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Pain is the principal symptom of bone metastases. It is composed of a biologic and a mechanical aspect. The biologic component reflects the rate of tumor growth and biologic characteristics of the tumor. The increased blood flow and cytokines are important causes of bone pain and contribute to bone lysis. Finally, nerves within bone have recently been described; these transmit many neuropeptides such as substance P and calcitonin gene-related protein, which are involved in both pain modulation and bone cancer.
Bone loss reduces bone strength and stiffness, increases strain, and leads to activity-related symptoms: so-called "mechanical bone pain." Pain from mechanical insufficiency often increases after a treatment reduces turgor within the tumor. Bone collapse and even dislocation can then occur.
The initial pain pattern of a metastasis mimics that of primary bone cancer and osteonecrosis. The symptoms are intermittent but may be sharp and severe. Pain tends to be worst at night.
General systemic issues are of concern in patients with skeletal metastases. Bed rest or reduced activity is frequently recommended for the bone pain of skeletal metastases.Pain relief and bone stabilization are the methods by which the medical goals of patient comfort and independence are achieved for bone cancer. Symptomatic relief is usually satisfactory from radiation therapy and chemotherapy. Most patients without a fracture do not require surgery for the bone cancer. Fractures are best treated by operative internal fixation.
Lung, colorectal, and melanoma tumors failed to heal. These lesions tended to occur late in the course of disease and were purely lytic. Multiple myeloma and breast and kidney cancers healed most frequently. These lesion often occurred early in the course of disease when patients had more therapeutic options available. Bone formation and reossification were often seen in these cases.
Rigid internal fixation supplemented with bone cement increases the probability of bone union. Alignment and position of bone fragments are also important as in the case of nonpathologic fractures. Bone cement not only contributes to stability but may present a mechanical obstacle to tumor regrowth in the fracture region.
Longer survival occurred in patients with earlier or more slowly progressing disease. This correlated with improved healing rates for patients living longer than 6 months.
High doses (greater than 3000 cGy) were associated with poor healing.
There were no data regarding the impact of chemotherapy of healing in this series.
Chemotherapy for bone cancer effects in animal models are difficult to extrapolate to the human condition because of the variation in dose intensity and treatment scheduling. Most studies suggest that healing is reduced 50% by common agents such as methotrexate or doxorubicin.
Other systemic factors may make a minor contribution to fracture healing. For example, osteoporosis, hormone manipulation, cachexia, and other factors may be important. Newly released bisphosphonates reportedly benefit bone healing in experimental animal models. These agents have not been shown to
Although most surgeons and patients choose internal fixation of fractures as the most effective and expedient way to control pain and restore function, external fixation is occasionally successful. It is particularly suitable for (1) patients with extensive localized disease that cannot be immobilized by