Calcium excretion (CaE) in metastatic breast cancer

Abstract

In 51 women with metastatic breast cancer calcium excretion per litre of glomerular filtrate (Ca_E) values were persistently higher in those with bone secondaries than in those with only soft tissue involvement despite a normal range of serum calcium in both groups. Measurement of Ca_E in 8 further patients who were severely hypercalcaemic as a result of their advanced breast cancer revealed the degree to which calcium resorption from bone secondaries and renal dysfunction contributed to the hypercalcaemia. Thus, in patients with breast cancer, Ca_E provides a reliable indicator of early changes of calcium homeostasis. It may provide an objective indication of progression of bone secondaries and also has important therapeutic implications in established hypercalcaemia.