CNS Surveillance Standards and Practice Gaps in EGFR-Mutated NSCLC

Dr. Nagpal notes that in both breast and lung cancer, consensus on appropriate CNS surveillance frequency remains unclear, despite 35% to 40% of patients with NSCLC eventually developing CNS metastases. Her group's retrospective data in stage 3 lung cancer found that the number needed to scan to detect one asymptomatic brain metastasis was 7, a clinically meaningful yield. Her practice aligns routine brain MRI with systemic imaging for metastatic patients.

A compelling emerging rationale for early surveillance is the potential link between emergency surgical intervention for symptomatic brain metastases and subsequent leptomeningeal disease development. Patients who undergo emergency surgery followed by stereotactic radiosurgery (SRS) may have higher rates of leptomeningeal disease than those who receive SRS first. This argues against allowing patients to become symptomatic before imaging, a practice that was historically less concerning when CNS local control did not clearly affect overall survival but is now reconsidered given these downstream risks.

Practical barriers to regular surveillance include reimbursement limitations and scheduling logistics. Dr. Nagpal anticipates that if surveillance recommendations reach national guideline status, implementation will improve. Both panelists frame standardized CNS surveillance as an important and evolving call to action across the field.