MRI Surveillance Improves Cognitive Outcomes in SCLC: WCLC 2026

PROPHYLACTIC cranial irradiation (PCI) was associated with poorer cognitive failure free survival (CFFS) than MRI surveillance alone in patients with small-cell lung cancer (SCLC), while preliminary overall survival (OS) data showed no significant difference between strategies. This data was presented at the IASLC 2026 World Conference on Lung Cancer.

Study Design and Patient Population

An international phase III trial evaluated whether regular brain MRI surveillance could provide better cognitive outcomes than MRI surveillance combined with PCI. The study enrolled patients with limited-stage or extensive-stage SCLC who had completed initial treatment and had no brain metastases (BM) on MRI before enrolment.

A total of 304 patients were randomly assigned between January 2020 and December 2025, with 68% having limited-stage disease. Patients underwent MRI every 3 months during the first year and every 6 months during the second year. Cognitive function was assessed at the same intervals using three established tests covering verbal learning, verbal fluency and executive function.

MRI Surveillance Improves Cognitive Outcomes

The primary analysis found that MRI surveillance alone was associated with improved CFFS compared with MRI surveillance plus PCI (hazard ratio (HR): 0.60; 90% CI: 0.46–0.78; p=0.001). CFFS was defined as the time to either cognitive failure on any test or death.

The observed benefit was consistent across disease stage, with no significant interaction between limited-stage and extensive-stage disease (interaction p=0.92). Receipt of immunotherapy also did not significantly alter the association (interaction p=0.25).

Preliminary OS data, based on 128 deaths, showed no significant difference between the groups (HR: 0.90; 90% CI: 0.67–1.20). BM-free survival was also not significantly different (HR: 1.25; 90% CI: 0.95–1.66).

Clinical Implications For SCLC

Treatment-related grade 3–5 adverse events occurred less frequently with MRI surveillance alone than with MRI surveillance plus PCI: 0.8% versus 7.9%, respectively (p=0.004). One grade 5 encephalopathy occurred in the PCI arm.

With a median follow-up of 22 months among living patients, the investigators concluded that MRI surveillance alone improved CFFS without an observed decline in OS. The final OS analysis is planned after 190 deaths.

The findings supported MRI surveillance alone as the standard of care for patients with SCLC, including those with both limited-stage and extensive-stage disease.

Reference

Rushthoven CG et al. PL02.01SWOG S1827 MAVERICK: Phase III Trial of Brain MRI Surveillance +/- Prophylactic Cranial Irradiation for Small-Cell Lung Cancer. Abstract PL02.01. WCLC Congress; September 12-15 2026.