Formation of internal carotid artery aneurysms following gamma knife radiosurgery for pituitary adenomas: a case series and literature review.

Only two aneurysm formations in the internal carotid artery after gamma knife radiosurgery (GKRS) for pituitary adenomas are reported so far. Here, out of the 482 patients who underwent GKRS for pituitary adenomas at our institute, at least five developed aneurysms within the area of high single-dose irradiation. Three patients presented with epistaxis due to aneurysmal rupture and one presented with abducens paralysis due to nerve compression, while one was asymptomatic.

Risk for Brain Arteriovenous Malformation Rupture During Pregnancy and Puerperium.

Background: The hemorrhage risk of unruptured and untreated cerebral arteriovenous malformations (AVMs) has been shown to be higher for female patients than male patients in their child bearing ages. Although it has been neurosurgical practice to advise female patients in their childbearing ages to postpone pregnancy until proven AVM obliteration, there is no literature consensus regarding this potential hemorrhage risk increase.

Objective: To accurately quantify the risk increase for AVM hemorrhage during pregnancy.

Retiform endothelial hyperplasia mimicking cavernous malformation as a late complication of Gamma Knife radiosurgery.

Objective: Gamma Knife radiosurgery (GKRS) is a powerful tool for the management of arteriovenous malformations; however, newly formed mass lesions resembling cavernous malformations are a rare late complication of GKRS. In this retrospective study, the authors tried to clarify the unique histological features of these mass lesions.

Methods: The authors retrospectively reviewed the clinical course of 889 patients who had undergone GKRS for arteriovenous malformations at their institute from 1991 to 2021.

Risk for Hemorrhage the First 2 Years After Gamma Knife Surgery for Arteriovenous Malformations: An Update.

Background: Knowledge about the natural course of brain arteriovenous malformations (AVMs) have increased during the past 20 years, as has the number of AVMs treated, especially larger ones. It is thus timely to again analyze the risk for hemorrhage after Gamma Knife Surgery (GKS).

Objective: To confirm or contradict conclusions drawn 20 years ago regarding factors that affect the risk for post-GKS hemorrhage.

A Practical Grading Scale for Predicting Outcomes of Radiosurgery for Dural Arteriovenous Fistulas: JLGK 1802 Study.

Background And Purpose: To assess the long-term outcomes of intracranial dural arteriovenous fistula (DAVF) treated with stereotactic radiosurgery (SRS) alone or embolization and SRS (Emb-SRS) and to develop a grading system for predicting DAVF obliteration.

Methods: This multi-institutional retrospective study included 200 patients with DAVF treated with SRS or Emb-SRS. We investigated the long-term obliteration rate and obliteration-associated factors.

Outcomes of Gamma Knife radiosurgery for skull base chondrosarcomas: a multi-institutional retrospective study.

Objective: Radiotherapy has an essential role in the management of skull base chondrosarcomas (SBCs) after resection. This multi-institutional study evaluated the outcomes of Gamma Knife radiosurgery (GKRS) for histopathologically proven SBCs.

Methods: Data of patients who underwent GKRS for SBCs at Gamma Knife centers in Japan were retrospectively collected.

Midterm prognosis and surgical implication for clival chordomas after extended transsphenoidal tumor removal and gamma knife radiosurgery.

Background: Treating chordoma through surgery alone is often ineffective. Thus, surgery often performed with irradiation, with a reported 5-year survival rate of 60-75%. The clinical course varies, and disease rarity prevents larger number of clinical investigations.

Simultaneous Truth and Performance Level Estimation Method for Evaluation of Target Contouring in Radiosurgery.

Background/aim: The problem of lack of standardisation in target delineation and herewith the variability of target contours in Gamma Knife radiosurgery is as severe as in linac-based radiotherapy in general. The first aim of this study was to quantify the contouring variability for a group of five radiosurgery targets and estimate their true-volume based on multiple delineations using the Simultaneous Truth and Performance Level Estimation (STAPLE) algorithm. The second aim was to assess the robustness of the STAPLE method for the assessment of the true-volume, with respect to the number of contours available as input.

Impact of breast cancer subtype on clinical outcomes after Gamma Knife radiosurgery for brain metastases from breast cancer: a multi-institutional retrospective study (JLGK1702).

Introduction: Brain metastasis (BM) is one of the most important issues in the management of breast cancer (BC), since BMs are associated with neurological deficits. However, the importance of BC subtypes remains unclear for BM treated with Gamma Knife radiosurgery (GKS). Thus, we conducted a multicenter retrospective study to compare clinical outcomes based on BC subtypes, with the aim of developing an optimal treatment strategy.

Clinical outcome following cerebral AVM hemorrhage.

Background: A significant difference exists between the published results reporting the clinical outcome following brain arteriovenous malformation (AVM) ruptures. Information about the outcome following hemorrhage in an AVM population treated with radiosurgery could provide additional information to assess the risk of mortality and morbidity following an AVM hemorrhage.

Methods: Clinical outcome was studied in 383 patients, the largest patient population yet studied, who suffered from a symptomatic hemorrhage after Gamma Knife® surgery (GKS) but before confirmed AVM obliteration.

The impact of EGFR-TKI use on clinical outcomes of lung adenocarcinoma patients with brain metastases after Gamma Knife radiosurgery: a propensity score-matched analysis based on extended JLGK0901 dataset (JLGK0901-EGFR-TKI).

Purpose: Recent advances in targeted therapy have prolonged overall survival (OS) for patients with lung cancer. The impact of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKI) on brain metastases (BM) treated with stereotactic radiosurgery (SRS) has not, however, been fully elucidated. We investigated the influence of post-SRS EGFR-TKI use on the efficacy and toxicity of SRS for BM from lung adenocarcinoma.

Stereotactic radiosurgery in elderly patients with brain metastases: comparison with non-elderly patients using database of a multi-institutional prospective observational study (JLGK0901-Elderly).

Purpose: Stereotactic radiosurgery (SRS) has been increasingly used for elderly patients with brain metastases (BMs). However, no studies based on a large sample size have been reported. To compare SRS treatment results between elderly and non-elderly patients, we performed a subset study of elderly patients using our prospectively-accumulated multi-institution study database (JLGK0901 Study, Lancet Oncol 15:387-395, 2014).

Local tumor progression treated with Gamma Knife radiosurgery: differences between patients with 2-4 versus 5-10 brain metastases based on an update of a multi-institutional prospective observational study (JLGK0901).

Objective: The Japanese Leksell Gamma Knife (JLGK)0901 study proved the efficacy of Gamma Knife radiosurgery (GKRS) in patients with 5-10 brain metastases (BMs) as compared to those with 2-4, showing noninferiority in overall survival and other secondary endpoints. However, the difference in local tumor progression between patients with 2-4 and those with 5-10 BMs has not been sufficiently examined for this data set. Thus, the authors reappraised this issue, employing the updated JLGK0901 data set with detailed observation via enhanced MRI.

A novel method to determine the natural course of unruptured brain arteriovenous malformations without the need for follow-up information.

OBJECTIVEThere is a strong clinical need to accurately determine the average annual hemorrhage risk in unruptured brain arteriovenous malformations (AVMs). This need motivated the present initiative to use data from a uniquely large patient population and design a novel methodology to achieve a risk determination with unprecedented accuracy. The authors also aimed to determine the impact of sex, pregnancy, AVM volume, and location on the risk for AVM rupture.

Multiinstitutional prospective observational study of stereotactic radiosurgery for patients with multiple brain metastases from non-small cell lung cancer (JLGK0901 study-NSCLC).

OBJECTIVEPrevious Japanese Leksell Gamma Knife Society studies (JLGK0901) demonstrated the noninferiority of stereotactic radiosurgery (SRS) alone as the initial treatment for patients with 5-10 brain metastases (BMs) compared with those with 2-4 BMs in terms of overall survival and most secondary endpoints. The authors studied the aforementioned treatment outcomes in a subset of patients with BMs from non-small cell lung cancer (NSCLC).METHODSPatients with initially diagnosed BMs treated with SRS alone were enrolled in this prospective observational study.

The NASSAU (New ASSessment of cerebral Arteriovenous Malformations yet Unruptured) Analysis: Are the Results From The ARUBA Trial Also Applicable to Unruptured Arteriovenous Malformations Deemed Suitable for Gamma Knife Surgery?

Background: The optimal management of unruptured brain arteriovenous malformations (AVMs) is controversial after the ARUBA trial.

Objective: To confirm or repudiate the ARUBA conclusion that "medical management only is superior to medical management with interventional therapy for unruptured brain arteriovenous malformations."

Methods: Data were collected from 1351 patients treated with Gamma Knife Surgery (GKS; Elekta AB, Stockholm, Sweden) for unruptured and untreated AVMs The follow-up was 8817 yr (median 5.

Effects of Surgery With Salvage Stereotactic Radiosurgery Versus Surgery With Whole-Brain Radiation Therapy in Patients With One to Four Brain Metastases (JCOG0504): A Phase III, Noninferiority, Randomized Controlled Trial.

Purpose Whereas whole-brain radiotherapy (WBRT) has been the standard treatment of brain metastases (BMs), stereotactic radiosurgery (SRS) is increasingly preferred to avoid cognitive dysfunction; however, it has not been clearly determined whether treatment with SRS is as effective as that with WBRT or WBRT plus SRS. We thus assessed the noninferiority of salvage SRS to WBRT in patients with BMs. Patients and Methods Patients age 20 to 79 years old with performance status scores of 0 to 2-and 3 if caused only by neurologic deficits-and with four or fewer surgically resected BMs with only one lesion > 3 cm in diameter were eligible.

Multi-institutional study of the variability in target delineation for six targets commonly treated with radiosurgery.

Background: Although accurate delineation of the target is a key factor of success in radiosurgery there are no consensus guidelines for target contouring.

Aim: The aim of the present study was therefore to quantify the variability in target delineation and discuss the potential clinical implications, for six targets regarded as common in stereotactic radiosurgery.

Material And Methods: Twelve Gamma Knife centers participated in the study by contouring the targets and organs at risks and performing the treatment plans.

Mid-term prognosis of non-functioning pituitary adenomas with high proliferative potential: really an aggressive variant?

Pituitary adenomas with high proliferation rate and rapid growth are well known, but the clinical characteristics, prognosis, and treatment algorithm remain unclear. The clinical characteristics and mid-term prognosis of patients with non-functioning pituitary adenomas with high proliferative potential were retrospectively investigated. This study identified 53 patients with Ki-67 labeling index of > 3% among 845 patients with non-functioning pituitary adenoma (6.

Clinical Features of Precocious, Synchronous, and Metachronous Brain Metastases and the Role of Tumor Resection.

Objective: The purpose of this study was to clarify clinical features, outcomes, and the role of tumor resection in precocious, synchronous, and metachronous brain metastases.

Methods: Brain metastases were found before primary cancer detection in the precocious group, within 2 months after primary cancer detection in the synchronous group, and 2 months or later after primary cancer detection in the metachronous group.

Results: Of 471 patients with brain metastases, 93 (20%) were included in the precocious group, 76 (16%) in the synchronous group, and 302 (64%) in the metachronous group.

A Multi-institutional Prospective Observational Study of Stereotactic Radiosurgery for Patients With Multiple Brain Metastases (JLGK0901 Study Update): Irradiation-related Complications and Long-term Maintenance of Mini-Mental State Examination Scores.

Purpose: The JLGK0901 study showed the noninferiority of stereotactic radiosurgery (SRS) alone as initial treatment of 5 to 10 brain metastases (BMs) compared with 2 to 4 BMs in terms of overall survival and most secondary endpoints (Lancet Oncol 2014;15:387-95). However, observation periods were not long enough to allow confirmation of the long-term safety of SRS alone in patients with 5 to 10 BMs.

Methods And Materials: This was a prospective observational study of Gamma Knife SRS-treated patients with 1 to 10 newly diagnosed BMs enrolled at 23 facilities between March 1, 2009, and February 15, 2012.

Gamma Knife radiosurgery for brain metastases from pulmonary large cell neuroendocrine carcinoma: a Japanese multi-institutional cooperative study (JLGK1401).

OBJECTIVE In 1999, the World Health Organization categorized large cell neuroendocrine carcinoma (LCNEC) of the lung as a variant of large cell carcinoma, and LCNEC now accounts for 3% of all lung cancers. Although LCNEC is categorized among the non-small cell lung cancers, its biological behavior has recently been suggested to be very similar to that of a small cell pulmonary malignancy. The clinical outcome for patients with LCNEC is generally poor, and the optimal treatment for this malignancy has not yet been established.

Assessment of organs-at-risk contouring practices in radiosurgery institutions around the world - The first initiative of the OAR Standardization Working Group.

Background And Purpose: This study was an initiative of the Organs-at-Risk Standardization Working Group for evaluating the current degree of variability in the clinical practice of contouring organs-at-risk (OAR) for radiosurgery planning.

Materials And Methods: Imaging datasets for typical lesions (cavernous sinus meningioma, vestibular schwannoma, pituitary adenoma) treated with Leksell Gamma Knife Perfexion were circulated to 12 centers. Observers were asked to contour the target and OARs as per their standard clinical practice.

A study of prognostic factors in 45 cases of atypical meningioma.

Background: Atypical meningioma differs from Grade I meningioma in terms of high recurrence rate and short life expectancy. We evaluated the clinical course of atypical meningioma and investigated prognostic factors affecting its outcomes.

Method: We reviewed 45 patients with atypical meningioma who underwent surgical intervention between January 2000 and December 2013.

Variability in target delineation for cavernous sinus meningioma and anaplastic astrocytoma in stereotactic radiosurgery with Leksell Gamma Knife Perfexion.

Background: Radiosurgery clinical practice relays on empirical observations and the experience of the practitioners involved in determining and delineating the target and therefore variability in target delineation might be expected for all the radiosurgery approaches, independent of the technique and the equipment used for delivering the treatment. The main aim of this study was to quantify the variability of target delineation for two radiosurgery targets expected to be difficult to delineate. The secondary aim was to investigate the dosimetric implications with respect to the plan conformity.