Clinical Parameters Associated With Intracranial Progression Burden Following an Initial Stereotactic Radiosurgery...

Area of Science:

• Neuro-oncology
• Radiation Oncology
• Medical Oncology

Background:

• Stereotactic radiosurgery (SRS) is a common treatment for brain metastases (BMs).
• Predicting high-burden intracranial progression (ICP) after SRS, which may necessitate whole brain radiation, requires further investigation.
• Understanding risk factors can guide treatment decisions and improve patient outcomes.

Purpose of the Study:

• To identify clinical parameters associated with high-burden ICP (defined as ≥5 or ≥11 new BMs) after initial SRS.
• To evaluate the impact of these factors on overall survival (OS) and freedom from ICP.

Main Methods:

• Retrospective analysis of 1383 patients who underwent SRS across two institutions (January 2015 - December 2020).
• ICP was defined as radiographic evidence of distant and/or in-field progression.
• Kaplan-Meier method estimated OS and freedom from ICP; Cox models assessed predictive factors for ICP5 and ICP11.

Main Results:

• 40.1% of patients experienced post-SRS ICP.
• High-burden ICP was associated with decreased 12-month OS (38.7% for ≥11 BMs) and increased neurologic symptoms (50.0% for ≥11 BMs).
• Negative predictive factors for high-burden ICP included oligometastatic disease at SRS, receipt of post-SRS immunotherapy, and a single BM at initial SRS.

Conclusions:

• High-burden ICP significantly impacts survival and neurological status.
• Oligometastatic disease, post-SRS immunotherapy, and single initial BM are associated with improved freedom from high-burden ICP.
• Findings may support considering upfront whole brain radiation for high-risk patients and warrant prospective surveillance studies.