Clinical Report: Trends and Disparities in Stereotactic Radiosurgery for Brain Metastases (2004–2020)

Overview

This study analyzed National Cancer Database data from 2004 to 2020 to evaluate trends in stereotactic radiosurgery (SRS) versus whole brain radiation therapy (WBRT) for brain metastases (BM). It highlights increasing SRS utilization over time alongside persistent disparities influenced by race, socioeconomic status, insurance coverage, and geographic factors.

Background

Brain metastases affect over 200,000 cancer patients annually in the United States and are associated with significant morbidity and mortality. WBRT has been the traditional treatment but carries risks of neurocognitive toxicity. Since the late 1990s, SRS has emerged as an effective alternative with comparable survival and reduced neurotoxicity, gaining preference especially after 2016. However, disparities in access to SRS remain, influenced by socioeconomic and systemic factors, with marginalized populations less likely to receive this advanced treatment. This study aims to comprehensively assess trends and disparities in SRS utilization using disaggregated racial data and considering Medicaid expansion effects.

Data Highlights

The study utilized the National Cancer Database, capturing over 70% of newly diagnosed US malignancies, including 12 cancer types with brain metastases treated between 2004 and 2020. Patients were categorized by radiotherapy modality: SRS (1–5 fractions) or WBRT (5–15 fractions). Sociodemographic variables included race (disaggregated into seven categories), ethnicity, income, education, insurance status, geographic region, and facility type. The analysis compared SRS versus WBRT utilization trends over time and across demographic groups.

Key Findings

• SRS utilization for brain metastases increased significantly from 2004 to 2020, reflecting evolving clinical practice favoring SRS due to reduced neurotoxicity.
• Disparities persist with patients from racially and ethnically marginalized groups, lower income households, and those without private insurance less likely to receive SRS compared to WBRT.
• Geographic and institutional factors, including Medicaid expansion status and access to academic centers, influence SRS utilization rates.
• Disaggregated racial data revealed heterogeneity within Asian subgroups and other minorities, underscoring the importance of detailed demographic analysis to identify specific disparities.
• Patients from marginalized backgrounds more often present with advanced disease requiring WBRT and face treatment delays, limiting access to SRS.

Clinical Implications

Clinicians should be aware of persistent disparities in access to stereotactic radiosurgery for brain metastases, which may affect patient outcomes and quality of life. Efforts to improve equitable access to SRS, including addressing socioeconomic barriers and expanding specialized treatment availability, are critical. Incorporating detailed demographic data can help tailor interventions to reduce inequities in advanced cancer care.

Conclusion

SRS utilization for brain metastases has increased over the past two decades, yet significant disparities remain across racial, socioeconomic, and geographic lines. Targeted strategies are needed to ensure equitable access to this effective treatment modality.

References

1. National Cancer Database/ACS/2020 -- Comprehensive oncology data source
2. NCCN Guidelines/2020 -- Radiotherapy fractionation standards for brain metastases
3. Affordable Care Act/2010 -- Medicaid expansion and healthcare access