Use and safety of denosumab in cancer patients

Background Few data have been reported on the use and safety of denosumab in patients with solid tumors and bone metastasis in clinical practice. Objectives To describe the use of denosumab and to analyze its adverse effects (AE) in tertiary hospital cancer outpatients. Methods Retrospective study of patients who started denosumab between January 2013 and June 2015. We recorded demographic, clinical, and treatment-related variables, as well as the reasons for discontinuation and AE. Results The study population comprised 104 patients, of whom 86 (82.7%) were receiving concomitant outpatient cancer treatment and 39 (38%) had previously received zoledronate. At baseline, albumin-corrected calcium levels were available for 48 patients (46.2%), and 70 (67.3%) were receiving calcium/vitamin D supplements. The median number of denosumab doses was 7.5 (range, 1–29). The main reasons for treatment discontinuation were disease progression (20.2%) and AE (25%). Hypocalcaemia was recorded in 38.5% of patients and osteonecrosis of the jaw in 12.5%. Monitoring of calcium levels was poor at baseline and during follow-up. Conclusions We found a higher incidence of all-grade osteonecrosis of the jaw than reported in the literature. Adherence to published recommendations on calcium supplementation and guidelines on calcium monitoring was poor. In line with our findings, a protocol for use and monitoring of denosumab has been promoted in our hospital.