2744 - Temporal Trends in Stereotactic Body Radiation Therapy (SBRT) Utilization for Extracranial Metastatic Disease

Purpose/Objective(s): Recommendations regarding stereotactic body radiotherapy (SBRT) to sites of metastatic cancer have evolved over the past decade. The publication of key studies exploring the impact of SBRT on symptom management and the control of oligometastatic disease has impacted practice patterns. The objective of this study is to evaluate the evolution of SBRT utilization for patients with metastatic disease over time.

Materials/Methods: The medical record at an academic center was reviewed to build a database of demographic, disease, and treatment characteristics among patients who received SBRT to extracranial sites of metastatic cancer between 2012-22. The overall cohort was split into three eras: treatment prior to 11/30/16 (Pre-Gomez), 12/1/16-4/30/19 (Gomez to SABR-COMET), and after 5/1/19 (Post-SABR-COMET). Descriptive statistics were performed and chi-square, Fisher’s exact test, and Kruskall-Wallis test were used to compare these three groups. Kaplan-Meier analysis was conducted and log rank test was performed to compare the overall survival (OS) distributions across groups.

Results: 546 patients were included. The number of patients receiving a first course of SBRT for metastatic disease increased from 3.1 patients/month in the Pre-Gomez era to 5.4 patients/month in the latter two eras. Multiple patient characteristics were noted to significantly change across the three eras (Table 1). SBRT for nonwhite patients increased (p=0.011) while treatment of uninsured patients simultaneously decreased across eras (p=0.020). Asymptomatic sites of disease were more commonly treated in the most recent era (p=0.023). Median OS from time of SBRT ranged from 22 to 29 months but did not differ across groups (p=0.679)

Conclusion: Shifts in the utilization of SBRT for metastatic disease included an increasing proportion of nonwhite patients undergoing treatment, increasing private insurance coverage of SBRT, and increased proportion of patients with asymptomatic disease. Characterization of these trends helps to contextualize the utilization of SBRT for metastatic disease in modern practice.

Table 1: Patient characteristics for SBRT to metastatic disease