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Background and purpose: Pathologic and impending fractures occur in patients with advanced metastatic disease and necessitate surgical interventions with high risk of complications. The aim of this study was to analyze the efficacy of combined treatment with denosumab and radiotherapy as an alternative to surgery in treating bone metastases of the pelvis and extremities.

Methods: This retrospective cohort study included 38 patients with impending and pathologic fractures due to carcinoma metastases who received monthly injections of denosumab (120 mg/dose) and radiotherapy. Twenty-three patients received denosumab and single-dose radiotherapy of 8 Gy, and 15 patients received denosumab and fractionated radiotherapy. We assessed pain, radiographic signs of fracture healing, survival and complications.

Results: Of the 38 patients 36 experienced pain reduction. Callus formation was observed in 11/17 patients with pathologic fractures, and increased mineralization was found in 12/21 patients with impending fractures. In 23/38 patients, we found both pain reduction and callus formation or increased mineralization. There were no statistically significant differences in treatment outcomes between the patients who received denosumab and single-dose radiotherapy and those who received denosumab and fractionated radiotherapy. The survival rates at 30 days and 1 year were 95% and 56%, respectively.

Interpretation: Combined treatment with denosumab and radiotherapy may reduce pain and promote bone healing in patients with metastatic impending and pathologic fractures. In this combined treatment, the effect of single-dose radiotherapy appears to be comparable to that of fractionated regimens.