Patients with small cell lung cancer that had spread to the brain lived a median of 17.4 months after focused radiosurgery, compared with 8.6 months after a form of whole-brain radiation, in a phase 3 trial presented Sept. 28 at the American Society for Radiation Oncology (ASTRO) Annual Meeting.
The finding comes with a major caveat. Survival was a secondary goal of the study, and the trial was not designed to prove a survival benefit. Its main question was whether radiosurgery better protected memory and thinking, and on that measure the two treatments showed no significant difference.
For patients and families facing this diagnosis, the result may still change the conversation. Small cell lung cancer has long been an exception in which whole brain radiation remained standard. The trial suggests focused treatment can be a reasonable option for some patients, with decisions made case by case.
Two Treatments for Cancer That Reach the Brain
The NRG-CC009 trial, led by NRG Oncology, enrolled 151 patients from 2021 to 2026, according to the ASTRO release. The release describes it as "the first randomized phase 3 trial to compare the treatment approaches in this population."
Patients were randomly assigned to stereotactic radiosurgery (SRS), which delivers high-dose radiation only to visible tumors, or to hippocampal-avoidant whole-brain radiation plus memantine. That second approach treats the entire brain while sparing the hippocampus, a region important for memory, and adds a drug meant to protect memory and thinking.
Eligible patients had brain tumors no larger than 4 centimeters and a total tumor volume of 30 cubic centimeters or less. The median number of brain metastases was two. The protocol initially limited enrollment to patients with up to 10 metastases, as NRG Oncology announced when the trial opened, but later removed that numerical limit.
Whole brain treatment became standard in small cell lung cancer because of a concern that treating only visible tumors could leave microscopic cancer elsewhere in the brain untreated. The tradeoff is that whole-brain radiation can affect memory and thinking. Radiosurgery avoids most healthy brain tissue, but it usually requires close follow-up scans to catch new spots early.
Memory Results Were Similar, While Survival Differed
Time to cognitive decline, the main endpoint listed on the trial's protocol page, did not differ significantly between groups, with a hazard ratio of 0.83 and a p-value of 0.39, the ASCO Post reported. One reason may be that the whole brain group already received memory-sparing techniques and memantine, which could have narrowed the expected gap.
Median overall survival was 17.4 months with radiosurgery and 8.6 months with whole brain treatment. After adjusting for baseline factors, radiosurgery was associated with a 40% lower risk of death, and the difference was statistically significant.
Cancer progression elsewhere in the brain was lower with whole brain radiation overall, but that difference was not significant after adjustment, News-Medical reported.
Limits That Call for Caution
Because survival was a secondary endpoint, the result should be read as a strong signal rather than proof. The trial was not designed to show a survival difference, and unmeasured differences between groups could have played a role, even though known baseline factors were balanced.
Fewer patients in the whole brain group were available for later cognitive testing, which could complicate the memory results. The findings are also conference data and have not yet been published in a peer-reviewed journal. The ASTRO release said funding was provided by NRG Oncology.
"Patients with small cell lung cancer have largely been left out of the randomized trials that established radiosurgery as a standard treatment for patients with brain metastases," said Charles Simone, chair of ASTRO's Lung Cancer Resource Panel and a radiation oncologist at New York Proton Center and Memorial Sloan Kettering Cancer Center. Simone was not involved in the trial.
The reasons for the survival difference still need study. It is not yet clear whether radiosurgery itself extended life or whether differences in later treatment explain part of the gap.
Doctors Say Patients Now Have More Room to Choose
"Although stereotactic radiosurgery is the preferred treatment for brain metastases caused by most other tumors, small cell lung cancer has been an exception where whole brain radiotherapy has remained standard of care," said Chad Rusthoven, co-principal investigator at the University of Colorado Anschutz School of Medicine.
"Our findings suggest that patients can now have a more individualized discussion about whether focused radiosurgery or whole brain treatment is right for them," he said.
Lead principal investigator Vinai Gondi of Northwestern Medicine said, "Advances in radiation therapy have fundamentally changed the options for patients with brain metastases." He added, "Overall, these results support SRS as a reasonable option for patients with brain metastases from SCLC."
Simone said the study "begins to close that evidence gap and gives clinicians much greater confidence that focused treatment can be a reasonable option for appropriately selected patients."
Patients with small cell lung cancer and brain metastases can ask their team whether radiosurgery fits the number and size of their tumors, how often follow-up brain scans would be needed, and what each approach means for memory, fatigue, and daily life. Families may also want to ask how each option affects the timing of chemotherapy or immunotherapy, and whether a clinical trial is available. New headaches, weakness, seizures, confusion, or vision or speech changes should be reported right away and may need emergency care, because they can signal new or growing tumors.
MedicalDaily will update this report when the NRG-CC009 results are published in full.
Key Questions Answered
What did the NRG-CC009 trial compare?
Focused stereotactic radiosurgery versus memory-sparing whole-brain radiation plus memantine in 151 patients with small-cell lung cancer that spread to the brain.
Did radiosurgery protect memory better?
No significant difference was found in time to cognitive decline, the trial's main goal.
How large was the survival difference?
Median survival was 17.4 months with radiosurgery versus 8.6 months with whole-brain treatment.
Does this prove radiosurgery extends life?
No. Survival was a secondary endpoint, and the trial was not designed to prove a survival benefit.
Who may be a candidate for radiosurgery?
Patients in the trial had brain tumors up to 4 centimeters with limited total tumor volume. A treating team decides eligibility.
Which symptoms need urgent attention?
New headaches, seizures, weakness, confusion, or vision or speech changes should be reported right away.
Published by Medicaldaily.com
