Hypercalcemia of Malignancy

Abstract

Hypercalcemia of malignancy (HCM) is the most common life-threatening metabolic complication of malignancy and affects 10 to 20% of patients with advanced cancer. In oncology units, its incidence varies between 0.5 and 10.9%. In more than half of the patients, it is associated with pulmonary and mammary cancers. In the presence of hypercalcemia, it is important to recognize co-existing conditions, like primary hyperparathyroidism, that could partially explain the elevation of serum calcium. HCM causes a series of symptoms which decrease quality of life. Constipation, nausea and vomiting, confusion and/or stupor, polyuria and polydipsia, as well as bone pain, are specific to HCM. The normalization of calcemia significantly improves all of these symptoms. However, HCM remains largely underdiagnosed in medical practice. Furthermore, specific treatment of HCM in the hospital is usually late, and patients are rarely given adequate rehydration. HCM should be treated as an emergency upon diagnosis. Patients with normalized calcium levels have a better quality of life and are usually able to return home. Treatments for patients with HCM include: (i) rapid rehydration with isotonic saline intravenously; (ii) intravenous bisphosphonates; and (iii) calcitonin in addition to bisphosphonates for patients whose levels of serum calcium are in the life-threatening range (≥4 mmo1/L). The most currently used bisphosphonates are clodronic acid and pamidronic acid; however, the increased convenience of a 15-minute infusion, greater efficacy (∼90%), and longer duration of response (∼30 days) should make zoledronic acid the new standard of treatment for patients with HCM. Corticosteroids are highly effective agents for the treatment of patients with hematological cancer and calcitriol-mediated hypercalcemia. Promising new treatments for patients with HCM include antibodies to parathyroid hormone-related peptide and osteoprotegrin.