Gamma Knife surgery for patients with nonfunctioning pituitary macroadenomas: predictors of tumor control, neurological deficits, and hypopituitarism

2012 ◽  
Vol 117 (1) ◽  
pp. 129-135 ◽  
Author(s):  
Robert M. Starke ◽  
Brian J. Williams ◽  
John A. Jane ◽  
Jason P. Sheehan
Keyword(s):  
Multivariate Analysis ◽  
Tumor Progression ◽  
Gamma Knife ◽  
Neurological Deficit ◽  
Tumor Volume ◽  
Neurological Deficits ◽  
Tumor Control ◽  
The Mean ◽  
Pituitary Macroadenomas

Object Nonfunctioning pituitary macroadenomas often recur after microsurgery and thereby require further treatment. Gamma Knife surgery (GKS) has been used to treat recurrent adenomas. In this study, the authors evaluated outcomes following GKS of nonfunctioning pituitary macroadenomas and assessed predictors of tumor control, neurological deficits, and delayed hypopituitarism. Methods Between June 1989 and March 2010, 140 consecutive patients with nonfunctioning pituitary macroadenomas were treated using GKS at the University of Virginia. The median patient age was 51 years (range 21–82 years), and 56% of patients were male. Mean tumor volume was 5.6 cm3 (range 0.6–35 cm3). Thirteen patients were treated with GKS as primary therapy, and 127 had undergone at least 1 open resection prior to GKS. Ninety-three patients had a history of hormone therapy prior to GKS. The mean maximal dose of GKS was 38.6 Gy (range 10–70 Gy), the mean marginal dose was 18 Gy (range 5–25 Gy), and the mean number of isocenters was 9.8 (range 1–26). Follow-up evaluations were performed in all 140 patients, ranging from 0.5 to 17 years (mean 5 years, median 4.2 years). Results Tumor volume remained stable or decreased in 113 (90%) of 125 patients with available follow-up imaging. Kaplan-Meier analysis demonstrated radiographic progression free survival at 2, 5, 8, and 10 years to be 98%, 97%, 91%, and 87%, respectively. In multivariate analysis, a tumor volume greater than 5 cm3 (hazard ratio = 5.0, 95% CI 1.5–17.2; p = 0.023) was the only factor predictive of tumor growth. The median time to tumor progression was 14.5 years. Delayed hypopituitarism occurred in 30.3% of patients. No factor was predictive of post-GKS hypopituitarism. A new or worsening cranial nerve deficit occurred in 16 (13.7%) of 117 patients. Visual decline was the most common neurological deficit (12.8%), and all patients experiencing visual decline had evidence of tumor progression. In multivariate analysis, a tumor volume greater than 5 cm3 (OR = 3.7, 95% CI 1.2–11.7; p = 0.025) and pre-GKS hypopituitarism (OR = 7.5, 95% CI 1.1–60.8; p = 0.05) were predictive of a new or worsened neurological deficit. Conclusions In patients with nonfunctioning pituitary macroadenomas, GKS confers a high rate of tumor control and a low rate of neurological deficits. The most common complication following GKS is delayed hypopituitarism, and this occurs in a minority of patients.

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

2011 ◽  
Vol 114 (5) ◽  
pp. 1399-1409 ◽  
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.

Gamma Knife surgery for skull base meningiomas

2012 ◽  
Vol 116 (3) ◽  
pp. 588-597 ◽  
Author(s):  
Robert M. Starke ◽  
Brian J. Williams ◽  
Claire Hiles ◽  
James H. Nguyen ◽  
Mohamed Y. Elsharkawy ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Tumor Progression ◽  
Skull Base ◽  
Gamma Knife ◽  
Cerebellopontine Angle ◽  
Tumor Volume ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Skull Base Meningiomas

Object Skull base meningiomas are challenging tumors owing in part to their close proximity to important neurovascular structures. Complete microsurgical resection can be associated with significant morbidity, and recurrence rates are not inconsequential. In this study, the authors evaluate the outcomes of skull base meningiomas treated with Gamma Knife surgery (GKS) both as an adjunct to microsurgery and as a primary treatment modality. Methods The authors performed a retrospective review of a prospectively compiled database detailing the outcomes in 255 patients with skull base meningiomas treated at the University of Virginia from 1989 to 2006. All patients had a minimum follow-up of 24 months. The group comprised 54 male and 201 female patients, with a median age of 55 years (range 19–85 years). One hundred nine patients were treated with upfront radiosurgery, and 146 patients were treated with GKS following 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 Meningiomas were centered over the cerebellopontine angle in 43 patients (17%), the clivus in 40 (16%), the petroclival region in 28 (11%), the petrous region in 6 (2%), and the parasellar region in 138 (54%). The median duration of follow-up was 6.5 years (range 2–18 years). The mean preradiosurgery tumor volume was 5.0 cm3 (range 0.3–54.8 cm3). At most recent follow-up, 220 patients (86%) displayed either no change or a decrease in tumor volume, and 35 (14%) displayed an increase in volume. Actuarial progression-free survival at 3, 5, and 10 years was 99%, 96%, and 79%, respectively. In Cox multivariate analysis, pre-GKS covariates associated with tumor progression included age greater then 65 years (HR 3.41, 95% CI 1.63–7.13, p = 0.001) and decreasing dose to tumor margin (HR 0.90, 95% CI 0.80–1.00, p = 0.05). At most recent clinical follow-up, 230 patients (90%) demonstrated no change or improvement in their neurological condition and the condition of 25 patients had deteriorated (10%). In multivariate analysis, the factors predictive of new or worsening symptoms were increasing duration of follow-up (OR 1.01, 95% CI 1.00–1.02, p = 0.015), tumor progression (OR 2.91, 95% CI 1.60–5.31, p < 0.001), decreasing maximum dose (OR 0.90, 95% CI 0.84–0.97, p = 0.007), and petrous or clival location versus parasellar, petroclival, and cerebellopontine angle location (OR 3.47, 95% CI 1.23–9.74, p = 0.018). Conclusions Stereotactic radiosurgery offers a high rate of tumor control and neurological preservation in patients with skull base meningiomas. After radiosurgery, better outcomes were observed for those receiving an optimal radiosurgery dose and harboring tumors located in a cerebellopontine angle, parasellar, or petroclival location.

CYBERKNIFE RADIOSURGERY FOR TRIGEMINAL SCHWANNOMAS

Neurosurgery ◽  
2009 ◽  
Vol 64 (suppl_2) ◽  
pp. A14-A18 ◽  
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.

Volume reduction in meningiomas after gamma knife surgery

2005 ◽  
Vol 102 ◽  
pp. 189-194 ◽  
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.

Long-term outcomes of Gamma Knife surgery for cavernous sinus meningioma

2007 ◽  
Vol 107 (4) ◽  
pp. 745-751 ◽  
Author(s):  
Toshinori Hasegawa ◽  
Yoshihisa Kida ◽  
Masayuki Yoshimoto ◽  
Joji Koike ◽  
Hiroshi Iizuka ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Gamma Knife ◽  
Cavernous Sinus ◽  
Initial Treatment ◽  
Gamma Knife Surgery ◽  
Tumor Control ◽  
Long Term Outcomes ◽  
The Mean

Object The aim of this study was to evaluate long-term outcomes, including tumor control and neurological function, in patients with cavernous sinus meningiomas treated using Gamma Knife surgery (GKS). Methods One hundred fifteen patients with cavernous sinus meningiomas, excluding atypical or malignant meningiomas, were treated with GKS between 1991 and 2003. Forty-nine patients (43%) underwent GKS as the initial treatment. The mean tumor volume was 14 cm3, and the mean maximum and margin doses applied to the tumor were 27 and 13 Gy, respectively. The median follow-up period was 62 months. During the follow-up, 111 patients were able to be evaluated with neuroimaging. Results The actuarial 5- and 10-year progression-free survival rates were 87 and 73%, respectively. Similarly, the actuarial 5- and 10-year focal tumor control rates were 94 and 92%, respectively. Regarding functional outcomes, 43 patients (46%) experienced some degree of improvement, 40 (43%) remained stable, and 11 (12%) had worse preexisting or newly developed symptoms. Patients who underwent GKS as the initial treatment experienced significant improvement of their symptoms (p = 0.006). Conclusions Gamma Knife surgery is a safe and effective treatment over the long term in selected patients with cavernous sinus meningiomas. Tumor progression is more likely to occur from the lesion margin outside the treatment volume. In small to medium-sized tumors, GKS is an excellent alternative to resection, preserving good neurological function. For relatively large-sized tumors, low-dose radiosurgery (≤ 12 Gy) is acceptable for the prevention of tumor progression.

Volume reduction in meningiomas after gamma knife surgery

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 189-194 ◽  
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.

scholarly journals Toxicity of Gamma Knife Radiosurgery May Be Greater in Patients with Lower Cranial Nerve Schwannomas

2018 ◽  
Vol 79 (06) ◽  
pp. 580-585
Author(s):  
Rawee Ruangkanchanasetr ◽  
John Lee ◽  
Suneel Nagda ◽  
Geoffrey Geiger ◽  
James Kolker ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Neurological Deficit ◽  
Cranial Nerve ◽  
Univariate Analysis ◽  
Small Sample ◽  
Neurological Deficits ◽  
Tumor Control ◽  
Lower Cranial Nerve ◽  
Glomus Jugulare

Objective Gamma Knife stereotactic radiosurgery (GK-SRS) is a preferred treatment option for tumors of the jugular foramen. We hypothesized that GK-SRS toxicity is higher for lower cranial nerve schwannomas than for glomus jugulare tumors despite anatomically similar locations. Methods We performed a retrospective review of all patients who received GK-SRS for glomus jugulare tumors and lower cranial nerve schwannomas at our institution between 2006 and 2014. Because of small sample sizes, Fisher's exact tests and logistic regression techniques were employed using SPSS. Result We identified 20 glomus jugulare tumors and 6 lower cranial nerve schwannoma patients with a median follow-up of 17 months. Median marginal dose was 16 Gy (range 13–18 Gy) and 12.5 Gy (range 12–14 Gy), respectively. All except one patient had tumor control at last follow-up visit. No worsening of pre-existing neurological deficits was observed. There were seven patients who developed any new neurological deficit after GK-SRS, four from the glomus group, and three from the schwannoma group (20 and 50% of each group, respectively). Only two of seven patients had permanent new neurological deficits. Both of them were in the schwannoma group. Univariate analysis showed that only a diagnosis of schwannoma had a greater risk of permanent new cranial nerve complication after GK-SRS compared with diagnosis of glomus jugulare (p = 0.046). Conclusion Although the marginal dose for glomus jugulare is greater, our study suggests that the risk of a new permanent neurological deficit after GK-SRS was higher in the schwannoma group compared with the glomus group.

Gamma knife surgery of superficially located meningioma

2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 255-258 ◽  
Author(s):  
Dong Gyu Kim ◽  
Chi Heon Kim ◽  
Hyun-Tai Chung ◽  
Sun Ha Paek ◽  
Sang Soon Jeong ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Gamma Knife ◽  
Complication Rate ◽  
Tumor Volume ◽  
Tumor Control ◽  
High Signal ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object. The authors analyzed tumor control rates and complications in patients with superficially located meningiomas after gamma knife surgery (GKS). Methods. Between 1998 and 2003, GKS was performed in 23 patients with 26 lesions in whom follow-up imaging for 1 year or more was available. The male/female ratio was 1:22. The mean age was 59 years. The median tumor volume was 4.7 cm3, and the mean margin dose was 16 Gy at the 50% isodose line. Peritumoral edema was revealed on magnetic resonance (MR) imaging in four patients before GKS. Magnetic resonance imaging and clinical examinations were performed every 6 months after GKS. The mean follow-up duration was 32 months. The tumor shrank in eight cases, was stable in 17, and enlarged in one; thus 25 (95%) of 26 tumors were controlled. A peritumoral high signal on T2-weighted MR images was found in eight lesions and preexisting edema was aggravated in three lesions after GKS. Ten of these 11 patients complained of severe headache, and three patients experienced neurological deficits at the same time after a mean latency of 3 months; however, high signal was not demonstrated on imaging before 6 months on average. Steroid agents, when required, gave relief to all patients. The complication rate was 43% (10 of 23 cases). High signal disappeared in nine patients and decreased in the remaining two. High signal was associated with a high integral dose and a large tumor volume. Tumor shrinkage at the last follow-up examination was more prominent in the patients with symptomatic high signal (p = 0.03). Conclusions. There was a good tumor control rate with a high complication rate. Longer follow up of more patients is needed. Adjusting the dose—volume relationship should be considered to reduce complications.

scholarly journals Gamma Knife radiosurgery in the treatment of abducens nerve schwannomas: a retrospective study

2016 ◽  
Vol 125 (4) ◽  
pp. 832-837 ◽  
Author(s):  
Govindaraju Lakshmi Prasad ◽  
Manish Singh Sharma ◽  
Shashank S. Kale ◽  
Deepak Agrawal ◽  
Manmohan Singh ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Tumor Volume ◽  
Gamma Knife Radiosurgery ◽  
Abducens Nerve ◽  
Symptomatic Improvement ◽  
Tumor Control ◽  
Imaging Features ◽  
Intracranial Tumors ◽  
The Mean

OBJECTIVE Of the intracranial schwannomas, those arising from the vestibular nerves are the most common. Abducens nerve (AN) schwannomas are very rare, and there is limited literature on their optimal management. Therapeutic options include surgery and/or stereotactic radiosurgery. The aim of this study was to evaluate the role of Gamma Knife radiosurgery (GKRS) in these sixth cranial nerve (CN) schwannomas. METHODS The authors performed a retrospective analysis of patients who had undergone GKRS for intracranial tumors at their institute in the period from 2003 to 2010. Inclusion criteria were as follows: isolated AN paresis on presentation, a lesion along the course of the sixth CN, and imaging features characteristic of a schwannoma. Patients with other CN deficits and neurofibromatosis Type 2 were excluded. Symptomatic improvement was defined as the resolution of or an improvement in diplopia noted on a subjective basis or as an improvement in lateral eyeball excursion noted objectively on follow-up. A reduction in tumor volume by at least 20%, as noted by comparing the pre- and post-GKRS images, was deemed significant. RESULTS Six patients with a mean age of 37.1 years (range 17–55 years) underwent primary GKRS. There were 2 prepontine cistern, 3 cavernous sinus, and 1 cisterno-cavernous tumor. The mean duration of symptoms was 6.1 months (range 3–12 months). The mean tumor volume was 3.3 cm3 (range 1.5–4.8 cm3). The mean tumor margin radiation dose was 12.5 Gy (range 12–14 Gy), while the median margin dose was 12 Gy (50% isodose line). The median number of isocenters used was 5 (range 4–8). The brainstem received an average 8.35-Gy radiation dosage (range 5.5–11 Gy). The mean follow-up duration was 44.3 months (range 24–78 months). Symptoms remained stable in 1 patient, improved in 3, and resolved in 2 (total improvement 83%). Magnetic resonance imaging at the last follow-up showed a stable tumor size in 3 patients (50%) and a reduction in the other 3. Thus, the tumor control rate achieved was 100%. No new CN deficits were noted. CONCLUSIONS Abducens nerve schwannomas are rare intracranial tumors. They can be cavernous, cisternal, or cisterno-cavernous in location. Excellent tumor control rates and symptomatic improvement can be achieved with GKRS, which appears to be a safe and effective, minimally invasive modality for the treatment of such lesions. Therefore, it is reasonable to consider GKRS as the initial treatment of choice for this rare pathology. Long-term follow-up will be essential for further recommendations.

Gamma knife surgery of superficially located meningioma

2005 ◽  
Vol 102 ◽  
pp. 255-258 ◽  
Author(s):  
Dong Gyu Kim ◽  
Chi Heon Kim ◽  
Hyun-Tai Chung ◽  
Sun Ha Paek ◽  
Sang Soon Jeong ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Gamma Knife ◽  
Complication Rate ◽  
Tumor Volume ◽  
Tumor Control ◽  
High Signal ◽  
Content Type ◽  
The Mean ◽  
Fine Print

Object.The authors analyzed tumor control rates and complications in patients with superficially located meningiomas after gamma knife surgery (GKS).Methods.Between 1998 and 2003, GKS was performed in 23 patients with 26 lesions in whom follow-up imaging for 1 year or more was available. The male/female ratio was 1:22. The mean age was 59 years. The median tumor volume was 4.7 cm3, and the mean margin dose was 16 Gy at the 50% isodose line. Peritumoral edema was revealed on magnetic resonance (MR) imaging in four patients before GKS. Magnetic resonance imaging and clinical examinations were performed every 6 months after GKS. The mean follow-up duration was 32 months.The tumor shrank in eight cases, was stable in 17, and enlarged in one; thus 25 (95%) of 26 tumors were controlled. A peritumoral high signal on T2-weighted MR images was found in eight lesions and preexisting edema was aggravated in three lesions after GKS. Ten of these 11 patients complained of severe headache, and three patients experienced neurological deficits at the same time after a mean latency of 3 months; however, high signal was not demonstrated on imaging before 6 months on average. Steroid agents, when required, gave relief to all patients. The complication rate was 43% (10 of 23 cases). High signal disappeared in nine patients and decreased in the remaining two. High signal was associated with a high integral dose and a large tumor volume. Tumor shrinkage at the last follow-up examination was more prominent in the patients with symptomatic high signal (p = 0.03).Conclusions.There was a good tumor control rate with a high complication rate. Longer follow up of more patients is needed. Adjusting the dose—volume relationship should be considered to reduce complications.

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