While there is clear evidence that denosumab prevent skeletal-related events in patients with malignant bone metastasis, there are concerns that it may be associated with atypical femoral fracture (AFF). AFF in osteoporotic patients receiving denosumab is reported, but few data have been reported in the context of monthly denosmab therapy for patients with malignant tumor and bone metastasis.
We reviewed the medical records and pharmacy database of patients who received denosumab at 120mg monthly for management of bone metastasis from May 2012 to March 2017 at our institution to analyze the incidence of AFF. To review the clinical courses of the patients who diagnosed AFF, we reviewed the clinical features and skeletal images of the patients.
We analyzed the data of 204 patients receiving a median of 7 doses (range; 1-60) of denosumab, and 150 (74%) patients received more than three times of denosumab. Three patients (1.5%, 95% confidence interval: 0.39-2.6) were diagnosed as AFF and performed intramedullary nail fixation, one case diagnosed of atypical femoral stress reaction (AFSR) with surgical indication. Three patients with AFF received 44, 45, and 45 doses of denosumab, and one patient with AFSR received 15 doses. Median age of the four patients was 59 (range; 50-66), and primary disease were breast cancer in three patients and non-small cell lung cancer in one patient.
We experienced three AFF events among 204 patients receiving denosumab 120mg monthly and incident rate was 1.5%. More data are needed about the occurrence of AFF in these patients.
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T. Takano: The author receives honorarium from Daiichi Sankyo Company
All other authors have declared no conflicts of interest.