Long-Term Hearing Outcomes Following Stereotactic Radiosurgery in Vestibular Schwannoma Patients-A Retrospective Cohort Study

CyberKnife Stereotactic Radiosurgery for Growing Vestibular Schwannoma: Longitudinal Tumor Control, Hearing Outcomes, and Predicting Post-Treatment Hearing Status

OBJECTIVES

(1) To determine tumor control rates for treating growing vestibular schwannoma (VS) with CyberKnife stereotactic radiosurgery (CK SRS); (2) to determine hearing outcomes after CK SRS; (3) to propose a set of variables that could be used to predict hearing outcomes for patients receiving CK SRS for VS.

STUDY DESIGN

Retrospective case series review.

METHODS

127 patients who received CK SRS for radiographically documented growing VS were reviewed. Tumors were monitored for post-procedure growth radiographically with linear measurements and three-dimensional segmental volumetric analysis (3D-SVA). Hearing outcomes were reviewed for 109 patients. Cox proportional hazard modeling was used to identify variables correlated with hearing outcomes.

RESULTS

Tumor control rate was 94.5% for treating VS with CK SRS. Hearing outcomes were categorized using the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) classification system. As of their last available audiogram, 33.3% of patients with pre-treatment class A and 26.9% of patients with class B retained their hearing in that class. 15.3% of patients starting with class A or B with extended follow-up (>60 months), maintained hearing within this same grouping. Our final model proposed to predict hearing outcomes included age, fundal cap distance (FCD), tumor volume, and maximum radiation dose to the cochlea; however, FCD was the only statistically significant variable.

CONCLUSION

CK SRS is an effective treatment for control of VS. Hearing preservation by class was achieved in a third of patients. Finally, FCD was found to be protective against hearing loss.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:S1-S12, 2024.

Management of Central and Peripheral Nervous System Tumors in Patients with Neurofibromatosis

Neurofibromatosis type I (NF1), neurofibromatosis type 2 (NF2), and schwannomatosis represent a diverse group of genetic tumor predisposition syndromes with a shared feature of tumors affecting the peripheral nerve sheaths. PURPOSE OF REVIEW: Many advancements have been made in understanding the biologic underpinnings of these conditions, and in 2016 the first drug was approved by the FDA to treat pediatric symptomatic unresectable plexiform neurofibromas. RECENT FINDINGS: Mek inhibitors have provided a much-needed therapeutic avenue for NF1 patients with unresectable plexiform neurofibromas (PN), both for reduction of tumor bulk and for improvement in symptoms. Selumetinib is the first FDA approved drug for PN, but is only approved for children. Some research suggests that alternative Mek inhibitors and other mixed tyrosine kinase inhibitors may have better efficacy in adults. Vascular endothelial growth factor (VEGF) inhibitor bevacizumab can prolong hearing and delay the need for surgery in NF2 patients with bilateral vestibular schwannomas. This article provides an update regarding considerations and approaches when treating the tumors associated with the neurofibromatoses (NF), including risk and prognosis metrics, clinical trial results, surgical techniques, and radiation therapy recommendations.

Outcomes and Prognostic Factors in the Treatment of Intracanalicular Vestibular Schwannomas Using Gamma Knife Stereotactic Radiation

BACKGROUND

No gold standard has been developed for the therapy of intracanalicular vestibular schwannomas (IVS). Options for treatment include a conservative approach, microsurgery, or radiosurgery. Although the efficacy of these treatment has been well-documented, little is known about the determinants of outcome in IVSs following radiosurgery. Therefore, we examined the results in relation to age, gender, tumor volume, distance to fundus, microcyst existence, and radiosensitivity in this group. In addition, we investigated possible predictors of facial nerve function and hearing preservation.

METHODS

Ninety-four patients with unilateral IVS were included in the evaluation (52 women and 42 males). The patients were separated into younger and older age groups based on their median age (55 years). The median IVS volume was 138 mm3, microcysts were identified in 16 tumors, and 63 tumors were adjacent to the fundus. The data were analyzed using Statistica software package ver. 13.3.

RESULTS

At final follow-up, a statistically significant decrease in tumor volume and no statistically significant decline in hearing were noted, but no differences between age groups were found. The sex had no effect on overall tumor growth control, facial nerve preservation, or hearing preservation. Localization of IVS close to the fundus and the presence of tumor microcysts had no effect on the control of tumor growth, preservation of hearing, and sparing of facial nerve following radiosurgery. Cochlear dose had no influence on hearing preservation. Higher tumor volume was associated with its pseudoprogression during early follow-up and a greater risk of hearing loss.

CONCLUSIONS

Age, sex, tumor volume, proximity to the fundus, and the existence of a microcyst were not predictive of radiosensitivity nor preservation of facial nerve function and hearing, based on the findings. There was no effect of cochlear dose on hearing. Initial greater tumor volume was associated with an increased probability of tumor pseudoprogression.

Impact of Cochlear Dose on Hearing Preservation Following Stereotactic Radiosurgery in Treatment of Vestibular Schwannomas: A Multi-Center Study

OBJECTIVE

Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration.

METHODS

Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990-2020 and had pre- and post-treatment audiograms.

RESULTS

Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12-60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS.

CONCLUSIONS

Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing.

Long-term clinical outcomes of stereotactic radiotherapy for bilateral vestibular schwannomas in neurofibromatosis type 2 patients

PURPOSE

The evidence for treating patients with neurofibromatosis 2-related vestibular schwannoma (VS-NF2) using hypofractionated stereotactic radiation therapy (HSRT) is limited. This study aimed to investigate clinical outcomes in patients with VS-NF2 treated with Robotic HSRT.

METHODS

We retrospectively analyzed 25 NF2 patients with 48 VSs who were treated using Robotic HSRT at Ramathibodi Hospital from January 2009 to January 2020.

RESULTS

Median follow-up was 98 months (range, 24-155 months). Median tumor volume was 2.3 cm3 (range, 0.4-28.3 cm3). Median prescribed dose was 18 Gy (range, 18-25 Gy) in three fractions (range, 3-5). The 5- and 10-year local control rates were 87% and 80%, respectively. The 5- and 10-year hearing preservation rates were 59% and 35%, respectively. Three patients developed new symptoms associated with transient volume expansion after treatment: hydrocephalus in one, facial weakness in one, and ataxia in one. No patient developed worsening of trigeminal nerve function. No histologically confirmed of radiation induced malignancy was reported in the study.

CONCLUSIONS

Robotic HSRT demonstrated excellent long-term tumor control with a low non-auditory complication rate in patients with VS-NF2. However, preservation of hearing remains a major concern.

Factors associated with hearing outcomes after a middle fossa approach in 131 consecutive patients with vestibular schwannomas

OBJECTIVE

The middle fossa approach is an effective option for the treatment of small (Koos grade I and II) vestibular schwannomas (VSs) when the goal is hearing preservation. The authors evaluated the rates of hearing preservation and examined the factors associated with improved hearing outcomes after the middle fossa approach for VSs.

METHODS

In this retrospective, single-center cohort study evaluating the clinical outcomes after resection of small VSs using the middle fossa approach, consecutive adult patients (> 18 years) who underwent surgery between January 2000 and December 2021 were included. Clinical and imaging characteristics were analyzed, including baseline hearing status, duration of surgery, anesthetic parameters, and imaging characteristics of the surgically treated tumors.

RESULTS

Among the 131 included patients, 102 had valid and discoverable pre- and postoperative audiology assessments. The mean follow-up was 26 months (range 1-180 months). There were 85 patients with serviceable hearing preoperatively, defined as American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) class A or B, of whom 78% retained class A or B hearing at the last follow-up. Binary logistic regression demonstrated that preoperative hearing AAO-HNS class (OR 0.19, 95% CI 0.05-0.77; p = 0.02), overlap between fundus and cochlea (OR 0.32, 95% CI 0.11-0.96; p = 0.04), and duration of anesthesia (OR 0.98, 95% CI 0.97-0.99; p = 0.03) were independent predictors of hearing outcomes. Additionally, 75% of patients with high diffusion-weighted imaging signal in the tumor (p = 0.009) and 67% of patients with the tumor originating at the modiolus of the cochlea (p = 0.004) had poor hearing outcomes.

CONCLUSIONS

The hearing preservation rates after microsurgical resection of small VSs using the middle fossa approach are high, with 78% of patients maintaining AAO-HNS class A or B hearing. Poor hearing status at baseline, longer duration of anesthesia, and large overlap between the fundus of the internal auditory canal and the cochlea were independently associated with unfavorable hearing outcomes. Imaging characteristics can be used to stratify patients' risk of hearing loss.

Guiding Patients Through Decision-Making in Management of Sporadic Vestibular Schwannoma

Decision-making in management of sporadic vestibular schwannoma aims to identify the most appropriate options based on tumor characteristics, symptoms, health, and goals for each patient. Advances in knowledge of tumor natural history, improvements in radiation techniques, and achievements in neurologic preservation with microsurgery have shifted emphasis toward maximizing quality of life using a personalized approach. To empower patients to make informed decisions, we present a framework to help match patient values and priorities with reasonable expectations from modern management options. Introduced herein are practical examples of communication strategies and decision aids to support shared decision-making in modern practice.

Epidemiology and Risk Factors for Development of Sporadic Vestibular Schwannoma

Vestibular schwannomas (VSs) are benign, slow-growing tumors of the eighth cranial nerve. Sporadic unilateral VSs constitute approximately 95% of all newly diagnosed tumors. There is little known about risk factors for developing sporadic unilateral VS. Potential risk factors that have been reported are familial or genetic risk, noise exposure, cell phone use, and ionizing radiation, whereas protective factors may include smoking and aspirin use. More research is needed to elucidate the risk factors for development of these rare tumors.

Hearing After Vestibular Schwannoma Surgery: Is It Preserved Forever?

INTRODUCTION

Currently, it is possible to preserve the auditory nerve in a large number of cases, but the preservation of the hearing itself is unpredictable. Apart from wait and scan strategy and stereoradiotherapy, hearing after vestibular schwannoma surgery is considered to remain stable even in long-term follow-up.

MATERIALS AND METHODS

Twenty-eight patients had preserved hearing after retrosigmoid suboccipital microsurgery of the vestibular schwannoma between 2008 and 2014. A standard audiological protocol was performed together with an magnetic resonance imaging evaluation of the fluid content of the inner ear.

RESULTS

The mean difference in pure-tone average between the direct and final postsurgical examination was 12.758 dB ( p = 2.5E - 06). The word recognition score deteriorated by 17.45% ( p = 0.03516). The mean American Academy of Otolaryngology-Head and Neck Surgery score on the second examination was 2.5, and that on the second examination was 3.111 ( p = 0.00483). There was no significant deterioration in the healthy ear.The signal intensity ratio in the basal turn of the cochlea increased by an average of 0.13 points ( p < 0.05).Patients with persistent tumor or nodular enhancement in the internal acoustic meatus deteriorated significantly in hearing according to the American Academy of Otolaryngology-Head and Neck Surgery scale compared with patients without any finding in the meatus ( p = 0.01299).

CONCLUSIONS

There is a discrete but gradual deterioration of the hearing in the postoperative period. Hearing impairment is more pronounced in patients with a nodular process in the internal acoustic meatus, regardless of whether it is growth active. After surgery, the pathological content of the inner ear normalizes (evaluated on T2 magnetic resonance imaging sequences).

Audiovestibular symptoms and facial nerve function comparing microsurgery versus SRS for vestibular schwannomas: a systematic review and meta-analysis

OBJECTIVE

Surgery and radiosurgery represent the most common treatment options for vestibular schwannoma. A systematic review and meta-analysis were conducted to compare the outcomes of surgery versus stereotactic radiosurgery (SRS).

METHODS

The Cochrane library, PubMed, Embase, and clinicaltrials.gov were searched through 01/2021 to find all studies on surgical and stereotactic procedures performed to treat vestibular schwannoma. Using a random-effects model, pooled odds ratios (OR) and their 95% confidence intervals (CI) comparing post- to pre-intervention were derived for pre-post studies, and pooled incidence of adverse events post-intervention were calculated for case series and stratified by intervention type.

RESULTS

Twenty-one studies (18 pre-post design; three case series) with 987 patients were included in the final analysis. Comparing post- to pre-intervention, both surgery (OR: 3.52, 95%CI 2.13, 5.81) and SRS (OR: 3.30, 95%CI 1.39, 7.80) resulted in greater odds of hearing loss, lower odds of dizziness (surgery OR: 0.10; 95%CI 0.02, 0.47 vs. SRS OR: 0.22; 95%CI 0.05, 0.99), and tinnitus (surgery OR: 0.23; 95%CI 0.00, 37.9; two studies vs. SRS OR: 0.11; 95%CI 0.01, 1.07; one study). Pooled incidence of facial symmetry loss was larger post-surgery (14.3%, 95%CI 6.8%, 22.7%) than post-SRS (7%, 95%CI 1%, 36%). Tumor control was larger in the surgery (94%, 95%CI 83%, 98%) than the SRS group (80%, 95%CI 31%, 97%) for small-to-medium size tumors.

CONCLUSION

Both surgery and SRS resulted in similar odds of hearing loss and similar improvements in dizziness and tinnitus among patients with vestibular schwannoma; however, facial symmetry loss appeared higher post-surgery.

Fractionated Proton Radiation Therapy and Hearing Preservation for Vestibular Schwannoma: Preliminary Analysis of a Prospective Phase 2 Clinical Trial

BACKGROUND

Local management for vestibular schwannoma (VS) is associated with excellent local control with focus on preserving long-term serviceable hearing. Fractionated proton radiation therapy (FPRT) may be associated with greater hearing preservation because of unique dosimetric properties of proton radiotherapy.

OBJECTIVE

To investigate hearing preservation rates of FPRT in adults with VS and secondarily assess local control and treatment-related toxicity.

METHODS

A prospective, single-arm, phase 2 clinical trial was conducted of patients with VS from 2010 to 2019. All patients had serviceable hearing at baseline and received FPRT to a total dose of 50.4 to 54 Gy relative biological effectiveness (RBE) over 28 to 30 fractions. Serviceable hearing preservation was defined as a Gardner-Robertson score of 1 to 2, measured by a pure tone average (PTA) of ≤50 dB and a word recognition score (WRS) of ≥50%.

RESULTS

Twenty patients had a median follow-up of 4.0 years (range 1.0-5.0 years). Local control at 4 years was 100%. Serviceable hearing preservation at 1 year was 53% (95% CI 29%-76%), and primary end point was not yet reached. Median PTA and median WRS both worsened 1 year after FPRT (P < .0001). WRS plateaued after 6 months, whereas PTA continued to worsen up to 1 year after FPRT. Median cochlea D90 was lower in patients with serviceable hearing at 1 year (40.6 Gy [RBE] vs 46.9 Gy [RBE]), trending toward Wilcoxon rank-sum test statistical significance (P = .0863). Treatment was well-tolerated, with one grade 1 cranial nerve V dysfunction and no grade 2+ cranial nerve dysfunction.

CONCLUSION

FPRT for VS did not meet the goal of serviceable hearing preservation. Higher cochlea doses trended to worsening hearing preservation, suggesting that dose to cochlea correlates with hearing preservation independent of treatment modality.

Comparing Hearing Outcomes in Irradiated and Conservatively Managed Vestibular Schwannoma

OBJECTIVE

Compare hearing outcome for vestibular schwannoma patients following stereotactic radiosurgery (SRS) or conservative management.

STUDY DESIGN

Retrospective review.

SETTING

University Hospital.

PATIENTS

Patients with small- or medium-sized sporadic vestibular schwannoma (intracanalicular or with CPA component <2 cm) who were managed conservatively or underwent SRS with available clinical, radiological, and audiometric data from the time of presentation (or just before radiotherapy for the SRS group) and most recent follow-up; with the two sets of data to be compared being at least 3 years apart (minimum follow-up period).

INTERVENTIONS

SRS or observation.

MAIN OUTCOME MEASURE

Pure-tone averages, speech discrimination scores, and corresponding hearing classifications.

RESULTS

Two hundred forty-seven patients met our inclusion criteria; 140 were managed conservatively with a mean follow-up period of 5.9 ± 1.6 years and 107 underwent SRS with a mean follow-up period of 7.1 ± 1.9 years. There was significant deterioration of hearing measures for both groups; with the SRS group displaying consistently worse measures. SRS patients showed worse mean pure-tone averages and speech discrimination scores decline rates by 2.72 dB/yr and 2.98 %/yr, respectively, when compared with conservatively managed patients. Stratifying patients according to Tokyo's hearing classification revealed that 68.75% of conservatively managed patients who had baseline serviceable hearing preserved their hearing throughout the studied period compared with only 15.38% of the SRS patients.

CONCLUSION

Based on our data we conclude that patients with small- and medium-sized tumors will have a better hearing outcome if managed via an initial conservative approach with radiotherapy reserved for those demonstrating disease progression.

Long non-coding RNA BRCAT54 sponges microRNA-21 in vestibular schwannoma to suppress cell proliferation

BRCAT54 (also known as MRPS30 divergent transcript) is an anti-tumor long non-coding RNA (lncRNA) in lung cancer, while its role in vestibular schwannoma (VS) is unclear. We predicted that BRCAT54 could interact with microRNA (miR)-21, which suppresses VS cell proliferation. This study was then carried out to study the interaction between BRCAT54 and miR-21 in VS. A total of 56 VS samples and 42 normal vestibular nerve (VN) samples were included in this study. The expression of BRCAT54 and miR-21 in these samples were analyzed with RT-qPCR. Subcellular location of BRCAT54 in primary VS cells was analyzed by subcellular fractionation assay. The direct interaction between BRCAT54 and miR-21 was analyzed through RNA pull-down assay. Overexpression assay was performed to explore the interaction between BRCAT54 and miR-21. The role of BRCAT54 and miR-21 in primary VS cell proliferation was analyzed using BrdU assay. We found that BRCAT54 was downregulated in VS samples than that in VN samples, while miR-21 was upregulated in VS samples. BRCAT54 and miR-21 were not closely correlated. BRCAT54 was detected in both nuclear and cytoplasm samples, and BRCAT54 directly interacted with miR-21. However, BRCAT54 and miR-21 did not affect the expression of each other. BRCAT54 suppressed primary VS cell proliferation and inhibited the role of miR-21 in promoting cell proliferation. Therefore, BRCAT54 may sponge miR-21 to suppress cell proliferation in VS.

Tufts Medical Center Experience With Long-Term Follow-Up of Vestibular Schwannoma Treated With Gamma Knife Stereotactic Radiosurgery: Novel Finding of Delayed Pseudoprogression

Purpose

Our purpose was to evaluate the long-term outcomes of patients with vestibular schwannoma (VS) treated with Gamma Knife stereotactic radiosurgery (GKSRS) with modern techniques, with attention to posttreatment tumor growth dynamics, dosimetric predictors, and late toxicities.

Methods and Materials

One hundred twelve patients with VS were treated with GKSRS with a median dose of 12.5 Gy to the 50% isodose line treated between 2004 and 2015, with patients followed up to 15 years. Target and organ-at-risk doses were recorded, and tumor diameter/volume, audiologic decline, and trigeminal/facial nerve preservation were tracked from treatment onward.

Results

GKSRS yielded local control of 5, 10, and 15 years at 96.9%, 90.0%, and 87.1% respectively. Pseudoprogression was found in 45%, with a novel pattern detected with peak swelling at 31 months. Pseudoprogression was associated with smaller tumor diameter at treatment and fewer treatment isocenters, but not with the development of any toxicity, nor was it predicted by any dosimetric factor. Median time to hearing loss was 3.4 years with actuarial hearing preservation at 2, 5, and 10 years of 66.5%, 43.1%, and 37.6%, with rate of hearing loss correlating with maximum cochlea and modiolus doses. Trigeminal and facial nerve preservation rates were 92.7% and 97.6%, respectively. Increasing maximum tumor dose was associated with facial paresthesia.

Conclusions

Modern GKSRS is a safe and effective treatment for VS on long-term follow-up, with high levels of facial and trigeminal nerve preservation. A novel pattern of pseudoprogression has been identified suggesting longer imaging follow-up may be needed before initiating salvage in those without symptomatic progression. Several tumor and dosimetric predictors have been suggested for the development of different toxicities, requiring further evaluation.

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

BACKGROUND

To better counsel vestibular schwannoma patients, it is necessary to understand the tumor control rates of stereotactic radiosurgery (SRS).

OBJECTIVES

To determine tumor control rates, factors determining control and complication rates following SRS.

METHODS

Tertiary hospital retrospective cohort.

RESULTS

579 tumors (576 patients) were treated with SRS. 477 tumors (474 patients, 82%) had ≥1 year follow up and 60% (344) ≥3 years follow up. 88% of tumors had primary SRS and 6.7% salvage SRS. Median follow up time was 4.6 years. At 3 years, the tumor control rate of primary SRS was 89% (258 of 290) in sporadic tumors compared to 43% in Neurofibromatosis type II (3 of 17) (p < 0.01). Our bivariable survival data analysis showed that Neurofibromatosis type II, documented pre-SRS growth, tumor measured by maximum dimension, SRS given as nonprimary treatment increased hazard of failure to control. There was one case of malignancy and another of rapid change following intra-tumoral hemorrhage. For tumors undergoing surgical salvage (25 of 59), 56% had a total or near-total resection, 16% had postoperative CSF leak, with 12% new facial paralysis (House-Brackmann grade VI) and worsening of facial nerve outcomes (House-Brackmann grade worse in 59% at 12 mo).

CONCLUSIONS

Control of vestibular schwannoma after primary SRS occurs in the large majority. Salvage surgical treatment was notable for higher rates of postoperative complications compared to primary surgery reported in the literature.

Stereotactic Radiosurgery for Vestibular Schwannoma Outcomes in Patients With Perfect Word Recognition-A Retrospective Cohort Study

OBJECTIVES

To investigate tumor control rate and hearing outcomes following stereotactic radiosurgery (SRS) for vestibular schwannoma (VS) cases with perfect (100%) word recognition score (WRS).

STUDY DESIGN

A retrospective cohort study.

SETTING

Tertiary referral center.

PATIENTS

Inclusion criteria were receiving primary SRS, a pretreatment WRS of 100%, and availability of both pre- and posttreatment audiometric data for evaluation.

INTERVENTION

SRS delivered by Cyberknife.

MAIN OUTCOME MEASURES

Tumor growth rates and audiological outcomes after SRS.

RESULTS

The cohort consisted of 139 patients, with more than 1-year follow-up (mean 6.1 yrs). SRS tumor control rate was 87% for the whole cohort. Growth before SRS was documented in 24% (n = 34 of 139). The proportion of sporadic VS cases who maintained hearing (decline <10 dB of pure-tone audiometry or <20% of WRS) at 3 years was 50%, at 5 years was 45%, and at 10 years was 42%. In multivariate analysis, increased age was found to be predictive of increased hearing loss (p = 0.03), while the following factors were shown not to be significant: sex (p = 0.5), tumor size (p = 0.2), pre-SRS tumor growth (p = 0.5), and target volume (p = 0.42).

CONCLUSIONS

Among patients with VS who had perfect WRS and underwent SRS, the overall tumor control rate was 87% comparable to observation. Hearing maintenance and preservation of "serviceable" hearing rates after 5 years in VS patients with perfect WRS treated by SRS is less than that when comparing to similar observation cohorts. Given this finding we do not advocate using SRS to preserve hearing, over observation, in tumors with perfect WRS.

Longitudinal Changes of Quality of Life and Hearing Following Radiosurgery for Vestibular Schwannoma

Simple Summary

Since vestibular schwannomas are slow-growing tumors that can be controlled with different treatment modalities such as neurosurgery or radiotherapy, preserving quality of life is an important consideration. In this study, we analyzed how quality of life (QoL) changes for patients who receive stereotactic radiation in the months and years after treatment and if there is a correlation between changes in QoL and changes in hearing function. The results suggest that proper hearing of the unaffected ear might compensate for a hearing loss of the other ear due to the tumor or the treatment and in turn preserve QoL. However, this association should be confirmed in additional studies.

Abstract

Background: Most existing publications on quality of life (QoL) following stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) gather information retrospectively by conducting surveys several years after treatment. The purpose of this study is therefore to provide longitudinal QoL data and assess how changes in hearing impact QoL. Methods: Patients completed the 12-item short-form (SF-12) health survey prior to treatment and at every follow-up visit. One hundred and seventy-five patients who had complete forms prior to treatment as well as at an early and at a late follow-up were included in the analysis. For 51 of these patients, longitudinal audiometry data were available. Results: Median follow-up was 7.2 years. Patients experienced a significant reduction in the physical composite score (PCS, p = 0.011) compared to before treatment. The mental composite score (MCS) increased significantly (p = 0.032). A decrease in PCS was not significantly correlated with an increased hearing threshold on the affected but rather on the unaffected ear (r(49) = −0.32, p = 0.023). Conclusions: It is unclear whether the decline in the PCS is due to treatment-related toxicity or the normal decline of PCS with age. Ensuring proper hearing on the untreated ear might be crucial to ensure good QoL for patients treated with SRS for VS, though this association should be confirmed in additional studies.

Efficacy and comorbidities of hypofractionated and single-dose radiosurgery for vestibular schwannomas: a systematic review and meta-analysis

Background

Vestibular schwannomas (VS) are tumors of the cerebellopontine angle with significant morbidity, causing hearing loss, tinnitus, and trigeminal and facial nerve compromise. An effective alternative to microsurgical resection is stereotactic radiosurgery (SRS), which can be delivered in either single-fraction (SRS) or hypofractionated stereotactic radiotherapy (hSRT) (3-5 treatments) regimens. It remains unclear which fractionation regimen provides superior outcomes.

Methods

Ovid MEDLINE, EMBASE, CINAHL, and Cochrane Reviews were searched for studies either comparing hSRT with SRS or focusing on hSRT alone in treating VS. Primary endpoints included tumor control, serviceable hearing, tinnitus, and cranial nerve V and VII symptoms. A random-effects analysis was employed to compare pre- and post-treatment effects (hSRT alone) or SRS and hSRT outcomes (two-arm studies).

Results

This analysis included 21 studies focusing on hSRT alone and 13 studies comparing SRS and hSRT. Significant heterogeneity was observed. Overall, when hSRT was analyzed alone, crude tumor control was achieved in 94% (95% CI: 88%, 99%) of 1571 patients. There was no difference between pre- and post-treatment odds ratios (OR) of tinnitus, facial, or trigeminal impairment. Serviceable hearing was diminished following hSRT (OR = 0.60, 95% CI: 0.44, 0.83). Comparison with SRS showed no difference with respect to tumor control, serviceable hearing, trigeminal or facial nerve impairment.

Conclusions

hSRT achieved excellent tumor control and, with the exception of serviceable hearing, did not result in worse post-treatment cranial nerve symptomatology. Analysis of comparative studies between hSRT and SRS did not reveal any significant difference in either tumor control or treatment morbidities.

[Hearing classification in patients with vestibular schwannoma using German-language test procedures]

BACKGROUND

Hearing function in patients with vestibular schwannoma is often classified according to the Gardner and Robertson (1988) or the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS, 1995) systems. These classification systems are based on English-language test procedures, there is no German-language equivalent. The aim of the study was to investigate the influence of various target parameters on hearing classification and to derive a recommendation for the use of German-language test methods.

MATERIALS AND METHODS

The rules for speech audiometry based on English-language test procedures were applied to German speech test materials. In 91 patients with vestibular schwannoma, pure tone hearing thresholds, speech recognition thresholds, and speech discrimination at different sound pressure levels were measured. The patients were categorized according to the Gardner and Robertson and AAO-HNS classifications.

RESULTS

In both the Gardner-Robertson and the AAO-HNS classifications, the number of patients in the hearing classes with serviceable hearing function (measured as Pure Tone Average across three (3PTA) or four (4PTA) frequencies) was highest when using the 3PTA_{0,5;1;2 kHz} condition, followed by 4PTA_{0,5;1;2;3 kHz}, 4PTA_{0,5;1;2;4 kHz}, and 4PTA_{0,5;1;2;"3"kHz}. If maximum word recognition score (WRS_max) was used instead of word recognition 40 dB above the sensation level (WRS_40SL), more patients were classified into the hearing classes with serviceable hearing function, irrespective of the mean pure tone hearing threshold.

CONCLUSION

The Gardner-Robertson and AAO-HNS classifications can be used in German-speaking settings. The Freiburg monosyllabic test can be used to determine speech discrimination scores or maximum word recognition.

A Novel Imaging Grading Biomarker for Predicting Hearing Loss in Acoustic Neuromas

PURPOSE

The aim of this study was to investigate an imaging biomarker based on contrast enhanced T1-weighted and T2-weighted magnetic resonance imaging (MRI) to determine the hearing loss related to acoustic neuromas (AN).

METHODS

In this retrospective study, 441 acoustic neuromas treated with microsurgery were included. The diagnostic and follow-up MRI and audiometry of these patients were compared.

RESULTS

We discovered a new MRI grading biomarker based on the percentage of tumor filling the inner auditory canal (TFIAC classification). The area under the receiver operating characteristics (AUROC) curve was highest for TFIAC (0.675), followed by period of observation (0.615) and tumor size (0.6) (P < 0.001). The percentage of patients in TFIAC grade III (90.1%) experiencing hypoacusis prior to microsurgery was significantly higher than that in TFIAC grade I (72.7%, P = 0.037) and TFIAC grade IV patients had a higher rate of non-serviceable hearing compared to TFIAC grade III patients (P < 0.001). During the follow-up, TFIAC grade IV patients experienced a significantly higher rate of non-serviceable hearing than TFIAC grade III patients in all ANs (P < 0.001) and in serviceable hearing acoustic neuroma cases prior to surgery (TFIAC grade IV 55.4%, TFIAC grade III 69.0%, P = 0.045). The TFIAC grade IV patients experienced a significantly higher rate of facial nerve dysfunction than TFIAC grade III patients after surgery (grade IV 48.0%, grade III 26.1%, P < 0.001).

CONCLUSION

The TFIAC classification serves as a potential imaging biomarker for preoperative and postoperative hearing prediction in ANs, which may aid neurosurgeons in predicting hearing loss and selecting optimal surgical strategies.

Clinical Results After Single-fraction Radiosurgery for 1,002 Vestibular Schwannomas

Background

Herein, we report clinical results for patients treated with stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) over a period of 10 years.

Methods

Clinical data and imaging follow-up were stored in a database of 1,378 patients, with 1,384 VS treated consecutively between 2005 and 2018 and analyzed retrospectively. A total of 996 patients with 1,002 tumors with at least one year of follow-up were included for analysis.

Results

Median follow-up was 3·6 years (1-12·5 years). The three, five, and 10-year Kaplan-Meier estimated local tumor control was 96·6%, 92·3%, and 90·8%, respectively. The median hearing loss of the affected ear as compared to its healthy counterpart was 17 dB at treatment start and increased to 23 and 29 dB at one and five years. Six patients (0·6%) developed symptomatic hydrocephalus and underwent the placement of a ventriculoperitoneal shunt. In 30 patients (3·0%), trigeminal sensory dysfunction developed, five patients (0·5%) had a mild transient weakness, and nine patients (0·9%) had a permanent facial weakness (House-Brackmann Grade > II) after SRS.

Conclusion

Single fraction SRS proves to be highly effective and shows low treatment-related toxicity for VS. SRS should be considered a primary treatment option for small and middle-sized VS.