Cancer in the bone may produce osteolysis, osteogenesis, or both. Osteolytic lesions result when the tumor produces substances that can directly elicit bone resorption (vitamin D–like steroids, prostaglandins, or parathyroid hormone–related peptide) or cytokines that can induce the formation of osteoclasts (interleukin 1 and tumor necrosis factor). Osteoblastic lesions result when the tumor produces cytokines that activate osteoblasts. In general, purely osteolytic lesions are best detected by plain radiography, but they may not be apparent until they are 1 cm. These lesions are more commonly associated with hypercalcemia and with the excretion of hydroxyproline-containing peptides indicative of matrix destruction | Chapter 094. Soft Tissue and Bone Sarcomas and Bone Metastases Part 7 Cancer in the bone may produce osteolysis osteogenesis or both. Osteolytic lesions result when the tumor produces substances that can directly elicit bone resorption vitamin D-like steroids prostaglandins or parathyroid hormone-related peptide or cytokines that can induce the formation of osteoclasts interleukin 1 and tumor necrosis factor . Osteoblastic lesions result when the tumor produces cytokines that activate osteoblasts. In general purely osteolytic lesions are best detected by plain radiography but they may not be apparent until they are 1 cm. These lesions are more commonly associated with hypercalcemia and with the excretion of hydroxyproline-containing peptides indicative of matrix destruction. When osteoblastic activity is prominent the lesions may be readily detected using radionuclide bone scanning which is sensitive to new bone formation and the radiographic appearance may show increased bone density or sclerosis. Osteoblastic lesions are associated with higher serum levels of alkaline phosphatase and if extensive may produce hypocalcemia. Although some tumors may produce mainly osteolytic lesions . kidney cancer and others mainly osteoblastic lesions . prostate cancer most metastatic lesions produce both types of lesion and may go through stages where one or the other predominates. In older patients particularly women it may be necessary to distinguish metastatic disease of the spine from osteoporosis. In osteoporosis the cortical bone may be preserved whereas cortical bone destruction is usually noted with metastatic cancer. Metastatic Bone Disease Treatment Treatment of metastatic bone disease depends on the underlying malignancy and the symptoms. Some metastatic bone tumors are curable lymphoma Hodgkin s disease and others are treated with palliative intent. Pain may be relieved by local radiation therapy. Hormonally responsive tumors are responsive to hormone inhibition
