Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose

Thomas, C.; Maio, Salvatore Di; Ma, Roy; Vollans, E.; Chu, Christina; Clark, Brenda; Lee, Richard; McKenzie, Michael; Martin, Montgomery; Toyota, Brian

doi:10.3171/jns-07/11/0917

Cited by 80 publications

(47 citation statements)

References 50 publications

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“…All studies that reported the details of their planning techniques used both computed tomography and MRI treatment plans (47,51,52,54,56,57,59,60). Most institutions used a 1-2-mm margin on the contrast-enhancing tumor as seen on MRI (52,54,56,57,59,60). Using various fractionation schemes, the rate of trigeminal and facial nerve preservation has been $95% and $94%, respectively (47,(51)(52)(53)(54)(55)(56)(57)(58)(59)(60).…”

Section: Fractionated Stereotactic Rtmentioning

confidence: 97%

“…Most institutions used a 1-2-mm margin on the contrast-enhancing tumor as seen on MRI (52,54,56,57,59,60). Using various fractionation schemes, the rate of trigeminal and facial nerve preservation has been $95% and $94%, respectively (47,(51)(52)(53)(54)(55)(56)(57)(58)(59)(60).…”

Section: Fractionated Stereotactic Rtmentioning

confidence: 97%

“…The current radiation dose prescribed for FSRT ranges between 40-57.6 Gy in 1.8-2-Gy/fraction (47,52,53,(55)(56)(57)(58)(59)(60). The ultimate goal of these fractionation schemes has been to improve the rate of hearing preservation.…”

Section: Fractionated Stereotactic Rtmentioning

confidence: 98%

“…The data reporting long-term follow-up of FSRT for VS have revealed a local tumor control rate of 94-100% (47, 51-60) ( Table 4). All studies that reported the details of their planning techniques used both computed tomography and MRI treatment plans (47,51,52,54,56,57,59,60). Most institutions used a 1-2-mm margin on the contrast-enhancing tumor as seen on MRI (52,54,56,57,59,60).…”

Section: Fractionated Stereotactic Rtmentioning

confidence: 98%

“…From the 13 studies reviewed for modern SRS results, only 2 groups(28,32) report the delineation of organs at risk during treatment planning. Only 3(52,57,60) of the 10 studies of long-term results of FSRT discussed contouring organs at risk as a part of their treatment planning. As we embark on improving treatment plans, we need to agree on a consensus of which critical structures should be included and how to contour the target and critical structures.…”

mentioning

confidence: 99%

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Radiotherapy for Vestibular Schwannomas: A Critical Review

Murphy

Suh

2011

International Journal of Radiation Oncology*Biology*Physics

166

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Section: Fractionated Stereotactic Rtmentioning

confidence: 97%

Section: Fractionated Stereotactic Rtmentioning

confidence: 97%

Section: Fractionated Stereotactic Rtmentioning

confidence: 98%

Section: Fractionated Stereotactic Rtmentioning

confidence: 98%

mentioning

confidence: 99%

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Radiotherapy for Vestibular Schwannomas: A Critical Review

Murphy

Suh

2011

International Journal of Radiation Oncology*Biology*Physics

166

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Radiosurgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2

Phi¹,

Kim²,

Chung³

et al. 2009

Cancer

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BACKGROUND:The radiosurgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2 (NF2) is controversial. The authors investigated the radiologically proven tumor control rate after gamma knife radiosurgery. The factors that affect tumor control and serviceable hearing preservation were analyzed.METHODS:Thirty‐six lesions in 30 patients were included. The median lengths of the clinical and radiologic follow‐ups were 48.5 months and 36.5 months, respectively. The median tumor volume was 3.2 cm3. The mean marginal dose was 12.1 grays (Gy) (range, 8–14 Gy) at an isodose line of 50%±0.6%. The Kaplan‐Meier method and Cox proportional hazards model were used for the statistical analyses.RESULTS:The actuarial tumor control rate was 81%, 74%, and 66%, respectively, in the first, second, and fifth years. Five tumors required a salvage surgery because of tumor control failure. A low marginal dose and a young age at radiosurgery were associated with poor tumor control. Of the 16 tumors with which ipsilateral hearing was serviceable, the actuarial serviceable hearing preservation rates were 50%, 45%, and 33%, respectively, in the first, second, and fifth years. Better ipsilateral hearing (Gardner‐Robertson grade 1, compared with grade 2) at the time of radiosurgery was associated with significantly greater serviceable hearing preservation.CONCLUSIONS:Gamma knife radiosurgery for vestibular schwannomas in NF2 patients provided 5‐year tumor control in approximately two‐thirds of patients and preserved serviceable hearing in approximately one‐third. The rates of other cranial nerve deficits were low, and no secondary malignancy was observed. Radiosurgery should be included in treatment options for NF2 patients. Cancer 2009. © 2009 American Cancer Society.

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Hearing preservation in patients with unilateral vestibular schwannoma who undergo stereotactic radiosurgery

Han¹,

Kim²,

Chung³

et al. 2012

Cancer

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BACKGROUND:The objective of this study was to identify the prognostic factors for hearing preservation that would allow the more accurate stratification of patients who undergo stereotactic radiosurgery (SRS) for unilateral, sporadic vestibular schwannoma (VS). METHODS: In total, 119 patients with VS who had serviceable hearing underwent SRS as primary treatment. The mean (AEstandard deviation) patient age was 48 AE 11 years, and the mean (AEstandard deviation) follow-up duration was 55.2 AE 35.7 months. The median marginal radiotherapy dose was 12.0 grays (Gy), and the mean (AEstandard deviation) tumor volume was 1.95 AE 2.24 cm 3 . The mean (AEstandard deviation) pure tone average (PTA) score was 26 AE 12 decibels (dB) (range, 4-50 dB), and the mean (AEstandard deviation) maximum speech discrimination score was 91 AE 12% (range, 52-100%). The mean (AEstandard deviation) baseline values for the interlatency (IL) of waves I and III (IL I-III) and the IL of waves I through V (IL I-V) on auditory brainstem response were 2.58 AE 0.60 milliseconds (mS) (range, 1.92-4.30 mS) and 4.80 AE 0.61 mS (range, 3.80-6.40 mS), respectively. RESULTS: In multivariate analysis, the PTA score and IL I-V were significant and independent prognostic factors (hazard ratio, 1.072; 95% confidence interval, 1.046-1.098; P < .001; and hazard ratio, 1.534; 95% confidence interval, 1.008-2.336; P ¼ .046, respectively). By using the PTA score and IL I-V, the patients were classified into 4 groups. The ratios of patients with serviceable hearing after SRS were 89.6%, 64.0%, 25.8%, and 6.7%, respectively, in Groups A through D (P < .001). CONCLUSIONS: The current results indicated that the classification system based on using the PTA score and the IL I-V of the auditory brainstem response may be useful and specific for predicting the rate of hearing preservation in each individual. Cancer 2012;118:5441-7. V C 2012 American Cancer Society.KEYWORDS: radiosurgery, vestibular schwannoma, hearing preservation, classification system, auditory brainstem response. INTRODUCTIONIn 1988, Gardner and Robertson described a classification system for predicting hearing preservation in patients who underwent surgery for unilateral vestibular schwannoma (VS). 1 This system, called the Gardner-Robertson classification system (G-R classification), is simple, straightforward, and can be performed from memory. Thus, the G-R classification also has been useful for classifying hearing levels both before and after stereotactic radiosurgery (SRS) for VS, 2-5 although this system was based on the results from a surgical series of patients with VS.SRS was first designed in 1951 by Lars Leksell, 6 and the use of SRS was expanded to include the treatment of VS in 1969. 7 Since the publication of Leksell's 1971 report, 7 numerous efforts have been made to increase the tumor control rate and reduce the risk of cranial nerve injury. Consequently, many reports on long-term outcomes after SRS for VS indicated not only excellent progression-free survival rates of 92% to 100% bu...

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Hearing preservation following fractionated stereotactic radiotherapy for vestibular schwannomas: prognostic implications of cochlear dose

Abstract: The radiation dose to the cochlea is strongly predictive for subsequent hearing deterioration. It is essential for the cochlea to be outlined as an organ at risk, and for radiation techniques to be optimized, to improve long-term hearing preservation.

Cited by 80 publications

References 50 publications

Radiotherapy for Vestibular Schwannomas: A Critical Review

Radiotherapy for Vestibular Schwannomas: A Critical Review

Radiosurgical treatment of vestibular schwannomas in patients with neurofibromatosis type 2

Hearing preservation in patients with unilateral vestibular schwannoma who undergo stereotactic radiosurgery

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