Dose selection and clinical decision-making after Gamma Knife surgery for large brain metastases: implications for early identification of true progression
In brief
For large brain metastases, 57.6-Gy effective dose linked to less progression
In this retrospective study of 143 patients treated with Gamma Knife surgery, a biologically effective dose of at least 57.6 Gy was associated with lower risk of true tumor progression. Recurrent swelling around an enlarging tumor within a year also pointed toward true progression, but the findings need confirmation and do not establish that higher doses cause better control.
- Journal
- Journal of neuro-oncology (Q1)
- Published
- 5 October 2026
- Study design
- Unclassified
- Evidence level
- Level 5, Expert Opinion (CEBM 5)
- Authors
- Yuta Koketsu, Toshinori Hasegawa, Takenori Kato, Takehiro Naito, Akihiro Mizuno, Yuto Ando, et al.
- PMID
- 42832083
- DOI
- 10.1007/s11060-026-05792-0
Why clinicians should know about it
- Picked for Radiation Oncology (paper of the day, 8 October 2026): BED≥57.6 Gy reduces true progression
Abstract
PURPOSE: To evaluate dose selection and post-treatment management after Gamma Knife surgery (GKS) for large brain metastases, with a focus on early identification of true progression. METHODS: This retrospective single-institution study included 143 patients with large brain metastases (tumor volume ≥ 4 cm3) treated with primary GKS between 2016 and 2024. One dominant lesion per patient was analyzed. Treatment modality (single-session, staged, or hypofractionated) and dose selection were individualized. Radiographic progression was defined as a ≥ 20% increase in longest tumor diameter from nadir. True progression was defined as sustained enlargement or the need for salvage treatment, whereas lesions that stabilized or regressed without intervention were classified as pseudoprogression. RESULTS: Median overall survival was 15.3 months. During follow-up, 47 lesions showed radiographic progression: 42 true progression, 4 pseudoprogression, and 1 intratumoral hemorrhage. The 6-, 12-, and 24-month cumulative incidences of true progression were 17.4%, 31.5%, and 33.1%, respectively. True progression did not differ by treatment modality or tumor volume. A marginal dose ≥ 57.6 Gy biologically effective dose (BED10) was associated with a lower risk of true progression (subdistribution hazard ratio [SHR], 0.46; p = 0.02). Recurrent peritumoral edema developed earlier in true progression than pseudoprogression (median, 173.5 vs. 564 days; p = 0.001). Lower marginal dose at repeat GKS was associated with subsequent true progression (SHR, 0.82; p = 0.02). CONCLUSION: A BED10 ≥ 57.6 Gy improved local control in large brain metastases. Recurrent peritumoral edema accompanying tumor enlargement within 1 year after GKS strongly suggested true progression and should prompt consideration of early salvage intervention. CLINICAL TRIAL REGISTRATION: Clinical trial number: not applicable.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.