Etiology and current management of cancer-related hypercalcemia

Important new information has been gained concerning the etiology of cancer-related hypercalcemia and thus treatment recommendations are changing. The most common cause of hypercalcemia in cancer patients is the parathyroid hormone-like peptide, PTH-RP. Patients with elevated serum calcium due to elaboration of parathyroid hormone-like peptide commonly present with hypophosphatemia and a relatively resistant form of hypercalcemia. Our new knowledge has led to recommendations against massive amounts of IV fluids and large doses of diuretics, which restore normocalcemia in only a minority of patients. New potent drugs such as pamidronate and gallium nitrate directly inhibit accelerated bone resorption. Thus, consideration should be given to the early administration of antiresorptive drugs immediately after intravascular volume has been repleted and urinary output has been established.