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

PurposeTo 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).MethodsBetween March 2019 and February 2023, 68 patien...

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Main Authors: Jialu Lai, An Li, Xianhu Zeng, Jia Liu, Lin Zhou
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-02-01
Series:Frontiers in Oncology
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Online Access:https://www.frontiersin.org/articles/10.3389/fonc.2025.1428922/full
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author Jialu Lai
An Li
Xianhu Zeng
Jia Liu
Lin Zhou
author_facet Jialu Lai
An Li
Xianhu Zeng
Jia Liu
Lin Zhou
author_sort Jialu Lai
collection DOAJ
description PurposeTo 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).MethodsBetween March 2019 and February 2023, 68 patients with a single BM treated with Linac-based HSRT (24–39 Gy in three 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.ResultsC-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- 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- 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%.ConclusionC-VMAT HSRT combined with a 3-mm PTV margin is an effective and safe treatment modality for small BMs.
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spelling doaj-art-8cc5c9fb55134ff080e405a47a681dd72025-08-20T02:45:19ZengFrontiers Media S.A.Frontiers in Oncology2234-943X2025-02-011510.3389/fonc.2025.14289221428922Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomesJialu Lai0An Li1Xianhu Zeng2Jia Liu3Lin Zhou4Radiotherapy Physics & Technology Center, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, ChinaRadiotherapy Physics & Technology Center, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, ChinaRadiotherapy Physics & Technology Center, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, ChinaDepartment of Oncology, Chengdu First People’ Hospital, Chengdu, Sichuan, ChinaThoracic Oncology Ward, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, ChinaPurposeTo 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).MethodsBetween March 2019 and February 2023, 68 patients with a single BM treated with Linac-based HSRT (24–39 Gy in three 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.ResultsC-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- 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- 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%.ConclusionC-VMAT HSRT combined with a 3-mm PTV margin is an effective and safe treatment modality for small BMs.https://www.frontiersin.org/articles/10.3389/fonc.2025.1428922/fullhypofractionated stereotactic radiotherapysmall brain metastasesplanning target volume margindosimetric parametersclinical outcome
spellingShingle Jialu Lai
An Li
Xianhu Zeng
Jia Liu
Lin Zhou
Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
Frontiers in Oncology
hypofractionated stereotactic radiotherapy
small brain metastases
planning target volume margin
dosimetric parameters
clinical outcome
title Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
title_full Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
title_fullStr Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
title_full_unstemmed Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
title_short Hypofractionated stereotactic radiotherapy using coplanar VMAT for single small brain metastasis: dosimetric analysis and clinical outcomes
title_sort hypofractionated stereotactic radiotherapy using coplanar vmat for single small brain metastasis dosimetric analysis and clinical outcomes
topic hypofractionated stereotactic radiotherapy
small brain metastases
planning target volume margin
dosimetric parameters
clinical outcome
url https://www.frontiersin.org/articles/10.3389/fonc.2025.1428922/full
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