Clinical outcomes and dosimetric factors associated with local control after two-fraction radiosurgery for brain metastases
In brief
Two-fraction brain radiosurgery had 18% local failure by one year; dose coverage mattered
In this retrospective study of 193 brain metastases, local failure reached 17.9% at 12 months after two-fraction radiosurgery. Lower dose coverage of nearly the entire target was independently associated with more local failures, while distant brain failure reached 50.2% by one year. The findings link target dosing to local control, but do not establish a specific dose threshold.
- Journal
- Radiation oncology journal (Q2)
- Published
- 30 October 2026
- Study design
- Cohort / observational study
- Evidence level
- Level 3, Low (CEBM 3b)
- Authors
- Nam Kyu Kang, Joo Hwan Lee, Jong Hoon Lee, Sung Hwan Kim, Hyo Chun Lee
- PMID
- 42957431
- DOI
- 10.3857/roj.2026.00577
Why clinicians should know about it
- Picked for Medical Physics (top studies of the week, 1 November 2026): PTV D98 links stereotactic dose coverage with local control
Abstract
PURPOSE: This study aimed to evaluate local control outcomes and dosimetric factors associated with local failure (LF) in patients with brain metastases treated with two-fraction stereotactic radiosurgery (two-fraction SRS). MATERIALS AND METHODS: We retrospectively analyzed 86 patients with 193 brain metastases who underwent two-fraction SRS between August 2018 and November 2025. LF was the primary endpoint, while distant intracranial failure (DIF) and overall survival (OS) were secondary endpoints. The cumulative incidence of LF and DIF was estimated using competing-risk analysis, with clustered Fine-Gray regression applied to the lesion-level LF analysis to account for intra-patient correlation. Dosimetric parameters, including planning target volume (PTV) coverage indices, were evaluated to identify factors associated with LF. Factors associated with OS were analyzed using Cox proportional hazards models. RESULTS: With a median follow-up of 24.4 months, the cumulative incidence of LF at 6 and 12 months was 11.5% (95% confidence interval [CI], 6.2% to 17.2%) and 17.9% (95% CI, 11.3% to 24.7%), respectively. In the integrated clustered multivariable analysis adjusting for clinical variables, lower PTV D98 (dose covering 98% of the target volume) was independently associated with an increased risk of LF, whereas no other variables remained significant in the final integrated model. The cumulative incidence of DIF was 33.2% at 6 months and 50.2% at 12 months. In multivariable Cox analysis, baseline performance status was the only independent factor significantly associated with OS. CONCLUSION: Two-fraction SRS achieved reasonable local control in patients with brain metastases. Maintaining an adequate absolute near-minimum dose to the target (PTV D98) was associated with improved local control, while OS was primarily influenced by baseline patient performance status.
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.