Acute effects of salmon calcitonin in multiple myeloma: a valuable method for serial evaluation of osteoclastic lesions and disease activity--a prospective study of 125 patients.

Hypocalcemia induced by salmon calcitonin (SCT) was evaluated in 125 patients with multiple myeloma (MM) and compared with 20 normal individuals (NCs) and 20 individuals with monoclonal gammopathy of undetermined significance (MGUS). It is now well documented that the maximum hypocalcemia (M delta CA) induced in man by SCT is related to the prevailing rate of osteoclastic resorption. In patients with MGUS, the level of M delta CA was normal. Conversely, the M delta CA was significantly abnormal in patients with MM (P less than .0001 for differences between NC/MGUS patients) and was correlated with (1) initial calcium levels (P less than .001), (2) the extent of lytic bone lesions (LBLs) (P less than .01), and (3) the myeloma cell mass (P less than .001) plus disease activity. The M delta CA was found to be of predictive value for new LBLs with or without hypercalcemia and to have dramatic influence on the survival of patients with MM. We conclude that the SCT-induced hypocalcemia test is of significant importance in the evaluation of the instantaneous rate of bone resorption and in the prognosis of patients with MM.