Antiresorptive Therapy Use in Patients with Skeletal Metastases – Are We Under Prescribing?

Purpose: Antiresorptive therapy (AT) reduces risk of pathologic fractures (PF) in patients with osseous metastases (OM). Recent data show AT is prescribed to only 7.7% of patients with OM, suggesting under-prescription. This study aims to determine rates of AT use and PF in patients with OM using Epic’s comprehensive, practice-based database “COSMOS,” and to identify patient factors associated with AT use and PF. Methods: A retrospective review was conducted using “COSMOS” to identify patients diagnosed with OM from January 2005 to July 2022 with minimum two-year follow-up. Cox proportional hazards regression models were used to identify factors associated with AT use and risk of PF. Results: Of 678,073 patients included, AT was prescribed for 13.9%. 10.8% sustained PF, of whom 17.38% received AT before or after fracture and 82.6% never received AT. Age 25–34 and primary lymphoma patients were less likely to receive AT (p <.001). Risk of PF was higher for age 25–34 (HR 2.00, p <0.001), primary renal cancer and multiple myeloma (HRs 1.75 and 1.70, p <0.001), and lower for males (HR .89, p <.001) and primary prostate cancer (HR .69, p <.001). Modeling suggests that up to 35.5% of fractures may be preventable through universal use of AT. Conclusions: AT is prescribed at a lower-than-expected rate given its known efficacy in reducing PF risk in patients with OM. Younger age, female gender, primary renal cancer and multiple myeloma are associated with increased fracture risk, with implications for optimizing patient selection for AT.