[Necessity of Serum Calcium Concentration Measurement for Investigating Hypocalcemia Induced by Denosumab].

Denosumab is widely used for treating bone metastases in patients with advanced cancer. However, hypocalcemia has been reported as a serious adverse effect during this treatment. Therefore, monitoring serum calcium concentration is essential. During long-term continuous administration ofdenosumab, the burden ofeach blood sampling occasion and medical economics should be clarified; however, the appropriate blood sampling frequency has not yet been confirmed. In the present study, we performed a retrospective investigation of serum calcium concentration after denosumab administration. The results indicated that serum calcium concentration tended to increase with repeated administration. A significant increase was observed at the time ofthe third and sixth administration. This suggested that it was possible to reduce the frequency ofblood sampling during long-term administration ofdenosumab with appropriate calcium supplementation.