Longitudinal Radiographic Outcomes of Vestibular Schwannoma in Single and Fractionated Stereotactic Radiosurgery: A Retrospective Cohort Study

Mohamed H. Khattab, Neil B. Newman, David M. Wharton, Alexander D. Sherry, Guozhen Luo, Nauman F. Manzoor, Alejandro Rivas, L. Taylor Davis, Lola B. Chambless, Albert Attia, Anthony J. Cmelak

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Management of vestibular schwannoma (VS) includes stereotactic radiosurgery (SRS) in single or fractionated treatments. There is a paucity of literature on the three-dimensional (3D) volumetric kinetics and radiological changes following SRS and no consensus on appropriate post-SRS surveillance imaging timeline. This is a retrospective cohort study with institutional review board approval. A total of 55 patients met study criteria. We collected volumetric kinetic data in VS treated with SRS over time using a target volume contouring software. We also tracked radiographic phenomena such as pseudoprogression and necrosis. A secondary objective was to describe our overall treatment success rate and any failures. For all treatments groups, pseudoprogression most typically occurred within 12 months post-SRS, after which tumor volumes on average normalized and then decreased from pretreatment size at the last follow-up. Only two patients required salvage therapy post-SRS and were considered SRS treatment failures. Both patients were in the five-fraction cohort but with a lower biologically equivalent dose. Our study is first to collect 3D volumetric kinetics of VS following single and fractionated SRS in contrast to extrapolations from single and two-dimensional measurements. Our longitudinal data also show initial increases in volume in the first 12 months post-SRS followed by later declines, setting up interesting questions regarding the utility of early posttreatment surveillance imaging in the asymptomatic patient. Finally, we show low rates of treatment failure (3.6%) and show in our cohort that SRS dose de-escalation posed a risk of treatment failure.

Original languageEnglish (US)
Pages (from-to)308-316
Number of pages9
JournalJournal of Neurological Surgery, Part B: Skull Base
Issue number3
StatePublished - Jun 1 2020
Externally publishedYes


  • fractionation
  • pseudoprogression
  • stereotactic radiosurgery
  • vestibular schwannoma
  • volumetric

ASJC Scopus subject areas

  • Clinical Neurology


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