Cochlear Radiation Dose Does Not Affect Hearing Preservation after Gamma Knife Radiosurgery in Those without Vestibular Schwannoma

Abstract BACKGROUND: Gamma Knife radiosurgery (GKRS) allows for the treatment of intracranial tumors with a high degree of dose conformality and precision. There are, however, certain situations wherein the dose conformality of GKRS is desired, but single-session treatment is contraindicated. In these situations, a traditional pin-based GKRS head frame cannot be used, because it precludes fractionated treatment. OBJECTIVE: To report our experience in treating patients with fractionated GKRS using a relocatable, noninvasive immobilization system. METHODS: Patients were considered candidates for fractionated GKRS if they had 1 or more of the following indications: a benign tumor >10 cc in volume or abutting the optic pathway, a vestibular schwannoma with the intent of hearing preservation, or a tumor previously irradiated with single-fraction GKRS. The immobilization device used for all patients was the Extend system (Leksell Gamma Knife Perfexion, Elekta, Kungstensgatan, Stockholm). RESULTS: We identified 34 patients treated with fractionated GKRS between August 2013 and February 2015. There were a total of 37 tumors treated including 15 meningiomas, 11 pituitary adenomas, 6 brain metastases, 4 vestibular schwannomas, and 1 hemangioma. At last follow-up, all 21 patients treated for perioptic tumors had stable or improved vision and all 4 patients treated for vestibular schwannoma maintained serviceable hearing. No severe adverse events were reported. CONCLUSION: Fractionated GKRS was well tolerated in the treatment of large meningiomas, perioptic tumors, vestibular schwannomas with intent of hearing preservation, and reirradiation of previously treated tumors.

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GAMMA KNIFE RADIOSURGERY IN YOUNGER PATIENTS WITH VESTIBULAR SCHWANNOMAS

Neurosurgery ◽

10.1227/01.neu.0000345944.14065.35 ◽

2009 ◽

Vol 65 (2) ◽

pp. 294-301 ◽

Cited By ~ 61

Author(s):

Javier Lobato-Polo ◽

Douglas Kondziolka ◽

Oscar Zorro ◽

Hideyuki Kano ◽

John C. Flickinger ◽

...

Keyword(s):

Gamma Knife ◽

Vestibular Schwannoma ◽

Gamma Knife Radiosurgery ◽

Hearing Preservation ◽

Vestibular Schwannomas ◽

Surgical Removal ◽

Management Options ◽

Younger Patients ◽

Cranial Nerve Dysfunction

Abstract OBJECTIVE Management options for patients with vestibular schwannoma include observation, surgical resection, stereotactic radiosurgery (SRS), and stereotactic radiation therapy. In younger patients, resection is often advocated because of concern regarding the long-term effects of radiation. We studied tumor response and clinical outcomes after SRS in such patients. METHODS We reviewed long-term outcomes in 55 patients with vestibular schwannomas. Patients were 40 years of age or younger, underwent gamma knife (GK) SRS between 1987 and 2003, and were followed up for a minimum of 4 years. The median patient age was 35 years (range, 13–40 years). Forty-one patients had Gardner-Robertson class 1 to 4 hearing. Thirteen patients (24%) had undergone surgical removal. The median tumor volume was 1.7 mm3. The median tumor margin dose was 13.0 Gy (range, 11–20 Gy). RESULTS At a median of 5.3 years, (range, 4–20 years), 2 of 55 patients underwent GK SRS for a second time; 1 of these patients had had a recurrence after initial resection. The 5-year rate of freedom from additional management was 96%. Hearing preservation rates (i.e., remaining within the same Gardner-Robertson hearing class) were 93%, 87%, and 87% at 3, 5, and 10 years, respectively. In patients with serviceable hearing before SRS, it was maintained in 100%, 93%, and 93% of patients at 3, 5, and 10 years, respectively. Hearing preservation was related to a margin dose lower than 13 Gy (P = 0.017). At the last assessment, facial and trigeminal nerve function was preserved in 98.2% and 96.4% of patients, respectively; the only facial deficit (House-Brackmann grade III) occurred in a patient who received a tumor dose of 20 Gy early in our experience (1988). None of the patients treated with doses lower than 13 Gy experienced facial or trigeminal neuropathy. All patients continued their previous level of activity or employment after GK SRS. No patient developed a secondary radiation-related tumor. CONCLUSION Our experience indicates that GK SRS is an effective management strategy for younger patients with vestibular schwannoma, most of whom have no additional cranial nerve dysfunction.

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Prognostic factors of hearing preservation after gamma knife radiosurgery for vestibular schwannoma

Journal of Clinical Neuroscience ◽

10.1016/j.jocn.2009.07.087 ◽

2010 ◽

Vol 17 (2) ◽

pp. 214-218 ◽

Cited By ~ 24

Author(s):

Chang-Hyun Kim ◽

Kyu Whan Chung ◽

Doo-Sik Kong ◽

Do-Hyun Nam ◽

Kwan Park ◽

...

Keyword(s):

Prognostic Factors ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Gamma Knife Radiosurgery ◽

Hearing Preservation

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Dosimetric and Clinical Analysis of Spatial Distribution of the Radiation Dose in Gamma Knife Radiosurgery for Vestibular Schwannoma

International Journal of Radiation Oncology*Biology*Physics ◽

10.1016/j.ijrobp.2011.03.047 ◽

2011 ◽

Vol 81 (4) ◽

pp. e511-e518 ◽

Cited By ~ 12

Author(s):

Nicolas Massager ◽

Sarah Lonneville ◽

Carine Delbrouck ◽

Nadir Benmebarek ◽

Françoise Desmedt ◽

...

Keyword(s):

Spatial Distribution ◽

Radiation Dose ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Gamma Knife Radiosurgery ◽

Clinical Analysis

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Patterns of Tumor Response and Nonauditory Morbidity Following Contemporary Reduced Dose Gamma Knife Radiosurgery for Vestibular Schwannoma

Skull Base ◽

10.1055/s-2011-1274246 ◽

2011 ◽

Vol 21 (S 01) ◽

Author(s):

Gelareh Zadeh ◽

Eric Monsalves ◽

Caroline Hayhurst

Keyword(s):

Gamma Knife ◽

Vestibular Schwannoma ◽

Tumor Response ◽

Gamma Knife Radiosurgery ◽

Reduced Dose

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Vestibular Schwannoma Tumor Size and Growth Rate Predict Response with Gamma Knife Stereotactic Radiosurgery

Journal of Neurological Surgery Part B Skull Base ◽

10.1055/s-0040-1716677 ◽

2020 ◽

Author(s):

Daniel E. Killeen ◽

Anthony M. Tolisano ◽

Brandon Isaacson ◽

J Walter Kutz ◽

Samuel Barnett ◽

...

Keyword(s):

Growth Rate ◽

Radiation Dose ◽

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Tumor Diameter ◽

Linear Measurements ◽

Level Of Evidence ◽

Axial Diameter ◽

Tumor Enlargement

Abstract Objective The aim of this study is to determine if pretreatment growth of sporadic vestibular schwannomas (VS) predicts postradiosurgery response. Methods This study was a retrospective chart review at a tertiary referral center of patients with VS that had at least two pretreatment magnetic resonance imaging (MRI) studies at least 6 months apart and underwent Gamma Knife radiosurgery with a minimum of 14 months postradiosurgery imaging surveillance. Tumor linear measurements and volumetric segmentation were assessed before and after radiosurgery. The main outcome measure was persistent enlargement following radiosurgery, defined as 2 mm enlargement in greatest axial diameter or 20% enlargement in volume without size regression. Results Thirty-five patients met the inclusion criteria. Patients were observed for median pre- and posttreatment intervals of 29.5 and 40.6 months, respectively. Median dose to the tumor margin was 13 Gy. Postradiosurgery enlargement occurred in six (17.1%) and nine (25.7%) patients based on linear and volumetric enlargement definitions, respectively. Pseudoprogression—defined as tumor enlargement—followed by linear or volumetric regression that occurred in 34.3% of tumors, reaching a maximum size at a median time of 6.3 months (3.3–8.4) postradiosurgery. When controlling for age, gender, and radiation dose, preradiosurgery tumor volume less than 0.3 cm3 (odds ratio [OR]: 59.7, p = 0.012) and preradiosurgery tumor diameter growth rate greater than or equal to 2.5 mm/year (OR: 19.3, p = 0.045) were associated with persistent postradiosurgery tumor enlargement. Conclusion Smaller pretreatment tumor volume and greater linear tumor growth rates were associated with postradiosurgery tumor enlargement when controlling for age, gender, and radiation dose. Level of Evidence :This study indicates that the level of evidence is V.

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Gamma Knife Radiosurgery does not alter the copy number aberration profile in sporadic vestibular schwannoma

Journal of Neuro-Oncology ◽

10.1007/s11060-020-03631-4 ◽

2020 ◽

Vol 149 (3) ◽

pp. 373-381

Author(s):

Aril Løge Håvik ◽

Ove Bruland ◽

Dhanushan Dhayalan ◽

Morten Lund-Johansen ◽

Per-Morten Knappskog

Keyword(s):

Radiation Exposure ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Copy Number ◽

Statistical Tests ◽

Gamma Knife Radiosurgery ◽

Copy Number Aberration ◽

Recurrent Event ◽

Chromosome 22 ◽

Increased Risk

Abstract Introduction Ionizing radiation is a known etiologic factor in tumorigenesis and its role in inducing malignancy in the treatment of vestibular schwannoma has been debated. The purpose of this study was to identify a copy number aberration (CNA) profile or specific CNAs associated with radiation exposure which could either implicate an increased risk of malignancy or elucidate a mechanism of treatment resistance. Methods 55 sporadic VS, including 18 treated with Gamma Knife Radiosurgery (GKRS), were subjected to DNA whole-genome microarray and/or whole-exome sequencing. CNAs were called and statistical tests were performed to identify any association with radiation exposure. Hierarchical clustering was used to identify CNA profiles associated with radiation exposure. Results A median of 7 (0–58) CNAs were identified across the 55 VS. Chromosome 22 aberration was the only recurrent event. A median aberrant cell fraction of 0.59 (0.25–0.94) was observed, indicating several genetic clones in VS. No CNA or CNA profile was associated with GKRS. Conclusion GKRS is not associated with an increase in CNAs or alteration of the CNA profile in VS, lending support to its low risk. This also implies that there is no major issue with GKRS treatment failure being due to CNAs. In agreement with previous studies, chromosome 22 aberration is the only recurrent CNA. VS consist of several genetic clones, addressing the need for further studies on the composition of cells in this tumor.

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