KEY POINTS
- This retrospective cohort study included 336 patients with limited-stage small cell lung cancer who achieved complete or partial response after first-line concurrent chemoradiotherapy; 199 received prophylactic cranial irradiation and 137 underwent magnetic resonance imaging surveillance.
- Inverse probability of treatment weighting was used to balance baseline factors including age, performance status, chemotherapy regimen, radiotherapy schedule, stage, and response.
- All patients in the prophylactic cranial irradiation group received 25 Gy in 10 fractions; 29.6% received hippocampal avoidance prophylactic cranial irradiation.
- After weighting, prophylactic cranial irradiation was associated with longer median overall survival — 70.0 vs 40.5 months — and longer brain metastasis-free survival — not reached vs 15.7 months, hazard ratio 0.57, 95% confidence interval 0.38–0.86.
- Early prophylactic cranial irradiation at 3–6 weeks after chemoradiotherapy was associated with lower brain metastasis risk than delayed treatment at 7–12 weeks — hazard ratio 0.33, 95% confidence interval 0.12–0.94 — but not improved overall survival.
CLINICAL TAKEAWAY
This study supports continued consideration of prophylactic cranial irradiation for selected limited-stage small cell lung cancer patients with response after chemoradiotherapy, even in the magnetic resonance imaging surveillance era. The signal is clinically relevant, especially for brain metastasis prevention and possibly for partial responders, but the evidence remains retrospective and vulnerable to residual selection bias. Neurocognitive safety should also be interpreted cautiously because formal standardized neuropsychological testing was not performed.