title: Efficacy of salvage stereotactic radiotherapy for recurrent glioma: impact of tumor morphology and method of target delineation on local control.
abstract: In this study, we assessed the efficacy of salvage stereotactic radiotherapy (SRT) for recurrent glioma. From August 2008 to December 2012, 30 patients with recurrent glioma underwent salvage SRT. The initial histological diagnoses were World Health Organization (WHO) grades II, III, and IV in 6, 9, and 15 patients, respectively. Morphologically, the type of recurrence was classified as diffuse or other. Two methods of clinical target delineation were used: A, a contrast-enhancing tumor; or B, a contrast-enhancing tumor with a 3-10-mm margin and/or surrounding fluid attenuation inversion recovery (FLAIR) high-intensity areas. The prescribed dose was 22.5-35 Gy delivered in five fractions at an isocenter using a dynamic conformal arc technique. The overall survival (OS) and local control probability (LCP) after SRT were calculated using the Kaplan-Meier method. A univariate analysis was used to test the effect of clinical variables on OS/LCP. The median follow-up period was 272 days after SRT. The OS and LCP were 83% and 56% at 6 months after SRT, respectively. Morphologically, the tumor type correlated significantly with both OS and LCP (P = 0.006 and <0.001, respectively). The method of target delineation also had a significant influence on LCP (P = 0.016). Grade 3 radiation necrosis was observed in two patients according to Common Terminology Criteria for Adverse Events, version 3. Salvage SRT was safe and effective for recurrent glioma, especially non-diffuse recurrences. Improved local control might be obtained by adding a margin to contrast-enhancing tumors or including increased FLAIR high-intensity areas.
authors.affiliation: Department of Radiation Oncology and Image-applied Therapy, Kyoto University Graduate School of Medicine, 54 Kawahara-cho Shogoin Sakyo-ku, Kyoto, 606-8507, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Ogura
authors.forename: Takashi
authors.initials: T
authors.lastname: Mizowaki
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Arakawa
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Sakanaka
authors.forename: Susumu
authors.initials: S
authors.lastname: Miyamoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Hiraoka
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use; D000970:Antineoplastic Agents / Q000627:therapeutic use; D000068258:Bevacizumab; D001921:Brain / Q000473:pathology; D001932:Brain Neoplasms / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D003131:Combined Modality Therapy; D005260:Female; D005910:Glioma / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects; D016879:Salvage Therapy / Q000009:adverse effects; D055815:Young Adult
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D000068258:Bevacizumab
keywords: Local control; re-irradiation; recurrent glioma; salvage therapy; stereotactic radiotherapy; target delineation