Role Of Gamma Knife Radiosurgery Research Articles

The role of Gamma Knife radiosurgery in trigeminal neuralgia management and technical considerations

The role of Gamma Knife radiosurgery in trigeminal neuralgia management and technical considerations

Factors Influencing Long-Term Outcomes of Single-Session Gamma Knife Radiosurgery in Large-Volume Meningiomas >10 cc

Introduction: Meningiomas are the most common primary intracranial tumour. Gamma knife radiosurgery (GKRS) is a frequently employed non-invasive method of treatment, with good remission rates and low morbidity in literature. However, the role of GKRS in the management of “large” meningiomas is unclear, with reported outcomes that vary by centre. We aimed to assess the factors that influence long-term outcomes following GKRS in meningiomas >10 cc in volume. Methods: A retrospectively analysed all patients with meningiomas exceeding 10 cc in volume who underwent GKRS between January 2006 and December 2021 at the National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru. Demographic, clinical, radiological, and follow-up data were acquired, and factors associated with progression following GKRS were assessed. Results: The cohort comprised 76 patients 29 males (38.2%) and 47 females (61.8%) with a mean age of 46.3 ± 11.02 years. Thirty-nine patients had been previously operated (51.3%). Meningiomas were most frequently located in the parasagittal region (26 tumours, 34.2%) and sphenopetroclival region (23 tumours, 30.3%), with mean lesion volume of 12.55 ± 5.22 cc, ranging 10.3 cc–25 cc. The mean dose administered to the tumour margin was 12.5 Gy ± 1.2 Gy (range 6–15 Gy). The median duration of clinical follow-up was 48 months, over which period radiological progression occurred in 14 cases (20%), with unchanged tumour volume in 20 cases (28.6%) and reduction in size of the tumour in 36 cases (51.4%). Progression-free survival after GKRS was 72% at 5 years, was significantly poorer among meningiomas with tumour volume >14 cc (log-rank test p = 0.045), tumours presenting with limb motor deficits (log-rank test p = 0.012), and tumours that underwent prior Simpson grade 3 or 4 excision (log-rank test p = 0.032). Conclusions: Meningiomas >10 cc in volume appear to display a high rate of progression and subsequent need for surgery following GKRS. Primary surgical resection, when not contraindicated, may be considered with GKRS serving an adjuvant role, especially in tumours exceeding 14 cc in volume, and presenting with limb motor deficits. Long-term clinical and radiological follow-up is essential following GKRS as the response of large meningiomas may be unpredictable.

Gamma knife radiosurgery as primary management for intracranial meningioma identified as growing on serial imaging.

Gamma knife radiosurgery (GKRS) has emerged as a highly effective therapeutic modality for the management of intracranial meningiomas. However, the role of GKRS in treating growing meningiomas detected during active surveillance remains unclear. This study seeks to investigate the long-term outcomes of GKRS treatment for growing meningiomas. A retrospective analysis was conducted on patients who underwent GKRS as the primary treatment for growing meningiomas between 2004 and 2021. Growing meningiomas were defined as those exhibiting a > 10% increase in tumor volume (TV) compared to the previous imaging. Fifty-nine patients who received GKRS as their initial treatment were included, with a minimum follow-up period of 12 months. Comprehensive clinical, radiological, and procedural data were analyzed. Serial TV assessments were performed for all tumors before and after GKRS. Tumor progression and regression were defined as a > 10% increase or decrease in TV, respectively, compared to the pretreatment image. At a median follow-up of 41 months (range 15-197 months), TV was unchanged in 16 patients (27.1%), decreased in 41 patients (69.5%), and increased in 2 patients (3.4%). Multivariate analysis revealed that both TV (cm3) (hazard ratio [HR], 1.107; 95% confidence interval [CI], 1.002-1.222; P = .045) and volume growing rate (%/yr) (HR, 1.013; 95% CI, 1.000-1.025; P = .04) significantly correlated with tumor progression. Eleven patients (18.6%) experienced new or worsening symptoms. In multivariate analysis, factor predicting new or worsening neurological function was preexisting calcification (HR, 5.297; 95% CI, 1.328-21.124; P = .018). GKRS demonstrates a promising level of tumor control with minimal risk of neurological deterioration when applied to growing meningiomas. These findings provide compelling support for considering GKRS as a valuable therapeutic option following an initial period of active surveillance for these tumors.

Promising outcome of patients with recurrent glioblastoma after Gamma Knife-based hypofractionated radiotherapy

BackgroundThe role of Gamma Knife radiosurgery (GKRS) in recurrent glioblastoma remains unclear. The purpose of this study is to evaluate the effects of GKRS in a group of patients with recurrent glioblastoma, focusing on survival and safety. MethodsPatients undergoing GKRS for recurrent glioblastoma between September 2014 and April 2019 were included in this study. Relevant clinical and radiosurgical data, including GKRS-related complications, were recorded and analyzed. Overall survival (OS), local progression free survival (LPFS) and prognostic factors for outcome were thoroughly evaluated. ResultsFifty-three patients were analyzed (24 female, 29 male). The median age was 50 years (range, 19–78 years). The median GKRS treatment volume was 35.01 cm3 (range, 2.38-115.57 cm3). Twenty patients (38%) were treated with single fraction GKRS, while 33 (62%) were treated with GKRS-based hypofractionated stereotactic radiotherapy (HSRT). The median prescription dose for single fraction GKRS, 3-fractions HSRT and 5-fractions HSRT were 16 Gy (range, 10−20 Gy), 27 Gy (range, 18−33 Gy) and 25 Gy (range, 25−30 Gy), respectively. The median LPFS and OS times were 8.1 months and 11.4 months after GKRS, respectively. HSRT and Bevacizumab were associated with improved LPFS, while HSRT alone was associated with longer OS. ConclusionOur findings suggested that HRST would likely improve LPFS and OS in definite settings; the addition of Bevacizumab to GKRS was associated with increased rates of local control. No major complications were reported. Further prospective studies are warranted to confirm our findings.

Role of Gamma Knife Radiosurgery in the Management of Diffuse Low Grade Astrocytoma

Role of Gamma Knife Radiosurgery in the Management of Diffuse Low Grade Astrocytoma

Gamma Knife Radiosurgery in Partially Embolised Arteriovenous Malformations: Management Dilemmas and Outcomes.

The role of Gamma Knife radiosurgery (GKRS) in partially embolized arteriovenous malformations (AVMs) has always remained a subject of debate. The aim of this study was to evaluate the efficacy of GKRS in partially embolized AVMs and to analyze factor that influence its obliteration. This was a retrospective study from a single institute performed over a period of 12 years (2005-2017). It included all patients who underwent GKRS for partially embolized AVMs. Demographic characteristics, treatment profiles, and clinical and radiological data were obtained during treatment and follow-up. Obliteration rates and factors affecting the same were sought and analyzed. A total of 46 patients with a mean age of 30 years (range: 9-60 years) were included in the study. Follow-up imaging was available for 35 patients either by digital subtraction angiography (DSA) or magnetic resonance imaging (MRI). We found complete AVM obliteration in 21 patients (60%): one had near total obliteration (>90% obliteration), 12 had subtotal obliteration (<90%), and one had no change in the volume following GKRS. Following embolization alone, an average of 67% of the AVM volume was obliterated which resulted in an average 79% final obliteration rate after Gamma Knife radiosurgery. Mean duration to complete obliteration was found to be 3.45 years (range: 1-10 years). There was a significant difference (P = 0.04) in the mean interval between embolization and GKRS among cases with complete obliteration (12 months) and those with incomplete obliteration (36 months). There was no significant difference (P = 0.49) in the average obliteration rate between the ARUBA-eligible unruptured AVMs (79.22%) and ruptured AVMs (79.04%). Bleeding after GKRS during the latency period had a negative impact on obliteration (P = 0.05). Other factors like age, sex, Spetzler-Martin (SM)-grade, Pollock Flickinger score (PF-score), nidus volume, radiation dose, or presentation before embolization had no significant influence on obliteration. Three patients had permanent neurological deficits after embolization and none after radiosurgery. Six out of nine patients (66%) presenting with seizures were seizure-free after the treatment. Hemorrhage was noted in three patients following combined treatment and were managed non-surgically. Obliteration rates in partially embolized AVM after Gamma Knife are inferior when compared to Gamma Knife alone; moreover with volume staging and/or dose staging being increasingly plausible due to the new ICON machine, embolization may be completely replaced. However we have shown that in complicated and carefully chosen AVMs, embolization followed by GKRS is a valid modality of management. This study represents a real-world picture of individualized AVM treatment depending on patient choices and resources available.

Role of Gamma Knife Radiosurgery in the Management of Functional Disorders - A Literature Review.

Role of radiosurgical lesioning in functional disorders has been restricted because of development of deep brain stimulation (DBS) techniques. However, many elderly patients with comorbidities and coagulation abnormalities may not be eligible for DBS. Radiosurgical lesioning may be a good alternative in such cases. The objective of the study was to review the role of radiosurgical lesioning for functional targets in common functional disorders. Literature reports pertaining to common disorders were reviewed. Disorders included are tremors (essential tremors, tremor-dominant Parkinson's disease [PD], multiple sclerosis [MS] related refractory tremors), Parkinson's disease (for rigidity, bradykinesia, drug-induced dyskinesias), dystonia, and obsessive-compulsive disorder (OCD). The most commonly performed procedure was ventral intermediate nucleus (VIM) lesioning for essential tremors and tremor-dominant PD, with about 90% patients demonstrating improvement. Intractable OCD with 60% responders is a promising indication. Other disorders are less commonly treated, with dystonia being the least commonly treated entity. Subthalamic nucleus (STN) and globus pallidus interna/posteroventral pallidum (GPi) lesioning are very rarely reported, and the available literature suggests caution due to high rates of adverse effects. Outcomes for radiosurgical lesioning for essential tremors (VIM) and OCD (anterior limb of internal capsule [ALIC]) are encouraging. Radiosurgical lesioning offers a lower immediate risk profile in patient population with several comorbidities; however, long-term adverse effects due to radiation are a concern, especially for STN and GPi lesioning.

The role of Gamma Knife radiosurgery in the management of skull base chordoma.

Chordoma is a slow-growing and locally aggressive cancer, which arises from the remnants of the primitive notochord. The first line treatment for the skull base chordoma is neurosurgery. Gamma Knife radiosurgery (GKS) is often be chosen especially in the setting of residual or recurrent chordomas. The purpose of this study is to evaluate the prognosis of patients with skull base chordoma who underwent GKS. The present study was a retrospective analysis of 53 patients with skull base chordomas who underwent GKS. Univariate Cox and Kaplan-Meier survival analysis were performed to analyze the relationship between the tumor control time and the clinical characteristics. The 1-, 2-, 3-, and 5-year progression free survival (PFS) rates were 87, 71, 51, and 18%, respectively. After performing the univariate analysis, the clinical characteristics were not found to be significantly associated with the time of PFS; however, surgical history, peripheral dose, and tumor volume did have tendencies to predict the prognosis. GKS provided a safe and relatively effective treatment for residual or recurrent chordomas after surgical resection. A higher tumor control rate depends on two approaches, an appropriate dose of radiation for the tumor and the accurate identification of the tumor margins.

Role of gamma knife radiosurgery in the management of intracranial pathologies of pediatric population: Current concepts, limitations, and future directions

Abstract The aim of treating pediatric brain tumors is not only tumor control but also preservation of the quality of life. To safeguard the neurocognitive outcome, progression-free survival, and overall survival, the field of radiotherapy has strived for better conformality, precision, and accuracy while mitigating the extracranial dose distribution. Stereotactic radiosurgery and in particular, Gamma Knife radiosurgery, has been a significant advancement in this direction with a gradually expanding horizon of its indications. Gamma Knife radiosurgery has been instrumental in changing the paradigm in the management of the disorders of the tender age group. In this review article, we tried to encompass all the spheres of application of Gamma Knife radiosurgery in pediatric cases highlighting the limitations and frontiers of the current practice in the field of radiosurgery pertinent to the pediatric population. While the traditional indications have been reviewed in depth and a bird's eye view of the possible future applications has also been presented.

Bevacizumab plus irinotecan with or without gamma knife radiosurgery after failure of concurrent chemo-radiotherapy for high-grade glioma.

Concurrent chemo-radiotherapy (CCRT) with temozolomide (TMZ) is a standard first-line treatment for high-grade glioma. However, if CCRT with TMZ treatment fails, second-line treatment options have limited value. Bevacizumab plus irinotecan is the only available treatment option for such patients. The role of gamma knife radiosurgery (GKS) in patients with high-grade gliomas is not well-established. In this study, we evaluated the efficacy and safety of bevacizumab plus irinotecan with or without GKS in the treatment of high-grade glioma patients who progressed after initially being treated with CCRT with TMZ. We collected clinical data of patients with biopsy-proven high-grade glioma (glioblastoma multiforme (GBM) or anaplastic astrocytoma) who were treated at Samsung Medical Center from January 2015 to December 2020, retrospectively. We evaluated the overall survival (OS), progression-free survival (PFS), and safety of bevacizumab plus irinotecan with or without GKS. In total, 203 patients were diagnosed with high-grade glioma, including GBM and anaplastic astrocytoma. The median OS was 8.73months (95% confidence interval [CI]: 7.27-10.18), and the median PFS was 4.36months (95% CI: 3.75-4.97). Sixty-eight (33.4%) patients underwent GKS prior to bevacizumab plus irinotecan treatment, which led to a significantly prolonged OS (10.13months, 95% CI: 8.65-11.60 vs. 8.26months, 95% CI: 7.01-9.51, p = 0.012). The most common adverse events of any grade were neutropenia (36.9%) and thrombocytopenia (22.6%). However, the incidence of adverse events in patients who underwent GKS prior to bevacizumab plus irinotecan was not different compared with those in patients who did not undergo GKS. Bevacizumab plus irinotecan was well-tolerated and moderately effective in patients with high-grade gliomas. The addition of GKS prior to bevacizumab plus irinotecan led to a significant OS benefit with a manageable safety profile. GKS prior to bevacizumab plus irinotecan can therefore be considered a potential treatment option for these patients.

Neurofibromatosis type 2-associated meningiomas: an international multicenter study of outcomes after Gamma Knife stereotactic radiosurgery.

The management of neurofibromatosis type 2 (NF2)-associated meningiomas is challenging. The role of Gamma Knife radiosurgery (GKRS) in the treatment of these tumors remains to be fully defined. In this study, the authors aimed to examine the role of GKRS in the treatment of NF2-associated meningiomas and to evaluate the outcomes and complications after treatment. Seven international medical centers contributed data for this retrospective cohort. Tumor progression was defined as a ≥ 20% increase from the baseline value. The clinical features, treatment details, outcomes, and complications were studied. The median follow-up was 8.5 years (range 0.6-25.5 years) from the time of initial GKRS. Shared frailty Cox regression was used for analysis. A total of 204 meningiomas in 39 patients treated with GKRS were analyzed. Cox regression analysis showed that increasing the maximum dose (p = 0.02; HR 12.2, 95% CI 1.287-116.7) and a lower number of meningiomas at presentation (p = 0.03; HR 0.9, 95% CI 0.821-0.990) were predictive of better tumor control in both univariable and multivariable settings. Age at onset, sex, margin dose, location, and presence of neurological deficit were not predictive of tumor progression. The cumulative 10-year progression-free survival was 94.8%. Radiation-induced adverse effects were noted in 4 patients (10%); these were transient and managed medically. No post-GKRS malignant transformation was noted in 287 person-years of follow-up. GKRS achieved effective tumor control with a low and generally acceptable rate of complications in NF2-associated meningiomas. There did not appear to be an appreciable risk of post-GKRS-induced malignancy in patients with NF2-treated meningiomas.

Role of Gamma Knife Radiosurgery in Small Cell Lung Cancer: A Multi-Institutional Retrospective Study of the International Radiosurgery Research Foundation (IRRF)

Cifarelli, Christopher P MD, PhD; Vargo, John A MD; Fang, Wei PhD; Liscak, Roman MD; Guseynova, Khumar MD; Warnick, Ronald E MD; Lee, Cheng-chia MD; Yang, Huai-che MD; Borghei-Razavi, Hamid MD; Maiti, Tonmoy MD; Siddiqui, Zaid A MD; Yuan, Justin C BS; Grills, Inga S MD; Mathieu, David MD; Touchette, Charles J MD; Cordeiro, Diogo MD; Chiang, Veronica MD; Hess, Judith BA; Tien, Christopher J PhD; Faramand, Andrew MD; Kano, Hideyuki MD, PhD; Barnett, Gene H MD; Sheehan, Jason P MD, PhD; Lunsford, L Dade MD

Role of Gamma Knife radiosurgery in trigeminal neuralgia – Its long term outcome and prediction using Artificial neural Network model

PurposeWe aimed to study the long-term efficacy, prognostic factors and complications associated with the GKRS for trigeminal neuralgia. Methods and MaterialsProspectively created database was analyzed for these patients. We created an Artificial neural Network – using Multilayer perceptron model in SPSS 23 by including all variables whose p value were<0.5 in univariate analysis. ResultsA total of 36 patients were included in the study. Patients pain free at 6 months were 25(69.44%), which reduced to 6(40 %) at 6 years. Median time to pain relief was 18.5 days. Only 5(13.88%) of them developed new onset or worsened numbness post Gamma Knife radio surgery. Median radiation dose was 80 Gy (prescribed at 100 percent isodose line). 1st GKT (P value < 0.05) and post GKT numbness (P value < 0.05) were the only factors favouring good outcome.Prior history of MVD was associated with poor pain relief post GKRS although p value was not significant (p = 0.136). ANN model could predict with 90.0 percent accuracy the favourable or unfavourable response on 11 Tested cases. In ANN model, a greater number of Pre GKT medications, previous MVD history, V2 dermatome involvement and negative history of post GKT numbness were negative prognostic factors. ConclusionsLesser number of pre GKRS drugs used, involvement of V1 dermatome, post GKT numbness are favourable prognostic factors. Also, history of failed MVD for trigeminal neuralgia is associated with poor outcome. Repeat GKRS failed to show improvement in BNI grades.

Immune Checkpoint Inhibitors for Non-Small-Cell Lung Cancer with Brain Metastasis : The Role of Gamma Knife Radiosurgery.

ObjectiveImmune checkpoint inhibitors (ICIs) are approved for treating non-small-cell lung cancer (NSCLC); however, the safety and efficacy of combined ICI and Gamma Knife radiosurgery (GKS) treatment remain undefined. In this study, we retrospectively analyzed patients treated with ICIs with or without GKS at our institute to manage patients with brain metastases from NSCLC. MethodsWe retrospectively reviewed medical records of patients with brain metastases from NSCLC treated with ICIs between January 2015 and December 2017. Of 134 patients, 77 were assessable for brain responses and categorized into three groups as follows : group A, ICI alone (n=26); group B, ICI with concurrent GKS within 14 days (n=24); and group C, ICI with non-concurrent GKS (n=27). ResultsThe median follow-up duration after brain metastasis diagnosis was 19.1 months (range, 1–77). At the last follow-up, 53 patients (68.8%) died, 20 were alive, and four were lost to follow-up. The estimated median overall survival (OS) of all patients from the date of brain metastasis diagnosis was 20.0 months (95% confidence interval, 12.5–27.7) (10.0, 22.5, and 42.1 months in groups A, B, and C, respectively). The OS was shorter in group A than in group C (p=0.001). The intracranial disease progression-free survival (p=0.569), local progression-free survival (p=0.457), and complication rates did not significantly differ among the groups. Twelve patients showed leptomeningeal seeding (LMS) during follow-up. The 1-year LMS-free rate in treated with ICI alone group (69.1%) was significantly lower than that in treated with GKS before ICI treatment or within 14 days group (93.2%) (p=0.004). ConclusionGKS with ICI showed no favorable OS outcome in treating brain metastasis from NSCLC. However, GKS with ICI did not increase the risk of complications. Furthermore, compared with ICI alone, GKS with ICI may be associated with a reduced incidence of LMS. Further understanding of the mechanism, which remains unknown, may help improve the quality of life of patients with brain metastasis.

Role of Gamma Knife Radiosurgery in Small Cell Lung Cancer: A Multi-Institutional Retrospective Study of the International Radiosurgery Research Foundation (IRRF).

Despite a high incidence of brain metastases in patients with small-cell lung cancer (SCLC), limited data exist on the use of stereotactic radiosurgery (SRS), specifically Gamma Knife™ radiosurgery (Elekta AB), for SCLC brain metastases. To provide a detailed analysis of SCLC patients treated with SRS, focusing on local failure, distant brain failure, and overall survival (OS). A multi-institutional retrospective review was performed on 293 patients undergoing SRS for SCLC brain metastases at 10 medical centers from 1991 to 2017. Data collection was performed according to individual institutional review boards, and analyses were performed using binary logistic regression, Cox-proportional hazard models, Kaplan-Meier survival analysis, and competing risks analysis. Two hundred thirty-two (79%) patients received SRS as salvage following prior whole-brain irradiation (WBRT) or prophylactic cranial irradiation, with a median marginal dose of 18 Gy. At median follow-up after SRS of 6.4 and 18.0 mo for surviving patients, the 1-yr local failure, distant brain failure, and OS were 31%, 49%, and 28%. The interval between WBRT and SRS was predictive of improved OS for patients receiving SRS more than 1 yr after initial treatment (21%, <1 yr vs 36%, >1 yr, P=.01). On multivariate analysis, older age was the only significant predictor for OS (hazard ratio 1.63, 95% CI 1.16-2.29, P=.005). SRS plays an important role in the management of brain metastases from SCLC, especially in salvage therapy following WBRT. Ongoing prospective trials will better assess the value of radiosurgery in the primary management of SCLC brain metastases and potentially challenge the standard application of WBRT in SCLC patients.

Gamma Knife radiosurgery as a primary treatment for central neurocytoma

OBJECTIVE This study was performed to evaluate the role of Gamma Knife radiosurgery (GKRS) as a primary treatment for central neurocytomas (CNs). METHODS The authors retrospectively assessed the treatment outcomes of patients who had undergone primary treatment with GKRS for CNs in the period between December 2001 and December 2018. The diagnosis of CN was based on findings on neuroimaging studies. The electronic medical records were retrospectively reviewed for additional relevant preoperative data, and clinical follow-up data had been obtained during office evaluations of the treated patients. All radiographic data were reviewed by a dedicated neuroradiologist. RESULTS Fourteen patients were treated with GKRS as a primary treatment for CNs in the study period. Seven patients (50.0%) were asymptomatic at initial presentation, and 7 (50.0%) presented with headache. Ten patients (71.4%) were treated with GKRS after the diagnosis of CN based on characteristic MRI findings. Four patients (28.6%) initially underwent either stereotactic or endoscopic biopsy before GKRS. The median tumor volume was 3.9 cm3 (range 0.46–18.1 cm3). The median prescription dose delivered to the tumor margin was 15 Gy (range 5.5–18 Gy). The median maximum dose was 30 Gy (range 11–36 Gy). Two patients were treated with fractionated GKRS, one with a prescription dose of 21 Gy in 3 fractions and another with a dose of 22 Gy in 4 fractions. Control of tumor growth was achieved in all 14 patients. The median volume reduction was 26.4% (range 0%–78.3%). Transient adverse radiation effects were observed in 2 patients but resolved with improvement in symptoms. No recurrences were revealed during the follow-up period, which was a median of 25 months (range 12–89 months). CONCLUSIONS Primary GKRS for CNs resulted in excellent tumor control rates without recurrences. These results suggest that GKRS may be a viable treatment option for patients with small- to medium-sized or incidental CNs.

Role of gamma knife radiosurgery for recurrent or residual World Health Organization grade II and III intracranial meningiomas

Background: To analysis the role of gamma knife radiosurgery (GKRS) in treatment of the recurrent or residual World Health Organization (WHO) grade II and III meningiomas.Methods: Between 1995 and 2015, a total of 1163 meningioma patients were treated with GKRS at our single institute; 26 atypical and 6 anaplastic meningiomas were enrolled. The group consisted of 16 men and 16 women with a median age of 59.5 years (range 30–78 years). The median follow-up was 106.5 months (range 40–216 months). All were cases of tumour recurrence except 7 cases of residual lesions. Six patients were given fractionated radiotherapy before the initial course of GKRS (median dose, 56 Gy).Results: The median tumour volume was 3035 mm3 (range 247–11400 mm3). The median prescribed dose to high grade meningioma margin was 14 Gy (range 12–20 Gy,). The median prescribed dose to WHO II and III meningioma were 14 Gy (range 12–18 Gy) and 15 Gy (range 14–20 Gy), respectively. After radiosurgery, local tumour control rate was 50%. Tumour progression was observed in 28 patients; 16 recurrences were local (12 atypical and 4 anaplastic), 8 were marginal (7 atypical and 1 anaplastic), and 4 were distal (3 atypical and 1 anaplastic). Seven patients (21.88%) developed adverse radiation effects after GKRS. WHO grade was strongly associated with survival, with grade II showing a much longer survival (p = 0.01), and a prior history of radiation was associated with decreased survival (p = 0.003). Multivariate analysis showed that WHO grade (hazard ratio, HR: 5.051, p = 0.01) and prior radiation (HR: 5.763, p = 0.004) were independently associated with survival.Conclusions: WHO grade and a prior history of radiation therapy are reliable long-term predictors of overall outcome when treated with GKRS.

Role of gamma knife radiosurgery in the management of intracranial gliomas.

Gamma knife for gliomas is a relatively obscure treatment modality with few reports and small series available on the same. An extensive search of English Language literature yields no comprehensive reviews of the same. We here, attempt to review the available literature on gamma knife for all types of gliomas: Low grade, High grade, recurrent, and also for pediatric populations. We used keywords such as "Gamma Knife Glioma," "Stereotactic Radiosurgery Glioma," "Gamma Knife," "Adjuvant therapy Glioma" "Recurrent Glioma" on PubMed search engine, and articles were selected with respect to their use of gamma Knife for Gliomas and outcome for the same. These were then analyzed and salient findings were elucidated. This was combined with National Comprehensive Cancer Network guidelines for the same and also included our own initial experience with these tumors. Gamma-knife improved long term survival and quality of life in patients with low grade gliomas. In pediatric low grade gliomas, it may be considered as a treatment modality with a marginal dose of 12-14 Gy, especially in eloquent structures such as brain stem glioma, anterior optic pathway hypothalamic glioma. However, in newly diagnosed high-grade glioma gamma knife radiosurgery (GKRS) is not recommended because of a lack of definitive evidence in tumor control and quality of life. GKRS may find its role in palliative care of recurrent gliomas irrespective of type and grade. Inspite of growing experience with GKRS for gliomas, there is no Level I evidence in support of GKRS, hence better designed randomized controlled trials with long term outcomes are warranted. Although this modality is not a "one size fits all' therapy, it has its moments when chosen correctly and applied wisely. Gliomas being the most common tumors operated in any neurosurgical setting, knowledge about this modality and its application is essential and useful.

Gamma Knife Radiosurgery For Brain Vascular Malformations: Current Evidence And Future Tasks.

Gamma Knife radiosurgery (GKRS) has long been used for treating brain vascular malformations, including arteriovenous malformations (AVMs), dural arteriovenous fistulas (DAVFs), and cavernous malformations (CMs). Herein, current evidence and controversies regarding the role of stereotactic radiosurgery for vascular malformations are described. 1) It has already been established that GKRS achieves 70–85% obliteration rates after a 3–5-year latency period for small to medium-sized AVMs. However, late radiation-induced adverse events (RAEs) including cyst formation, encapsulated hematoma, and tumorigenesis have recently been recognized, and the associated risks, clinical courses, and outcomes are under investigation. SRS-based therapeutic strategies for relatively large AVMs, including staged GKRS and a combination of GKRS and embolization, continue to be developed, though their advantages and disadvantages warrant further investigation. The role of GKRS in managing unruptured AVMs remains controversial since a prospective trial showed no benefit of treatment, necessitating further consideration of this issue. 2) Regarding DAVFs, GKRS achieves 41–90% obliteration rates at the second post-GKRS year with a hemorrhage rate below 5%. Debate continues as to whether GKRS might serve as a first-line solo therapeutic modality given its latency period. Although the post-GKRS outcomes are thought to differ among lesion locations, further outcome analyses regarding DAVF locations are required. 3) GKRS is generally accepted as an alternative for small or medium-sized CMs in which surgery is considered to be too risky. The reported hemorrhage rates ranged from 0.5–5% after GKRS. Higher dose treatments (>15 Gy) were performed during the learning curve, while, with the current standard treatment, a dose range of 12–15 Gy is generally selected, and has resulted in acceptable complication rates (< 5%). Nevertheless, further elucidation of long-term outcomes is essential.

Role of gamma knife radiosurgery in the treatment of prolactinomas

Stereotactic radiosurgery is one of the treatment options for prolactinomas, the most commonly used being Gamma Knife Radiosurgery (GKRS). GKRS is indicated mainly in the treatment of dopamine agonist (DA)-resistant prolactinomas. In our study, we report on our experience in treating prolactinoma patients by GKRS. Twenty-eight patients were followed-up after GKRS for 26-195months (median 140months). Prior to GKRS, patients were treated with DAs and 9 of them (32.1%) underwent previous neurosurgery. Cavernous sinus invasion was present in 16 (57.1%) patients. Indications for GKRS were (i) resistance to DA treatment (17 patients), (ii) drug intolerance (5 patients), or (iii) attempts to reduce the dosage and/or shorten the length of DA treatment (6 patients). After GKRS, normoprolactinaemia was achieved in 82.1% of patients, out of which hormonal remission (normoprolactinaemia after discontinuation of DAs) was achieved in 13 (46.4%), and hormonal control (normoprolactinaemia while taking DAs) in 10 (35.7%) patients. GKRS arrested adenoma growth or decreased adenoma size in all cases. Two patients (8.3%) developed hypopituitarism after GKRS. Prolactinoma cystic transformation with expansive behaviour, manifested by bilateral hemianopsia, was observed in one patient. GKRS represents an effective treatment option, particularly for DA-resistant prolactinomas. Normoprolactinaemia was achieved in the majority of patients, either after discontinuation of, or while continuing to take, DAs. Tumour growth was arrested in all cases. The risk of the development of hypopituitarism can be limited if the safe dose to the pituitary and infundibulum is maintained.