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Shayan Moosa, Ching-Jen Chen, Dale Ding, Cheng-Chia Lee, Srinivas Chivukula, Robert M. Starke, Chun-Po Yen, Zhiyuan Xu and Jason P. Sheehan

large AVMs involve the delivery of radiation doses in stages with dose- or volume-staged SRS. Dose staging is described in the literature as either hypofractionated stereotactic radiotherapy (HSRT) or repeat SRS. Hypofractionated stereotactic radiotherapy is typically performed by administering several small doses of radiation to the AVM over a period of a few weeks. Repeat radiosurgery uses a higher initial dose (yet still lower than traditional single-session SRS for small to moderate AVMs), and another dose is administered after several months or years if there is

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Adeel Ilyas, Ching-Jen Chen, Dale Ding, Davis G. Taylor, Shayan Moosa, Cheng-Chia Lee, Or Cohen-Inbar and Jason P. Sheehan

T he optimal management of large (volume > 10 cm 3 ) brain arteriovenous malformations (AVMs) is controversial. Options for intervention include resection, embolization, and stereotactic radiosurgery (SRS), alone or in combination. 6 , 16 , 17 , 26 , 64 , 79 As stand-alone treatment modalities for large AVMs, microsurgery is associated with relatively high rates of morbidity and mortality, whereas embolization results in low rates of complete nidal obliteration. 35 , 39 , 41 Single-session SRS (SS-SRS) is effective for many small- to medium-sized AVMs but

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Manjul Tripathi

TO THE EDITOR: I read with great interest the article by Ilyas et al. 1 ( Ilyas A, Chen CJ, Ding D, et al: Volume-staged versus dose-staged stereotactic radiosurgery outcomes for large brain arteriovenous malformations: a systematic review. J Neurosurg 128:154–164, January 2018 ) and the commentary by Ye et al. 4 ( Ye Z, Ai X, You C: Volume-staged vs dose-staged SRS for large brain AVMs. J Neurosurg 129:262–265, July 2018 ). Management of a large-volume symptomatic arteriovenous malformation (AVM) is a daunting task, not only for the treatment team but also

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Cheng-Chia Lee, Chun-Po Yen, Zhiyuan Xu, David Schlesinger and Jason Sheehan

available for all 109 patients. The study was approved by the institutional review board of the University of Virginia. The median age of these patients was 60.5 years, and the group included 51 males and 58 females. The median tumor volume was 16.8 cm 3 (range 6.0–74.8 cm 3 ). Most patients (68.8%%) had multiple intracranial lesions, and 31.2% of patients had metastasis to other organs. The most common tumor of origin was NSCLC (29.4% of cases), followed by breast cancer (22.9%) and melanoma (21.1%). Of note, those patients included in the current series with SCLC had

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Or Cohen-Inbar, Cheng-Chia Lee, Zhiyuan Xu, David Schlesinger and Jason P. Sheehan

region of the AVM on post-GKRS sequences. A maximum slice thickness of 5 mm or less was required on these MR sequences to perform reliable volumetric analysis of the changes. ARE Volumetric Assessment The volumes of the AVM nidus (estimated using the irradiated volume) and AREs were determined for each imaging data set available for patients in a longitudinal fashion. ARE volume was determined from T2-weighted or FLAIR MRI sequences, and the nidus volume was determined from postcontrast T1-weighted imaging used for the Gamma Knife treatment plan. Volumes were

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Zengpanpan Ye, Xiaolin Ai and Chao You

TO THE EDITOR: It was a great pleasure to read the article by Ilyas et al., 3 which pooled the data to compare the effects of volume-staged (VS) and dose-staged (DS) stereotactic radiosurgery (SRS) in patients with large brain arteriovenous malformations (AVMs) ( Ilyas A, Chen CJ, Ding D, et al: Volume-staged versus dose-staged stereotactic radiosurgery outcomes for large brain arteriovenous malformations: a systematic review. J Neurosurg 128:154–164, January 2018 ). The meta-analysis suggested that VS-SRS afford a higher obliteration rate and a less favorable

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Jason P. Sheehan, Cheng-Chia Lee, Zhiyuan Xu, Colin J. Przybylowski, Patrick D. Melmer and David Schlesinger

/parafalcine meningioma. 5 Meningiomas involving the parasagittal or parafalcine region frequently abut or even invade venous structures. The proximity of the tumor to a sinus or draining vein can lead to venous congestion. Venous obstruction, pial supply, location, tumor volume, tumor grade and histological subtype, vascular growth factor receptor expression, and patient age have been associated with peritumoral edema in meningiomas. 7 , 17 , 18 , 21 Peritumoral edema associated with parasagittal or parafalcine meningiomas is common, with some series showing edema in 48% of

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Cheng-Chia Lee, Ching-Jen Chen, Benjamin Ball, David Schlesinger, Zhiyuan Xu, Chun-Po Yen and Jason Sheehan

when prior embolization decreased nidus volume to less than 8 cm 3 . Nevertheless, the literature regarding benefits of preradiosurgical embolization consists of conflicting reports. Several recent series have shown that preradiosurgical embolization may be disadvantageous in AVM patients treated with particle embolization. 5 , 27 , 55 The lower radiosurgical obliteration rate in patients with prior embolization has been attributed to several potential factors, including recanalization of the embolized AVM, 30 , 36 increased difficulty in AVM delineation and

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Cheng-Chia Lee, Hsiu-Mei Wu, Wen-Yuh Chung, Ching-Jen Chen, David Hung-Chi Pan and Sanford P. C. Hsu

Veterans General Hospital. Between 1993 and 2012, 708 patients with VS were treated with GKS at our institution. Of these, 600 with imaging follow-up of at least 1 year after GKS treatment were included for analysis. The demographic data collected included patient sex and age at the time of treatment, and data collected on VS characteristics included tumor volume, tumor lateralization, and histological diagnosis. The radiosurgical data included margin/maximum dose, isodose line, and treatment volume. Patients' pretreatment and posttreatment symptoms, neurological

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Yi-Chieh Hung, Cheng-Chia Lee, Kang-Du Liu, Wen-Yuh Chung, David Hung-Chi Pan and Huai-Che Yang

Their study indicated that increased radiation volume did not improve rates of pain relief; however, the incidence of facial hypesthesia increased. Although the design and purpose of their study differed from those of our study, distinct factors that might increase the incidence of post-GKS facial hypesthesia were observed in both studies. On the basis of our findings, we assumed that the 2-isocenter radiosurgical plan might irradiate more of the proximal part of the trigeminal nerve than does the 1-isocenter plan, which might explain the increased incidence of facial