Pathophysiology of Skeletal Complications of Cancer

Tumors frequently affect the skeleton and alter the function of normal bone cells. In most patients, they increase the activity and probably the formation of bone-resorbing osteoclasts. The result is a destructive or osteolytic bone lesion. Occasionally they lead to an increase in activation of osteoblasts or bone-forming cells. In a relatively small number of patients, this increase in osteoblastic activity is profound and the result is an area of newly formed bone around the tumor cell deposit which can be detected radiologically and is referred to as an osteoblastic or sclerotic metastasis. In this chapter, we plan to review what is known of the mechanisms responsible for development of osteolytic and osteoblastic bone lesions.