Patterns of treatment (tx) with bone-modifying agents (BMA) in patients with bone metastases (mets).

e20690 Background: Bone mets can lead to serious and debilitating skeletal-related events (SREs: fracture, spinal cord compression, and surgery or radiation to bone). Three BMAs are approved in the US for prevention of SREs in cancer patients (pts) with bone mets: 2 intravenous bisphosphonates (IV BP) with recommended dosing every 3-4 weeks (pamidronate [PAM] and zoledronic acid [ZA]), and 1 RANK ligand inhibitor with subcutaneous injection every 4 weeks (denosumab). Monitoring real-world tx trends is important, particularly as low persistence has been linked to higher rates of SREs (Hatoum et al 2008). Methods: A retrospective cohort was defined from the Oncology Services Comprehensive Electronic Records (OSCER) database, which includes medical records from >500K pts treated at 76 US oncology practices. Adult solid tumor pts with bone mets who initiated tx with a BMA between Jan 2011 and Oct 2011 were included and followed for 12 mos after tx initiation. Pts were either naive (no BMA in previous 6 mos) o...