Factors predicting growth of vestibular schwannoma in neurofibromatosis type 2

Natural history of hearing and tumor growth in vestibular schwannoma in neurofibromatosis type 2-related schwannomatosis

OBJECTIVES

To determine the natural history of hearing loss and tumor volume in patients with untreated neurofibromatosis type 2 (NF2)-related schwannomatosis. Moreover, we statistically examined the factors affecting hearing prognosis.

METHODS

This retrospective cohort study was conducted on 37 ears of 24 patients with NF2-related vestibular schwannomatosis followed up without treatment for more than 1 year. We obtained detailed chronological changes in the PTA and tumor volume in each case over time, and the rate of change per year was obtained. Multivariate analysis was also conducted to investigate factors associated with changes in hearing.

RESULTS

The average follow-up period was approximately 9 years, and hearing deteriorated at an average rate of approximately 4 dB/year. The rate of maintaining effective hearing decreased from 30 ears (81%) at the first visit to 19 ears (51%) at the final follow-up. The average rate of change in tumor growth for volume was approximately 686.0 mm3/year. This study revealed that most patients with NF2 experienced deterioration in hearing acuity and tumor growth during the natural course. A correlation was observed between an increase in tumor volume and hearing loss (r = 0.686; p < 0.001).

CONCLUSIONS

Although the hearing preservation rate in NF2 cases is poor with the current treatment methods, many cases exist in which hearing acuity deteriorates, even during the natural course. Patients with an increased tumor volume during the follow-up period were more likely to experience hearing deterioration. Trial registration number 20140242 (date of registration: 27 October 2014).

Cochlear Implantation in Neurofibromatosis Type 2-Related Schwannomatosis: Long-Term Hearing Outcomes

OBJECTIVE

To evaluate long-term hearing outcomes following cochlear implantation in patients with neurofibromatosis type 2 and ipsilateral vestibular schwannoma.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary general hospital.

METHODS

Twenty-two patients undergoing cochlear implantation between 2004 and 2018 with at least 1 year of follow-up were included. Patients were categorized as "users" or "nonusers" of their cochlear implant (CI). For users, speech perception (disyllabic words) without lip-reading was assessed in quiet conditions 1-year postimplantation, and annually thereafter. CI users were classified into 2 groups on the basis of speech intelligibility (≥40% or <40%). Demographic data, treatment options, and tumor size were also recorded.

RESULTS

One year after implantation, 16 (73%) patients used their CI daily. Twelve of these patients had a speech intelligibility ≥40% (mean: 74 ± 21.9%). Three had a Koos stage IV tumor. At the last visit (mean duration of follow-up: 6 ± 5 years), 12 of these 16 patients were still using their implant daily, and 6 had a speech intelligibility ≥40%. No predictive factors for good performance at 1 year or performance stability were identified.

CONCLUSION

Neurofibromatosis type 2 is a complex disease profoundly affecting patient quality of life, and cochlear implantation should always be considered on a case-by-case basis. In some individuals, cochlear implantation can provide good speech intelligibility for extended periods, even posttreatment or in cases of large tumors.

Managing NF2-associated vestibular schwannomas in children and young adults: review of an institutional series regarding effects of surgery and bevacizumab on growth rates, tumor volume, and hearing quality

We reviewed our experience in managing of NF2-associated vestibular schwannoma (VS) in children and young adults regarding the effect of surgery and postoperative bevacizumab treatment. A total of 579 volumetric and hearing data sets were analyzed. The effect of surgery on tumor volume and growth rate was investigated in 46 tumors and on hearing function in 39 tumors. Long-term hearing follow-up behavior was compared with 20 non-operated ears in additional 15 patients. Sixteen operated VS were treated with bevacizumab. Mutation analysis of the NF2 gene was performed in 25 patients. Surgery significantly slowed down VS growth rate. Factors associated with a higher growth rate were increasing patient age, tumor volume, and constitutional truncating mutations. Immediately after surgery, functional hearing was maintained in 82% of ears. Deterioration of hearing was associated with initial hearing quality, larger tumor volumes, and larger resection amounts. Average hearing scores were initially better in the group of non-operated VS. Over time, hearing scores in both groups worsened with a similar dynamic. During bevacizumab treatment of residual tumors, four different patterns of growth were observed. Decompression of the internal auditory canal with various degrees of tumor resection decreases the postoperative tumor growth rates. Carefully tailored BAEP-guided surgery does not cause additional hearing deterioration. Secondary bevacizumab treatment showed heterogenous effects both regarding tumor size and hearing preservation. It seems that postoperative tumor residuals, that grow slower, behave differently to bevacizumab than reported for not-operated faster growing VS.

Management of NF2-associated vestibular schwannomas in children and young adults: influence of surgery and clinical factors on tumor volume and growth rate

OBJECTIVE

The authors' aim was to evaluate the tumor volume and growth rate of neurofibromatosis type 2 (NF2)-associated vestibular schwannomas (VSs) and the clinical factors or type of mutations before and after surgery in children and adults younger than 25 years at the time of diagnosis.

METHODS

A total of 579 volumetric measurements were performed in 46 operated tumors in 28 NF2 patients, using thin-slice (< 3 mm) T1-weighted contrast-enhanced MRI. The follow-up period ranged from 21 to 167 months (mean 75 months). Growth rate was calculated using a multilinear regression model. Mutation analysis of the NF2 gene was performed in 25 patients.

RESULTS

Surgery significantly (p = 0.013) slowed the VS growth rate from 0.69 ± 1.30 cm3/yr to 0.23 ± 0.42 cm3/yr. Factors significantly associated with a higher growth rate of VSs were increasing patient age (p < 0.0005), tumor volume (p = 0.006), tumor size (p = 0.001), and constitutional truncating mutations in the NF2 gene (p = 0.018). VS growth rates tended to be higher in patients with spinal ependymomas and in right-sided tumors and lower in the presence of peripheral schwannomas; however, no statistical significance was achieved.

CONCLUSIONS

Decompression of the internal auditory canal with various degrees of tumor resection decreases the postoperative tumor growth rate in children and young adults with NF2-associated VS. Patients with potential risk factors for accelerated growth (e.g., large volume, truncating mutations) and with increasing age should be monitored more closely before and after surgery.

Factors influencing the growth rate of vestibular schwannoma in patients with neurofibromatosis type 2

BACKGROUND

Neurofibromatosis type 2 (NF2) is a devastating disease with no well-accepted management guidelines. Better understanding of the disease process provides the basis for how or when to initiate treatment. Only few studies have addressed the factors influencing the growth rate of NF2-related vestibular schwannomas (VSs), and these studies have reported variable results. This study aimed to assess the clinical factors influencing the growth rate of NF2-related VSs.

METHODS

The medical records of 66 patients (totalling 74 VSs) were retrospectively analysed. The tumours were measured according to a two-component box model. The tumour growth rate was estimated by linear regression analysis of the changes in VS volumes over time. The clinical characteristics of all the patients were recorded. The relationship between the tumour growth rate and clinical factors were analysed. Linear regression, Pearson's correlation and Student's t-test were conducted using the SPSS 19.0 statistical package.

RESULTS

The median follow-up duration was 4.9 years. The VSs growth rate was highly correlated with the initial VS volume (r = 0.97, p < 0.01). However, it was inversely correlated with the age at symptom onset (r = -0.41, p < 0.01). The average VS growth rate in patients with spinal tumours was 13.18 cm(3)/year compared with 0.19 cm(3)/year in patients without spinal tumours (p < 0.01). The VS growth rate in patients who had resection of a contralateral VS was slightly higher than that of patients with untreated VSs (p < 0.01). Other factors including sex, vestibular symptom, presence of other cranial schwannomas, family history and dermal abnormalities did not affect the VS growth rate.

CONCLUSIONS

The potential clinical factors influencing the VS growth rate are the age at symptom onset, initial tumour volume and presence of spinal tumours. Surgical resection of VSs might accelerate the growth rate of contralateral tumours. The effects of these factors require further experimental confirmation.

Retrosigmoid Versus Translabyrinthine Approach for Acoustic Neuroma Resection: An Assessment of Complications and Payments in a Longitudinal Administrative Database

Object

Retrosigmoid (RS) and translabyrinthine (TL) surgery remain essential treatment approaches for symptomatic or enlarging acoustic neuromas (ANs). We compared nationwide complication rates and payments, independent of tumor characteristics, for these two strategies.

Methods

We identified 346 and 130 patients who underwent RS and TL approaches, respectively, for AN resection in the 2010-2012 MarketScan database, which characterizes primarily privately-insured patients from multiple institutions nationwide.

Results

Although we found no difference in 30-day general neurological or neurosurgical complication rates, in TL procedures there was a decreased risk for postoperative cranial nerve (CN) VII injury (20.2% vs 10.0%, CI 0.23–0.82), dysphagia (10.4% vs 3.1%, CI 0.10–0.78), and dysrhythmia (8.4% vs 2.3%, CI 0.08–0.86). Overall, there was no difference in surgical repair rates of CSF leak; however, intraoperative fat grafting was significantly higher in TL approaches (19.8% vs 60.2%, CI 3.95–9.43). In patients receiving grafts, there was a trend towards a higher repair rate after RS approach, while in those without grafts, there was a trend towards a higher repair rate after TL approach. Median total payments were $16,856 higher after RS approaches ($67,774 vs $50,918, p < 0.0001), without differences in physician or 90-day postoperative payments.

Conclusions 

Using a nationwide longitudinal database, we observed that the TL, compared to RS, approach for AN resection experienced lower risks of CN VII injury, dysphagia, and dysrhythmia. There was no significant difference in CSF leak repair rates. The payments for RS procedures exceed payments for TL procedures by approximately $17,000. Data from additional years and non-private sources will further clarify these trends.

Natural history of vestibular schwannoma growth and hearing decline in newly diagnosed neurofibromatosis type 2 patients

OBJECTIVE

To determine the rate of growth in vestibular schwannomas and the rate of hearing decline in neurofibromatosis type 2 (NF2) patients not undergoing active treatment

STUDY DESIGN

Prospective study.

SETTING

Data were collected at 10 NF2 centers, including hospital-based, academic, and tertiary care centers.

PATIENTS

120 NF2 patients with 200 vestibular schwannomas.

OUTCOME MEASURES

Hearing decline, defined as a decrease in word recognition score outside the 95% critical difference compared with baseline, and radiographic progression, defined as a 20% or greater increase in tumor volume compared with baseline.

RESULTS

During a total of 313.4 patient-years of follow-up, the rate of hearing decline was 5% at 1 year, 13% at 2 years, and 16% at 3 years; the rate of tumor progression was 31% at 1 year, 64% at 2 years, and 79% at 3 years. For this cohort, the median time to tumor progression (14 mo) was significantly shorter than the median time to hearing decline (62.0 mo).

CONCLUSION

These data provide potentially useful information for the design of clinical trials for NF2 vestibular schwannoma.

Conservative management of bilateral vestibular schwannomas in neurofibromatosis type 2 patients: hearing and tumor growth results

BACKGROUND

As new treatment modalities develop for the management of vestibular schwannomas (VS) in patients with neurofibromatosis type 2, it remains crucial to ascertain the natural history of the disease.

OBJECTIVE

To determine the relationship between hearing and tumor growth in patients undergoing conservative VS management.

METHODS

Patients harboring bilateral VS with at least 1 year of radiological follow-up were selected. Conservative management was proposed based on the small tumor size and/or serviceable hearing at presentation. Tumor size was calculated by using the 2-component box model and reported as mean tumor diameter. Hearing was evaluated by using pure-tone average and the American Academy of Otololaryngologists and Head and Neck Surgery classification.

RESULTS

Forty-six patients harboring 92 VS were included. The mean clinical and radiological follow-up times were 6.0 and 4.2 years, respectively. The mean tumor diameter was 13 mm at presentation and 20 mm at the end of follow-up. Mean tumor growth rate was 1.8 mm/year. During follow-up, 17 patients (37%) underwent surgery for VS. Surgery-free rate for VS was 88% at 5 years. The number of patients with at least 1 serviceable ear was 39 (85%) at presentation and 34 (74%) at the end of follow-up, including 22 (66%) with binaural serviceable hearing maintained. There was no statistical correlation between tumor growth rate and preservation of serviceable hearing. Tumor growth rates and age at presentation were inversely correlated.

CONCLUSION

This study illustrates the high variability among neurofibromatosis type 2 patients regarding hearing status and VS growth rate and justifies the choice of initial conservative management in selected cases.

ABBREVIATIONS

: AAO-HNS, American Academy of Otololaryngologists and Head and Neck Surgery classificationMTD, mean tumor diameterNF2, neurofibromatosis type 2PTA, pure-tone averageSDS, speech discrimination scoreVS, vestibular schwannomas.

The impact of stereotactic radiosurgery in the management of neurofibromatosis type 2-related vestibular schwannomas

Although there is an ongoing debate about the ideal management of vestibular schwannomas, radiosurgical treatment has become popular in the past decade with good to excellent results reported. Given the young age at presentation, the bilateral nature of vestibular schwanomas, the presence of other associated central nervous system tumors, patients with neurofibromatosis Type 2 (NF2) are very complex and present significant management challenges. Although results do not seem to be as good as for patients with sporadic unilateral tumors, stereotactic radiosurgery has proven a safe, attractive, and effective management modality for NF2 vestibular schwannomas. An overview of the impact stereotactic radiosurgery has had in the management of these tumors is discussed.

Long-term natural history of neurofibromatosis Type 2-associated intracranial tumors

OBJECT

Neurofibromatosis Type 2 (NF2) is a heritable tumor predisposition syndrome that leads to the development of multiple intracranial tumors, including meningiomas and schwannomas. Because the natural history of these tumors has not been determined, their optimal management has not been established. To define the natural history of NF2-associated intracranial tumors and to optimize management strategies, the authors evaluated long-term clinical and radiographic data in patients with NF2.

METHODS

Consecutive NF2 patients with a minimum of 4 years of serial clinical and MRI follow-up were analyzed.

RESULTS

Seventeen patients, 9 males and 8 females, were included in this analysis (mean follow-up 9.5±4.8 years, range 4.0-20.7 years). The mean age at initial evaluation was 33.2±15.5 years (range 12.3-57.6 years). Patients harbored 182 intracranial neoplasms, 164 of which were assessable for growth rate analysis (18 vestibular schwannomas [VSs], 11 nonvestibular cranial nerve [CN] schwannomas, and 135 meningiomas) and 152 of which were assessable for growth pattern analysis (15 VSs, 9 nonvestibular CN schwannomas, and 128 meningiomas). New tumors developed in patients over the course of the imaging follow-up: 66 meningiomas, 2 VSs, and 2 nonvestibular CN schwannomas. Overall, 45 tumors (29.6%) exhibited linear growth, 17 tumors (11.2%) exhibited exponential growth, and 90 tumors (59.2%) displayed a saltatory growth pattern characterized by alternating periods of growth and quiescence (mean quiescent period 2.3±2.1 years, range 0.4-11.7 years). Further, the saltatory pattern was the most frequently identified growth pattern for each tumor type: meningiomas 60.9%, VSs 46.7%, and nonvestibular schwannoma 55.6%. A younger age at the onset of NF2-related symptoms (p=0.01) and female sex (p=0.05) were associated with an increased growth rate in meningiomas. The identification of saltatory growth in meningiomas increased with the duration of follow-up (p=0.01).

CONCLUSIONS

Neurofibromatosis Type 2-associated intracranial tumors most frequently demonstrated a saltatory growth pattern. Because new tumors can develop in NF2 patients over their lifetime and because radiographic progression and symptom formation are unpredictable, resection may be best reserved for symptom-producing tumors. Moreover, establishing the efficacy of nonsurgical therapeutic interventions must be based on long-term follow-up (several years).

Increased growth rate of vestibular schwannoma after resection of contralateral tumor in neurofibromatosis type 2

Surgical management of bilateral vestibular schwannomas (VS) in neurofibromatosis type 2 (NF2) is often difficult, especially when both tumors threaten the brainstem. When the largest tumor has been removed, the management of the contralateral VS may become puzzling. To give new insights into the growth pattern of these tumors and to determine the best time point for treatment (surgery or medical treatment), we studied radiological growth in 11 VS (11 patients with NF2) over a long period (mean duration, 7.6 years), before and after removal of the contralateral tumor while both were threatening the brainstem. We used a quantitative approach of the radiological velocity of diametric expansion (VDE) on consecutive magnetic resonance images. Before first surgery, growth patterns of both tumors were similar in 9 of 11 cases. After the first surgery, VDE of the remaining VS was significantly elevated, compared with the preoperative period (2.5 ± 2.2 vs 4.4 ± 3.4 mm/year; P = .01, by Wilcoxon test). Decrease in hearing function was associated with increased postoperative growth in 3 cases. Growth pattern of coexisting intracranial meningiomas was not modified by VS surgery on the first side. In conclusion, removal of a large VS in a patient with NF2 might induce an increase in the growth rate of the contralateral medium or large VS. This possibility should be integrated in NF2 patient management to adequately treat the second VS.