Brain MRIs Instead of Preventive Radiation Better Protected Memory in Small Cell Lung Cancer

For decades, many people with small cell lung cancer (SCLC) have been offered prophylactic cranial irradiation (PCI): radiation to the whole brain to prevent the cancer from spreading there. It can lower the risk of brain metastases, but it can also affect memory and thinking.

In a phase 3 trial presented Sept. 12, 2026, at the International Association for the Study of Lung Cancer (IASLC) World Conference on Lung Cancer, people who had regular brain MRIs instead of PCI kept their memory and thinking intact longer. The results have not yet been published in a peer-reviewed journal.

What the MAVERICK Trial Tested

The SWOG S1827 MAVERICK trial enrolled 304 people with limited-stage or extensive-stage SCLC whose cancer had not spread to the brain after their first treatment. They were randomly assigned to either:

• regular brain MRIs alone, or
• regular brain MRIs plus PCI.

MRIs were scheduled about every three months in the first year and every six months in the second.

What It Found

The main goal was cognitive failure-free survival: how long people lived without a meaningful decline in memory or thinking. After a median follow-up of 22 months, people who had MRI surveillance alone had a 40% lower risk of cognitive decline or death than those who also received PCI. The benefit held for both limited-stage and extensive-stage disease, and regardless of whether patients received immunotherapy.

There was no clear difference in overall survival between the two groups so far. The final survival analysis has not been reported.

Study presenter Dr. Chad Rusthoven of the University of Colorado School of Medicine said in the IASLC news release that the results support MRI surveillance alone as the standard of care for SCLC.

The Trade-Offs

Skipping PCI isn't risk-free. Brain metastases were more common in the MRI-only group, which is why the MRI schedule matters: the goal is to find any spread early, when it can be treated with focused radiation. Keeping up with frequent MRIs can be hard for people who live far from a cancer center.

Questions to Ask Your Care Team

• Based on these results, do you recommend PCI or MRI surveillance for me?
• How often would I need brain MRIs, and where can I get them?
• If cancer shows up in my brain, how would it be treated?
• What memory or thinking changes should I report?

References

1. "Phase III MAVERICK Trial Supports Brain MRI Surveillance Alone as Standard of Care for Small-Cell Lung Cancer." International Association for the Study of Lung Cancer. Sept. 12, 2026.
2. "S1827 (MAVERICK)." SWOG Cancer Research Network. ClinicalTrials.gov, NCT04155034.

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