Studies of Calcium Metabolism in Multiple Myeloma with Calcium 47 and Metabolic - Balance Techniques

Despite the fact that approximately 90% of patients with multiple myeloma present themselves with skeletal complaints (1, 2), few studies of bone mineral metabolism in this disease have been reported. Stable calcium studies in multiple myeloma were first reported in the literature by Blatherwick (3) in 1916. Since that time there have been only infrequent reports using balance techniques, or isotopic-tracer methods, or both. Adams, Mason, and Bassett (4) used metabolicbalance techniques to investigate the influence of ACTH on mineral metabolism in three patients with multiple myeloma. Case studies of one or two patients using tracer methods and balance techniques have been reported by Anderson, Emery, McAllister, and Osborn (5), after a therapeutic dose of Ca45; by Spencer, Li, Samachson, and Laszlo (6), who have studied the comparative excretion and retention of Sr85 and Ca45; and recently, by Skoog, Adams, and MacDonald (7), who have reported balance and Sr85-tracer studies in a patient with multiple myeloma treated with various combination of hormones. The study of calcium metabolism in multiple myeloma is of great interest, since diffuse osteoporosis, or osteolytic lesions, or both, are most always present, and hypercalcemia is a frequent (8) but poorly understood complication. With the increasing availability of clinically suitable radioactive isotopes of calcium, calcium-balance measurements can now be supplemented with kinetic-tracer studies. Stable calcium-balance studies alone measure only the net difference between bone formation and resorption. With Ca47tracer studies in addition to balance techniques, calcium absorption, endogenous fecal calcium, exchangeable or miscible calcium, and miscible cal-