Stereotactic Radiosurgery for Vestibular Schwannomas: Tumor Control Probability Analyses and Recommended Reporting Standards

OBJECTIVEThis report evaluates the outcomes of stereotactic radiosurgery (SRS) as the first-line treatment of intracanalicular vestibular schwannomas (VSs).METHODSBetween 1987 and 2017, the authors identified 209 patients who underwent SRS as the primary intervention for a unilateral intracanalicular VS. The median patient age was 54 years (range 22–85 years); 94 patients were male and 115 were female. Three patients had facial neuropathy at the time of SRS. One hundred fifty-five patients (74%) had serviceable hearing (Gardner-Robertson [GR] grades I and II) at the time of SRS. The median tumor volume was 0.17 cm3 (range 0.015–0.63 cm3). The median margin dose was 12.5 Gy (range 11.0–25.0 Gy). The median maximum dose was 24.0 Gy (range 15.7–50.0 Gy).RESULTSThe progression-free survival rates of all patients with intracanalicular VS were 97.5% at 3 years, 95.6% at 5 years, and 92.1% at 10 years. The rates of freedom from the need for any additional intervention were 99.4% at 3 years, 98.3% at 5 years, and 98.3% at 10 years. The serviceable hearing preservation rates in GR grade I and II patients at the time of SRS were 76.6% at 3 years, 63.5% at 5 years, and 27.3% at 10 years. In univariate analysis, younger age (< 55 years, p = 0.011), better initial hearing (GR grade I, p < 0.001), and smaller tumor volumes (< 0.14 cm3, p = 0.016) were significantly associated with improved hearing preservation. In multivariate analysis, better hearing (GR grade I, p = 0.001, HR 2.869, 95% CI 1.569–5.248) and smaller tumor volumes (< 0.14 cm3, p = 0.033, HR 2.071, 95% CI 1.059–4.047) at the time of SRS were significantly associated with improved hearing preservation. The hearing preservation rates of patients with GR grade I VS were 88.1% at 3 years, 77.9% at 5 years, and 38.1% at 10 years. The hearing preservation rates of patients with VSs smaller than 0.14 cm3 were 85.5% at 3 years, 77.7% at 5 years, and 42.6% at 10 years. Facial neuropathy developed in 1.4% from 6 to 156 months after SRS.CONCLUSIONSSRS provided sustained tumor control in more than 90% of patients with intracanalicular VS at 10 years and freedom from the need for additional intervention in more than 98% at 10 years. Patients with initially better hearing and smaller VSs had enhanced serviceable hearing preservation during an observation interval up to 10 years after SRS.

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Tumor Control Following Stereotactic Radiosurgery in Patients with Vestibular Schwannomas – A Retrospective Cohort Study

Otology & Neurotology ◽

10.1097/mao.0000000000003285 ◽

2021 ◽

Vol Publish Ahead of Print ◽

Author(s):

Peter L. Santa Maria ◽

Yangyang Shi ◽

Ksenia A. Aaron ◽

Richard K. Gurgel ◽

C. Eduardo Corrales ◽

...

Keyword(s):

Cohort Study ◽

Stereotactic Radiosurgery ◽

Retrospective Cohort Study ◽

Retrospective Cohort ◽

Vestibular Schwannomas ◽

Tumor Control

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Stereotactic radiosurgery for vestibular schwannomas: average 10-year follow-up results focusing on long-term hearing preservation

Journal of Neurosurgery ◽

10.3171/2016.7.gks161494 ◽

2016 ◽

Vol 125 (Supplement_1) ◽

pp. 64-72 ◽

Cited By ~ 34

Author(s):

Shinya Watanabe ◽

Masaaki Yamamoto ◽

Takuya Kawabe ◽

Takao Koiso ◽

Tetsuya Yamamoto ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Tumor Volume ◽

Hearing Preservation ◽

Interquartile Range ◽

Vestibular Schwannomas ◽

Long Term Results ◽

Tumor Control ◽

Univariable Analysis

OBJECTIVEThe aim of this study was to reappraise long-term treatment outcomes of stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs). The authors used a database that included patients who underwent SRS with a unique dose-planning technique, i.e., partial tumor coverage designed to avoid excess irradiation of the facial and cochlear nerves, focusing on tumor control and hearing preservation. Clinical factors associated with post-SRS tumor control and long-term hearing preservation were also analyzed.METHODSThis institutional review board–approved, retrospective cohort study used the authors' prospectively accumulated database. Among 207 patients who underwent Gamma Knife SRS for VSs between 1990 and 2005, 183 (who were followed up for at least 36 post-SRS months) were studied. The median tumor volume was 2.0 cm3 (range 0.05–26.2 cm3). The median prescribed dose at the tumor periphery was 12.0 Gy (range 8.8–15.0 Gy; 12.0 Gy was used in 171 patients [93%]), whereas tumor portions facing the facial and cochlear nerves were irradiated with 10.0 Gy. As a result, 72%–99% of each tumor was irradiated with the prescribed dose. The mean cochlear doses ranged from 2.3 to 5.7 Gy (median 4.1 Gy).RESULTSThe median durations of imaging and audiometric follow-up were 114 months (interquartile range 73–144 months) and 59 months (interquartile range 33–109 months), respectively. Tumor shrinkage was documented in 110 (61%), no change in 48 (27%), and enlargement in the other 22 (12%) patients. A further procedure (FP) was required in 15 (8%) patients. Thus, the tumor growth control rate was 88% and the clinical control rate (i.e., no need for an FP) was 92%. The cumulative FP-free rates were 96%, 93%, and 87% at the 60th, 120th, and 180th post-SRS month, respectively. Six (3%) patients experienced facial pain, and 2 developed transient facial palsy. Serviceable hearing was defined as a pure tone audiogram result better than 50 dB. Among the 66 patients with serviceable hearing before SRS who were followed up, hearing acuity was preserved in 23 (35%). Actuarial serviceable hearing preservation rates were 49%, 24%, and 12% at the 60th, 120th, and 180th post-SRS month, respectively. On univariable analysis, only cystic-type tumor (HR 3.36, 95% CI 1.18–9.36; p = 0.02) was shown to have a significantly unfavorable association with FP. Multivariable analysis followed by univariable analysis revealed that higher age (≥ 65 years: HR 2.66, 95% CI 1.16–5.92; p = 0.02), larger tumor volume (≥ 8 cm3: HR 5.36, 95% CI 1.20–17.4; p = 0.03), and higher cochlear dose (mean cochlear dose > 4.2 Gy: HR 2.22, 95% CI 1.07–4.77; p = 0.03) were unfavorable factors for hearing preservation.CONCLUSIONSStereotactic radiosurgery achieved good long-term results in this series. Tumor control was acceptable, and there were few serious complications in patients with small- to medium-sized VSs. Unfortunately, hearing preservation was not satisfactory. However, the longer the observation period, the more important it becomes to compare post-SRS hearing decreases with the natural decline in untreated cases.

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Tumor Control Rates in Patients Undergoing Stereotactic Radiosurgery for Cystic Vestibular Schwannomas: A Systematic Review and Meta-Analysis

Neurosurgery ◽

10.1093/neuros/nyz310_648 ◽

2019 ◽

Vol 66 (Supplement_1) ◽

Author(s):

Kevin Ding ◽

Edwin Ng ◽

Prasanth Romiyo ◽

Dillon Dejam ◽

Courtney Duong ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Meta Analysis ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Limiting Factor ◽

Tumor Control Rate ◽

Pertinent Data ◽

Funnel Plots ◽

Initial Impressions

Abstract INTRODUCTION Cystic vestibular schwannomas (VS) represent a subtype that grows more rapidly due to expansion of cystic contents and are important candidates for stereotactic radiosurgery (SRS) intervention due to their tendency to adhere to the neurovasculature. However, the paucity of comprehensive outcomes data is currently a limiting factor to understanding the potential of using SRS to treat cystic VS. METHODS This study was conducted in accordance with the PRISMA guidelines. A search was conducted in October 2018 through the PubMed, Scopus, Embase, Web of Science, and Cochrane databases. Data on tumor control rates were extracted and analyzed using meta-analysis and tests for heterogeneity between articles, with the t2, Cochran's Q, and I2 statistics reported. Publication bias was assessed using funnel plots and Egger's testing. RESULTS A total of 246 patients underwent SRS for cystic VS, with reported mean or median follow-up of 49.7 to 150 mo. Following SRS treatment for cystic VS across all studies, 92% of patients had tumor control at follow up, (95%-CI: 88%-95%). In studies that specifically reported tumor control rate at 5 yr, control rate was also 92% (95%-CI: 87%-95%). Tumor control rate specifically for patients who underwent GammaKnife was 93% (95%-CI: 88%-95%). CONCLUSION Results of our meta-analysis suggest that SRS is a viable treatment option for cystic VS, exhibiting effective tumor control rates. Despite the paucity of pertinent data, our conclusions provide evidence in contrast to the initial impressions of SRS treatment for cystic VS within the neurosurgical community.

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A Dose-Response Model of Local Tumor Control Probability After Stereotactic Radiosurgery for Brain Metastases Resection Cavities

Advances in Radiation Oncology ◽

10.1016/j.adro.2020.06.007 ◽

2020 ◽

Vol 5 (5) ◽

pp. 840-849

Author(s):

Chengcheng Gui ◽

Jimm Grimm ◽

Lawrence Richard Kleinberg ◽

Peter Zaki ◽

Nicholas Spoleti ◽

...

Keyword(s):

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Dose Response ◽

Local Tumor Control ◽

Tumor Control ◽

Response Model ◽

Tumor Control Probability ◽

Local Tumor

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Meta-analysis of tumor control rates in patients undergoing stereotactic radiosurgery for cystic vestibular schwannomas

Clinical Neurology and Neurosurgery ◽

10.1016/j.clineuro.2019.105571 ◽

2020 ◽

Vol 188 ◽

pp. 105571 ◽

Cited By ~ 1

Author(s):

Kevin Ding ◽

Edwin Ng ◽

Prasanth Romiyo ◽

Dillon Dejam ◽

Methma Udawatta ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Meta Analysis ◽

Vestibular Schwannomas ◽

Tumor Control

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Multisession Stereotactic Radiosurgery for Vestibular Schwannomas: Single-Institution Experience With 383 Cases

Neurosurgery ◽

10.1227/neu.0b013e318222e451 ◽

2011 ◽

Vol 69 (6) ◽

pp. 1200-1209 ◽

Cited By ~ 51

Author(s):

Ake Hansasuta ◽

Clara Y. H. Choi ◽

Iris C. Gibbs ◽

Scott G. Soltys ◽

Victor C. K. Tse ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Tumor Volume ◽

Medical Center ◽

Neurofibromatosis Type ◽

Hearing Preservation ◽

Additional Treatment ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Complication Rates ◽

Kaplan Meier

Abstract BACKGROUND Single-session stereotactic radiosurgery (SRS) treatment of vestibular schwannomas results in excellent tumor control. It is not known whether functional outcomes can be improved by fractionating the treatment over multiple sessions. OBJECTIVE To examine tumor control and complication rates after multisession SRS. METHODS Three hundred eighty-three patients treated with SRS from 1999 to 2007 at Stanford University Medical Center were retrospectively reviewed. Ninety percent were treated with 18 Gy in 3 sessions, targeting a median tumor volume of 1.1 cm3 (range, 0.02-19.8 cm3). RESULTS During a median follow-up duration of 3.6 years (range, 1-10 years), 10 tumors required additional treatment, resulting in 3- and 5-year Kaplan-Meier tumor control rates of 99% and 96%, respectively. Five-year tumor control rate was 98% for tumors > 3.4 cm3. Neurofibromatosis type 2–associated tumors were associated with worse tumor control (P = .02). Of the 200 evaluable patients with pre-SRS serviceable hearing (Gardner-Robertson grade 1 and 2), the crude rate of serviceable hearing preservation was 76%. Smaller tumor volume was associated with hearing preservation (P = .001). There was no case of post-SRS facial weakness. Eight patients (2%) developed trigeminal dysfunction, half of which was transient. CONCLUSION Multisession SRS treatment of vestibular schwannomas results in an excellent rate of tumor control. The hearing, trigeminal nerve, and facial nerve function preservation rates reported here are promising.

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Proton Beam Radiosurgery for Vestibular Schwannoma: Tumor Control and Cranial Nerve Toxicity

Neurosurgery ◽

10.1227/01.neu.0000079369.59219.c0 ◽

2003 ◽

Vol 53 (3) ◽

pp. 577-588 ◽

Cited By ~ 81

Author(s):

Damien C. Weber ◽

Annie W. Chan ◽

Marc R. Bussiere ◽

Griffith R. Harsh ◽

Marek Ancukiewicz ◽

...

Keyword(s):

Stereotactic Radiosurgery ◽

Proton Beam ◽

Trigeminal Nerve ◽

Cranial Nerve ◽

Univariate Analysis ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Transverse Diameter ◽

Nerve Function ◽

Function Preservation

Abstract OBJECTIVE We sought to determine the tumor control rate and cranial nerve function outcomes in patients with vestibular schwannomas who were treated with proton beam stereotactic radiosurgery. METHODS Between November 1992 and August 2000, 88 patients with vestibular schwannomas were treated at the Harvard Cyclotron Laboratory with proton beam stereotactic radiosurgery in which two to four convergent fixed beams of 160-MeV protons were applied. The median transverse diameter was 16 mm (range, 2.5–35 mm), and the median tumor volume was 1.4 cm3 (range, 0.1–15.9 cm3). Surgical resection had been performed previously in 15 patients (17%). Facial nerve function (House-Brackmann Grade 1) and trigeminal nerve function were normal in 79 patients (89.8%). Eight patients (9%) had good or excellent hearing (Gardner-Robertson [GR] Grade 1), and 13 patients (15%) had serviceable hearing (GR Grade 2). A median dose of 12 cobalt Gray equivalents (range, 10–18 cobalt Gray equivalents) was prescribed to the 70 to 108% isodose lines (median, 70%). The median follow-up period was 38.7 months (range, 12–102.6 mo). RESULTS The actuarial 2- and 5-year tumor control rates were 95.3% (95% confidence interval [CI], 90.9–99.9%) and 93.6% (95% CI, 88.3–99.3%). Salvage radiosurgery was performed in one patient 32.5 months after treatment, and a craniotomy was required 19.1 months after treatment in another patient with hemorrhage in the vicinity of a stable tumor. Three patients (3.4%) underwent shunting for hydrocephalus, and a subsequent partial resection was performed in one of these patients. The actuarial 5-year cumulative radiological reduction rate was 94.7% (95% CI, 81.2–98.3%). Of the 21 patients (24%) with functional hearing (GR Grade 1 or 2), 7 (33.3%) retained serviceable hearing ability (GR Grade 2). Actuarial 5-year normal facial and trigeminal nerve function preservation rates were 91.1% (95% CI, 85–97.6%) and 89.4% (95% CI, 82–96.7%). Univariate analysis revealed that prescribed dose (P = 0.005), maximum dose (P = 0.006), and the inhomogeneity coefficient (P = 0.03) were associated with a significant risk of long-term facial neuropathy. No other cranial nerve deficits or cancer relapses were observed. CONCLUSION Proton beam stereotactic radiosurgery has been shown to be an effective means of tumor control. A high radiological response rate was observed. Excellent facial and trigeminal nerve function preservation rates were achieved. A reduced prescribed dose is associated with a significant decrease in facial neuropathy.

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