KEY POINTS
- The systematic review and meta-analysis included 24 studies and 4,673 patients with World Health Organization grade 1 meningioma treated with conventionally fractionated proton therapy, fractionated photon radiotherapy, linac-based stereotactic radiosurgery/radiotherapy or Gamma Knife radiosurgery.
- The modality groups contained 450 proton, 1,544 fractionated-photon, 1,446 linac stereotactic and 1,233 Gamma Knife patients. Median follow-up was approximately 65–81 months, providing relatively mature local-control estimates.
- Patient selection differed markedly by technique. Median gross tumor volume was 15.4 mL with protons and 18.6 mL with fractionated photons, compared with only 5.0 mL with linac stereotactic treatment and **4.8 mL with Gamma Knife.
- Pooled five-year local control was 95.9% (95% CI 89.0–98.5%) with protons, 93.0% (86.8–96.3%) with fractionated photons, 95.3% (92.6–97.0%) with linac stereotactic treatment and 89.8% (82.9–94.0%) with Gamma Knife.
- Multivariable meta-regression found no significant association between treatment modality and local control at any evaluated time point from one to five years. Gross tumor volume likewise was not significantly associated with local control despite the substantial between-modality volume differences.
- In the proton cohort, pooled overall survival remained 93.1% at five years, but survival was not formally compared with the other modalities because corresponding data were insufficient.
- Severe treatment-related toxicity was uncommon overall, although reporting was heterogeneous and not suitable for a robust modality comparison. The review searched only PubMed, had no registered protocol, and compared predominantly observational cohorts with substantial selection differences; equivalent local control therefore does not imply equivalent late toxicity, neurocognitive outcome or second-malignancy risk.
CLINICAL TAKEAWAY
For World Health Organization grade 1 meningioma, contemporary radiation techniques all appear capable of excellent tumor control, even though fractionated treatment was generally used for larger lesions. The unresolved clinical question is therefore increasingly about late toxicity and survivorship rather than local control alone — an area this meta-analysis cannot resolve.