Prospective observational study on health resource utilization and patterns of care for skeletal-related events in patients with bone metastases secondary to solid tumors.

Abstract

12052 Background: Bone metastases are a common complication of advanced solid tumors, leading to significant morbidity through skeletal-related events (SREs). This study evaluates health resource utilization (HRU), treatment patterns, and clinical outcomes associated with SREs, with a focus on bone-modifying agents (BMAs) such as zoledronic acid and denosumab. Methods: This single-center, prospective, observational study included 199 patients with bone metastases secondary to solid tumors who experienced at least one SRE. Eligible patients were adults (≥18 years) with an Eastern Cooperative Oncology Group (ECOG) performance status of 0–3. Data collected included demographics, primary cancer type, comorbidities, treatment patterns, type and timing of SREs, and HRU. The impact of BMAs on SRE-free survival and overall survival (OS) was assessed using Kaplan-Meier analysis and multivariate Cox regression models. Results: The median age at the first SRE was 56 years, with 51.8% of patients being female. Breast cancer was the most common primary tumor site (30.2%), followed by genitourinary (22.1%) and gastrointestinal (18.6%) cancers. Visceral metastases were present in 56.3% of patients. Radiation therapy accounted for 80.9% of first SREs, followed by cord compression (8.5%), pathological fractures (7%), and surgical fixation (3.5%). Only 16.5% of patients received BMAs before their first SRE, increasing to 38.2% after the first SRE. Patients who received BMAs before the first SRE had significantly prolonged SRE-free survival (median 9.9 vs. 2.03 months, p = 0.001) and OS (median 45.6 vs. 29.8 months, p = 0.05). Similarly, BMA use after the first SRE improved SRE-free survival (median 18.9 vs. 10.3 months, p < 0.001) and OS (median 25.9 vs. 13.6 months, p = 0.001). The most common BMA-related adverse event was hypocalcemia (44.7%). Conclusions: This study highlights the underutilization of BMAs before the first SRE despite their significant impact on SRE-free survival and OS. Post-SRE BMA use was associated with improved outcomes, underscoring the need for earlier initiation of BMA therapy. Future research should focus on identifying barriers to early BMA utilization, optimizing management of therapy-related complications, and assessing the cost-effectiveness of BMAs in real-world settings.