Gamma Knife Radiosurgery as Primary Treatment for Large Vestibular Schwannomas: Clinical Results at Long-Term Follow-Up in a Series of 59 Patients

Bailo, Michele; Boari, Nicola; Franzin, Alberto; Gagliardi, Filippo; Spina, Alfio; Vecchio, Antonella Del; Gemma, Marco; Bolognesi, Angelo; Mortini, Pietro

doi:10.1016/j.wneu.2016.07.117

Cited by 42 publications

(33 citation statements)

References 96 publications

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“…There was a significant risk of developing hydrocephalus after GKRS, even in our modern radiosurgical era, whereas, at least in our series, other complications were comparable to those observed for other Koos neuroma grades. 6,16 Radiosurgery has been described as an effective management option for patients whose tumors remain or recur after microsurgery. 17 In our series, we found high tumor control rates after a combined microsurgical-radiosurgical treatment as well.…”

Section: Evolution Of Radiosurgical Treatment Planning and Postradiosmentioning

confidence: 99%

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Long-term outcome after Gamma Knife radiosurgery for acoustic neuroma of all Koos grades: a single-center study

Frischer¹,

Gruber²,

Schöffmann³

et al. 2019

Journal of Neurosurgery

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OBJECTIVE The authors present long-term follow-up data on patients treated with Gamma Knife radiosurgery (GKRS) for acoustic neuroma. METHODS Six hundred eighteen patients were radiosurgically treated for acoustic neuroma between 1992 and 2016 at the Department of Neurosurgery, Medical University Vienna. Patients with neurofibromatosis and patients treated too recently to attain 1 year of follow-up were excluded from this retrospective study. Thus, data on 557 patients with spontaneous acoustic neuroma of any Koos grade are presented, as are long-term follow-up data on 426 patients with a minimum follow-up of 2 years. Patients were assessed according to the Gardner-Robertson (GR) hearing scale and the House-Brackmann facial nerve function scale, both prior to GKRS and at the times of follow-up. RESULTS Four hundred fifty-two patients (81%) were treated with radiosurgery alone and 105 patients (19%) with combined microsurgery-radiosurgery. While the combined treatment was especially favored before 2002, the percentage of cases treated with radiosurgery alone has significantly increased since then. The overall complication rate after GKRS was low and has declined significantly in the last decade. The risk of developing hydrocephalus after GKRS increased with tumor size. One case (0.2%) of malignant transformation after GKRS was diagnosed. Radiological tumor control rates of 92%, 91%, and 91% at 5, 10, and 15 years after GKRS, regardless of the Koos grade or pretreatment, were observed. The overall tumor control rate without the need for additional treatment was even higher at 98%. At the last follow-up, functional hearing was preserved in 55% of patients who had been classified with GR hearing class I or II prior to GKRS. Hearing preservation rates of 53%, 34%, and 34% at 5, 10, and 15 years after GKRS were observed. The multivariate regression model revealed that the GR hearing class prior to GKRS and the median dose to the cochlea were independent predictors of the GR class at follow-up. CONCLUSIONS In small to medium-sized spontaneous acoustic neuromas, radiosurgery should be recognized as the primary treatment at an early stage. Although minimizing the cochlear dose seems beneficial for hearing preservation, the authors, like others before, do not recommend undertreating intracanalicular tumors in favor of low cochlear doses. For larger acoustic neuromas, radiosurgery remains a reliable management option with tumor control rates similar to those for smaller acoustic neuromas; however, careful patient selection and counseling are recommended given the higher risk of side effects. Microsurgery must be considered in acoustic neuromas with significant brainstem compression or hydrocephalus.

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Section: Evolution Of Radiosurgical Treatment Planning and Postradiosmentioning

confidence: 99%

“…(10)(11)(12)(13)(14)(15)(16)(17) 12(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15) Median central dose in Gy (range) 24 …”

mentioning

confidence: 99%

Long-term outcome after Gamma Knife radiosurgery for acoustic neuroma of all Koos grades: a single-center study

Frischer¹,

Gruber²,

Schöffmann³

et al. 2019

Journal of Neurosurgery

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“…According to recent publications [27][28][29][30][31][32][33] , our study is the first that comprises LINAC and Cyberknife ® data (Table 4). Tumor control rates in our series, in those from the literature and in other SRS series with smaller VS 2,5,34-36 , varied between 87-100%.…”

Section: Radiosurgery Wolbers Et Almentioning

confidence: 99%

Outcome and toxicity analysis of single dose stereotactic radiosurgery in vestibular schwannoma based on the Koos grading system

Rueß

Pöhlmann

Grau

et al. 2020

Sci Rep

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Stereotactic radiosurgery (SRS) has evolved as widely accepted treatment option for small-sized (Koos i up to ii) vestibular schwannoma (VS). for larger tumors (prevalent Koos Vi), microsurgery or combined treatment strategies are mostly recommended. However, in patients not suited for microsurgery, SRS might also be an alternative to balance tumor control, hearing preservation and adverse effects. The purpose of this analysis was to evaluate the efficacy and toxicity of SRS for VS with regard to different Koos grades. All patients with untreated VS who received SRS at our center were included. outcome analysis included tumor control, preservation of serviceable hearing based on median pure tone averages (ptA), and procedure-related adverse events rated by the common terminology criteria for Adverse Events (CTCAE; v4.03) classification. In total, 258 patients (median age 58 years, range 21-84) were identified with a mean follow-up of 52 months (range 3-228 months). Mean tumor volume was 1.8 ml (range 0.1-18.5). The mean marginal dose was 12.3 Gy ± 0.6 (range 11-13.5). The cohort was divided into two groups: A (Koos grades i and ii, n = 186) and B (Koos grades III and IV, n = 72). The actuarial tumor control rate was 98% after 2 years and 90% after 5 and 10 years. Koos grading did not show a significant impact on tumor control (p = 0.632) or hearing preservation (p = 0.231). After SRS, 18 patients (7%) had new transient or permanent symptoms classified by the CTCAE. The actuarial rate of ctcAe-free survival was not related to Koos grading (p = 0.093). Based on this selected population of Koos grade iii and iV VS without or with only mild symptoms from brainstem compression, SRS can be recommended as the primary therapy with the advantage of low morbidity and satisfactory tumor control. The overall hearing preservation rate and toxicity of SRS was influenced by age and cannot be predicted by tumor volume or Koos grading alone.

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“…These strategies have shown good results for large VSs and obtained acceptable radiationinduced morbidities. [7][8][9][10][11][12][13][14] Nevertheless, radiosurgical treatments of large VSs remain controversial due to the possible transient tumor enlargement (TTE). This radiation-induced swelling of the tumor, also known as pseudoprogression, occurs in a broad range of 11%-74% of all VS patients in the two to three years following treatment and can cause a temporary increase in cranial nerve morbidities.…”

Section: Introductionmentioning

confidence: 99%

“…Since the risks involved in microsurgery can be contra‐indicative for this strategy, less invasive treatments such as radiosurgery and radiotherapy have been considered increasingly in the last decade. These strategies have shown good results for large VSs and obtained acceptable radiation‐induced morbidities …”

Section: Introductionmentioning

confidence: 99%

Prediction of transient tumor enlargement using MRI tumor texture after radiosurgery on vestibular schwannoma

et al. 2020

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Purpose: Vestibular schwannomas (VSs) are uncommon benign brain tumors, generally treated using Gamma Knife radiosurgery (GKRS). However, due to the possible adverse effect of transient tumor enlargement (TTE), large VS tumors are often surgically removed instead of treated radiosurgically. Since microsurgery is highly invasive and results in a significant increased risk of complications, GKRS is generally preferred. Therefore, prediction of TTE for large VS tumors can improve overall VS treatment and enable physicians to select the most optimal treatment strategy on an individual basis. Currently, there are no clinical factors known to be predictive for TTE. In this research, we aim at predicting TTE following GKRS using texture features extracted from MRI scans. Methods: We analyzed clinical data of patients with VSs treated at our Gamma Knife center. The data was collected prospectively and included patient-and treatment-related characteristics and MRI scans obtained at day of treatment and at follow-up visits, 6, 12, 24 and 36 months after treatment. The correlations of the patient-and treatment-related characteristics to TTE were investigated using statistical tests. From the treatment scans, we extracted the following MRI image features: first-order statistics, Minkowski functionals (MFs), and three-dimensional gray-level co-occurrence matrices (GLCMs). These features were applied in a machine learning environment for classification of TTE, using support vector machines. Results: In a clinical data set, containing 61 patients presenting obvious non-TTE and 38 patients presenting obvious TTE, we determined that patient-and treatment-related characteristics do not show any correlation to TTE. Furthermore, first-order statistical MRI features and MFs did not significantly show prognostic values using support vector machine classification. However, utilizing a set of 4 GLCM features, we achieved a sensitivity of 0.82 and a specificity of 0.69, showing their prognostic value of TTE. Moreover, these results increased for larger tumor volumes obtaining a sensitivity of 0.77 and a specificity of 0.89 for tumors larger than 6 cm 3 . Conclusions: The results found in this research clearly show that MRI tumor texture provides information that can be employed for predicting TTE. This can form a basis for individual VS treatment selection, further improving overall treatment results. Particularly in patients with large VSs, where the phenomenon of TTE is most relevant and our predictive model performs best, these findings can be implemented in a clinical workflow such that for each patient, the most optimal treatment strategy can be determined.

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Gamma Knife Radiosurgery as Primary Treatment for Large Vestibular Schwannomas: Clinical Results at Long-Term Follow-Up in a Series of 59 Patients

Cited by 42 publications

References 96 publications

Long-term outcome after Gamma Knife radiosurgery for acoustic neuroma of all Koos grades: a single-center study

Long-term outcome after Gamma Knife radiosurgery for acoustic neuroma of all Koos grades: a single-center study

Outcome and toxicity analysis of single dose stereotactic radiosurgery in vestibular schwannoma based on the Koos grading system

Prediction of transient tumor enlargement using MRI tumor texture after radiosurgery on vestibular schwannoma

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