Effect Of Gamma Knife Radiosurgery Research Articles

Investigation of the effects of Gamma Knife radiosurgery on optic pathways using diffusion tensor MRI within the first year after treatment.

To investigate the radiation-induced effects of Gamma Knife radiosurgery (GKRS) for sellar-parasellar tumors on optic pathways using DTI parameters within the first year after treatment. Twenty-five patients with sellar-parasellar tumors underwent MRI before and 3months after GKRS, including T1WI, DTI, T2WI. Moreover, 21 patients underwent follow-up DTI 6-8months after radiosurgery. ROIs were set on optic nerves, optic radiations, and control localizations; DTI parameters for each were calculated. Pre- and post-radiosurgery differences in DTI values were statistically compared and assessed with respect to tumor size changes. Following GKRS, DTI parameters, notably ADC, FA, and RD, showed statistically significant changes in optic nerves and anterior optic radiations. DTI changes were more significant in the group of cases with tumor shrinkage. In this group, DTI of the anterior optic radiations further deteriorated 3months post-GKRS, whereas acute changes in DTI parameters of the optic nerves resolved within 6-8months. DTI of central and posterior optic radiations did not differ significantly following radiosurgery; 6-8months after radiosurgery, visual function was stable in 14 (56%) patients and improved in 11 (44%), showing no correlation with tumor size changes or DTI parameters. White Matter (WM) injury in the optic pathways can be induced by Gamma Knife radiosurgery targeted to sellar and parasellar tumors. Following GKRS, microstructural abnormalities occurred in the optic radiations as well as the optic nerves within the first post-treatment year. Our findings could support modifications to radiosurgical treatment strategies to minimize the risk of permanent WM injury.

The effect of gamma knife radiosurgery on the endocrine profile in patients with non-sellar pathologies: A short-term study

The effect of gamma knife radiosurgery on the endocrine profile in patients with non-sellar pathologies: A short-term study

Can Trigeminal Schwannoma-Related Symptoms be Controlled With Gamma Knife Radiosurgery?

The effectiveness of gamma knife radiosurgery (GKRS) for the management of trigeminal schwannomas (TS) has been established. Although GKRS has been shown to inhibit tumor growth, the effect of GKRS on the symptoms caused by TS has not been sufficiently studied. In this study, symptomatic changes following GKRS for the management of symptomatic TS were investigated using long-term follow-up results. A retrospective analysis was performed on 32 patients with TS who underwent GKRS between May 1994 and December 2016. Clinical charts, radiographic results, and surgical records were reviewed. To evaluate whether symptoms improved after GKRS, patient demographics, GKRS profile, radiological tumor size change, and tumor location were analyzed. Tumor control after GKRS for symptomatic TS was 87%. The improvement rates for facial pain at 6, 12, and 24months after GKRS were 46%, 72%, and 86%, respectively. For the same time intervals, facial hypesthesia improved by 12%, 46%, and 52%, respectively. Of the patients with diplopia, 17% had improved symptoms 12months after GKRS, and 50% of the patients improved after 24months. GKRS can be an effective treatment modality for TS tumor control and shows favorable resultsin improving TS-related symptom, especially facial pain.

P01.06.B Interim results from CAR-Study B: An ongoing randomized trial on the effect of SRS or WBRT on cognitive performance in patients with 11-20 brain metastases

Abstract Background Both stereotactic radiosurgery (SRS) and whole brain radiation therapy (WBRT) have proven to be effective treatments for multiple brain metastases (BM) with similar overall survival. Cognition and Radiation (CAR) Study B is a randomized trial on the effect of Gamma Knife radiosurgery (GKRS) or WBRT on cognitive performance in patients with 11-20 BM. The primary and secondary aim of this interim analysis were to check whether Bayesian stopping rules for cognitive failure were met, and to compare cognitive changes after treatment respectively, for the first 45 patients enrolled. Material and Methods Patients with 11-20 newly diagnosed BM on a triple-dose contrast-enhanced MRI-scan, expected survival >3 months and Karnofsky Performance Status (KPS) ≥70, were stratified by age, histology, total BM volume, systemic treatment, KPS, and baseline Hopkins Verbal Learning total recall (HVLT-R TR) score, and randomized 1:1 (minimization) to GKRS or WBRT. Neuropsychological tests were administered before (T0) treatment (n=21 vs n=20), and at 3 (T3; n=16 vs n=14) and 6 (T6; n=9 vs n=9) months thereafter. A decline of ≥5 points in HVLT-R TR score was considered a cognitive failure. The trial would be halted if the posterior probability for a higher cognitive failure rate in one group versus the other was >0·975 at T3 or T6 according to the employed beta (2.09,2.91) prior (prior mean of 42%), based on the average failure rates at 4 months reported by Chang et al. (2009). Between-group differences in changes of test performances over 6 months were analyzed using mixed ANOVAs. Proportions of cognitive changes (T0-T6) at the individual level based on reliable change indices correcting for practice effects, were determined. Results HVLT-R TR failure rates in the GKRS versus WBRT group were 31% versus 29% at T3, and 0% versus 33% at T6. The observed failure rates after WBRT at T3 and T6 were lower than the average failure rates of Chang et al. (2009). Posterior probabilities were 0·451 at T3 and 0·918 at T6. Over 6 months, changes in performance on tests of immediate (p=·003) and delayed recall (p=·024), and information processing speed (p=·003) were significantly different between groups (large effect sizes), with significant declines after WBRT, but not after GKRS. Over 6 months, at the individual patient level, there were no declines in performances across all tests in the GKRS group (n=8) while performances declined in 4 out of 8 patients in the WBRT group. Conclusion The stopping rules were not met since the posterior probabilities did not cross the threshold. Other preliminary findings in this small sample suggest that cognitive decline, both at group and individual level, is more pronounced after WBRT compared to GKRS. Accrual is continued (NCT02953717; ZonMw 842003006).

Lack of delayed neurocognitive side effects of Gamma Knife radiosurgery in acromegaly: the Later-Ac study.

Persistent growth hormone hypersecretion can be observed in roughly 50% of patients operated for somatotroph adenomas, requiring additional treatments. Despite its proven antisecretory efficacy, the use of Gamma Knife radiosurgery (GK) is limited probably due to the lack of data on long-term side effects, including potential cognitive consequences. The LATe Effects of Radiosurgery in Acromegaly study was a cross-sectional exposed/unexposed non-randomized study. The primary objective was to determine the long-term neurocognitive effects of GK focusing on memory, executive functions, and calculation ability. Exposed patients had been treated by GK for acromegaly at least 5 years before inclusion. Unexposed patients (paired for age) had to be cured or controlled at last follow-up without any radiation technique. Patients of both groups were cured or controlled at the last follow-up. Sixty-four patients were evaluated (27 exposed and 37 unexposed). Mean follow-up after GK was 13 ± 6 years (including 24 patients followed for at least 10 years). While up to 23.8% of the patients of the whole cohort presented at least one abnormal cognitive test, we did not observe any significant difference in neurocognitive function between both groups. During the follow-up, 11 patients presented at least one new pituitary deficiency (P = 0.009 for thyroid-stimulating hormone deficiency with a higher rate in exposed patients), two presented a stroke (1 in each group), and one presented a meningioma (12 years after GK). While GK exposes patients to a well-known risk of pituitary deficiency, it does not seem to induce long-term cognitive consequences in patients treated for acromegaly.

Effect of gammaknife radiosurgery on memory in patients with intracranial arteriovenous malformations- A prospective study

Effect of gammaknife radiosurgery on memory in patients with intracranial arteriovenous malformations- A prospective study

Short-term Effect of Gamma Knife Radiosurgery for a Choroidal Tumor

ëª©ì  ë§¥ë½ë§‰ì¢ ì–‘ 환자에서 감마나이프 ë°©ì‚¬ì„ ìˆ˜ìˆ ì˜ 효과와 ì•ˆì „ì„±ì— 대해서 ì•Œì•„ë³´ê³ ìž 하였다. 대상과 방법 2016ë „ 1월부터 2019ë „ 2월까지 ë§¥ë½ë§‰ì¢ ì–‘ì„ ì§„ë‹¨ë°›ê³ ê°ë§ˆë‚˜ì´í”„ ë°©ì‚¬ì„ ìˆ˜ìˆ ì„ 받은 환자들 중 1개월 이상 ì¶”ì  관찰이 가능하였던 8ëª , 10안을 대상으로 의무기록을 í›„í–¥ì ìœ¼ë¡œ 분석하였다. ê²°ê³¼ 대상 환자의 í‰ê· ì—°ë ¹ì€ 57.9 ± 14.6세(32-83세)였으며, 맥락막 ì „ì´ì•”ì´ 6안, ë§¥ë½ë§‰í‘ìƒ‰ì¢ ì´ 4안이었다. 감마나이프 ë°©ì‚¬ì„ ìˆ˜ìˆ í›„ í‰ê· ì¶”ì  관찰 기간은 7.0 ± 4.3개월(2-13개월)ì´ì—ˆê³ , í‰ê· ëˆ„ì  주변부 ì„ ëŸ‰ì€ 25.36 ± 7.35 Gy (16-45 Gy)이었다. 치료 ì „í›„ì˜ ìžê¸°ê³µëª ì˜ìƒê²€ì‚¬ìƒ 10안 중 8안에서 ì¢ ì–‘ì˜ 크기가 감소하였으며, 이 중 5안에서 ì£¼ê´€ì ì¸ 증상의 í˜¸ì „ì´ 관찰되었다. 1ëª ì˜ 환자에서 ì¢ ì–‘ì˜ 크기가 증가하였으나 새로운 병변이 관찰되지 않았다. 다른 1ëª ì˜ 환자는 ì¢ ì–‘ì˜ 크기에 변화를 보이지 않았으나 통증이 ì• í™”ë˜ì–´ ì•ˆêµ¬ì ì¶œìˆ ì„ 시행하였다. ì¢ ì–‘ì˜ í‰ê· í¬ê¸°ëŠ” 감마나이프 ë°©ì‚¬ì„ ìˆ˜ìˆ ì „ í‰ê· ìµœëŒ€ì§ê²½ 1.60 ± 0.37 cm에서 치료 후 1.22 ± 0.47 cm (p=0.004)로, í‰ê· ìµœì†Œì§ê²½ 0.62 ± 0.27 cm에서 0.38 ± 0.35 cm로 감소하였다(p=0.031). 대상 환자의 ì¶”ì  관찰 기간 동안 ë°©ì‚¬ì„ ê´€ë ¨ 망막병증, ì‹œì‹ ê²½ë³‘ì¦, 백내장 등의 합병증은 관찰되지 않았다. ê²°ë¡ ê°ë§ˆë‚˜ì´í”„ ë°©ì‚¬ì„ ìˆ˜ìˆ ì€ 안와 ìžê¸°ê³µëª ì˜ìƒì—ì„œ ë§¥ë½ë§‰ì¢ ì–‘ 확인이 가능한 병변인 경우에 ì¢ ì–‘ì˜ 크기 감소를 ê¸°ëŒ€í• ìˆ˜ ìžˆê³ , 안구 보존을 ê¸°ëŒ€í• ìˆ˜ 있는 ë¹„êµì  ì•ˆì „í•œ 대체 치료 방법의 하나로 판단된다. Keywords: Choroidal melanoma, Choroidal metastasis, Gamma knife radiosurgery

Gamma Knife Radiosurgery in Patients with Crooke Cell Adenoma

Crooke cell adenoma is a very rare subtype of pituitary neoplasm that is known to be clinically aggressive. These tumors can secrete adrenocorticotropic hormone or may be endocrinologically silent. We evaluated the effect of Gamma Knife radiosurgery (GKRS) on endocrine remission and tumor control. This study comprised 5patients (2 men, 3 women; median age at GKRS, 55 years [range, 21-65 years]) with pathology-confirmed Crooke cell adenoma treated with GKRS at the Gamma Knife Center of the University of Virginia. The median time interval between transsphenoidal resection and GKRS was 5.8 months. The median margin dose was 25 Gy (range, 18-25 Gy). Median treated adenoma volume was 3.12 mL. Median follow-up was 107 months (range, 44-122 months). Tumor control was achieved in all patients. Three patients achieved endocrine remission at the last follow-up. The median time interval to cortisol normalization when off of anti-hormone secreting medication was 12 months (range, 6-24 months). Newly developed or worsening endocrinopathy occurred in 3 patients at 6, 15, and 18 months, respectively. Cranial nerve III neuropathy developed in 1 patient. Two patients required bilateral adrenalectomy at 44 months and 50 months, respectively, following GKRS. GKRS appears to be a safe and reasonably effective treatment option for Crooke cell adenoma. Multicenter studies with larger numbers of patients are needed to verify these findings.

The effect of Gamma Knife radiosurgery on large posterior fossa metastases and the associated mass effect from peritumoral edema.

Gamma Knife radiosurgery (GKRS) as monotherapy is an option for the treatment of large (≥ 2 cm) posterior fossa brain metastases (LPFMs). However, there is concern regarding possible posttreatment increase in peritumoral edema (PTE) and associated compression of the fourth ventricle. This study evaluated the effects and safety of GKRS on tumor and PTE control in LPFM. The authors performed a single-center retrospective review of 49 patients with 51 LPFMs treated with GKRS. Patients with at least 1 clinical and radiological follow-up visit were included. Tumor, PTE, and fourth ventricle volumetric measurements were used to assess efficacy and safety. Overall survival was a secondary outcome. Fifty-one lesions in 49 consecutive patients were identified; 57.1% of patients were male. At the time of GKRS, the median age was 61.5 years, and the median Karnofsky Performance Status score was 90. The median number of LPFMs and overall brain metastases were 1 and 2, respectively. The median overall tumor, PTE, and fourth ventricle volumes at diagnosis were 4.96 cm3 (range 1.4-21.1 cm3), 14.98 cm3 (range 0.6-71.8 cm3), and 1.23 cm3 (range 0.3-3.2 cm3), respectively, and the median lesion diameter was 2.6 cm (range 2.0-5.07 cm). The median follow-up time was 7.3 months (range 1.6-57.2 months). At the first follow-up, 2 months posttreatment, the median tumor volume decreased by 58.66% (range -96.95% to +48.69%, p < 0.001), median PTE decreased by 78.10% (range -99.92% to +198.35%, p < 0.001), and the fourth ventricle increased by 24.97% (range -37.96% to +545.6%, p < 0.001). The local control rate at first follow-up was 98.1%. The median OS was 8.36 months. No patient required surgical intervention, external ventricular drainage, or shunting between treatment and first follow-up. However, 1 patient required a ventriculoperitoneal shunt at 23 months from treatment. Posttreatment, 65.30% received our general steroid taper, 6.12% received no steroids, and 28.58% required prolonged steroid treatment. In this retrospective analysis, patients with LPFMs treated with GKRS had a statistically significant posttreatment reduction in tumor size and PTE and marked opening of the fourth ventricle (all p < 0.001). This study demonstrates that GKRS is well tolerated and can be considered in the management of select cases of LPFMs, especially in patients who are poor surgical candidates.

Gamma Knife Radiosurgery in Recurrent Trigeminal Neuralgia after Other Procedures

Objectives Trigeminal neuralgia (TN) is undurable paroxysmal pain in the distribution of the fifth cranial nerve. Invasive treatment modalities for TN include microvascular decompression (MVD) and percutaneous procedures, such as, radiofrequency rhizotomy (RFR). Gamma Knife radiosurgery (GKRS) is a considerable option for patients with pain recurrence after an initial procedure. This study was undertaken to analyze the effects of gamma knife radiosurgery in recurrent TN after other procedures. Methods Eleven recurrent TN patients after other procedures underwent GKRS in our hospital from September 2004 to August 2016. Seven patients had previously undergone MVD alone, two underwent MVD with partial sensory rhizotomy (PSR), and two underwent RFR. Mean patient age was 60.5 years. We retrospectively analyzed patient's characteristics, clinical results, sites, and divisions of pain. Outcomes were evaluated using the Visual Analog Scales (VAS) score. Results Right sides were more prevalent than left sides (7:4). The most common distribution of pain was V1 + V2 division (n = 5) following V2 + V3 (n = 3), V2 (n = 2), and V1 + V2 + V3 (n = 1) division. Median GKRS dose was 80 Gy and the mean interval between the prior treatment and GKRS was 74.45 months. The final outcomes of subsequent GKRS were satisfactory in most cases, and at 12 months postoperatively ten patients (90.0%) had a VAS score of ≤ 3. Conclusions In this study, the clinical result of GKRS was satisfactory. Invasive procedures, such as, MVD, RFR are initially effective in TN patients, but GKRS provides a safe and satisfactory treatment modality for those who recurred after prior invasive treatments.

Radiation dose to neuroanatomical structures of pituitary adenomas and the effect of Gamma Knife radiosurgery on pituitary function.

Gamma Knife radiosurgery (GKRS) provides a safe and effective management option for patients with all types of pituitary adenomas. The long-term adverse effects of targeted radiation to the hypothalamic-pituitary axis in relationship to radiation dose remain unclear. In this retrospective review, the authors investigated the role of differential radiation doses in predicting long-term clinical outcomes and pituitary function after GKRS for pituitary adenomas. A cohort of 236 patients with pituitary tumors (41.5% nonfunctioning, 58.5% functioning adenomas) was treated with GKRS between 1998 and 2015. Point dosimetric measurements, with no minimum volume, to 14 consistent points along the hypothalamus bilaterally, pituitary stalk, and normal pituitary were made. Statistical analyses were performed to determine the impact of doses to critical structures on clinical, radiological, and endocrine outcomes. With a median follow-up duration of 42.9 months, 18.6% of patients developed new loss of pituitary function. The median time to endocrinopathy was 21 months (range 2-157 months). The median dose was 2.1 Gy to the hypothalamus, 9.1 Gy to the pituitary stalk, and 15.3 Gy to the normal pituitary. Increasing age (p = 0.015, HR 0.98) and ratio of maximum dose to the pituitary stalk over the normal pituitary gland (p = 0.013, HR 0.22) were independent predictors of new or worsening hypopituitarism in the multivariate analysis. Sex, margin dose, treatment volume, nonfunctioning adenoma status, or ratio between doses to the pituitary stalk and hypothalamus were not significant predictors. GKRS offers a low rate of delayed pituitary insufficiency for pituitary adenomas. Doses to the hypothalamus are low and generally do not portend endocrine deficits. Patients who are treated with a high dose to the pituitary stalk relative to the normal gland are at higher risk of post-GKRS endocrinopathy. Point dosimetry to specific neuroanatomical structures revealed that a ratio of stalk-to-gland radiation dose of 0.8 or more significantly increased the risk of endocrinopathy following GKRS. Improvement in the gradient index toward the stalk and normal gland may help preserve endocrine function.

Effect of Gamma Knife Radiosurgery on Vestibular Schwannoma with Serviceable Hearing: A Single-Center Indian Study

Gamma Knife radiosurgery (GKRS) is an established treatment modality for vestibular schwannomas (VSs). The tumor control and hearing preservation rates suggest that GKRS is a good alternative treatment for small- and medium-size VS. Data are lacking from India regarding GKRS for VSs. Our aim was to find the hearing preservation and tumor control rates and the factors contributing to these. In a retrospective 9-year study period, 87 patients had undergone GKRS for unilateral VS with Gardner-Robertson (GR) class I or II serviceable hearing. All 87 had been evaluated with magnetic resonance imaging and audiometry before GKRS and during follow-up to assess for the factors influencing tumor control and hearing preservation. Of the 87 patients, 77 with a minimum follow-up of 2 years and magnetic resonance imaging and audiometry evaluations available were included in the present study. The median follow-up period was 30 months. The tumor control rate and hearing preservation rate was 96.1% and 79.2%, respectively. Hearing preservation was not affected by the tumor volume. However, age >40 years, pre-GKRS pure tone average <30 decibels, speech discrimination score >85%, pre-GKRS Gardner-Robertson grade I hearing, mean cochlear dose <4 Gy, and pre-GKRS Ohata class of laterality C, D, E were significant on univariate analysis. The multivariate analysis revealed that age >40years (P= 0.017), pre-GKRS pure tone average <30decibels (P= 0.002), and Gardner-Robertson class I (P= 0.001) were significant factors. No patient developed cranial nerve dysfunction, hydrocephalus, or malignant degeneration. For most patients with small VSs, GKRS will be an effective alternative treatment to microsurgery with retained serviceable hearing and good tumor control.

Cortical Neuroplasticity after Focused Peripheral Radiation: Longitudinal Effects of Gamma Knife Radiosurgery for Classic Trigeminal Neuralgia

POSTER ABSTRACTIntroduction/Aim: Classic trigeminal neuralgia (TN) is a severe chronic neuropathic facial pain disorder that, despite frequently being linked to microstructural changes within trigeminal nerve root entry zone, has well-documented cortical thickness alterations. These alterations occur in brain regions important for sensory and affective processing of pain and can be reversed by successful surgical interventions. As existing studies are limited to pre-treatment and early post-treatment time-points, longitudinal effects of non-invasive surgical interventions like Gamma Knife radiosurgery (GKRS) on the cortical thickness in TN patients remains unclear and are thus the focus of our current structural magnetic resonance imaging study.Methods: 18 patients treated with GKRS as their first surgery for TN underwent pre-treatment, 6 months post-treatment, and 12 months post-treatment 3-Tesla imaging. FreeSurfer 6.0 facilitated extraction of cortical thickness from 68 Desikan-Killiany brain regions. 7 false discovery rate-corrected paired Student’s t-tests were then conducted per region to contrast cortical thicknesses between hemispheres and across time-points.Results: GKRS resulted in longitudinal, bilateral increases in cortical thickness within fusiform gyrus, precentral gyrus, paracentral lobule, and inferior temporal gyrus. GKRS also resulted in transient increases in cortical thickness in contralateral banks of superior temporal sulcus, ipsilateral superior frontal gyrus, and contralateral caudal middle frontal gyrus.Discussion/Conclusions: For the first time, we demonstrated that radiosurgery for TN leads to longitudinal and transient cortical thickness changes within default mode, executive control, limbic, somatomotor, and visual brain networks. Further studies are needed to ascertain the functional role these structural changes may play in GKRS’ therapeutic effect.

Non-Vestibular Schwannoma Radiosurgery.

There is a growing body of studies regarding the effects of Gamma Knife radiosurgery on vestibular schwannomas. However, due to their rare presence and variability, our experience with the management of non-vestibular schwannomas is relatively limited. Management strategies include radiological monitoring, microsurgical resection, microsurgery combined with radiosurgery, or upfront radiosurgery. The lack of large series and heterogeneous data makes it difficult to suggest a definitive treatment strategy and management should be tailored for each patient's radiological and clinical characteristics. Available data suggest that stereotactic radiosurgery, alone or combined with microsurgery, led to good outcomes with relatively low complication rates and constitutes an efficient treatment modality for patients with non-vestibular schwannomas.

Effect of Gamma Knife Radiosurgery and Programmed Cell Death 1 Receptor Antagonists on Metastatic Melanoma.

Learning objectivesTo evaluate radiation-induced changes in patients with brain metastasis secondary to malignant melanoma who received treatment with Gamma Knife radiosurgery (GKRS) and programmed cell death 1 (PD-1) receptor antagonists.Introduction Stereotactic radiosurgery and chemotherapeutics are used together for treatment of metastatic melanoma and have been linked to delayed radiation-induced vasculitic leukoencephalopathy (DRIVL). There have been reports of more intense interactions with new immunotherapeutics targeting PD-1 receptors, but their interactions have not been well described and may result in an accelerated response to GKRS. Here we present data on subjects treated with this combination from a single institution.MethodsRecords from patients who underwent treatment for metastatic melanoma to the brain with GKRS from 2011 to 2016 were reviewed. Demographics, date of brain metastasis diagnosis, cause of death when applicable, immunotherapeutics, and imaging findings were recorded. The timing of radiation therapy and medications were also documented. ResultsA total of 79 subjects were treated with GKRS, and 66 underwent treatment with both GKRS and immunotherapy. Regarding the 30 patients treated with anti-PD-1 immunotherapy, 21 patients received pembrolizumab, seven patients received nivolumab, and two patients received pembrolizumab and nivolumab. Serial imaging was available for interpretation in 25 patients, with 13 subjects who received GKRS and anti-PD-1 immunotherapy less than six weeks of each other. While four subjects had indeterminate/mixed findings on subsequent magnetic resonance imaging (MRI), nine subjects were noted to have progression. Two of these patients showed progression but subsequent imaging revealed a decrease in progression or improvement on MRI to previously targeted lesions by GKRS. None of the 13 subjects had surgery following their combined therapies.ConclusionsThis data suggests that there is need for further investigation of the role for concurrent treatment with PD-1 inhibitors and GKRS to enhance the treatment of metastatic melanoma. We present data on 13 patients who appear to have some radiologic benefit to this treatment combination, two of whom had radiographic pseudoprogression.

Postoperative Gamma Knife Radiosurgery for Cavernous Sinus-Invading Growth Hormone-Secreting Pituitary Adenomas.

We aimed to determine the long-term effects of Gamma knife radiosurgery (GKS) on remnants in the cavernous sinus (CS) after transsphenoidal surgery (TSS) for acromegaly and to identify its possible adverse effects. Thirty patients who had remnant tumors only inside the CS after TSS and who consequently underwent GKS were included. They were followed for a median period of 47 months after GKS with regular hormonal and radiologic examinations. The mean tumor volume and margin dose irradiated by GKS was 3.7 cm3 and 26.2 Gy, respectively. Radiologic tumor control was identified in all patients, and no tumor regrowth or recurrent tumors were identified. For 14 patients who achieved endocrinologic remission, the median duration from GKS until remission was 35 months. The actuarial rates of remission at 2, 5, and 10 years were 7.1%, 43.6%, and 65.6%, respectively. The degree of decrease in the nadir GH level in the OGTT at 6 months after GKS was a statistically significant predictor of remission. Newly developed hypopituitarism frequently developed in a time-dependent manner. Radiation necrosis developed in 4 patients with relatively large remnant volumes. GKS is an effective adjuvant treatment option for remnant tumors inside the CS after TSS. Maximal surgical resection, leaving minimal volume of remnants only inside the CS, allows the safe and sufficient delivery of a radiation dose to tumors, thereby increasing the possibility of remission. However, the risk of new hypopituitarism and radiation necrosis should be considered when tumors inside the CS are treated with GKS.

Genetic landscape of sporadic vestibular schwannoma.

OBJECTIVE Vestibular schwannoma (VS) is a benign tumor with associated morbidities and reduced quality of life. Except for mutations in NF2, the genetic landscape of VS remains to be elucidated. Little is known about the effect of Gamma Knife radiosurgery (GKRS) on the VS genome. The aim of this study was to characterize mutations occurring in this tumor to identify new genes and signaling pathways important for the development of VS. In addition, the authors sought to evaluate whether GKRS resulted in an increase in the number of mutations. METHODS Forty-six sporadic VSs, including 8 GKRS-treated tumors and corresponding blood samples, were subjected to whole-exome sequencing and tumor-specific DNA variants were called. Pathway analysis was performed using the Ingenuity Pathway Analysis software. In addition, multiplex ligation-dependent probe amplification was performed to characterize copy number variations in the NF2 gene, and microsatellite instability testing was done to investigate for DNA replication error. RESULTS With the exception of a single sample with an aggressive phenotype that harbored a large number of mutations, most samples showed a relatively low number of mutations. A median of 14 tumor-specific mutations in each sample were identified. The GKRS-treated tumors harbored no more mutations than the rest of the group. A clustering of mutations in the cancer-related axonal guidance pathway was identified (25 patients), as well as mutations in the CDC27 (5 patients) and USP8 (3 patients) genes. Thirty-five tumors harbored mutations in NF2 and 16 tumors had 2 mutational hits. The samples without detectable NF2 mutations harbored mutations in genes that could be linked to NF2 or to NF2-related functions. None of the tumors showed microsatellite instability. CONCLUSIONS The genetic landscape of VS seems to be quite heterogeneous; however, most samples had mutations in NF2 or in genes that could be linked to NF2. The results of this study do not link GKRS to an increased number of mutations.

The current role of Gamma Knife radiosurgery in the management of intracranial haemangiopericytoma.

Haemangiopericytomas (HPCs) are rare tumours characterised by aggressive behaviour with tendency to local recurrence and to metastasise. WHO grade II and grade III tumours show different progression-free survival and overall survival rates. Gross total tumour resection is still considered the treatment of choice. Adjuvant radiation therapies represent an option in the treatment strategy regardless the extent of resection. Based on this consideration, Gamma Knife radiosurgery has been introduced either as a primary treatment or as an adjuvant treatment for residual or recurrent tumours. A systematic search was performed on PubMed, Web of Science and Google Scholar for clinical series reporting Gamma Knife radiosurgery, Cyberknife and Linear Accelerator (LINAC) for the management of intracranial HPCs. Fourteen studies focusing on the effects of Gamma Knife radiosurgery for intracranial HPCs were included. Four studies reported data on Cyberknife radiosurgery and LINAC. A total of 208 patients harbouring 366 tumours have been reported. Patient's features, radiosurgical treatment characteristics and follow-up data of the pertinent literature have been critically revised. Gamma Knife radiosurgery and the other radiosurgical techniques represent a feasible and effective therapy in the management of HPCs. Tumour control and survival rate are comparable to those reported for radiotherapy. Further studies should be focused to define the exact role of Gamma Knife radiosurgery in the management of HPCs.

Microsurgical Resection for Persistent Arteriovenous Malformations Following Gamma Knife Radiosurgery: A Case-Control Study

To explore outcomes after microsurgery of brain arteriovenous malformations (AVMs) that failed to be obliterated by Gamma Knife radiosurgery (GKRS). From January 2000 to January 2014, 42 consecutive patients underwent surgical resection of persistent AVMs after GKRS. These 42 patients with AVMs who underwent radiosurgery (radiosurgery group) were individually matched with 42 patients with AVMs who did not undergo radiosurgery (no radiosurgery group) based on patient and AVM characteristics. The modified Rankin Scale was used to assess neurologic status of patients. The effects of GKRS on AVM resection and surgical outcomes were analyzed. After GKRS, the mean AVM volume was significantly reduced by 76.8% (P < 0.01), the size was reduced by 41% (P < 0.01), and the Spetzler-Martin grade was reduced in 61.9% of the patients (P < 0.01). During the time interval from radiosurgery to surgical resection, subsequent hemorrhages led to significant neurologic deterioration (P= 0.046). Compared with the control group, the frequency of preoperative embolization, operative time, and blood loss were significantly lower in the radiosurgery group (all P < 0.05). The no radiosurgery group had a significantly higher rate of worsening in mRS scores at 6 months after surgery (40.5% vs. 16.7%, P= 0.029). Good neurologic status (mRS score <3) was achieved in 81% of the radiosurgery group and 83% of the no radiosurgery group at the final follow-up evaluation. GKRS performed several years before microsurgical resection can facilitate resectability of AVMs and decrease the rate of postoperative neurologic deterioration. For patients with persistent AVMs several years after GKRS, microsurgical resection is recommended to achieve good clinical outcomes.

Cavernous sinus cavernous hemangioma: Imaging features and therapeutic effect of Gamma Knife radiosurgery

ObjectTo investigate the imaging features of cavernous sinus cavernous hemangioma (CSCH) and evaluate the therapeutic effect of Gamma Knife radiosurgery (GKRS) in treatment of CSCH. Methods and materialsFifteen patients with CSCH treated by GKRS in our institute, including 6 males and 9 females, age range 20–77 years old, were analyzed retrospectively. Three of them were given craniotomies as the initial therapy. All cases had performed conventional and contrast-enhanced MRI and 5 patients underwent dynamic enhanced MRI preoperatively. In 6 cases, the multi-directional continuous data of axial, coronal and sagittal enhanced MRI were acquired. Three cases performed digital subtraction angiography (DSA) simultaneously. The diagnoses of lesions were determined mainly depending on typical imaging features. In 3 patients, the diagnoses of CSCH were confirmed histopathologically. The radiation dosimetry was done with a goal of conformal and selective coverage of the lesion with a 50% prescription isodose line. The mean marginal dose constituted 13.4Gy (range 10–16Gy). After GKRS was performed, all patients were arranged regular clinical and MRI follow-up every 6 months during the first 12 months, and once per year thereafter. ResultsOn MRI, the lesions were typically demonstrated as iso/hypo-intensities on T1WI and remarkable hyper-intensities on T2WI, and apparent homogeneous enhancement. The phenomenon of dynamic enhancement was found in 11 cases. The progressive enhancing process from heterogeneous to uniform was displayed in the 5 patients performed same-slice dynamic MRI, including imaging characteristics of ‘edge to center’ enhancement in 2 case. In the other 6 cases, the delayed homogeneous enhancement of lesion was observed. Ten patients obtained radiological follow-up results after GKRS. Reviewing the follow-up data of 8 patients during the period of 3–6 months, the lesions were apparently shrunk in 5 patients with shrinkage rate of 20.8–46.8%. In 4 patients with imaging follow-up during the period of 6–12 months, the lesions of 3 patients were remarkably shrunk with shrinkage rate of 53.5–81.7%. Four patients had imaging follow-up data over 12 months, and all their lesion sizes were reduced with shrinkage rate of 19–83.6%. The clinical presentations of all patients after GKRS were followed up during the period of 1–30 months. In 7 of 9 cases with headache, the symptom was improved; in 5 of 6 cases, facial hypesthesia was improved; in 6 of 9 cases with visual impairments, the visions were markedly improved; and in 8 cases with preoperative diplopia, the symptoms were all resolved. ConclusionAlthough bright hyper-intensities on T2WI and significant homogeneous enhancement on contrast-enhanced T1WI are considered as typical imaging characteristics of CSCH, the dynamic process of progressive delayed enhancement on contrast-enhanced MR is more persuasive in diagnosis. According to our study, GKRS could be chosen as an effective and safe alternative treatment for CSCH. We consider that using relatively low marginal dose may get better effects in tumor shrinkage and protection of cranial nerves.