Science1 publisher2 min readPublished
Radiosurgery doubled median survival over whole-brain radiotherapy in a small cell lung cancer trial
NRG-CC009 found median survival of 17.4 months with radiosurgery versus 8.6 with whole-brain radiotherapy for small cell lung cancer brain metastases. Cognition, the primary endpoint, did not differ significantly, so radiosurgery's case here rests on survival.
The Scientist · Science desk
Drafted by a language model from the sources cited here and checked against its claim ledger before publication. How we use AISend a correction
What happened
- After adjusting for patient and disease characteristics, radiosurgery was associated with a 40% lower risk of death than whole-brain treatment.
- Rates of serious treatment-related side effects and of death from neurologic causes were similar in the two groups.
- Patients had a median of two metastases, though some entered the trial with more than 20.
Compiled by The ScientistSomething wrong?How this is made
Why it matters
- decision For small cell lung cancer brain metastases, choosing between radiosurgery and modern whole-brain treatment now turns on survival, since this trial found no memory advantage for either option.
- precedent Small cell lung cancer was the main holdout from radiosurgery-first practice for brain metastases, and this first phase III result gives guideline writers a basis to remove the exception.
- exposure If the survival gap reproduces in later trials, patients still sent to whole-brain radiotherapy by default for this cancer are the group giving up months of life.
Chad Rusthoven of the University of Colorado Anschutz School of Medicine presented the trial at ASTRO 2026 in Boston [1][5]. It used a demanding comparator. Rusthoven noted that recent advances have improved outcomes for patients receiving whole-brain radiotherapy [6]. "This includes addition of memantine [a drug that helps protect cognitive function], as well as hippocampal avoidance techniques," he said [7]. "As a result, HA-WBRT plus memantine is now the preferred whole-brain treatment strategy for cognitive preservation." [8]
That comparator changes what the cognition result means. Earlier randomized trials showed radiosurgery preserved cognition and quality of life better than conventional whole-brain radiotherapy, in which the entire brain is irradiated to reach visible tumours and microscopic disease [3]. The idea that radiosurgery better protects thinking and memory comes from those comparisons [3]. Against hippocampal avoidance plus memantine, NRG-CC009 found no significant difference in time to cognitive decline, its primary endpoint [11].
Survival is where the trial surprised. Median survival on radiosurgery ran 8.8 months longer [1], about twice the whole-brain figure [2]. The historical objection to radiosurgery alone in this cancer pointed the other way: the concern that omitting whole-brain treatment would lead to worse survival [16]. Rusthoven said the result "addresses a fundamental historical objection to SRS alone for small cell lung cancer brain metastases" [15].
The thing this doesn't tell you is why patients lived longer while their cognitive outcomes did not differ. Survival was not the primary endpoint [11]. The 40% reduction in risk of death is an estimate adjusted for patient and disease characteristics [13], and it comes from 151 patients [9].
I think Rusthoven's own wording fits the evidence. "Overall these findings support SRS as a treatment option for patients with brain metastases from small cell lung cancer," he said [17]. For most cancers, radiosurgery is already the preferred approach [2], and small cell lung cancer has been the exception where whole-brain radiotherapy stayed standard [4]. I would want a second randomized trial to reproduce the survival gap before calling that exception closed.
A second trial at the same briefing took up a different radiosurgery question. Ayal Aizer of Mass General Brigham/Dana-Farber Cancer Institute explained how fractionated radiosurgery can reduce recurrence after surgery for large brain metastases without significantly increasing side effects [18]. Fractionation divides the dose into several treatments, so healthy tissue can recover between them [19]. Current guidelines recommend radiosurgery to the surgical cavity [20]. "In both of these trials where single-fraction SRS was utilized, the one-year surgical bed recurrence rates were high: 40% in one trial, 28% in the other," Aizer said [21]. He described results from Alliance A071801, a randomized trial [22].
What to watch
- Full peer-reviewed publication of NRG-CC009 with confidence intervals and unadjusted survival estimates.
- Whether treatment guidelines for small cell lung cancer brain metastases add radiosurgery alone as an accepted option.
- Detailed Alliance A071801 recurrence results for fractionated radiosurgery to the surgical cavity.