Real-life use of denosumab 120 mg every 12 weeks in prolonged treatment over 2 years of patients with breast cancer bone metastases

Purpose: To analyze the activity and safety of denosumab (DNS) 120 mg every 3 months over 2 years of standard treatment (120 mg SC every 4 weeks) of patients with breast cancer bone metastases in real life. Methods: We prospectively analyzed the activity and safety of denosumab 120 mg every 3 months and 120 mg every 4 weeks in the treatment of 22 patients with breast cancer bone metastases over 2 years of standard treatment. All patients received specific concomitant antineoplastic treatment, chemotherapy or endocrine therapy and/or target therapy. Oral daily calcium (≥500 mg) and vitamin D (≥1000 U) supplement was recommended. Results: Of the 22 patients treated with denosumab, 4 (18.1%) had at least 1 skeletal related event (SRE); 3 (13.6%) had 1 SRE and 1 patient (4.5%) had 2 SRE, all 10% treated with radiotherapy. Overall, no denosumab-related G3 adverse events occurred; in particular, no cases of osteonecrosis of the jaw have been recorded. The decrease in serum calcium levels was mild (G1, 2 patients, 9%), and recovered in a short time (within 2 weeks) with an increase in the oral support of calcium and vitamin D. Conclusions: Denosumab confirms a good activity profile in terms of delaying and preventing SREs in breast cancer patients and a good safety profile. It represents an optimal treatment resource which doesn’t necessitate renal function monitoring and has the convenience of a subcutaneous administration.