Vestibular Schwannoma: The Evolution of Hearing and Tumor Size in Natural Course and after Treatment by LINAC Stereotactic Radiosurgery

Ikonomidis, Christos; Pica, Alessia; Bloch, Jocelyne; Maire, Richard

doi:10.1159/000441119

Cited by 15 publications

(16 citation statements)

References 31 publications

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“…The estimated TCP is consistent with clinical reports, in which prescription doses of at least 12 Gy for SRS and 50 Gy for IMRT yielded TCP values of >90%. 9 , 10 , 11 , 12 All NTCP predictions for SNHL were significantly higher for the clinical plans than for the 4π plans. The average NTCP was 10.0% higher for the clinical plans at 3 years and 18.4% higher at 5 years posttreatment.…”

Section: Resultsmentioning

confidence: 88%

“…All model parameters were selected on the basis of published clinical data on the relationship between treatment outcomes (tumor control and complication rates) and dose delivered to the tumor and cochleae. 9 , 10 , 11 , 12 Because the fractionation schemes varied widely among patients in this study, all plan doses were normalized to a reference dose of 2 Gy per fraction for radiobiologic modeling.…”

Section: Methodsmentioning

confidence: 99%

“…Almost half of patients may also experience some degree of sensorineural hearing loss (SNHL), which continues to worsen for years after treatment. 6 , 7 , 8 , 9 , 10 , 11 , 12 …”

Section: Introductionmentioning

confidence: 99%

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Cochlea-sparing acoustic neuroma treatment with 4π radiation therapy

Woods

Lee

Kaprealian

et al. 2018

Advances in Radiation Oncology

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PurposeThis study investigates whether 4π noncoplanar radiation therapy can spare the cochleae and consequently potentially improve hearing preservation in patients with acoustic neuroma who are treated with radiation therapy.Methods and materialsClinical radiation therapy plans for 30 patients with acoustic neuroma were included (14 stereotactic radiation surgery [SRS], 6 stereotactic radiation therapy [SRT], and 10 intensity modulated radiation therapy [IMRT]). The 4π plans were created for each patient with 20 optimal beams selected using a greedy column generation method and subsequently recalculated in Eclipse for comparison. Organ-at-risk (OAR) doses, homogeneity index, conformity, and tumor control probability (TCP) were compared. Normal tissue complication probability (NTCP) was calculated for sensorineural hearing loss (SNHL) at 3 and 5 years posttreatment. The dose for each plan was then escalated to achieve 99.5% TCP.Results4π significantly reduced the mean dose to both cochleae by 2.0 Gy (32%) for SRS, 3.2 Gy (29%) for SRT, and 10.0 Gy (32%) for IMRT. The maximum dose to both cochleae was also reduced with 4π by 1.6 Gy (20%), 2.2 Gy (15%), and 7.1 Gy (18%) for SRS, SRT, and IMRT plans, respectively. The reductions in mean/maximum brainstem dose with 4π were also statistically significant. Mean doses to other OARs were reduced by 19% to 56% on average. 4π plans had a similar CN and TCP, with a significantly higher average homogeneity index (0.93 vs 0.92) and significantly lower average NTCP for SNHL at both 3 years (30.8% vs 40.8%) and 5 years (43.3% vs 61.7%). An average dose escalation of approximately 116% of the prescription dose achieved 99.5% TCP, which resulted in 32.6% and 43.4% NTCP for SNHL at 3 years and 46.4% and 64.7% at 5 years for 4π and clinical plans, respectively.ConclusionsCompared with clinical planning methods, optimized 4π radiation therapy enables statistically significant sparing of the cochleae in acoustic neuroma treatment as well as lowering of other OAR doses, potentially reducing the risk of hearing loss.

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Section: Resultsmentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

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Cochlea-sparing acoustic neuroma treatment with 4π radiation therapy

Woods

Lee

Kaprealian

et al. 2018

Advances in Radiation Oncology

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“…Spontaneous shrinkage of VS has been reported in 3–11% of VS managed conservatively [2–4,6,7,13], but few studies have characterized these tumors in detail with accurate imaging and volumetric analysis.…”

Section: Discussionmentioning

confidence: 99%

“…Most of the growing tumors grow slowly, frequently allowing a wait-and-scan strategy that usually consists of a first MRI 6 months after diagnosis, to detect the fast growing VSs that will require treatment, followed by an annual MRI [5]. Spontaneous shrinkage has rarely been observed [2–4,6,7].…”

Section: Introductionmentioning

confidence: 99%

How to radiologically identify a spontaneous regression of sporadic vestibular schwannoma?

et al. 2019

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Background The natural history of sporadic vestibular schwannoma is unpredictable, with tumors growing, non-growing and even showing spontaneous regression in some rare cases. Objective This retrospective study aims to describe the radiologic signs characterizing and identifying the shrinking vestibular schwannoma. Methods Involution was considered to have occurred if tumor size had decreased by 2 mm or more on its largest diameter. All magnetic resonance imaging scans were reviewed for tumor size, internal auditory meatus size, and tumor characteristics. Volumetric measurements were performed on the first and last scan. Audiometric data were collected at the first and last visit. Results Fourteen patients with a confirmed spontaneous regression were included, with a mean follow-up of 5 ± 2.6 years. The mean shrinkage rate was 0.9 ± 0.59 mm/year on 2D measurements, and 0.2 ± 0.17 cm 3 /year on volumetric measurements, with a relative shrinkage of 40 ± 16.9%. Two remarkable radiologic features were observed: First, a festooned aspect, defined by multiple curves in the tumor outline, noticed in 12 cases (86%); second, the appearance of cerebrospinal fluid filling the internal auditory meatus, associated with an enlargement of the internal auditory meatus compared to the contralateral side, and observed in 10 out of 13 cases with internal auditory meatus invasion (77%). Those two aspects were associated in 64% of cases. Conclusion These two newly reported radiologic features could help neurosurgeons, oto-neurosurgeons and neuroradiologists to identify a spontaneous vestibular schwannoma involution at first visit. This could allow any treatment to be postponed, monitoring to be more widely spaced, and patients to be reassured.

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