Severe and prolonged hypocalcemia after a single dose of denosumab for metastatic breast cancer with diffuse bone involvement without prior calcium/vitamin D supplementations.

Several cases of severe hypocalcemia associated with denosumab have been reported. However, to the authors' knowledge, this is the first report that highlights the importance of early vitamin D/calcium supplementations for a patient with diffuse metastatic bone disease with pre-existing low levels of calcium.