologic fracture can result from structural insufficiency and can develop in the absence of a viable tumor following treatment with irradiation and/or systemic therapy.
Other considerations Patients deemed to be candidates for surgery should have an expected longevity of > 1 month. All patients should be medically able to withstand the planned surgical procedure. The surgical goals should be achievable with reasonable certainty, and the potential benefits should outweigh the operative risks. All surgical interventions should be performed with the intent to provide benefit that will outlast the patient’s anticipated survival.
Lesion site Major long bones (femur, tibia, and humerus), the vertebrae, and periacetabular regions demand specific attention, as optimal patient function and mobility are predicated on a stable, painless extremity. Osseous destruction sufficient to compromise the mechanical integrity of these bones should be addressed surgically. Lesions in the weight-bearing bones of the lower extremity (femur and tibia) are particularly vulnerable to fracture.
Lesions in the humerus should be treated surgically when the upper extremities serve a weight-bearing function (eg, assisted ambulation using a walker, crutches, or cane). Early surgical intervention, aggressive rehabilitation, and vigilant postoperative surveillance may optimize patient outcome.
Cancer pain can often be relieved by radiation therapy delivered by localized external-beam irradiation (also known as involved-field irradiation), wide-field external-beam irradiation (eg, hemibody irradiation), or systemic treatment with radioactive isotopes (eg, strontium-89 chloride [Metastron], samarium SM 153 lexidronam [Quadramet], phosphorus-32, and iridium-131). Because the most common cause of cancer pain is bone metastasis, this discussion will focus on the use of irradiation in its treatment. Other examples of cancer pain due to primary or metastatic cancer that are amenable to irradiation include headache from CNS involvement, pain due to localized neural involvement (eg, brachial plexus or sciatic nerve), visceral pain (eg, liver or adrenal), pain due to effusions (eg, pericardial or pleural), and pain due to obstruction (eg, urethral, esophageal).
Strontium-89 is a systemic radionuclide that has clinical efficacy in the palliation of pain from bone metastases. Reduction of pain due to bone metastases has been observed most frequently in patients with metastases from prostate cancer.
The primary toxicity of strontium-89 is myelosuppression, particularly thrombocytopenia. Therefore, it should not be administered to patients with thrombocytopenia or significant bone marrow suppression. Strontium-89 levels in bone are regulated much like calcium, and strontium-89 has less hematologic toxicity than phosphorus-32.
Samarium-153 is a β-emitting radioisotope that is bound to a phosphonate that preferentially localizes in active bone, specifically in sites of metastatic disease. Mild-to-moderate myelosuppression was noted in the samarium-153 group, yet use of samarium-153 is associated with a lower incidence and severity of hematologic toxicity than is strontium-89.