Incorporating an NCCN-Based Systemic Therapy CNS Activity Score Into SRS Decision-Making for Patients With 5 or More...

Area of Science:

• Neurosurgery
• Radiation Oncology
• Medical Oncology

Background:

• Historically, stereotactic radiosurgery (SRS) was limited for patients with 5 or more brain metastases (BM).
• Modern advancements necessitate reevaluation of BM management strategies, including SRS for multiple lesions.
• The study addresses the evolving role of SRS in managing a higher burden of brain metastases.

Purpose of the Study:

• To compare overall survival (OS) between patients receiving SRS for 5-9 BMs versus ≥10 BMs.
• To identify prognostic factors associated with favorable outcomes in patients with multiple BMs treated with SRS.
• To evaluate the impact of lesion number on survival after SRS for ≥5 BMs.

Main Methods:

• Retrospective analysis of 557 patients with ≥5 BMs treated with Gamma Knife surgery between 2015-2022.
• Exclusion of patients with prior central nervous system (CNS) radiation.
• Assessment of outcomes including OS, whole-brain radiation therapy-free survival (WBRT-FS), and CNS progression-free survival (CNS-PFS).

Main Results:

• Median OS was 11.0 months and did not significantly differ between patients with 5-9 BMs (n=440) and ≥10 BMs (n=117).
• Multivariable analysis identified good performance status and post-SRS CNS-active systemic therapy as predictors of improved OS.
• Lesion number was not associated with OS; a nomogram for WBRT-FS prediction demonstrated good performance.

Conclusions:

• The number of brain metastases (≥5) does not impact overall survival following SRS.
• Favorable outcomes are associated with good performance status, CNS-active systemic therapy, and stable systemic disease.
• A publicly available nomogram can aid in patient-specific treatment decisions for multiple BMs.