Feasibility and Outcomes of Hypofractionated Simultaneous Integrated Boost-Intensity Modulated Radiotherapy for Malignant Gliomas: A Preliminary Report |
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Authors: | Jihye Cha Chang-Ok Suh Kwangwoo Park Jong Hee Chang Kyu Sung Lee Se Hoon Kim Jee Suk Chang Joo Ho Kim Yang-Gun Suh Jun Won Kim Jaeho Cho |
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Institution: | 1.Department of Radiation Oncology, Yonsei University College of Medicine, Seoul, Korea.;2.Department of Neurosurgery, Yonsei University College of Medicine, Seoul, Korea.;3.Department of Pathology, Yonsei University College of Medicine, Seoul, Korea. |
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Abstract: | PurposeThe aim of this study was to assess the feasibility and efficacy of hypofractionated simultaneous integrated boost-intensity modulated radiotherapy (SIB-IMRT) using three-layered planning target volumes (PTV) for malignant gliomas.Materials and MethodsWe conducted a retrospective analysis of 12 patients (WHO grade IV-10; III-2) postoperatively treated with SIB-IMRT with concurrent temozolomide. Three-layered PTVs were contoured based on gadolinium-enhanced magnetic resonance imaging as follows; high risk PTV (H-PTV) as the area of surgical bed including residual gross tumor with a 0.5 cm margin; low risk PTV (L-PTV) as the area surrounding the high risk PTV with 1.5 cm margin; moderate risk PTV (M-PTV) as a line at one-third the distance from high risk PTV to low risk PTV. Total dose to high risk PTV was 70 Gy in 8 and 62.5 Gy in 4 patients.ResultsThe median follow-up time was 52 months in surviving patients. The 2- and 5-year overall survival (OS) rates were 66.6% and 47.6%, respectively. The 2- and 5-year progression-free survival (PFS) rates were 57.1% and 45.7%, respectively. The median OS and PFS were 48 and 31 months, respectively. Six patients (50%) progressed: in-field only in one, out-field or disseminated in 4, and both in one patient. All patients completed planned treatments without a toxicity-related gap. Asymptomatic radiation necrosis was observed in 4 patients at post-radiotherapy 9-31 months.ConclusionAn escalated dose of hypofractionated SIB-IMRT using three-layered PTVs can be safely performed in patients with malignant glioma, and might contribute to better tumor control and survival. |
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Keywords: | Radiotherapy intensity-modulated malignant glioma hypofractionation simultaneous integrated boost |
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