The use of Denosumab for breast cancer patients with bone metastases: experience from a tertiary center

A total of 43 patients suffering from breast cancer with bone metastases were treated with subcutaneous denosumab every 4 weeks within the study period from Jan 2012 to Mar 2014. All patients were given calcium and vitamin D supplement. Their tumor characteristics, exposure to bisphosphonate, control of bone metastases, skeletal related events and side effects from denosumab were retrospectively reviewed. Results: The median age at the time of diagnosis of bone metastases was 51 (range: 30 - 81), and that at the initiation of denosumab was 54 (range: 31 - 81). The proportion of patients with endocrine responsive, HER2 positive and triple negative diseases were 81.4%, 41.9% and 11.6%, respectively. Among them, 67.4% had previous exposure to bisphosphonate, most commonly zoledronic acid. The median duration of treatment with denosumab was 7.4 months (range: 1-26.3). Seven patients died of breast cancer during the study period. The median time to radiological bone progression was not reached yet. Within the study period, 4 patients (9.3%) required palliative radiotherapy to the bone while none of them developed cord compression or required surgery to the bone. No clinically significant hypocalcaemia or deterioration of renal function was noted. One patient was found to have grade 2 osteonecrosis of jaw after 5 months of denosumab. Conclusion: Denosumab is commonly used for patients who suffer from breast cancer with bone metastases. Side effect was infrequent but high clinical alertness should be maintained