Long-term results of Gamma-knife stereotactic radiosurgery for vestibular schwannomas in patients with type 2 neurofibromatosis

Fractionated Stereotactic Radiotherapy Compared to Stereotactic Radiosurgery for Vestibular Schwannoma in Patients with Type 2 Neurofibromatosis

BACKGROUND

The use of radiotherapy (RT) for the treatment of vestibulocochlear schwannomas is standard in patients with type 2 neurofibromatosis (NF2). In the general population, fractionated RT (FRT) can achieve good results compared to single-dose radiosurgery (SRS). We aimed to assess whether this is true for NF2 patients as well.

METHODS

This retrospective cohort study included 34 patients and 54 lesions treated between 2010 and 2023 in a single university hospital.

RESULTS

Thirty-four patient charts were assessed. The median follow-up was 62.6 months (range, 7.1-135.8 months). Lesion size (median larger diameter, 2.5 cm) was correlated with the use of FRT (P > 0.001). Younger age also was correlated with FRT (P = 0.006). Median overall survival and progression-free survival (PFS) were not reached. The overall control rate was 76.5%, and the mean PFS was 49.8 months, compared with . 90.5% and 57.2 months, respectively, for SRS and 66.7% and 44.9 months, respectively, for FRT. There were no differences between the 2 groups in hearing loss, tinnitus, and facial palsy.

CONCLUSIONS

In the NF2 population, FRT may yield worse control rates than SRS. Whenever possible, it is preferable to not fractionate treatment for these patients. Nevertheless, the FRT results were still good. More and larger prospective trials are warranted.

Phase II trial of icotinib in adult patients with neurofibromatosis type 2 and progressive vestibular schwannoma

OBJECTIVE

Neurofibromatosis type 2 (NF2) is a rare autosomal dominant syndrome associated primarily with bilateral vestibular schwannomas (VSs). Conventional surgical or radiosurgical treatments for VS in NF2 usually result in high risks of hearing loss and facial nerve impairment, while there is no validated medical option to date. This single-institution phase II study evaluated the efficacy and safety of icotinib, an oral epidermal growth factor receptor tyrosine kinase inhibitor, in patients with NF2 and progressive VS.

METHODS

Icotinib was administered daily at 375 mg orally in a continuous 28-day course for up to 12 courses. The primary endpoint of the study was radiographic response assessed by brain MRI using 3D volumetric tumor analysis and defined as a ≥ 20% decrease in VS volume. Hearing function was evaluated as a secondary endpoint, with response defined as a statistically significant increase in word recognition scores.

RESULTS

Ten eligible patients with a mean age of 23.8 years were enrolled. One patient (10%) with bilateral tumors experienced an objective radiographic response (-23.58% and -22.01%). Three (43%) of 7 patients met the hearing response criteria. At 12 months, the estimated progression-free survival was 82.0% (95% CI 42.3%-95.5%) for volumetric progression and 69.2% (95% CI 37.3%-87.2%) for hearing progression. Common mild to moderate adverse events included rash (90%), diarrhea (50%), myalgia (20%), and nausea/gastrointestinal pain (20%).

CONCLUSIONS

Icotinib carries minor toxicity and is associated with radiographic and hearing responses in patients with NF2 and progressive VS.

Two-Stage Resection of a Giant Trigeminal Schwannoma in a Non-Neurofibromatosis Type 2 Pediatric Patient: A Case Report, Systematic Review, and Intraoperative Video

BACKGROUND

Trigeminal schwannoma is an uncommon tumor in pediatric patients. Several surgical approaches have been described in the literature.

METHODS

The case of an 11-year-old boy with a giant dumbbell-shaped trigeminal schwannoma removed through a 2-stage approach was presented with an intraoperative video. Using PubMed and Scopus, the literature on trigeminal schwannoma in pediatric patients was searched according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines.

RESULTS

The search strategy yielded 312 titles, of which 13 were included in the review. Cases of trigeminal schwannoma were described, with a highly variable clinical presentation and anatomical arrangement in cranial fossae. Two-stage approaches were reported, although most studies described single-stage approaches. Common postoperative outcomes were a range of disturbances of cranial nerve V.

CONCLUSIONS

The surgical approach varies based on the tumor conformation. However, a 2-stage pterional subtemporal and semisitting retrosigmoid approach is a safe, practical, and effective strategy for the removal of dumbbell-shaped trigeminal schwannoma in a pediatric patient.

Tumor Control and Hearing Preservation After Gamma Knife Radiosurgery for Vestibular Schwannomas in Neurofibromatosis Type 2-A Retrospective Analysis of 133 Tumors

OBJECTIVE

This study was conducted with the aim to estimate long-term tumor control and hearing preservation rates in patients with neurofibromatosis 2 (NF2)-related vestibular schwannoma (VS), document retreatment success rate, and assess the associated predictive factors.

METHODS

This was a retrospective analysis of patients with NF2-associated VS who underwent Gamma Knife radiosurgery (GKRS) between 2009 and 2020 and had a minimum follow-up of 1 year. Loss of tumor control was defined as greater than 10% increase in volume in more than one follow-up imaging or the need for retreatment in the form of repeat GKRS or surgery. The Kaplan-Meier method was used to evaluate actuarial tumor control and hearing preservation rates.

RESULTS

In total, 85 patients with 133 VSs were included in the study. The mean age was 29.8 years. In total, 57 tumors showed tumor regression, 35 showed stable disease, and 23 progressed in size at last follow up. Actuarial tumor control rates after 1, 3, 5, and 9 years were 95%, 79%, 75%, and 55%, respectively, with overall tumor control rate being 85%. Hearing worsened in 39 patients, and facial nerve dysfunction occurred in 4 patients. Five tumors underwent retreatment with GKRS at a median duration of 27.6 months (19-36 months) following the first GKRS.

CONCLUSIONS

This is the largest radiosurgical series of NF2-associated VS reported to date. GKRS provides a high rate of long-term local tumor control with a low risk of neurologic deprivation for patients with these tumors. The need for retreatment with GKRS, although low, is associated with good tumor control and lesser complications.

Vestibular schwannoma associated with neurofibromatosis type 2: Clinical course following stereotactic radiosurgery

Objective

A lack of understanding of the clinical course of neurofibromatosis type 2 (NF2)-associated vestibular schwannoma (VS) often complicates the decision-making in terms of optimal timing and mode of treatment. We investigated the outcomes of stereotactic radiosurgery (SRS) in this population.

Methods

We retrospectively analyzed NF2 patients treated with Gamma-Knife SRS for VS in our tertiary referral center. A total of 41 treated lesions from 33 patients were collected with a follow-up period of 69.1 (45.0-104.8) months. We reviewed the treatment history, hearing function, and other treatment-related morbidities in individual cases. We also analyzed pre- and post-treatment tumor volumes via imaging studies. Longitudinal volumetric analyses were conducted for the tumor volume response of the 41 treated lesions following SRS. The growth pattern of 22 unirradiated lesions during an observation period of 83.4 (61.1-120.4) months was separately evaluated.

Results

Most treated lesions showed effective tumor control up to 85% at 60 months after SRS, whereas unirradiated lesions progressed with a relative volume increase of 14.0% (7.8-27.0) per year during the observation period. Twelve (29%) cases showed pseudoprogression with significant volume expansion in the early follow-up period, which practically reduced the rate of tumor control to 57% at 24 months. Among the patients with serviceable hearing, two (20%) cases lost the hearing function on the treated side during the early follow-up period within 24 months.

Conclusions

Progressive NF2-associated VS can be adequately controlled by SRS but the short-term effects of this treatment are not highly advantageous in terms of preserving hearing function. SRS treatment candidates should therefore be carefully selected.

Stereotactic radiosurgery for vestibular schwannomas in neurofibromatosis type 2 patients: a systematic review and meta-analysis

INTRODUCTION

Neurofibromatosis type 2 (NF2) is characterized by often bilateral vestibular schwannomas (VS) that result in progressive hearing loss and compression of nearby brainstem structures causing cranial nerve palsies. Treatment of these tumors remains challenging, as both surgical removal and expectant management can result in symptom progression. Stereotactic radiosurgery (SRS) has been investigated for the management of NF2-associated VS; however, the role, promises, and pitfalls of this treatment modality remain unclear.

METHODS

Ovid MEDLINE, EMBASE, Web of Science, and Cochrane Reviews were searched for studies assessing SRS outcome in NF2-associated VS only. Primary endpoints included tumor control, serviceable hearing, presence of tinnitus, and cranial nerve V and VII symptoms.

RESULTS

A total of 16 studies (589 patients harboring 750 tumors) were analyzed. Clinical tumor control was achieved in 88% of cases (95% CI 80-95%); salvage surgery was needed in 8% (95% CI 4-13%) of cases. Treatment resulted in a worsening of pre-treatment serviceable hearing (OR = 0.26, p < 0.01), increased facial nerve (OR = 1.62, p < 0.01) and trigeminal nerve (OR = 1.42, p = 0.07) impairment. The incidence of vestibular symptoms and hydrocephalus were not consistently reported and thus could not be assessed.

CONCLUSIONS

The treatment of NF2-associated VS continues to pose a challenge, as current SRS regimens result in impaired hearing and worse cranial nerve comorbidities, despite achieving high tumor control. It remains unclear if these findings have to be regarded as treatment complications or, rather, continued disease progression.

Glioblastoma multiforme as a secondary malignancy following stereotactic radiosurgery of a meningioma: case report

The documentation and exact incidence of stereotactic radiosurgery (SRS)-induced neoplasia is not well understood, with most literature restricted to single case reports and single-center retrospective reviews. The authors present a rare case of radiosurgery-induced glioblastoma multiforme (GBM) following radiosurgical treatment of a meningioma. A 74-year-old patient with a sporadic meningioma underwent radiosurgery following surgical removal of a WHO grade II meningioma. Eighteen months later she presented with seizures, and MRI revealed an intraaxial tumor, which was resected and proven to be a glioblastoma. As far as the authors are aware, this case represents the third case of GBM following SRS for a meningioma. This report serves to increase the awareness of this possible complication following SRS. The possibility of this rare complication should be explained to patients when obtaining their consent for radiosurgery.

A Systematic Review of Radiosurgery Versus Surgery for Neurofibromatosis Type 2 Vestibular Schwannomas

OBJECTIVE

Neurofibromatosis type 2 (NF2) is an autosomal dominant disease characterized by bilateral vestibular schwannomas (VSs). NF2-associated VSs (NF2-VSs) are routinely treated with microsurgery; however, stereotactic radiosurgery (SRS) has emerged as an effective alternative in recent decades. To elucidate the role of SRS in NF2-VSs, a systematic review of the literature was conducted to compare outcomes of SRS versus surgery.

METHODS

PubMed, Web of Science, Scopus, Embase, and Cochrane databases were queried using relevant search terms. Retrospective studies investigating outcomes of NF2-VS patients treated with either SRS or surgery were included. Single-patient case reports were excluded. Outcome measures between the SRS and surgery groups were compared using χ² 2-sample tests for equality of proportions on the pooled patient data.

RESULTS

A total of 974 patients (485 SRS, 489 surgery) were identified. The mean 5-year local control rate for SRS was 75.1%, and the mean recurrence rate for surgery was 8.1%. The mean hearing and facial nerve preservation rates were 40.1% and 92.3%, respectively, for SRS and 52.0% and 75.7%, respectively, for surgery. Rates of hearing preservation were higher after surgery than after SRS (P = 0.006), whereas rates of facial nerve preservation were higher after SRS than after surgery (P < 0.001).

CONCLUSIONS

SRS appears to be a safe and effective alternative to surgery for NF2-VS. Although rates of hearing preservation were higher in the surgery cohorts, SRS demonstrated high rates of local control and significantly lower facial nerve complications. Certain patients may therefore benefit more from SRS than surgery.