KEY POINTS
- This single-center retrospective study included 337 patients with SCLC brain metastases treated between 2019 and 2026: 95 received stereotactic radiotherapy, 181 WBRT alone and 61 WBRT plus a focal boost. Median age was 63 years, and 307 patients were male.
- Treatment selection was clearly non-random. Before matching, only 20% of the SRT group had more than three brain metastases compared with 49.7% receiving WBRT, while extracranial metastases were present in 46.3% versus 68.5%, respectively—important imbalances favoring the SRT population.
- Most patients receiving WBRT ± boost were treated with 30 Gy in 10 fractions. SRT was predominantly delivered in 2–5 fractions, generally using total doses of 15–35 Gy, while the boost strategy used either simultaneous or sequential focal dose escalation.
- Before adjustment, SRT appeared superior to WBRT, with median overall survival of 13.47 versus 8.27 months (p=0.013). After 1:1 propensity matching, that apparent advantage disappeared: survival was 11.77 versus 8.70 months (p=0.412), and adjusted analysis likewise showed no significant benefit (HR 0.70, 95% CI 0.39–1.27; p=0.241).
- Intracranial progression-free survival was also similar between matched SRT and WBRT cohorts at 5.47 versus 6.30 months (p=0.582). Against SRT, WBRT plus boost produced a longer unadjusted matched intracranial progression-free interval of 8.17 versus 5.87 months (p=0.021).
- That WBRT-plus-boost signal is considerably weaker than the headline p-value suggests. Stratified Cox analysis no longer showed a significant association (HR 1.27, 95% CI 0.64–2.49; p=0.494), and Rosenbaum sensitivity analysis was also non-significant (p=0.166). Simultaneous versus sequential boost produced no significant survival or intracranial-control difference.
- Prognosis depended more clearly on disease biology and burden than RT technique. Karnofsky performance status ≥90 was associated with better survival (HR 0.63, p=0.006), whereas extracranial metastases (HR 2.24, p<0.001) and more than three brain metastases (HR 1.44, p=0.045) predicted worse survival. The authors also report a favorable association with post-radiotherapy immunotherapy, but neurocognitive outcomes and quality of life—the principal reasons to prefer SRT over WBRT—were not measured.
CLINICAL TAKEAWAY
The apparent survival advantage of SRT disappeared once baseline differences were addressed, reinforcing how strongly selection bias affects retrospective SCLC brain-metastasis comparisons. WBRT plus boost may improve intracranial control, but the result was not robust after adjusted and sensitivity analyses, so these data support individualized selection rather than establishing a superior strategy.