Hypercalcemia and bone resorption in malignancy.

Hypercalcemia is the most common paraneoplastic syndrome associated with cancer. This paper addresses the etiology and pathogenesis of hypercalcemia of malignancy and discusses the relative contributions of local and humoral effects on bone and renal calcium homeostasis. The roles of parathyroid hormone-related protein and other osteolytic cytokines are outlined. New biochemical markers that enable more specific monitoring of the response of bone metastases to treatment are introduced, including urinary excretion of the collagen crosslinks pyridinoline and deoxypyridinoline. The clinical management and prevention of hypercalcemia is systemically outlined, including indications for bisphosphonate, glucocorticoid, and calcitonin therapy. The results of recent trials of bisphosphonate therapy for the prevention of tumor progression and its subsequent problems such as bone pain, fracture, and hypercalcemia also are discussed.