CNS Downstaging: An Emerging Treatment Paradigm for Extensive Brain Metastases in Oncogene-Addicted Lung Cancer

Area of Science:

• Oncology
• Neurology
• Radiotherapy

Background:

• Extensive brain metastases (BrM) in oncogene-addicted non-small cell lung cancer (NSCLC) present significant treatment challenges.
• Traditional treatment often involves whole-brain radiotherapy (WBRT), which can lead to neurocognitive deficits.
• Emerging CNS-active tyrosine kinase inhibitors (TKIs) offer potential for targeted intracranial disease control.

Purpose of the Study:

• To evaluate the efficacy of upfront CNS-active TKIs in downstaging extensive BrM in ALK, EGFR, and ROS1-driven NSCLC.
• To assess the potential to avoid upfront WBRT and identify candidates for focal stereotactic radiosurgery (SRS).

Main Methods:

• Retrospective analysis of 12 patients with extensive BrM ( > 10 BrMs or leptomeningeal disease) treated with upfront newer generation CNS-active TKIs (osimertinib, alectinib, brigatinib, lorlatinib, entrectinib) from 2012-2021.
• BrM volume and number were assessed at baseline, nadir, and first CNS progression.
• Modified-RECIST criteria were used to evaluate CNS response.

Main Results:

• Eleven of twelve patients (91.7%) achieved a CNS response, with a median 91.7% reduction in BrM number and 96.5% reduction in BrM volume at nadir.
• Median overall survival was 43.2 months from TKI initiation.
• Seven patients (58.3%) received salvage SRS, and none received salvage WBRT.

Conclusions:

• Upfront CNS-active TKIs demonstrate significant CNS downstaging in extensive BrM from oncogene-addicted NSCLC.
• This approach represents a promising multidisciplinary paradigm to potentially avoid upfront WBRT and enable SRS.
• Further investigation is warranted to confirm these findings in larger cohorts.