REPEAT GAMMA KNIFE SURGERY FOR REGROWTH OF VESTIBULAR SCHWANNOMAS

Abstract OBJECTIVE Gamma knife surgery (GKS) has become established as a minimally invasive treatment modality for patients with vestibular schwannomas. Treatment failure and/or tumor regrowth, however, is occasionally encountered, and microsurgical resection is usually warranted in such cases. The role of repeat GKS in these situations is still unclear. The goal of this study was to investigate whether repeat GKS is an effective treatment for recurrent vestibular schwannomas and to assess the conservation of residual neurological function. METHODS Between July 1992 and December 2007, 1951 patients harboring a unilateral vestibular schwannoma were treated with GKS. Of these, 48 patients (2.5%) had to undergo a subsequent intervention because of progression or regrowth of the tumor. Repeat GKS was performed in a total of 15 patients, 8 of whom had more than 2 years of follow-up and were eligible to be enrolled in the present study. The median follow-up period after repeat GKS was 64 months, and the median interval between these interventions was 46 months. The median tumor volume was 0.51 and 1.28 mL at the initial and second GKS treatments, respectively. Patients received a median prescription dose of 12.0 Gy at both interventions. RESULTS We report no cases of failure. Six patients demonstrated a significant reduction in tumor volume. In 1 patient, the final tumor volume was less than the initial volume. The other 2 patients showed stabilization of tumor growth. Useful hearing ability was preserved in only 1 of the 3 patients who had serviceable hearing ability at the time of the second GKS. Neither aggravation of facial nerve dysfunction nor other neurological deficits secondary to GKS were observed. CONCLUSION This is the first report to address repeat GKS for vestibular schwannomas. After long-term follow-up, repeat GKS with a low marginal dose seems to be a safe and effective treatment in selected patients harboring regrowth of small vestibular schwannomas that have previously been treated with GKS.

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Gamma Knife surgery for incidental cerebral arteriovenous malformations

Journal of Neurosurgery ◽

10.3171/2014.7.jns131397 ◽

2014 ◽

Vol 121 (5) ◽

pp. 1015-1021 ◽

Cited By ~ 42

Author(s):

Chun-Po Yen ◽

Dale Ding ◽

Ching-Hsiao Cheng ◽

Robert M. Starke ◽

Mark Shaffrey ◽

...

Keyword(s):

Gamma Knife ◽

Arteriovenous Malformations ◽

Latency Period ◽

Invasive Procedure ◽

Gamma Knife Surgery ◽

Neurological Deficits ◽

Cerebral Arteriovenous Malformations ◽

Long Term Follow Up

Object A relatively benign natural course of unruptured cerebral arteriovenous malformations (AVMs) has recently been recognized, and the decision to treat incidentally found AVMs has been questioned. This study aims to evaluate the long-term imaging and clinical outcomes of patients with asymptomatic, incidentally discovered AVMs treated with Gamma Knife surgery (GKS). Methods Thirty-one patients, each with an incidentally diagnosed AVM, underwent GKS between 1989 and 2009. The nidus volumes ranged from 0.3 to 11.1 cm3 (median 3.2 cm3). A margin dose between 15 and 26 Gy (median 20 Gy) was used to treat the AVMs. Four patients underwent repeat GKS for still-patent AVM residuals after the initial GKS procedure. Clinical follow-up ranged from 24 to 196 months, with a mean of 78 months (median 51 months) after the initial GKS. Results Following GKS, 19 patients (61.3%) had a total AVM obliteration on angiography. In 7 patients (22.6%), no flow voids were observed on MRI but angiographic confirmation was not available. In 5 patients (16.1%), the AVMs remained patent. A small nidus volume was significantly associated with increased AVM obliteration rate. Thirteen patients (41.9%) developed radiation-induced imaging changes: 11 were asymptomatic (35.5%), 1 had only headache (3.2%), and 1 developed seizure and neurological deficits (3.2%). Two patients each had 1 hemorrhage during the latency period (116.5 risk years), yielding an annual hemorrhage rate of 1.7% before AVM obliteration. Conclusions The decision to treat asymptomatic AVMs, and if so, which treatment approach to use, remain the subject of debate. GKS as a minimally invasive procedure appears to achieve a reasonable outcome with low procedure-related morbidity. In those patients with incidental AVMs, the benefits as well as the risks of radiosurgical intervention will only be fully defined with long-term follow-up.

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Tumor shrinkage of vestibular schwannomas after Gamma Knife surgery: results after more than 5 years of follow-up

Journal of Neurosurgery ◽

10.3171/2010.8.gks10960 ◽

2010 ◽

Vol 113 (Special_Supplement) ◽

pp. 122-127 ◽

Cited By ~ 19

Author(s):

Osamu Nagano ◽

Toru Serizawa ◽

Yoshinori Higuchi ◽

Shinji Matsuda ◽

Makoto R.T. Sato ◽

...

Keyword(s):

Gamma Knife ◽

Volume Expansion ◽

Tumor Volume ◽

Gamma Knife Surgery ◽

Vestibular Schwannomas ◽

Mr Images ◽

Volume Changes ◽

Cardiovascular Center ◽

The Mean

Object The authors prospectively analyzed volume changes in vestibular schwannomas (VSs) after Gamma Knife surgery (GKS). Methods Among 104 VSs treated by GKS at the Chiba Cardiovascular Center between 1998 and 2004, 87 consecutively treated unilateral VSs observed on follow-up MR imaging for at least 5 years were analyzed. These lesions were harbored by 31 men and 56 women, with a mean age of 58.6 years (range 29–80 years). The Gd-enhanced volume of each lesion was measured serially every 3 months during the 1st year and every 6 months thereafter using GammaPlan or SurgiPlan. The frequency and degree of volume shrinkage were documented and possible prognostic factors were analyzed. Results The mean tumor volume at GKS was 2.5 cm3 (range 0.1–13.2 cm3). The lesions were irradiated by directing a mean dose of 12.0 Gy (range 10.5–13.0 Gy) to the tumor margin, which was located at the mean 52.2% isodose line (range 50%–67% isodose line). The mean follow-up period was 7.5 years (range 5.0–11.1 years). Peak tumor volume expansion was most frequently observed at 8.6 months after GKS and averaged 58% (range 0%–613%). Five years after GKS, the mean reduction in tumor volume was 31%, and 9 tumors still remained larger than their initial volumes. Tumors that homogeneously enhanced on MR images displayed less shrinkage than other tumors. Conclusions Most VSs exhibit shrinkage 5 years after GKS. The mean volume reduction in this series was 31%. These results indicate that careful serial follow-up is necessary for patients who harbor tumors that display homogeneous enhancement on MR images and patients whose tumors continue to expand in size after GKS.

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Long-term outcomes in patients with vestibular schwannomas treated using gamma knife surgery: 10-year follow up

Journal of Neurosurgery ◽

10.3171/jns.2005.102.1.0010 ◽

2005 ◽

Vol 102 (1) ◽

pp. 10-16 ◽

Cited By ~ 138

Author(s):

Toshinori Hasegawa ◽

Yoshihisa Kida ◽

Tatsuya Kobayashi ◽

Masayuki Yoshimoto ◽

Yoshimasa Mori ◽

...

Keyword(s):

Effective Treatment ◽

Gamma Knife ◽

Gamma Knife Surgery ◽

Vestibular Schwannomas ◽

Long Term Outcomes ◽

Content Type ◽

The Mean ◽

Fine Print

Object. Gamma knife surgery (GKS) has been a safe and effective treatment for vestibular schwannomas in both the short and long term, although less is known about long-term outcomes in the past 10 years. The aim of this study was to clarify long-term outcomes in patients with vestibular schwannomas treated using GKS based on techniques in place in the early 1990s. Methods. Eighty patients harboring a vestibular schwannoma (excluding neurofibromatosis Type 2) were treated using GKS between May 1991 and December 1993. Among these, 73 patients were assessed; seven were lost to follow up. The median duration of follow up was 135 months. The mean patient age at the time of GKS was 56 years old. The mean tumor volume was 6.3 cm3, and the mean maximal and marginal radiation doses applied to the tumor were 28.4 and 14.6 Gy, respectively. Follow-up magnetic resonance images were obtained in 71 patients. Forty-eight patients demonstrated partial tumor remission, 14 had tumors that remained stable, and nine demonstrated tumor enlargement or radiation-induced edema requiring resection. Patients with larger tumors did not fare as well as those with smaller lesions. The actuarial 10-year progression-free survival rate was 87% overall, and 93% in patients with tumor volumes less than 10 cm3. No patient experienced malignant transformation. Conclusions. Gamma knife surgery remained an effective treatment for vestibular schwannomas for longer than 10 years. Although treatment failures usually occurred within 3 years after GKS, it is necessary to continue follow up in patients to reveal delayed tumor recurrence.

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Gamma Knife surgery of meningiomas located in the posterior fossa: factors predictive of outcome and remission

Journal of Neurosurgery ◽

10.3171/2010.11.jns101193 ◽

2011 ◽

Vol 114 (5) ◽

pp. 1399-1409 ◽

Cited By ~ 30

Author(s):

Robert M. Starke ◽

James H. Nguyen ◽

Jessica Rainey ◽

Brian J. Williams ◽

Jonathan H. Sherman ◽

...

Keyword(s):

Multivariate Analysis ◽

Tumor Progression ◽

Posterior Fossa ◽

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Surgery ◽

Neurological Deficits ◽

Tumor Margin ◽

Kaplan Meier

Object Although numerous studies have analyzed the role of stereotactic radiosurgery for intracranial meningiomas, few studies have assessed outcomes of posterior fossa meningiomas after stereotactic radiosurgery. In this study, the authors evaluate the outcomes of posterior fossa meningiomas treated with Gamma Knife surgery (GKS). The authors also assess factors predictive of new postoperative neurological deficits and tumor progression. Methods A retrospective review was performed of a prospectively compiled database documenting the outcomes of 152 patients with posterior fossa meningiomas treated at the University of Virginia from 1990 to 2006. All patients had a minimum follow-up of 24 months. There were 30 males and 122 females, with a median age of 58 years (range 12–82 years). Seventy-five patients were treated with radiosurgery initially, and 77 patients were treated with GKS after resection. Patients were assessed clinically and radiographically at routine intervals following GKS. Factors predictive of new neurological deficit following GKS were assessed via univariate and multivariate analysis, and Kaplan-Meier analysis and Cox multivariate regression analysis were used to assess factors predictive of tumor progression. Results Patients had meningiomas centered over the tentorium (35 patients, 23%), cerebellopontine angle (43 patients, 28%), petroclival region (28 patients, 18%), petrous region (6 patients, 4%), and clivus (40 patients, 26%). The median follow-up was 7 years (range 2–16 years). The mean preradiosurgical tumor volume was 5.7 cm3 (range 0.3–33 cm3), and mean postradiosurgical tumor volume was 4.9 cm3 (range 0.1–33 cm3). At last follow-up, 55 patients (36%) displayed no change in tumor volume, 78 (51%) displayed a decrease in volume, and 19 (13%) displayed an increase in volume. Kaplan-Meier analysis demonstrated radiographic progression-free survival at 3, 5, and 10 years to be 98%, 96%, and 78%, respectively. In Cox multivariable analysis, pre-GKS covariates associated with tumor progression included age greater than 65 years (hazard ratio [HR] 3.24, 95% CI 1.12–9.37; p = 0.03) and a low dose to the tumor margin (HR 0.76, 95% CI 0.60–0.97; p = 0.03), and post-GKS covariates included shunt-dependent hydrocephalus (HR 25.0, 95% CI 3.72–100.0; p = 0.001). At last clinical follow-up, 139 patients (91%) demonstrated no change or improvement in their neurological condition, and 13 patients showed symptom deterioration (9%). In multivariate analysis, the only factors predictive of new or worsening symptoms were clival or petrous location (OR 4.0, 95% CI 1.1–13.7; p = 0.03). Conclusions Gamma Knife surgery offers an acceptable rate of tumor control for posterior fossa meningiomas and accomplishes this with a low incidence of neurological deficits. In patients selected for GKS, tumor progression is associated with age greater than 65 years and decreasing dose to the tumor margin. Clival- or petrous-based locations are predictive of an increased risk of new or worsening neurological deficit following GKS.

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Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases

Journal of Neurosurgery ◽

10.3171/sup.2005.102.s_supplement.0087 ◽

2005 ◽

Vol 102 (Special_Supplement) ◽

pp. 87-97 ◽

Cited By ~ 19

Author(s):

Wen-Yuh Chung ◽

Kang-Du Liu ◽

Cheng-Ying Shiau ◽

Hsiu-Mei Wu ◽

Ling-Wei Wang ◽

...

Keyword(s):

Mr Imaging ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Tumor Volume ◽

Radiation Effect ◽

Gamma Knife Surgery ◽

Homogeneous Distribution ◽

Content Type ◽

Fine Print

Object. The authors conducted a study to determine the optimal radiation dose for vestibular schwannoma (VS) and to examine the histopathology in cases of treatment failure for better understanding of the effects of irradiation. Methods. A retrospective study was performed of 195 patients with VS; there were 113 female and 82 male patients whose mean age was 51 years (range 11–82 years). Seventy-two patients (37%) had undergone partial or total excision of their tumor prior to gamma knife surgery (GKS). The mean tumor volume was 4.1 cm3 (range 0.04–23.1 cm3). Multiisocenter dose planning placed a prescription dose of 11 to 18.2 Gy on the 50 to 94% isodose located at the tumor margin. Clinical and magnetic resonance (MR) imaging follow-up evaluations were performed every 6 months. A loss of central enhancement was demonstrated on MR imaging in 69.5% of the patients. At the latest MR imaging assessment decreased or stable tumor volume was demonstrated in 93.6% of the patients. During a median follow-up period of 31 months resection was avoided in 96.8% of cases. Uncontrolled tumor swelling was noted in five patients at 3.5, 17, 24, 33, and 62 months after GKS, respectively. Twelve of 20 patients retained serviceable hearing. Two patients experienced a temporary facial palsy. Two patients developed a new trigeminal neuralgia. There was no treatment-related death. Histopathological examination of specimens in three cases (one at 62 months after GKS) revealed a long-lasting radiation effect on vessels inside the tumor. Conclusions. Radiosurgery had a long-term radiation effect on VSs for up to 5 years. A margin 12-Gy dose with homogeneous distribution is effective in preventing tumor progression, while posing no serious threat to normal cranial nerve function.

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Treating Vestibular Schwannomas with Gamma-Knife Radiosurgery Versus Microsurgery: Long-Term Follow-up of 702 Cases

The Medical Journal of Cairo University ◽

10.21608/mjcu.2019.54877 ◽

2019 ◽

Vol 87 (June) ◽

pp. 2599-2610

Author(s):

AHMED R. RIZK, M.D. GUIHERME LEPSLI, M.D. ◽

GERHARD A. HORSTMANN, M.D. MARCOS TATABIBA, M.D.

Keyword(s):

Gamma Knife ◽

Gamma Knife Radiosurgery ◽

Vestibular Schwannomas ◽

Long Term Follow Up

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Clinical results of Gamma Knife surgery for cavernous sinus hemangiomas

Journal of Neurosurgery ◽

10.3171/2012.7.gks12992 ◽

2012 ◽

Vol 117 (Special_Suppl) ◽

pp. 89-95 ◽

Cited By ~ 8

Author(s):

Peng Li ◽

Haibo Ren ◽

Shizhen Zhang ◽

Wei Wang

Keyword(s):

Gamma Knife ◽

Cavernous Sinus ◽

Adjuvant Treatment ◽

Clinical Results ◽

Gamma Knife Surgery ◽

Mr Images ◽

Peripheral Dose ◽

Long Term Follow Up ◽

Model C

Object The purpose of this study was to gain an understanding of the efficacy and safety of Gamma Knife surgery (GKS) for the treatment of cavernous sinus hemangiomas (CSHs). The authors report on 16 patients who underwent GKS as a primary or adjuvant treatment for CSH. Methods Sixteen patients harboring CSHs (14 women and 2 men ranging in age from 21 to 65 years [mean 41.3 years]) underwent GKS at West China Hospital. In 4 patients the diagnosis was based on histological findings; in the other 12 patients it was based on findings on MR images. After patients were given a local anesthetic agent, the treatments were performed using a Leksell Gamma Knife model C. Gadolinium-enhanced MR images of T1-weighted, T2-weighted, and FLAIR sequences were obtained to determine the pretreatment location of the lesion. A mean peripheral dose of 13.3 Gy (range 11–14 Gy) was directed to the 40%–50% isodose line. Results The mean follow-up time in this study was 21.5 months (range 12–36 months). In 11 of 12 patients with symptoms, clinical improvement was reported at an average of 3.3 months (range 1–8 months) after GKS. Significant or partial tumor shrinkage was observed in 14 patients (87.5%) at the last follow-up. No new neurological impairments were reported after GKS. Conclusions Magnetic resonance imaging may play an important role in the preoperative diagnosis of CSHs. Gamma Knife surgery may be a safe and effective primary or adjuvant treatment option for CSHs; however, long-term follow-up with more cases is needed to verify the benefits of this treatment.

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Gamma knife surgery for vestibular schwannoma: 10-year experience of 195 cases

Journal of Neurosurgery ◽

10.3171/jns.2005.102.s_supplement.0087 ◽

2005 ◽

Vol 102 ◽

pp. 87-97 ◽

Cited By ~ 75

Author(s):

Wen-Yuh Chung ◽

Kang-Du Liu ◽

Cheng-Ying Shiau ◽

Hsiu-Mei Wu ◽

Ling-Wei Wang ◽

...

Keyword(s):

Mr Imaging ◽

Gamma Knife ◽

Vestibular Schwannoma ◽

Tumor Volume ◽

Radiation Effect ◽

Gamma Knife Surgery ◽

Homogeneous Distribution ◽

Content Type ◽

Fine Print

Object.The authors conducted a study to determine the optimal radiation dose for vestibular schwannoma (VS) and to examine the histopathology in cases of treatment failure for better understanding of the effects of irradiation.Methods.A retrospective study was performed of 195 patients with VS; there were 113 female and 82 male patients whose mean age was 51 years (range 11–82 years). Seventy-two patients (37%) had undergone partial or total excision of their tumor prior to gamma knife surgery (GKS). The mean tumor volume was 4.1 cm3(range 0.04–23.1 cm3). Multiisocenter dose planning placed a prescription dose of 11 to 18.2 Gy on the 50 to 94% isodose located at the tumor margin. Clinical and magnetic resonance (MR) imaging follow-up evaluations were performed every 6 months.A loss of central enhancement was demonstrated on MR imaging in 69.5% of the patients. At the latest MR imaging assessment decreased or stable tumor volume was demonstrated in 93.6% of the patients. During a median follow-up period of 31 months resection was avoided in 96.8% of cases. Uncontrolled tumor swelling was noted in five patients at 3.5, 17, 24, 33, and 62 months after GKS, respectively. Twelve of 20 patients retained serviceable hearing. Two patients experienced a temporary facial palsy. Two patients developed a new trigeminal neuralgia. There was no treatment-related death. Histopathological examination of specimens in three cases (one at 62 months after GKS) revealed a long-lasting radiation effect on vessels inside the tumor.Conclusions.Radiosurgery had a long-term radiation effect on VSs for up to 5 years. A margin 12-Gy dose with homogeneous distribution is effective in preventing tumor progression, while posing no serious threat to normal cranial nerve function.

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Volume reduction in meningiomas after gamma knife surgery

Journal of Neurosurgery ◽

10.3171/jns.2005.102.s_supplement.0189 ◽

2005 ◽

Vol 102 ◽

pp. 189-194 ◽

Cited By ~ 26

Author(s):

Guenther C. Feigl ◽

Otto Bundschuh ◽

Alireza Gharabaghi ◽

Madjid Samii ◽

Gerhard A. Horstmann

Keyword(s):

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Surgery ◽

Volume Reduction ◽

World Health ◽

Tumor Control ◽

Content Type ◽

The Mean ◽

Fine Print

Object.The purpose of this study was to evaluate the volume-reducing effects of gamma knife surgery (GKS) of meningiomas with and without previous surgical treatment.Methods.A group of 127 patients with a mean age of 57.1 years (range 9–81 years) with 142 meningiomas (128 World Health Organization Grade I and 14 Grade II) were included in this study. The management strategy reduces tumor volume with surgery when necessary (81 patients). Stereotactic GKS with a Gamma Knife model C was performed in all tumors of suitable size. Magnetic resonance imaging follow-up examinations with volumetric tumor analysis was performed 6 months after treatment and annually thereafter.The mean tumor volume was 5.9 cm3(range < 5 to > 40 cm3). The mean follow-up time after GKS was 29.3 months (range 11–61 months). The mean prescription dose was 13.8 Gy (range 10–18 Gy). A reduction in volume occurred in 117 (82.4%) of all tumors, and in 20 tumors (14.1%) growth ceased. The overall tumor control rate of 96.4%. The mean volume reduction achieved with GKS was more than 46.1%. Only five tumors (3.5%) showed a volume increase.Conclusions.Gamma knife surgery was effective in reducing meningioma volume at short-term follow up. Further studies are needed to examine the development of these findings over a longer period.

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