CT is more specific than bone scan and can distinguish between osteolytic and osteoblastic lesions. MRI is the most sensitive method of detection bone metastases because cells can spotted before local bone reaction has occurred. Metastatic bone lesions can be described as osteolytic, osteoblastic and mixed. The osteolytic lesions are most common where the destructive processes outstrip the laying down of new bone. New treatments with medicines that may block bone lysis by tumor cells are currently in clinical trials.
Osteoblastic lesions result from new bone growth that is stimulated by the tumor.
Microscopically, most lesions are mixed. Treatment for bone metastasis is normally palliative. An assessment of the risk of pathological fracture must be made by an experienced orthopaedic surgeon. Lesions that do not represent a risk for fracture may be treated with radiation or by appropriate chemotherapy directed at the tumor. Lesions that are regarded as a risk for pathologic fracture should be surgically stabilized on an elective basis before a fracture occurs.