Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter

OBJECTIVEStereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs.METHODSBetween 2000 and 2014, 35 patients with large VSs, defined as having both a single dimension > 3 cm and a volume > 10 cm3, underwent Gamma Knife radiosurgery (GKRS). Nine patients (25.7%) had previously undergone resection. The median total volume covered in this group of patients was 14.8 cm3 (range 10.3–24.5 cm3). The median tumor margin dose was 11 Gy (range 10–12 Gy).RESULTSThe median follow-up duration was 48 months (range 6–156 months). All 35 patients had regular MRI follow-up examinations. Twenty tumors (57.1%) had a volume reduction of greater than 50%, 5 (14.3%) had a volume reduction of 15%–50%, 5 (14.3%) were stable in size (volume change < 15%), and 5 (14.3%) had larger volumes (all of these lesions were eventually resected). Four patients (11.4%) underwent resection within 9 months to 6 years because of progressive symptoms. One patient (2.9%) had open surgery for new-onset intractable trigeminal neuralgia at 48 months after GKRS. Two patients (5.7%) who developed a symptomatic cyst underwent placement of a cystoperitoneal shunt. Eight (66%) of 12 patients with pre-GKRS trigeminal sensory dysfunction had hypoesthesia relief. One hemifacial spasm completely resolved 3 years after treatment. Seven patients with facial weakness experienced no deterioration after GKRS. Two of 3 patients with serviceable hearing before GKRS deteriorated while 1 patient retained the same level of hearing. Two patients improved from severe hearing loss to pure tone audiometry less than 50 dB.The authors found borderline statistical significance for post-GKRS tumor enlargement for later resection (p = 0.05, HR 9.97, CI 0.99–100.00). A tumor volume ≥ 15 cm3 was a significant factor predictive of GKRS failure (p = 0.005). No difference in outcome was observed based on indication for GKRS (p = 0.0761).CONCLUSIONSAlthough microsurgical resection remains the primary management choice in patients with VSs, most VSs that are defined as having both a single dimension > 3 cm and a volume > 10 cm3 and tolerable mass effect can be managed satisfactorily with GKRS. Tumor volume ≥ 15 cm3 is a significant factor predicting poor tumor control following GKRS.

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Gamma Knife radiosurgery for larger-volume vestibular schwannomas

Journal of Neurosurgery ◽

10.3171/2010.8.jns10674 ◽

2011 ◽

Vol 114 (3) ◽

pp. 801-807 ◽

Cited By ~ 40

Author(s):

Huai-che Yang ◽

Hideyuki Kano ◽

Nasir Raza Awan ◽

L. Dade Lunsford ◽

Ajay Niranjan ◽

...

Keyword(s):

Gamma Knife ◽

Tumor Volume ◽

Univariate Analysis ◽

Gamma Knife Radiosurgery ◽

Volume Reduction ◽

Vestibular Schwannomas ◽

Maximum Diameter ◽

Tumor Control ◽

Recent Experience

Object Stereotactic radiosurgery (SRS) is an important management option for patients with small- and medium-sized vestibular schwannomas. To assess the potential role of SRS in larger tumors, the authors reviewed their recent experience. Methods Between 1994 and 2008, 65 patients with vestibular schwannomas between 3 and 4 cm in one extracanalicular maximum diameter (median tumor volume 9 ml) underwent Gamma Knife surgery. Seventeen patients (26%) had previously undergone resection. Results The median follow-up duration was 36 months (range 1–146 months). At the first planned imaging follow-up at 6 months, 5 tumors (8%) were slightly expanded, 53 (82%) were stable in size, and 7 (11%) were smaller. Two patients (3%) underwent resection within 6 months due to progressive symptoms. Two years later, with 63 tumors overall after the 2 post-SRS resections, 16 tumors (25%) had a volume reduction of more than 50%, 22 (35%) tumors had a volume reduction of 10–50%, 18 (29%) were stable in volume (volume change < 10%), and 7 (11%) had larger volumes (5 of the 7 patients underwent resection and 1 of the 7 underwent repeat SRS). Eighteen (82%) of 22 patients with serviceable hearing before SRS still had serviceable hearing after SRS more than 2 years later. Three patients (5%) developed symptomatic hydrocephalus and underwent placement of a ventriculoperitoneal shunt. In 4 patients (6%) trigeminal sensory dysfunction developed, and in 1 patient (2%) mild facial weakness (House-Brackmann Grade II) developed after SRS. In univariate analysis, patients who had a previous resection (p = 0.010), those with a tumor volume exceeding 10 ml (p = 0.05), and those with Koos Grade 4 tumors (p = 0.02) had less likelihood of tumor control after SRS. Conclusions Although microsurgical resection remains the primary management choice in patients with low comorbidities, most vestibular schwannomas with a maximum diameter less than 4 cm and without significant mass effect can be managed satisfactorily with Gamma Knife radiosurgery.

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Magnetic resonance imaging characteristics and the prediction of outcome of vestibular schwannomas following Gamma Knife radiosurgery

Journal of Neurosurgery ◽

10.3171/2016.9.jns161510 ◽

2017 ◽

Vol 127 (6) ◽

pp. 1384-1391 ◽

Cited By ~ 6

Author(s):

Chih-Chun Wu ◽

Wan-Yuo Guo ◽

Wen-Yuh Chung ◽

Hisu-Mei Wu ◽

Chung-Jung Lin ◽

...

Keyword(s):

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Reduction Ratio ◽

Volume Reduction ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Mri Features ◽

Before And After

OBJECTIVEGamma Knife surgery (GKS) is a promising treatment modality for patients with vestibular schwannomas (VSs), but a small percentage of patients have persistent postradiosurgical tumor growth. The aim of this study was to determine the clinical and quantitative MRI features of VS as predictors of long-term tumor control after GKS.METHODSThe authors performed a retrospective study of all patients with VS treated with GKS using the Leksell Gamma Knife Unit between 2005 and 2013 at their institution. A total of 187 patients who had a minimum of 24 months of clinical and radiological assessment after radiosurgery were included in this study. Those who underwent a craniotomy with tumor removal before and after GKS were excluded. Study patients comprised 85 (45.5%) males and 102 (54.5%) females, with a median age of 52.2 years (range 20.4–82.3 years). Tumor volumes, enhancing patterns, and apparent diffusion coefficient (ADC) values were measured by region of interest (ROI) analysis of the whole tumor by serial MRI before and after GKS.RESULTSThe median follow-up period was 60.8 months (range 24–128.9 months), and the median treated tumor volume was 3.54 cm3 (0.1–16.2 cm3). At last follow-up, imaging studies indicated that 150 tumors (80.2%) showed decreased tumor volume, 20 (10.7%) had stabilized, and 17 (9.1%) continued to grow following radiosurgery. The postradiosurgical outcome was not significantly correlated with pretreatment volumes or postradiosurgical enhancing patterns. Tumors that showed regression within the initial 12 months following radiosurgery were more likely to have a larger volume reduction ratio at last follow-up than those that did not (volume reduction ratio 55% vs 23.6%, respectively; p < 0.001). Compared with solid VSs, cystic VSs were more likely to regress or stabilize in the initial postradiosurgical 6–12-month period and during extended follow-up. Cystic VSs exhibited a greater volume reduction ratio at last follow-up (cystic vs solid: 67.6% ± 24.1% vs 31.8% ± 51.9%; p < 0.001). The mean preradiosurgical maximum ADC (ADCmax) values of all VSs were significantly higher for those with tumor regression or stabilization at last follow-up compared with those with progression (2.391 vs 1.826 × 10−3 mm2/sec; p = 0.010).CONCLUSIONSLoss of central enhancement after radiosurgery was a common phenomenon, but it did not correlate with tumor volume outcome. Preradiosurgical MRI features including cystic components and ADCmax values can be helpful as predictors of treatment outcome.

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Long-term outcomes of Gamma Knife radiosurgery in patients with vestibular schwannomas

Journal of Neurosurgery ◽

10.3171/2009.12.jns091339 ◽

2011 ◽

Vol 114 (2) ◽

pp. 432-440 ◽

Cited By ~ 51

Author(s):

Erin S. Murphy ◽

Gene H. Barnett ◽

Michael A. Vogelbaum ◽

Gennady Neyman ◽

Glen H. J. Stevens ◽

...

Keyword(s):

Gamma Knife ◽

Gamma Knife Radiosurgery ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Tumor Diameter ◽

Long Term Effects ◽

Median Dose ◽

The Mean

Object The authors sought to determine the long-term tumor control and side effects of Gamma Knife radiosurgery (GKRS) in patients with vestibular schwannomas (VS). Methods One hundred seventeen patients with VS underwent GKRS between January 1997 and February 2003. At the time of analysis, at least 5 years had passed since GKRS in all patients. The mean patient age was 60.9 years. The mean maximal tumor diameter was 1.77 ± 0.71 cm. The mean tumor volume was 1.95 ± 2.42 ml. Eighty-two percent of lesions received 1300 cGy and 14% received 1200 cGy. The median dose homogeneity ratio was 1.97 and the median dose conformality ratio was 1.78. Follow-up included MR imaging or CT scanning approximately every 6–12 months. Rates of progression to surgery were calculated using the Kaplan-Meier method. Results Of the 117 patients in whom data were analyzed, 103 had follow-up MR or CT images and 14 patients were lost to follow-up. Fifty-three percent of patients had stable tumors and 37.9% had a radiographically documented response. Imaging-documented tumor progression was present in 8 patients (7.8%), but in 3 of these the lesion eventually stabilized. Only 5 patients required a neurosurgical intervention. The estimated 1-, 3-, and 5-year rates of progression to surgery were 1, 4.6, and 8.9%, respectively. One patient (1%) developed trigeminal neuropathy, 4 patients (5%) developed permanent facial neuropathy, 3 patients (4%) reported vertigo, and 7 patients (18%) had new gait imbalance following GKRS. Conclusions Gamma Knife radiosurgery results in excellent local control rates with minimal toxicity for patients with VS. The authors recommend standardized follow-up to gain a better understanding of the long-term effects of GKRS.

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Gamma Knife radiosurgery for vestibular schwannomas: evaluation of tumor control and its predictors in a large patient cohort in The Netherlands

Journal of Neurosurgery ◽

10.3171/2015.4.jns142415 ◽

2016 ◽

Vol 124 (6) ◽

pp. 1619-1626 ◽

Cited By ~ 41

Author(s):

Stijn Klijn ◽

Jeroen B. Verheul ◽

Guus N. Beute ◽

Sieger Leenstra ◽

Jef J. S. Mulder ◽

...

Keyword(s):

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Hearing Preservation ◽

Cox Proportional Hazards Model ◽

Tumor Control ◽

Complication Rates ◽

Tumor Control Rate ◽

Large Patient

OBJECT The authors of this study sought to assess tumor control and complication rates in a large cohort of patients who underwent Gamma Knife radiosurgery (GKRS) for vestibular schwannoma (VS) and to identify predictors of tumor control. METHODS The records of 420 patients treated with GKRS for VS with a median marginal dose of 11 Gy were retrospectively analyzed. Patients with neurofibromatosis Type 2 or who had undergone treatment for VS previously were excluded. The authors assessed tumor control and complication rates with chart review and used the Cox proportional hazards model to identify predictors of tumor control. Preservation of serviceable hearing, defined as Gardner-Robertson Class I–II, was evaluated in a subgroup of 71 patients with serviceable hearing at baseline and with available follow-up audiograms. RESULTS The median VS tumor volume was 1.4 cm3, and the median length of follow-up was 5.1 years. Actuarial 5-and 10-year tumor control rates were 91.3% and 84.8%, respectively. Only tumor volume was a statistically significant predictor of tumor control rate. The tumor control rate decreased from 94.1% for tumors smaller than 0.5 cm3 to 80.7% for tumors larger than 6 cm3. Thirteen patients (3.1%) had new or increased permanent trigeminal nerve neuropathy, 4 (1.0%) had new or increased permanent facial weakness, and 5 (1.2%) exhibited new or increased hydrocephalus requiring a shunting procedure. Actuarial 3-year and 5-year hearing preservation rates were 65% and 42%, respectively. CONCLUSIONS The 5-year actuarial tumor control rate of 91.3% in this cohort of patients with VS compared slightly unfavorably with the rates reported in other large studies, but the complication and hearing preservation rates in this study were similar to those reported previously. Various factors may contribute to the observed differences in reported outcomes. These factors include variations in treatment indication and in the definition of treatment failure, as well as a lack of standardization of terminology and of evaluation of complications. Last, differences in dosimetric variables may also be an explanatory factor.

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CYBERKNIFE RADIOSURGERY FOR TRIGEMINAL SCHWANNOMAS

Neurosurgery ◽

10.1227/01.neu.0000341629.57676.db ◽

2009 ◽

Vol 64 (suppl_2) ◽

pp. A14-A18 ◽

Cited By ~ 7

Author(s):

Gordon T. Sakamoto ◽

D. John Borchers ◽

Furen Xiao ◽

Hee-Jin Yang ◽

Steven D. Chang ◽

...

Keyword(s):

Surgical Resection ◽

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Benign Tumors ◽

Tumor Control ◽

Modest Improvement ◽

Facial Numbness ◽

The Mean

Abstract OBJECTIVE Trigeminal schwannomas (TS) are benign tumors that are managed by surgical resection and/or stereotactic radiosurgery. Most radiosurgical series report results using the gamma knife. The CyberKnife (Accuray, Inc., Sunnyvale, CA) is a frameless, robotic stereotactic radiosurgical system. In this series, we report our experience using the CyberKnife in the treatment of TS. METHODS We retrospectively reviewed the medical records and diagnostic imaging in 13 consecutive patients with TS who were treated with the CyberKnife from 2003 to 2007. Seven patients had a previous surgical resection. The mean tumor volume was 6.3 mL (range, 0.39–19.98 mL), and the mean marginal dose was 18.5 Gy. Six of the tumors were treated in a single session. The mean clinical follow-up period was 21.8 months (range, 7–53 months). RESULTS In this series, the tumor control rate was 100%. The average reduction in tumor volume was 45% (range, 14–98%). A modest improvement in facial pain was noted in 4 of the 6 patients who presented with this symptom. One patient had improvement in facial numbness, and another had improvement in pretreatment headaches. One patient developed jaw weakness and facial dysesthesia, and another patient developed asymptomatic radiation necrosis. CONCLUSION Although the length of follow-up is limited, we report our initial experience with CyberKnife treatment of TS. Our results demonstrate tumor control rates and clinical outcomes that parallel those of previous reports using gamma knife radiosurgery; however, long-term follow-up studies are needed.

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Gamma Knife radiosurgery for treatment of growing vestibular schwannomas in patients with neurofibromatosis Type 2: a matched cohort study with sporadic vestibular schwannomas

Journal of Neurosurgery ◽

10.3171/2016.9.jns161463 ◽

2018 ◽

Vol 128 (1) ◽

pp. 49-59 ◽

Cited By ~ 11

Author(s):

Ivo J. Kruyt ◽

Jeroen B. Verheul ◽

Patrick E. J. Hanssens ◽

Henricus P. M. Kunst

Keyword(s):

Gamma Knife ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Neurofibromatosis Type ◽

Hearing Preservation ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Nerve Function

OBJECTIVENeurofibromatosis Type 2 (NF2) is a tumor syndrome characterized by an autosomal dominant pattern of inheritance. The hallmark of NF2 is the development of bilateral vestibular schwannomas (VSs), generally by 30 years of age. One of the first-line treatment options for small to medium-large VSs is radiosurgery. Although radiosurgery shows excellent results in sporadic VS, its use in NF2-related VS is still a topic of dispute. The aim of this study was to evaluate long-term tumor control, hearing preservation rates, and factors influencing outcome of optimally dosed, contemporary Gamma Knife radiosurgery (GKRS) for growing VSs in patients with NF2 and compare the findings to data obtained in patients with sporadic VS also treated by means of GKRS.METHODSThe authors performed a retrospective analysis of 47 growing VSs in 34 NF2 patients who underwent GKRS treatment performed with either the Model C or Perfexion Leksell Gamma Knife, with a median margin dose of 11 Gy. Actuarial tumor control rates were estimated using the Kaplan-Meier method. For patient- and treatment-related factors, a Cox proportional hazards model was used to identify predictors of outcome. Trigeminal, facial, and vestibulocochlear nerve function were assessed before and after treatment. NF2-related VS patients were matched 1:1 with sporadic VS patients who were treated in the same institute, and the same indications for treatment, definitions, and dosimetry were used in order to compare outcomes.RESULTSActuarial tumor control rates in NF2 patients after 1, 3, 5, and 8 years were 98%, 89%, 87%, and 87%, respectively. Phenotype and tumor volume had significant hazard rates of 0.086 and 22.99, respectively, showing that Feiling-Gardner phenotype and a tumor volume not exceeding 6 cm3 both were associated with significantly better outcome. Actuarial rates of serviceable hearing preservation after 1, 3, 5, and 7 years were 95%, 82%, 59%, and 33%, respectively. None of the patients experienced worsening of trigeminal nerve function. Facial nerve function worsened in 1 patient (2.5%). No significant differences in tumor control, hearing preservation, or complications were found in comparing the results of GKRS for NF2-related VS versus GKRS for sporadic VS.CONCLUSIONSWith modern GKRS, the use of low margin doses for treating growing VSs in patients with NF2 demonstrates good long-term tumor control rates. Feiling-Gardner phenotype and tumor volume smaller than 6 cm3 seem to be independently associated with prolonged progression-free survival, highlighting the clinical importance of phenotype assessment before GKRS treatment. In addition, no significant differences in tumor control rates or complications were found in the matched-control cohort analysis comparing GKRS for VS in patients with NF2 and GKRS for sporadic VS. These results show that GKRS is a valid treatment option for NF2-related VS, in addition to being a good option for sporadic VS, particularly in patients with the Feiling-Gardner phenotype and/or tumors that are small to medium in size. Larger tumors in patients with the Wishart phenotype appear to respond poorly to radiosurgery, and other treatment modalities should therefore be considered in such cases.

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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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Safety and Efficacy of Gamma Knife Radiosurgery for the Management of Koos Grade 4 Vestibular Schwannomas

Neurosurgery ◽

10.1227/neu.0000000000001154 ◽

2015 ◽

Vol 78 (4) ◽

pp. 521-530 ◽

Cited By ~ 15

Author(s):

Christian Iorio-Morin ◽

Fahd AlSubaie ◽

David Mathieu

Keyword(s):

Gamma Knife ◽

Tumor Size ◽

Gamma Knife Radiosurgery ◽

Vestibular Schwannomas ◽

Tumor Control ◽

Inclusion Criteria ◽

Shunt Insertion ◽

Safety And Efficacy ◽

Nerve Preservation

Abstract BACKGROUND: Gamma Knife radiosurgery (GKRS) is commonly used in treating small vestibular schwannomas; however, its use for larger vestibular schwannomas is still controversial. OBJECTIVE: To assess the long-term safety and efficacy of treating eligible Koos grade 4 vestibular schwannomas with GKRS. METHODS: We conducted a single-center, retrospective evaluation of patient undergoing GKRS for Koos grade 4 vestibular schwannomas. We evaluated clinical, imaging, and treatment characteristics and assessed treatment outcome. Inclusion criteria were tumor size of ≥4 cm3 and follow-up of at least 6 months. Patients with neurofibromatosis type 2 were excluded. Primary outcomes measured were tumor control rate, hearing and facial function preservation rate, and complications. All possible factors were analyzed to assess clinical significance. RESULTS: Sixty-eight patients met inclusion criteria. Median follow-up was 47 months (range, 6-125 months). Baseline hearing was serviceable in 60%. Median tumor volume at radiosurgery was 7.4 cm3 (range, 4-19 cm3). The median marginal dose used was 12 Gy at the 50% isodose line. Actuarial tumor control rates were 95% and 92% at 2 and 10 years, respectively. Actuarial serviceable hearing preservation rates were 89% and 49% at 2 and 5 years, respectively. Facial nerve preservation was 100%. Clinical complications included balance disturbance (11%), facial pain (10%), facial numbness (5%), and tinnitus (10%). Most complications were mild and transient. Hydrocephalus occurred in 3 patients, requiring ventriculoperitoneal shunt insertion. Larger tumor size was significantly associated with persisting symptoms post-treatment. CONCLUSION: Patients with Koos grade 4 vestibular schwannomas and minimal symptoms can be treated safely and effectively with GKRS.

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Volume reduction in meningiomas after gamma knife surgery

Journal of Neurosurgery ◽

10.3171/sup.2005.102.s_supplement.0189 ◽

2005 ◽

Vol 102 (Special_Supplement) ◽

pp. 189-194 ◽

Cited By ~ 8

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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Gamma Knife Radiosurgery as a Primary Treatment for Nonfunctioning Pituitary Adenoma Invading the Cavernous Sinus

Stereotactic and Functional Neurosurgery ◽

10.1159/000508737 ◽

2020 ◽

Vol 98 (6) ◽

pp. 371-377

Author(s):

Won Jae Lee ◽

Kyung-Rae Cho ◽

Jung-Won Choi ◽

Doo-Sik Kong ◽

Ho Jun Seol ◽

...

Keyword(s):

Pituitary Adenoma ◽

Gamma Knife ◽

Cavernous Sinus ◽

Tumor Volume ◽

Gamma Knife Radiosurgery ◽

Primary Treatment ◽

Tumor Control ◽

Nonfunctioning Pituitary Adenoma ◽

Maximal Diameter

Objectives: Surgical resection of nonfunctioning pituitary adenoma (NFPA) invading the cavernous sinus (CS) remains a challenging and significant factor associated with incomplete resection. The residual tumor in CS is usually treated with adjuvant stereotactic radiosurgery (SRS), but there is little information concerning SRS as an initial treatment for CS-invading NFPA. In this study, we investigated the tumor control rate and clinical outcomes of the patients who received primary gamma knife radiosurgery (GKRS) for CS-invading NFPA. Methods: This was a single-institute retrospective analysis of 11 patients. CS invasion of tumor was categorized using the modified Knosp grading system. The median tumor volume and maximal diameter were 1.6 cm3 (range 0.4–6.5) and 17.2 mm (range 11.6–23.3), respectively. The median clinical follow-up period was 48.5 months (range 16.4–177.8). The median prescription dose at tumor margin was 15 Gy (range 11–25) and median prescription isodose was 50% (range 45–50). The maximum radiation dose to optic chiasm and optic nerve were 7.2 Gy (range 3.4–9.2) and 7.5 Gy (range 4.5–11.5), respectively. Results: Tumor control was achieved in all patients. The median tumor volume and maximal diameter at last follow-up were 0.4 cm3 (range 0.1–2.3) and 11.4 mm (range 4.7–19.5), respectively. The median volume reduction rate was 52% (range 33–88). Six patients showed downgrading of modified Knosp grade after GKRS. No patients developed GKRS-related complications such as hypopituitarism or visual disturbance. Conclusions: SRS may be an alternative primary treatment option for CS-invading NFPA if there is no urgent and absolute indication for surgery such as optic apparatus compression.

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