Development of an evidence-based decision pathway for vestibular schwannoma treatment options

The impact of multiple deprivation on the management of vestibular schwannomas

PURPOSE

While some factors have been well-shown to affect the decision-making in treating patients with vestibular schwannomas (VS), little is known on the role of deprivation. Our objective was to assess the effect of socioeconomic background on the management of patients with VS.

METHODS

This retrospective cohort study included 460 patients with sporadic VS from West of Scotland. The postcode-based, multifactorial Scottish Index of Multiple Deprivation (SIMD) was used to assess the socioeconomic background of each patient. We performed a multivariate analysis including tumour size, growth and patient age with management modality (observation, stereotactic radiotherapy, microsurgery) being the main outcome measure and outcome (need for additional treatment) an additional measure.

RESULTS

We found no significant difference in the demographics, tumour characteristics and primary treatment choice between patients with different SIMD scores. In addition, there was no statistically significant difference in the growth occurrence rates following first-line treatment (p = 0.964) and in the second-line treatment choice (p = 0.460).

CONCLUSIONS

Multiple deprivation does not affect decision making in patients with VS in the examined cohort. This is probably linked to the centralisation and uniformity of the service and might not necessarily be applicable to other health services without centralisation.

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.

From the perspective of pseudo-progression rather than treatment failure, how long should we wait before considering treatment failure if large cystic enlargement occurs after Gamma Knife radiosurgery for vestibular schwannoma?: insight into pseudoprogression based on two case reports

Gamma knife radiosurgery (GKRS) has been accepted as a safe and effective treatment for vestibular schwannoma (VS). However, during follow-up, tumor expansion induced by irradiation can occur, and diagnosis of failure in radiosurgery for VS is still controversial. Tumor expansion with cystic enlargement causes some confusion regarding whether further treatment should be performed. We analyzed more than 10 years of clinical findings and imaging of patients with VS with cystic enlargement after GKRS. A 49-year-old male with hearing impairment was treated with GKRS (12 Gy; isodose, 50%) for a left VS with a preoperative tumor volume of 0.8 cc. The tumor size increased with cystic changes from the third year after GKRS, reaching a volume of 10.8 cc at 5 years after GKRS. At the 6th year of follow-up, the tumor volume started to decrease, up to 0.3 cc by the 14th year of follow-up. A 52-year-old female with hearing impairment and left facial numbness was treated with GKRS for a left VS (13 Gy; isodose, 50%). The preoperative tumor volume was 6.3 cc, which started to increase with cystic enlargement from the first year after GKRS, and reaching 18.2 cc by 5 years after GKRS. The tumor maintained a cystic pattern with slight changes in size, but no other neurologic symptoms developed during the follow-up period. After 6 years of GKRS, tumor regression was observed, eventually reaching a volume of 3.2 cc by the 13th year of follow-up. In both cases, persistent cystic enlargement in VS was observed at 5 years after GKRS, after which the tumors began to stabilize. After more than 10 years of GKRS, the tumor volume was less than that before GKRS. Enlargement with large cystic formation in the first 3-5 years after GKRS has been considered as treatment failure. However, our cases show that further treatment for cystic enlargement should be deferred for at least 10 years, especially in patients without neurological deterioration, as inadequate surgery can be prevented within that period.

After the Knife: A Detailed Roadmap for Vestibular Schwannoma Resection in the Semi-Sitting Position - How I do it

BACKGROUND

Vestibular schwannoma surgery remains a neurosurgical challenge, with known risks, dependent on a number of factors, from patient selection to surgical experience of the team. The semi-sitting position has gained popularity as an alternative to the traditional supine position for vestibular schwannoma resection due to potential advantages such as improved surgical exposure due to clearer surgical field and anatomical orientation. However, there is a lack of standardized protocols for performing the procedure in the semi-sitting position, leading to variations in surgical techniques and outcomes.

METHODS

In this study, we aimed to establish a standardized approach for vestibular schwannoma resection using the semi-sitting position. Initiating after final position for semi-sitting, the authors have divided the surgical steps into five major parts for improved understanding and replication. Surgical techniques were analyzed through one hundred steps to identify commonalities, determining the optimal procedural steps for the semi-sitting position using surgical video for visual conceptualization.

RESULTS

The analysis described one hundred steps for vestibular schwannoma resection in the semi-sitting position, with visual demonstration of the various parts of the procedure through surgical videos. Specific recommendations for each step were outlined, including appropriate approach, monitoring strategies, and tumor and posterior fossa structures manipulation. Five major parts of the procedure were identified, leading to a reproducible standardization of the surgical procedure of vestibular schwannoma resection in the semi-sitting position.

CONCLUSIONS

This study provides a comprehensive standardized protocol for the semi-sitting procedure in vestibular schwannoma resection. By establishing a consistent approach, surgeons can minimize variations in surgical techniques and improve patient outcomes. The identified steps and recommendations can serve as a valuable resource for surgical teams involved in vestibular schwannoma resection and facilitate the dissemination and reproducibility of best practices.

Development of Predictive Models for the Response of Vestibular Schwannoma Treated with Cyberknife®: A Feasibility Study Based on Radiomics and Machine Learning

PURPOSE

to predict vestibular schwannoma (VS) response to radiosurgery by applying machine learning (ML) algorithms on radiomic features extracted from pre-treatment magnetic resonance (MR) images.

METHODS

patients with VS treated with radiosurgery in two Centers from 2004 to 2016 were retrospectively evaluated. Brain T1-weighted contrast-enhanced MR images were acquired before and at 24 and 36 months after treatment. Clinical and treatment data were collected contextually. Treatment responses were assessed considering the VS volume variation based on pre- and post-radiosurgery MR images at both time points. Tumors were semi-automatically segmented and radiomic features were extracted. Four ML algorithms (Random Forest, Support Vector Machine, Neural Network, and extreme Gradient Boosting) were trained and tested for treatment response (i.e., increased or non-increased tumor volume) using nested cross-validation. For training, feature selection was performed using the Least Absolute Shrinkage and Selection Operator, and the selected features were used as input to separately build the four ML classification algorithms. To overcome class imbalance during training, Synthetic Minority Oversampling Technique was used. Finally, trained models were tested on the corresponding held out set of patients to evaluate balanced accuracy, sensitivity, and specificity.

RESULTS

108 patients treated with Cyberknife^® were retrieved; an increased tumor volume was observed at 24 months in 12 patients, and at 36 months in another group of 12 patients. The Neural Network was the best predictive algorithm for response at 24 (balanced accuracy 73% ± 18%, specificity 85% ± 12%, sensitivity 60% ± 42%) and 36 months (balanced accuracy 65% ± 12%, specificity 83% ± 9%, sensitivity 47% ± 27%).

CONCLUSIONS

radiomics may predict VS response to radiosurgery avoiding long-term follow-up as well as unnecessary treatment.

Patient-reported factors that influence the vestibular schwannoma treatment decision: a qualitative study

Purpose

In cases of small- to medium-sized vestibular schwannomas, three management strategies can be opted for: active surveillance, surgery or radiotherapy. In these cases, the patient’s preference is pivotal in decision-making. The aim of this study was to identify factors that influence a patient’s decision for a particular management strategy.

Methods

A qualitative inductive thematic analysis was performed based on semi-structured interviews. Eighteen patients with small- to medium-sized vestibular schwannomas were interviewed. All patients were diagnosed or treated at one of the two participating university medical centers in the Netherlands.

Results

Ten themes were identified that influenced the decision, classified as either medical or patient-related. The medical themes that emerged were: tumor characteristics, the physician’s recommendation, treatment outcomes and the perceived center’s experience. The patient-related themes were: personal characteristics, anxiety, experiences, cognitions, logistics and trust in the physician.

Conclusion

Knowledge of the factors that influence decision-making helps physicians to tailor their consultations to arrive at a true shared decision on vestibular schwannoma management.

Repeat Stereotactic Radiosurgery for Progressive or Recurrent Vestibular Schwannomas

BACKGROUND

Stereotactic radiosurgery (SRS) is a highly effective management approach for patients with vestibular schwannomas (VS), with 10-yr control rates up 98%. When it fails, however, few data are available to guide management.

OBJECTIVE

To perform a retrospective analysis of patients who underwent 2 SRS procedures on the same VS to assess the safety and efficacy of this practice.

METHODS

This study was opened to centers of the International Gamma Knife Research Foundation (IGKRF). Data collected included patient characteristics, clinical symptoms at the time of SRS, radiosurgery dosimetric data, imaging response, clinical evolution, and survival. Actuarial analyses of tumor responses were performed.

RESULTS

Seventy-six patients from 8 IGKRF centers were identified. Median follow-up from the second SRS was 51.7 mo. Progression after the first SRS occurred at a median of 43 mo. Repeat SRS was performed using a median dose of 12 Gy. Actuarial tumor control rates at 2, 5, and 10 yr following the second SRS were 98.6%, 92.2%, and 92.2%, respectively. Useful hearing was present in 30%, 8%, and 5% of patients at first SRS, second SRS, and last follow-up, respectively. Seventy-five percent of patients reported stable or improved symptoms following the second SRS. Worsening of facial nerve function attributable to SRS occurred in 7% of cases. There were no reports of radionecrosis, radiation-associated edema requiring corticosteroids, radiation-related neoplasia, or death attributable to the repeat SRS procedure.

CONCLUSION

Patients with progressing VS after radiosurgery can be safely and effectively managed using a second SRS procedure.