[Evaluation of osteoclastic activity in multiple myeloma: results of a randomized trial studying hypocalcemia induced by human and salmon calcitonin in 49 patients].

Forty-nine subjects have been included in a randomized cross-over study evaluating acute hypocalcemia induced by calcitonin in the staging of multiple myeloma, and comparing 0.5 mg of human calcitonin and 100 IU of salmon calcitonin. Subjects were divided in 11 controls, 15 myelomas before primary treatment, 11 myelomas in plateau-phase and 12 in relapse. All the subjects had both tests with the two calcitonins at an interval of 3 days. Decrease of calcemia was important and similar in patients before primary treatment and in relapse (0.16 mmol/l mean value). Decrease was moderate in patients in plateau-phase (0.07 mmol/l mean value), similar to the decrease observed in controls. Decrease of calcemia was correlated with tumoral cellular mass in initial phase patients, but not in patients in plateau-phase. Both human and salmon calcitonins had similar effects on onset, magnitude and duration of hypocalcemia inside each group. This study confirms the interest of acute hypocalcemia test induced by calcitonin in the clinical staging of myeloma, and the similar effectiveness of both calcitonins in man.