Effective method to reduce the normal brain dose in single-isocenter hypofractionated stereotactic radiotherapy for multiple brain metastases.
Strahlenther Onkol
; 197(7): 592-600, 2021 07.
Article
en En
| MEDLINE
| ID: mdl-33725135
ABSTRACT
BACKGROUND AND PURPOSE:
Island blocking and dose leakage problems will lead to unnecessary irradiation to normal brain tissue (NBT) in hypofractionated stereotactic radiotherapy (HSRT) for multiple brain metastases (BM) with single-isocenter volumetric modulated arc therapy (VMAT). The present study aimed at investigating whether reducing the number of metastases irradiated by each arc beam could minimize these two problems. MATERIALS ANDMETHODS:
A total of 32 non-small-cell lung cancer (NSCLC) patients with multiple BM received HSRT (24-36â¯Gy/3 fractions) with single-isocenter VMAT, where each arc beam only irradiated partial metastases (pm-VMAT), were enrolled in this retrospective study. Conventional single-isocenter VMAT plans, where each arc beam irradiated whole metastases (wm-VMAT), was regenerated and compared with pm-VMAT plans. Furthermore, the clinical efficacy and toxicities were evaluated.RESULTS:
Pm-VMAT achieved similar target coverage as that with wm-VMAT, with better dose fall-off (Pâ¯<â¯0.001) and NBT sparing (Pâ¯<â¯0.001). However, pm-VMAT resulted in more monitor units (MU) and longer beam-on time (Pâ¯<â¯0.001). The intracranial objective response rate and disease control rate for all patients were 75% and 100%, respectively. The local control rates at 1 year and 2 year were 96.2% and 60.2%, respectively. The median progression-free survival and overall survival were 10.3 months (95% confidence interval [CI] 6.8-13.2) and 18.5 months (95% CI 15.9-20.1), respectively. All treatment-related adverse events were grade 1 or 2, and 3 lesions (2.31%) from 2 patients (6.25%) demonstrated radiation necrosis after HSRT.CONCLUSION:
HSRT with pm-VMAT is effective and has limited toxicities for NSCLC patients with multiple BM. Pm-VMAT could provide better NBT sparing while maintaining target dose coverage.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Neoplasias Encefálicas
/
Carcinoma de Pulmón de Células no Pequeñas
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Hipofraccionamiento de la Dosis de Radiación
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Neoplasias Pulmonares
Tipo de estudio:
Observational_studies
Límite:
Adult
/
Aged
/
Aged80
/
Female
/
Humans
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Male
/
Middle aged
Idioma:
En
Revista:
Strahlenther Onkol
Asunto de la revista:
NEOPLASIAS
/
RADIOTERAPIA
Año:
2021
Tipo del documento:
Article
País de afiliación:
China