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ORIGINAL RESEARCH article

Front. Oncol.
Sec. Radiation Oncology
Volume 15 - 2025 | doi: 10.3389/fonc.2025.1428922
This article is part of the Research Topic Efficacy and Safety of SRS/SBRT in Oligometastatic Disease Management View all 5 articles

Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes

Provisionally accepted
Jialu Lai Jialu Lai 1An Li An Li 1Xianhu Zeng Xianhu Zeng 1Jia Liu Jia Liu 2Lin Zhou Lin Zhou 1*
  • 1 West China Hospital, Sichuan University, Chengdu, China
  • 2 Chengdu Integrated TCM and Western Medical Hospital, Chengdu, China

The final, formatted version of the article will be published soon.

    Purpose: To evaluate the dosimetric parameters and clinical outcomes of hypofractionated stereotactic radiotherapy (HSRT) for small brain metastases (BMs; planning target volume [PTV] ≤ 4 cm3) via coplanar volumetric modulated arc therapy (C-VMAT).Methods: Between March 2019 and February 2023, sixty-eight patients with a single BM treated with Linac-based HSRT (24–39 Gy in 3 fractions) via C-VMAT and a 3-mm PTV margin were enrolled in this retrospective analysis. A frameless head–neck-shoulder thermoplastic mask, whose immobilization accuracy is inferior to that of specialized mask fixation systems, was used to immobilize patients. Dosimetric parameters and clinical outcomes were evaluated.Results: C-VMAT provided clinically satisfactory treatment plans, with median gradient index, conformity index, homogeneity index and PTV coverage values of 4.30, 1.05, 1.28, and 98%, respectively. The median volumes of normal brain tissue receiving 18 Gy, 21 Gy and 23 Gy were 7.29 cm3, 5.33 cm3 and 4.40 cm3, respectively. High delivery accuracy was observed, with a gamma passing rate ≥90% for all plans. As of June 2023, the median follow-up time was 9.1 months. The intracranial objective response rate and disease control rate were 64% and 96%, respectively. The median intracranial progression-free survival was 26.9 (95% CI: 12.7–41.1) months. The 1-year and 2-year local control (LC) rates were 91.5% (95% CI: 80.1%-100%) and 83.2% (95% CI: 64.6%-100%), respectively. The 1-year and 2-year intracranial control rates were 70.9% (95% CI: 55.2%-86.6%) and 51.2% (95% CI: 32.6%-69.8%), respectively. Only four irradiated lesions progressed at the end of follow-up. The cerebral radiation necrosis rate of all patients was 7.4%.Conclusion: C-VMAT HSRT combined with a 3-mm PTV margin is an effective and safe treatment modality for small BMs.Keywords: Hypofractionated stereotactic radiotherapy; Small brain metastases; Planning target volume margin; Dosimetric parameters; Clinical outcome

    Keywords: Hypofractionated stereotactic radiotherapy, Small brain metastases, Planning target volume margin, Dosimetric parameters, clinical outcome

    Received: 07 May 2024; Accepted: 06 Feb 2025.

    Copyright: © 2025 Lai, Li, Zeng, Liu and Zhou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Lin Zhou, West China Hospital, Sichuan University, Chengdu, China

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