Hypercalcaemia in patients with advanced mammary cancer.

Hypercalcaemia and hypercalciuria are common complications of advanced mammary cancer. Of 127 patients with the disease 63 (49.5%) had some abnormality of calcium balance. Eighteen (14%) of these patients developed severe progressive hypercalcaemia and became acutely ill.Most patients had skeletal metastases, and the usual cause of hypercalcaemia was rapid destruction of bone by the cancer. One patient with severe uncontrollable hypercalcaemia and minimal skeletal involvement probably developed the complication due to inappropriate secretion of a parathyroid-hormone-like substance by massive hepatic deposits.Severe hypercalcaemia was controlled successfully in 13 of the 18 patients, the serum calcium levels returning to normal and the acute symptoms disappearing. Unfortunately, successful correction of the hypercalcaemia rarely was followed by prolonged survival from the underlying malignant disease. The incidence of subsequent objective response to pituitary ablation was less than usual, and only three patients survived for more than one year after the episode of hypercalcaemia.