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Bin-Alamer O, Abou-Al-Shaar H, Peker S, Samanci Y, Pelcher I, Begley S, Goenka A, Schulder M, Tourigny JN, Mathieu D, Hamel A, Briggs RG, Yu C, Zada G, Giannotta SL, Speckter H, Palque S, Tripathi M, Kumar S, Kaur R, Kumar N, Rogowski B, Shepard MJ, Johnson BA, Trifiletti DM, Warnick RE, Dayawansa S, Mashiach E, Vasconcellos FDN, Bernstein K, Schnurman Z, Alzate J, Kondziolka D, Sheehan JP. Vestibular Schwannoma International Study of Active Surveillance Versus Stereotactic Radiosurgery: The VISAS Study. Int J Radiat Oncol Biol Phys 2024; 120:454-464. [PMID: 38588868 DOI: 10.1016/j.ijrobp.2024.04.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 03/23/2024] [Accepted: 04/02/2024] [Indexed: 04/10/2024]
Abstract
PURPOSE The present study assesses the safety and efficacy of stereotactic radiosurgery (SRS) versus observation for Koos grade 1 and 2 vestibular schwannoma (VS), benign tumors affecting hearing and neurological function. METHODS AND MATERIALS This multicenter study analyzed data from Koos grade 1 and 2 VS patients managed with SRS (SRS group) or observation (observation group). Propensity score matching balanced patient demographics, tumor volume, and audiometry. Outcomes measured were tumor control, serviceable hearing preservation, and neurological outcomes. RESULTS In 125 matched patients in each group with a 36-month median follow-up (P = .49), SRS yielded superior 5- and 10-year tumor control rates (99% CI, 97.1%-100%, and 91.9% CI, 79.4%-100%) versus observation (45.8% CI, 36.8%-57.2%, and 22% CI, 13.2%-36.7%; P < .001). Serviceable hearing preservation rates at 5 and 9 years were comparable (SRS 60.4% CI, 49.9%-73%, vs observation 51.4% CI, 41.3%-63.9%, and SRS 27% CI, 14.5%-50.5%, vs observation 30% CI, 17.2%-52.2%; P = .53). SRS were associated with lower odds of tinnitus (OR = 0.39, P = .01), vestibular dysfunction (OR = 0.11, P = .004), and any cranial nerve palsy (OR = 0.36, P = .003), with no change in cranial nerves 5 or 7 (P > .05). Composite endpoints of tumor progression and/or any of the previous outcomes showed significant lower odds associated with SRS compared with observation alone (P < .001). CONCLUSIONS SRS management in matched cohorts of Koos grade 1 and 2 VS patients demonstrated superior tumor control, comparable hearing preservation rates, and significantly lower odds of experiencing neurological deficits. These findings delineate the safety and efficacy of SRS in the management of this patient population.
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Affiliation(s)
- Othman Bin-Alamer
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Hussam Abou-Al-Shaar
- Department of Neurosurgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Selcuk Peker
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Yavuz Samanci
- Department of Neurosurgery, Koc University School of Medicine, Istanbul, Turkey
| | - Isabelle Pelcher
- Department of Neurosurgery, Donald & Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York
| | - Sabrina Begley
- Department of Neurosurgery, Donald & Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York
| | - Anuj Goenka
- Department of Neurosurgery, Donald & Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York
| | - Michael Schulder
- Department of Neurosurgery, Donald & Barbara Zucker School of Medicine at Hofstra/Northwell, Manhasset, New York
| | - Jean-Nicolas Tourigny
- Department of Neurosurgery, Université de Sherbrooke, Centre de recherche du CHUS, Sherbrooke, Quebec, Canada
| | - David Mathieu
- Department of Neurosurgery, Université de Sherbrooke, Centre de recherche du CHUS, Sherbrooke, Quebec, Canada
| | - Andréanne Hamel
- Department of Neurosurgery, Université de Sherbrooke, Centre de recherche du CHUS, Sherbrooke, Quebec, Canada
| | - Robert G Briggs
- Department of Neurosurgery, University of Southern California, Los Angeles, California
| | - Cheng Yu
- Department of Neurosurgery, University of Southern California, Los Angeles, California
| | - Gabriel Zada
- Department of Neurosurgery, University of Southern California, Los Angeles, California
| | - Steven L Giannotta
- Department of Neurosurgery, University of Southern California, Los Angeles, California
| | - Herwin Speckter
- Dominican Gamma Knife Center and Radiology Department, CEDIMAT, Santo Domingo, Dominican Republic
| | - Sarai Palque
- Dominican Gamma Knife Center and Radiology Department, CEDIMAT, Santo Domingo, Dominican Republic
| | - Manjul Tripathi
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Saurabh Kumar
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rupinder Kaur
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Narendra Kumar
- Department of Neurosurgery, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Brandon Rogowski
- Drexel University School of Medicine, Philadelphia, Pennsylvania
| | - Matthew J Shepard
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania
| | - Bryan A Johnson
- Department of Radiation Oncology, Mayo Clinic, Jacksonville, Florida
| | | | - Ronald E Warnick
- Gamma Knife Center, Jewish Hospital, Mayfield Clinic, Cincinnati, Ohio
| | - Samantha Dayawansa
- Department of Neurosurgery, University of Virginia, Charlottesville, Virginia
| | - Elad Mashiach
- Department of Neurosurgery, NYU Langone, Manhattan, New York
| | | | | | - Zane Schnurman
- Department of Neurosurgery, NYU Langone, Manhattan, New York
| | - Juan Alzate
- Department of Neurosurgery, NYU Langone, Manhattan, New York
| | | | - Jason P Sheehan
- Department of Neurosurgery, University of Virginia, Charlottesville, Virginia.
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Taori S, Bin-Alamer O, Tang A, Niranjan A, Flickinger JC, Hadjipanayis CG, Lunsford LD. Repeat stereotactic radiosurgery for progressive vestibular schwannomas after primary gamma knife radiosurgery. J Neurooncol 2024; 169:591-599. [PMID: 39073686 PMCID: PMC11341587 DOI: 10.1007/s11060-024-04761-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 06/28/2024] [Indexed: 07/30/2024]
Abstract
PURPOSE Limited data provides guidance on the management of vestibular schwannomas (VSs) that have progressed despite primary Gamma Knife radiosurgery (GKRS). The present article reports our long-term experience after repeat GKRS for VS with sustained progression after solely primary GKRS management. METHODS A retrospective review of 1997 patients managed between 1987 and 2023 was conducted. Eighteen patients had sustained tumor progression after primary GKRS and underwent repeat GKRS. The median repeat GKRS margin dose was 11 Gy (IQR: 11-12), the median tumor volume was 2.0 cc (IQR: 1.3-6.3), and the median cochlear dose in patients with preserved hearing was 3.9 Gy (IQR: 3-4.1). The median time between initial and repeat GKRS was 65 months (IQR: 38-118). RESULTS The median follow-up was 70 months (IQR: 23-101). After repeat GKRS, two patients had further tumor progression at 4 and 21 months and required partial resection of their tumors. The 10-year actuarial tumor control rate after repeat GKRS was 88%. Facial nerve function was preserved in 13 patients who had House-Brackmann grade 1 or 2 function at the time of repeat GKRS. Two patients with serviceable hearing preservation (Gardner-Robertson grade 1 or 2) at repeat GKRS retained that function afterwards. In patients with tinnitus, vestibular dysfunction, and trigeminal neuropathy, symptoms remained stable or improved for 16/16 patients, 12/15 patients, and 10/12 patients, respectively. One patient developed facial twitching in the absence of tumor growth 21 months after repeat GKRS. CONCLUSIONS Repeat GKRS effectively controlled tumor growth and preserved cranial nerve outcomes in most patients whose VS had sustained progression after initial primary radiosurgery.
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Affiliation(s)
- Suchet Taori
- School of Medicine, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
| | - Othman Bin-Alamer
- Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop Street, Pennsylvania, PA, 15213, USA.
| | - Anthony Tang
- School of Medicine, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
| | - Ajay Niranjan
- School of Medicine, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
- Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop Street, Pennsylvania, PA, 15213, USA
| | - John C Flickinger
- Department of Radiation Oncology, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
| | - Constantinos G Hadjipanayis
- School of Medicine, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
- Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop Street, Pennsylvania, PA, 15213, USA
| | - L Dade Lunsford
- School of Medicine, University of Pittsburgh Medical Center, Pennsylvania, PA, USA
- Department of Neurological Surgery, University of Pittsburgh Medical Center, 200 Lothrop Street, Pennsylvania, PA, 15213, USA
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Noble DJ, Ramaesh R, Brothwell M, Elumalai T, Barrett T, Stillie A, Paterson C, Ajithkumar T. The Evolving Role of Novel Imaging Techniques for Radiotherapy Planning. Clin Oncol (R Coll Radiol) 2024; 36:514-526. [PMID: 38937188 DOI: 10.1016/j.clon.2024.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 05/20/2024] [Accepted: 05/30/2024] [Indexed: 06/29/2024]
Abstract
The ability to visualise cancer with imaging has been crucial to the evolution of modern radiotherapy (RT) planning and delivery. And as evolving RT technologies deliver increasingly precise treatment, the importance of accurate identification and delineation of disease assumes ever greater significance. However, innovation in imaging technology has matched that seen with RT delivery platforms, and novel imaging techniques are a focus of much research activity. How these imaging modalities may alter and improve the diagnosis and staging of cancer is an important question, but already well served by the literature. What is less clear is how novel imaging techniques may influence and improve practical and technical aspects of RT planning and delivery. In this review, current gold standard approaches to integration of imaging, and potential future applications of bleeding-edge imaging technology into RT planning pathways are explored.
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Affiliation(s)
- D J Noble
- Department of Clinical Oncology, Edinburgh Cancer Centre, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK; Edinburgh Cancer Research Centre, Institute of Genetics and Cancer, The University of Edinburgh, Edinburgh, UK.
| | - R Ramaesh
- Department of Radiology, Western General Hospital, Edinburgh, UK
| | - M Brothwell
- Department of Clinical Oncology, University College London Hospitals, London, UK
| | - T Elumalai
- Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
| | - T Barrett
- Department of Radiology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
| | - A Stillie
- Department of Clinical Oncology, Edinburgh Cancer Centre, Western General Hospital, Crewe Road South, Edinburgh EH4 2XU, UK
| | - C Paterson
- Beatson West of Scotland Cancer Centre, Great Western Road, Glasgow G12 0YN, UK
| | - T Ajithkumar
- Department of Oncology, Cambridge University Hospitals NHS Foundation Trust, Addenbrooke's Hospital, Cambridge, UK
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Palavani LB, Oliveira LDB, Nogueira BV, Batista S, Negri H, Bertani R. Letter to the Editor Regarding "Comparison of Stereotactic Radiosurgery and Hypofractionated Radiosurgery for Vestibular Schwannomas: A Meta-Analysis of Available Literature". World Neurosurg 2024; 185:474-475. [PMID: 38741312 DOI: 10.1016/j.wneu.2024.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 05/16/2024]
Affiliation(s)
| | | | | | - Sávio Batista
- Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Herika Negri
- Department of Neurologic Surgery, Mayo Clinic, Phoenix, Arizona, USA
| | - Raphael Bertani
- Department of Neurologic Surgery, University of São Paulo, São Paulo, Brazil
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Sharma M, Papisetty S, Dhawan S, Ahluwalia MS, Venteicher AS, Chen CC. Comparison of Stereotactic Radiosurgery and Hypofractionated Radiosurgery for Vestibular Schwannomas: A Meta-Analysis of Available Literature. World Neurosurg 2024; 182:e742-e754. [PMID: 38092351 DOI: 10.1016/j.wneu.2023.12.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 01/07/2024]
Abstract
BACKGROUND Stereotactic radiosurgery (SRS) and recently, hypofractionated radiosurgery (hSRS) are increasingly utilized as treatment for vestibular schwannomas (VS). We performed a meta-analysis of literature comparing these modalities. METHODS The PubMed database of articles was searched for studies that compared SRS and hSRS in patients with VS. Variables analyzed include tumor control, hearing preservation, facial nerve preservation, trigeminal nerve preservation, and total complications. Heterogeneity across the studies was gauged using Higgins's inconsistency index. Funnel plots and Egger's regression intercept test were used to address the publication bias. RESULTS Thirteen studies that satisfied the search criteria were selected for meta-analysis. The studies identified in our study included 353 SRS and 511 hSRS-treated patients. Analysis of heterogeneity showed that hSRS is employed for relatively larger tumor sizes in comparison to SRS. Pooled meta-analysis estimates showed no significant differences between SRS and hSRS in terms of tumor control (odds ratio [OR], 0.620; 95% confidence interval [CI], 0.21-1.86, P = 0.39), hearing preservation (OR, 1.07; 95% CI, 0.59-1.93, P = 0.83), facial nerve preservation (OR, 0.53; 5% CI, 0.23-1.21, P = 0.13), or trigeminal nerve preservation (OR, 0.67; 95% CI, 0.24-1.89, P = 0.49) at a mean follow-up of 39 months. Statistically significant heterogeneity was found across the studies only for tumor diameter (Higgins's inconsistency index = 65.69%, P = 0.003) but not for other variables. CONCLUSIONS Meta-analysis of thirteen studies comparing SRS and hSRS as treatment for VS showed comparable tumor control, hearing preservation, facial nerve preservation, and trigeminal nerve preservation.
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Affiliation(s)
- Mayur Sharma
- Department of Neurosurgery, University of Minnesota, MMC 96, Minneapolis, Minnesota, USA.
| | - Saikarthik Papisetty
- Department of Neurosurgery, University of Minnesota, MMC 96, Minneapolis, Minnesota, USA
| | - Sanjay Dhawan
- Department of Neurosurgery, University of Minnesota, MMC 96, Minneapolis, Minnesota, USA
| | - Manmeet S Ahluwalia
- Department of Medical Oncology, Miami Cancer Institute, Baptist Health South Florida, Miami, Florida, USA
| | - Andrew S Venteicher
- Department of Neurosurgery, University of Minnesota, MMC 96, Minneapolis, Minnesota, USA
| | - Clark C Chen
- Department of Neurosurgery, University of Minnesota, MMC 96, Minneapolis, Minnesota, USA
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Perez-Calatayud MJ, Menéndez A, Lliso F, Carmona V, Conde A, Celada F, Bernisz M, Botella C, Perez-Calatayud J. A single center, inter-observer evaluation of vestibular schwannoma stereotactic radiosurgery and its dosimetric impact. JOURNAL OF RADIOSURGERY AND SBRT 2024; 9:113-120. [PMID: 39087056 PMCID: PMC11288650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/01/2023] [Indexed: 08/02/2024]
Abstract
The aim of this work was to evaluate the inter- and intra-observer variation in contouring vestibular schwannoma (VS) and the organs-at-risk (OAR), and its dosimetric impact in Volumetric Modulated Arc Therapy (VMAT). Three VS typical cases were contoured by four clinicians. The Agreement Volume Index (AVI) appeared to be notably higher in VS than in OARs, such that the dose coverage of VS is fairly robust. In OARs, the largest variation was +1.02Gy in dmax for the brainstem, +0.78Gy in dmean for the cochlea and +1.05Gy in dmax of the trigeminal nerve. Accordingly, it was decided that all VS delineations for stereotactic radiosurgery (SRS), and all frame-based SRS contouring in general, should always be reviewed by a second physician. In addition, the retrospective presentation of VS cases at daily peer review meetings has also been adopted to ensure that the consensus is constantly updated, as well as for training purposes.
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Affiliation(s)
| | | | | | | | - Antonio Conde
- Radiotherapy Department, Hospital La Fe, Valencia, Spain
| | | | | | - Carlos Botella
- Neurosurgery Department, Hospital La Fe, Valencia, Spain
| | - Jose Perez-Calatayud
- Radiotherapy Department, Hospital La Fe, Valencia, Spain
- Radiotherapy Department, Hospital Clinica Benidorm, Alicante, Spain
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Kang H, Ji SY, Kim C, Koo J, Song J, Choi BY, Hwang K, Han JH. Hearing preservation after stereotactic radiosurgery for sporadic intracanalicular vestibular schwannomas classified as Koos grade 1. Cancer Med 2024; 13:e6990. [PMID: 38348957 PMCID: PMC10839155 DOI: 10.1002/cam4.6990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/19/2023] [Accepted: 01/22/2024] [Indexed: 02/15/2024] Open
Abstract
INTRODUCTION The mechanism of hearing loss following stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs) remains unclear. There is conflicting evidence regarding cochlear nerve damage by transient volume expansion of VSs after radiosurgery and radiation-induced cochlear damage. This study aimed to investigate whether there is a specific patient population that can achieve definite hearing preservation after SRS for VSs. METHODS A total of 37 consecutive patients with sporadic unilateral intracanalicular VSs and serviceable hearing (Gardner-Roberson [G-R] class I or II) were treated with SRS from 2009 to 2023. This is a retrospective study. Survival analysis with Cox regression for hearing deterioration was performed. RESULTS The median age was 55 years old. The median tumor volume was 0.089 cm3 , and the median marginal dose was 12.0 Gy. Nonserviceable hearing deterioration occurred in 9 patients (24.3%), with a median onset of 11.9 months after SRS. The actuarial rates of serviceable hearing preservation were 86%, 82%, and 70% at 1, 2, and 3 years after SRS, respectively. In a multivariate analysis, only baseline pure tone average > 30 dB increased the risk of nonserviceable hearing deterioration with significant hazard ratio. There were 13 patients with petit VSs whose tumor volume was smaller than 0.05 cm3 , and 11 of them were treated by a 4-mm single shot with a marginal dose of 12 Gy. None of the 13 patients had nonserviceable hearing deterioration. CONCLUSIONS Petit VSs that can be treated with 4-mm single or double shots with a marginal dose of 12 Gy may achieve hearing preservation after SRS.
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Affiliation(s)
- Ho Kang
- Department of NeurosurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - So Young Ji
- Department of NeurosurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Chae‐Yong Kim
- Department of NeurosurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Ja‐Won Koo
- Department of OtorhinolaryngologySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Jae‐Jin Song
- Department of OtorhinolaryngologySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Byung Yoon Choi
- Department of OtorhinolaryngologySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Kihwan Hwang
- Department of NeurosurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
| | - Jung Ho Han
- Department of NeurosurgerySeoul National University Bundang Hospital, Seoul National University College of MedicineSeongnam‐siKorea
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Dinh CT, Chen S, Nourbakhsh A, Padgett K, Johnson P, Goncalves S, Bracho O, Bas E, Bohorquez J, Monje PV, Fernandez-Valle C, Elsayyad N, Liu X, Welford SM, Telischi F. Single Fraction and Hypofractionated Radiation Cause Cochlear Damage, Hearing Loss, and Reduced Viability of Merlin-Deficient Schwann Cells. Cancers (Basel) 2023; 15:2818. [PMID: 37345155 PMCID: PMC10216287 DOI: 10.3390/cancers15102818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/09/2023] [Accepted: 05/11/2023] [Indexed: 06/23/2023] Open
Abstract
BACKGROUND Vestibular schwannomas (VS) are benign intracranial tumors caused by loss of function of the merlin tumor suppressor. We tested three hypotheses related to radiation, hearing loss (HL), and VS cell survival: (1) radiation causes HL by injuring auditory hair cells (AHC), (2) fractionation reduces radiation-induced HL, and (3) single fraction and equivalent appropriately dosed multi-fractions are equally effective at controlling VS growth. We investigated the effects of single fraction and hypofractionated radiation on hearing thresholds in rats, cell death pathways in rat cochleae, and viability of human merlin-deficient Schwann cells (MD-SC). METHODS Adult rats received cochlear irradiation with single fraction (0 to 18 Gray [Gy]) or hypofractionated radiation. Auditory brainstem response (ABR) testing was performed for 24 weeks. AHC viabilities were determined using immunohistochemistry. Neonatal rat cochleae were harvested after irradiation, and gene- and cell-based assays were conducted. MD-SCs were irradiated, and viability assays and immunofluorescence for DNA damage and cell cycle markers were performed. RESULTS Radiation caused dose-dependent and progressive HL in rats and AHC losses by promoting expression of apoptosis-associated genes and proteins. When compared to 12 Gy single fraction, hypofractionation caused smaller ABR threshold and pure tone average shifts and was more effective at reducing MD-SC viability. CONCLUSIONS Investigations into the mechanisms of radiation ototoxicity and VS radiobiology will help determine optimal radiation regimens and identify potential therapies to mitigate radiation-induced HL and improve VS tumor control.
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Affiliation(s)
- Christine T. Dinh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Si Chen
- Department of Otolaryngology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Aida Nourbakhsh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
| | - Kyle Padgett
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Radiology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Perry Johnson
- Department of Radiation Oncology, University of Florida College of Medicine, Gainesville, FL 32610, USA
| | - Stefania Goncalves
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
| | - Olena Bracho
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
| | - Esperanza Bas
- Department of Research Pharmacy, Sylvester Comprehensive Cancer Center, Miami, FL 33136, USA
| | - Jorge Bohorquez
- Department of Biomedical Engineering, University of Miami, Miami, FL 33146, USA
| | - Paula V. Monje
- Department of Neurosurgery, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - Cristina Fernandez-Valle
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA;
| | - Nagy Elsayyad
- Allina Health Cancer Institute—Radiation Oncology, St. Paul, MN 55102, USA
| | - Xuezhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Scott M. Welford
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Fred Telischi
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA (O.B.)
- Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
- Department of Biomedical Engineering, University of Miami, Miami, FL 33146, USA
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Gehin W, Lassalle B, Salleron J, Anxionnat R, Peiffert D, Marchesi V, Bernier-Chastagner V. Dosimetric predictive factors for facial nerve paralysis after cyberknife® stereotactic radiotherapy for vestibular schwannomas: A single institution experience of 88 patients. Radiother Oncol 2023; 181:109519. [PMID: 36736859 DOI: 10.1016/j.radonc.2023.109519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 02/04/2023]
Abstract
PURPOSE To identify dosimetric predictive factors of facial nerve paralysis for patients with vestibular schwannomas (VS) treated in a single institution with Cyberknife® (CK) hypofractionated stereotactic radiotherapy (SRT). METHODS AND MATERIALS Eighty-eight patients were treated from 2010 to 2020. Different treatment schedules were used over that period, some prescribed to the 80% isodose line (4 × 5 Gy, 3 × 7 Gy, 3 × 8 Gy and 5 × 5 Gy) and one to the 70% isodose line (3 × 7.7 Gy). Local control tumor and facial nerve toxicity were recorded, as well as various dosimetric indicators. RESULTS Median follow-up 37 months (range, 7-96). Of the 88 stereotactic treatments, 20 patients (23%) developed objectively diagnosed radiation-induced facial nerve paralysis. The 2-year and 5-year local tumor control were respectively 95% and 88%, and the overall 2-year facial nerve preservation was 76%. Prescriptions with a maximum dose point (Dmax) of 33 Gy were at a substantially higher risk of facial paralysis than prescriptions with a Dmax less than or equal to 30 Gy (HR = 4.51, 95% CI = [1.04;19.6], p = 0.045). The 2-years cumulative incidences of facial paralysis were 32% [20%;44%] in the case of a 33 Gy Dmax, against 7% [1%;21%] otherwise. We identified four significative dosimetric predictive factors for radiation-induced facial nerve dysfunction: a GTV minimal dose over 22 Gy (EQD2 = 45.5 Gy, p = 0.019), a GTV mean dose over 29 Gy (EQD2 = 73.5 Gy, HR = 2.84, 95% CI = [1.10;7.36], p = 0.024), a PTV mean dose over 27 Gy (EQD2 = 64.8 Gy, HR = 10.52, 95% CI = [1.39;79.76], p = 0.002) and a PTV maximal dose of 32 Gy (EQD2 = 87.5 Gy,HR = 5.09, 95% CI = [1.17;22.15], p = 0.013). CONCLUSION We identified four dosimetric predictive factors for post-treatment facial paralysis. Increasing the doses of hypofractionated stereotactic radiotherapy for vestibular schwannomas leads to higher facial nerve toxicity and may lead to lower local control rates than other published series. Our three-hypofractionated regimens may have also played a role in these results.
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Affiliation(s)
- William Gehin
- Institut de Cancérologie de Lorraine, Radiotherapy, Nancy, France.
| | - Benoîte Lassalle
- Centre Louis-Perquin Institut Régional de Réadaptation, Nancy, France
| | - Julia Salleron
- Institut de Cancérologie de Lorraine, Radiotherapy, Nancy, France
| | - René Anxionnat
- Centre Hospitalier Régional Universitaire de Nancy, Department of Neuroimaging, Nancy, France
| | - Didier Peiffert
- Institut de Cancérologie de Lorraine, Radiotherapy, Nancy, France
| | - Vincent Marchesi
- Institut de Cancérologie de Lorraine, Radiotherapy, Nancy, France
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Koffler D, Sidiqi B, Keohane M, Viswanatha S, Huang L, Garcia B, Calugaru E, Chang J, Ellis J, Schulder M, Goenka A. Does Size Matter? On the Role of Stereotactic Radiosurgery for Large Vestibular Schwannomas as Seen in an Institutional Experience of Gamma Knife Radiosurgery for High-Grade Tumors. World Neurosurg 2023; 172:e120-e129. [PMID: 36587898 DOI: 10.1016/j.wneu.2022.12.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 12/27/2022] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Management of large vestibular schwannoma (VS) is controversial. Surgery has historically been the treatment of choice, but emerging literature suggests that definitive stereotactic radiosurgery is feasible. We report our institutional experience of control and morbidity outcomes treating Koos grade 3-4 VS with Gamma Knife radiosurgery (GKRS). METHODS An institutional review board-approved database compiled outcomes of Koos grade 3-4 VS treated by GKRS from March 2014 to January 2021 with >6 months' follow-up. Baseline symptoms per Common Terminology Criteria for Adverse Events definitions were recorded. Control rates, toxicities, and post-treatment volumetric changes were analyzed. Aggregate impairment scores (AIs) were defined by the sum of relevant Common Terminology Criteria for Adverse Events grades to categorize symptomatic burdens. Baseline and post-treatment AIs were tested for association with definitive versus adjuvant strategies. RESULTS In total, 34 patients with Koos grade 3-4 VS were identified, 19 treated with definitive GKRS (GKRS-D) and 15 with adjuvant GKRS (GKRS-A). Median follow-up was 34.2 months for GKRS-D and 48.8 months for GKRS-A. Patients who received GKRS-A had greater AIs at presentation (3.73 vs. 2.11, P = 0.017). Irrespective of treatment approach, tumor control rates were 100% without instances of brainstem necrosis or shunt placement. Six of 19 patients who received GKRS-D had improved post-treatment AI, and 63% of patients who received GKRS-D and 66% of patients who received GKRS-A had tumor shrinkage >20%. CONCLUSIONS In well-selected patients with Koos grade 3-4 VS, definitive stereotactic radiosurgery may be an appropriate strategy with excellent control and minimal toxicity. Our data suggest that the need for surgical decompression should be considered based on pretreatment symptom burden rather than tumor size.
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Affiliation(s)
- Daniel Koffler
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Baho Sidiqi
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Megan Keohane
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Sirisha Viswanatha
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Lyu Huang
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Barbara Garcia
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Emel Calugaru
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Jenghwa Chang
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Jason Ellis
- Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA; Department of Neurosurgery, Northwell Health Cancer Institute, Lake Success, New York, USA
| | - Michael Schulder
- Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA; Department of Neurosurgery, Northwell Health Cancer Institute, Lake Success, New York, USA
| | - Anuj Goenka
- Department of Radiation Medicine, Northwell Health Cancer Institute, Lake Success, New York, USA; Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA.
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11
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Sharma M, Milano MT, Cummings M, Naqa IE. Tumor Control Probability following Radiosurgery of Brain Metastases with and without Retreatment. Int J Radiat Oncol Biol Phys 2022; 114:537-544. [PMID: 35863671 DOI: 10.1016/j.ijrobp.2022.06.102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 06/12/2022] [Accepted: 06/30/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE To develop and compare tumor-control-probability (TCP) models for single-fraction stereotactic radiosurgery (SRS) for brain metastasis (BMs) with and without retreatment. METHODS We developed three different schemas to model TCP of BMs treated with LINAC-based SRS. Dose to 99% of each planning-target-volume (PTV D99) and six-month local-control was fit using linear-quadratic-linear (LQ-L) models based on equivalent-dose conversions in 2Gy (EQD2). The M1 schema had separate LQ-L TCP models for initial dose (M1-initial) and retreatment dose (M1-retreat), and the M2 schema had an LQ-L model using the sum of 50% of the initial SRS dose plus the retreatment SRS dose. The M1-initial and M1-retreat schema modeled local control following 1st SRS to 48 lesions (patients=22) and 2nd SRS to 46 lesions (patients=21). The M0 schema included a whole dataset of 349 lesions (patients=136) receiving first SRS (no retreatment and M1-initial). RESULTS LQ-L models fitted the data well (Chi-2=0.059-0.525 and p=0.999-1.000). For M0 and M1-retreat, the fitted models EQD250 and γ50 parameters, were similar. The LQ-L fitted EQD250 was ∼8.0Gy for M0 and M1-retreat, ∼24Gy for M1-initial, and ∼19Gy for M2. The model fitted γ50 was 0.1Gy for M0, M1-retreat, and M2 and 0.5 for M1-initial. For the PTV D99 of 10Gy and 20Gy, the steepest to shallowest dose-response or largest change in TCP, i.e., TCP20Gy - TCP10Gy was observed in M1-initial (0.49) and M2 (0.17). M0 and M1-retreat showed a similar change in TCP of 0.21. CONCLUSION The model fitted parameters predict the recurrent BMs required a higher threshold dose and had a steeper dose-response for 1st SRS vs. 2nd SRS and M0. Alternatively, the recurrent BMs required ∼2Gy higher predicted PTV D99 dose for 1st SRS to achieve the same TCP of 0.75 when compared to 2nd SRS and M0. Further investigations on larger patient cohorts are needed for validating our findings in predictive modeling of recurrent brain metastases.
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12
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Outcome after Radiotherapy for Vestibular Schwannomas (VS)—Differences in Tumor Control, Symptoms and Quality of Life after Radiotherapy with Photon versus Proton Therapy. Cancers (Basel) 2022; 14:cancers14081916. [PMID: 35454823 PMCID: PMC9025388 DOI: 10.3390/cancers14081916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 03/28/2022] [Indexed: 02/04/2023] Open
Abstract
Background: To evaluate differences in local tumor control (LC), symptoms and quality of life (QOL) of 261 patients with VS after stereotactic radiosurgery/hypofractionated stereotactic radiotherapy (SRS/HFSRT) vs. fractionated radiotherapy (FRT) vs. fractionated proton therapy (FPT) were studied. Methods: For SRS/HFSRT (n = 149), the median fraction dose applied was 12 Gy. For FRT (n = 87) and FPT (n = 25), the median cumulative doses applied were 57.6 Gy and 54 Gy (RBE), respectively. FRT and FPT used single median doses of 1.8 Gy/Gy (RBE). Median follow-up was 38 months. We investigated dosimetry for organs at risk and analyzed toxicity and QOL by sending out a questionnaire. Results: LC was 99.5% at 12 months after RT with no statistical difference between treatment groups (p = 0.19). LC was significantly lower in NF2 patients (p = 0.004) and in patients with higher tumor extension grade (p = 0.039). The hearing preservation rate was 97% at 12 months after RT with no statistical difference between treatment groups (p = 0.31). Facial and trigeminal nerve affection after RT occurred as mild symptoms with highest toxicity rate in FPT patients. Conclusion: SRS/HFSRT, FRT and FPT for VS show similar overall clinical and functional outcomes. Cranial nerve impairment rates vary, potentially due to selection bias with larger VS in the FRT and FPT group.
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13
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Hall JC, Chang SD, Wilson TJ, Ganjoo KN, Toland A, Vogel H, Pollom EL, Rahimy E. Post-operative Stereotactic Radiosurgery of Malignant Melanotic Schwannoma. Cureus 2022; 14:e22849. [PMID: 35399431 PMCID: PMC8980252 DOI: 10.7759/cureus.22849] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2022] [Indexed: 11/25/2022] Open
Abstract
Melanotic schwannoma is an extremely rare schwannoma variant with malignant potential, demonstrating high local and distant recurrence. Given the paucity of data, recommended treatment with localized disease is radical resection, with the unclear benefit of adjuvant therapy. We present a case of an 18-year-old female with no past medical history or genetic syndromes who underwent margin-positive resection of an S1 nerve root melanotic schwannoma followed by adjuvant stereotactic radiosurgery (SRS). SRS was delivered without acute or late toxicity by 2.5 years post-treatment. She remains without evidence of recurrent disease, although longer follow-up is needed given the risk of late recurrence. Our case adds to the limited literature documenting the efficacy of adjuvant radiotherapy in melanotic schwannoma and is the first to describe the successful use of SRS for this rare disease.
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14
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Thielhelm TP, Goncalves S, Welford SM, Mellon EA, Cohen ER, Nourbakhsh A, Fernandez-Valle C, Telischi F, Ivan ME, Dinh CT. Understanding the Radiobiology of Vestibular Schwannomas to Overcome Radiation Resistance. Cancers (Basel) 2021; 13:4575. [PMID: 34572805 PMCID: PMC8467596 DOI: 10.3390/cancers13184575] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/06/2021] [Accepted: 09/06/2021] [Indexed: 12/12/2022] Open
Abstract
Vestibular schwannomas (VS) are benign tumors arising from cranial nerve VIII that account for 8-10% of all intracranial tumors and are the most common tumors of the cerebellopontine angle. These tumors are typically managed with observation, radiation therapy, or microsurgical resection. Of the VS that are irradiated, there is a subset of tumors that are radioresistant and continue to grow; the mechanisms behind this phenomenon are not fully understood. In this review, the authors summarize how radiation causes cellular and DNA injury that can activate (1) checkpoints in the cell cycle to initiate cell cycle arrest and DNA repair and (2) key events that lead to cell death. In addition, we discuss the current knowledge of VS radiobiology and how it may contribute to clinical outcomes. A better understanding of VS radiobiology can help optimize existing treatment protocols and lead to new therapies to overcome radioresistance.
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Affiliation(s)
- Torin P Thielhelm
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Stefania Goncalves
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Scott M Welford
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Eric A Mellon
- Department of Radiation Oncology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Erin R Cohen
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Aida Nourbakhsh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Cristina Fernandez-Valle
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, FL 32816, USA
| | - Fred Telischi
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Michael E Ivan
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Christine T Dinh
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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15
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Pialat PM, Fieux M, Tringali S, Beldjoudi G, Pommier P, Tanguy R. Vestibular Schwannoma: Results of Hypofractionated Stereotactic Radiation Therapy. Adv Radiat Oncol 2021; 6:100694. [PMID: 34409203 PMCID: PMC8361054 DOI: 10.1016/j.adro.2021.100694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 02/11/2021] [Accepted: 03/11/2021] [Indexed: 11/23/2022] Open
Abstract
PURPOSE Our purpose was to study the outcomes of hypofractionated stereotactic radiation therapy (HSRT) in terms of hearing and radiologic response for vestibular schwannomas. METHODS AND MATERIALS This was a longitudinal retrospective study at a referral center from 2011 to 2016. All treatments were performed on a Cyberknife device with a dose of 21 Gy (3 × 7 Gy) or 25 Gy (5 × 5 Gy). We assessed tumor response, neurologic outcomes (hearing and facial nerve function), and treatment toxicity. RESULTS A total of 82 patients were included. Fifty-three patients were treated with the 3 × 7 Gy scheme and 29 with the 5 × 5 Gy. Sixteen patients (20%) had a previous surgery. The median follow-up was 48 months (range, 12-88 months). We noted 3 recurrences leading to a control rate of 96.3%. In our cohort, predictive factors of vestibular schwannoma growth were a tumor volume >2 mm3 and a conformal index <1.1 (P < .0001). The treatment was well tolerated with only 5 grade III acute toxicities (4 vertigo and 1 headache) and no grade IV or V. As for late toxicity, we noticed 2 cases of mild peripheral facial palsy (House and Brackman grade II) in previously operated patients. There was 46.0% hearing preservation among patients with serviceable hearing after HSRT. CONCLUSIONS Our results suggest that HSRT using 3 or 5 fractions is a well-tolerated and effective regimen. These findings are in addition to the few previous hypofractionation studies and contribute to the validity of this treatment modality.
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Affiliation(s)
| | - Maxime Fieux
- Department of Otolaryngology and Otoneurosurgery, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Claude Bernard University Lyon 1, Lyon, France
| | - Stéphane Tringali
- Department of Otolaryngology and Otoneurosurgery, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Claude Bernard University Lyon 1, Lyon, France
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16
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Cesme DH, Alkan A, Gultekin MA, Sari L, Alkan G, Kaya A, Mayadagli A, Akdur K, Uysal O, Hatiboglu MA. Diffusion Tensor Imaging Features of the Auditory Pathways in Patients With Vestibular Schwannoma After Gamma Knife Radiosurgery. Cureus 2021; 13:e14143. [PMID: 33927945 PMCID: PMC8075324 DOI: 10.7759/cureus.14143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Objective In this study, we aimed to investigate whether there is any change in diffusion tensor imaging (DTI) parameters in ipsilateral and contralateral auditory pathways after Gamma Knife radiosurgery (GKR) in patients with vestibular schwannoma (VS) and the relationship between radiosurgery variables. Methods Sixty-six patients were evaluated with MRI and DTI before and after GKR. The apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured from the bilateral lateral lemniscus (LL), inferior colliculus (IC), medial geniculate body (MGB), and Heschl's gyrus (HG). Results There was no significant difference in ADC and FA values obtained from bilateral LL, IC, and MGB before and after radiosurgery. However, there was a significant difference between pretreatment and post-radiosurgery contralateral HG ADC values. The ADC values obtained from the contralateral HG and IC positively correlated with the duration after radiosurgery. As the duration after radiosurgery increases, the difference between the ADC values obtained from ipsilateral and contralateral HG also increases. Conclusion The high ADC values in the contralateral HG after radiosurgery may indicate microstructural alterations such as demyelination and axonal loss. Radiation exposure doses to the brainstem and cochlea are the most important factors that can cause microstructural damage to the auditory pathways. When planning radiosurgery, extreme care should be taken to prevent the harmful effects of radiation on the auditory pathways.
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Affiliation(s)
- Dilek H Cesme
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Alpay Alkan
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Mehmet Ali Gultekin
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Lutfullah Sari
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Gokberk Alkan
- Otorhinolaryngology, Abdurrahman Yurtaslan Oncology Training and Research Hospital, Ankara, TUR
| | - Ahmet Kaya
- Department of Radiology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Alpaslan Mayadagli
- Radiation Oncology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Kerime Akdur
- Radiation Oncology, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Omer Uysal
- Biostatistics, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
| | - Mustafa A Hatiboglu
- Neurosurgery, Faculty of Medicine, Bezmialem Vakif University, Istanbul, TUR
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