Response is associated with elevated serum calcium. Patients who develop hypercalcemia in this setting should be treated with intravenous fluids and, in some cases, plicamycin. The hormonal agent may be withheld during the acute hypercalcemia but reinstituted once the calcium normalizes. Bone metastases usually are caused by hematogenous spread of malignant cells. Direct extension of a tumor into bone and lymphatic spread occur less frequently.
Bone metastases are usually multiple.
Patients with advanced, metastatic solid tumors who develop multiple metastases on bone scan in a characteristic distribution do not need histologic confirmation. Some patients will have achieved long-term remission of a malignancy and present with multiple bone scan abnormalities and no obvious extraosseous tumor. Generally such patients should undergo biopsies to differentiate recurrence versus a second, possibly more treatable, malignancy. In addition, bisphosphonates have been shown to promote healing and lessen pain in patients with osteolytic metastases. Radioisotopes such as strontium-89 have been shown to decrease pain in patients with osteoblastic metastases resulting from prostate cancer.