[Human calcitonin in neoplastic hypercalcemia. Results of a prospective randomized trial]

Forty patients with hypercalcaemia (2.75 to 3.5 mmoles/l) due to bone metastases or to a neoplastic syndrome were treated with synthetic human calcitonin after previous hyperhydration. On entering the study, the patients were allocated at random to either an 0.5 mg dose or a 1 mg dose of the compound administered 6-hourly by the intravenous route. Calcemia was measured every 6 hours: if it became normal, treatment was discontinued 12 hours later, but if after 3 injections the blood calcium level had not been reduced by more than 0.4 mmoles/l, incremental doses of calcitonin were given. Synthetic human calcitonin reduced calcemia by more than 0.4 mmoles/l in 22 patients (group 1) and brought it down to normal value in 18 of these 8 hours on average after the first injection. A new rise in calcemia was observed in 12/18 cases 44 hours on average after treatment was discontinued. Reduction of calcemia by less than 0.4 mmoles/l was observed in 11 patients (group 2). Treatment was ineffective in 7 patients (group 3). There were no significant differences between the 3 groups in mean values and variances of the initial blood calcium levels. Whatever the initial dose of calcitonin, the therapeutic effect was obtained within the first 24 hours of treatment. In patients with incomplete results increasing the dosage did not result in a further reduction of calcemia. No hypocalcaemia was observed. This study confirms that synthetic human calcitonin has a normalizing effect on calcemia. This effect is not dose-dependent, and blood calcium levels rise again after treatment is discontinued.