{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,15]],"date-time":"2026-10-15T07:04:39Z","timestamp":1792047879945,"version":"4.4.0"},"reference-count":23,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"5","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2023,5,1]]},"abstract":"\nOBJECTIVE<\/jats:title>\nGamma Knife radiosurgery (GKRS) is an effective treatment for vestibular schwannomas (VSs) and has been used in > 100,000 cases worldwide. In the present study the authors sought to define the serial volumetric tumor response of Koos grade I\u2013IV VS after radiosurgery.<\/jats:p>\n<\/jats:sec>\n\nMETHODS<\/jats:title>\nA total of 201 consecutive VS patients underwent GKRS at a single institution between 2015 and 2019. All patients had a minimum follow-up of 18 months and at least 2 interval postprocedure MRI scans. The contrast-enhanced tumor volumes were contoured manually and compared between pre- and post-GKRS imaging. The percentages of tumor volume change at 18 months (short-term follow-up) and up to 5 years after GKRS (long-term follow-up) were compared with the baseline tumor volume. An increase of 20% was considered a significant increase of tumor volume. Trends of tumor volume over time were assessed with linear models using time as a continuous variable. A test for linear trend was evaluated according to the initial Koos tumor classification.<\/jats:p>\n<\/jats:sec>\n\nRESULTS<\/jats:title>\nKoos grade II VS was the most frequently occurring tumor (n = 74, 36.8%), followed by grade III (n = 57, 28.4%), grade I (n = 41, 20.4%), and grade IV (n = 29, 14.4%). The mean tumor volume at the time of GKRS was 2.12 \u00b1 2.82 cm3<\/jats:sup> (range 0.12\u201318.77 cm3<\/jats:sup>) and the median margin dose was 12 Gy. Short-term follow-up revealed that tumor volumes transiently increased in 34.2% and 28.4% of patients at 6 and 18 months, respectively, regardless of Koos grade. Linear regression analysis of Koos grade II, III, and IV tumors showed a significant longitudinal volume decrease on long-term follow-up. At last follow-up (median 30 months, range 18\u201354 months), 19 patients (9.4%) showed a persistent increase of tumor volume. Five patients received additional management after GKRS.<\/jats:p>\n<\/jats:sec>\n\nCONCLUSIONS<\/jats:title>\nAlthough selected VS patients demonstrate an early and measurable transient volumetric increase after GKRS, > 90% have stable or reduced tumor volumes over an observed period of up to 5 years. Volumetric regression is most pronounced in Koos grade II, III, and IV tumors and may not be fully detectable until 3 years after GKRS.<\/jats:p>\n<\/jats:sec>","DOI":"10.3171\/2022.7.jns22812","type":"journal-article","created":{"date-parts":[[2022,9,9]],"date-time":"2022-09-09T17:53:33Z","timestamp":1662746013000},"page":"1273-1280","source":"Crossref","is-referenced-by-count":18,"title":["The longitudinal volumetric response of vestibular schwannomas after Gamma Knife radiosurgery"],"prefix":"10.3171","volume":"138","author":[{"given":"Luigi","family":"Albano","sequence":"first","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hansen","family":"Deng","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhishuo","family":"Wei","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lena","family":"Vodovotz","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ajay","family":"Niranjan","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"L. Dade","family":"Lunsford","sequence":"additional","affiliation":[{"name":"Department of Neurological Surgery and"},{"name":"Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"1","key":"b1","series-title":"Am J Epidemiol","first-page":"58","article-title":"Loud noise exposure and acoustic neuroma","volume":"180","author":"Fisher JL","year":"2014","unstructured":"Fisher JL, Pettersson D, Palmisano S, Loud noise exposure and acoustic neuroma. Am J Epidemiol. 2014;180(1):58\u201367."},{"issue":"14","key":"b2","series-title":"N Engl J Med","first-page":"1335","article-title":"Vestibular schwannomas","volume":"384","author":"Carlson ML","year":"2021","unstructured":"Carlson ML, Link MJ. Vestibular schwannomas. 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