Stylianos Pikis

Mediterraneo Hospital

Background The optimal management of patients with an incidental meningiomas remains unclear. The aim of this study was to characterize the radiologic and neurological outcomes of expectant and SRS management of asymptomatic meningioma patients. Methods Using data from 14 centers across 10 countries, the study compares SRS outcomes to active surve...

PurposeTo evaluate the incidence of internal carotid artery (ICA) stenosis and cerebrovascular accident in a series of patients treated with stereotactic radiosurgery (SRS) for recurrent or residual pituitary adenoma.Methods All patients treated with single fraction SRS in our institution for recurrent or residual non-functioning-, growth hormone-...

Background Optimal management of asymptomatic skull base meningiomas is controversial. We evaluated the safety and efficiency of Gamma Knife radiosurgery (GKRS) for the management of asymptomatic skull base meningiomas. Methods This retrospective study involved patients managed with GKRS for asymptomatic, skull base meningiomas from 1997 to 2019....

Objective Acute ischemic stroke and silent cerebral infarctions following pipeline embolization device (PED) treatment of intracranial aneurysms have been estimated to occur in 3–6% and in 50.9–90% of patients respectively. The PED with Shield technology (PED-Shield) incorporates a surface phosphorylcholine polymer to reduce the thrombogenicity of...

Pituitary adenomas have an incidence of 3.9 to 7.4/100,000 per year. Medical therapy and/or resection are often initial treatments for patients with pituitary adenomas. Stereotactic radiosurgery (SRS) is frequently used for treating patients with recurrent or residual pituitary adenomas. SRS affords a high rate of local tumor control and, for funct...

Brainstem cerebral cavernous malformations (CCM) are clinically more aggressive compared to superficial CCMs. Due to their location, resection can be challenging, making stereotactic radiosurgery (SRS) an attractive alternative for symptomatic patient. Brainstem CCM patients (n = 170) were treated with Gamma Knife SRS at 11 radiosurgical centers. H...

BACKGROUND AND OBJECTIVES Better local control but higher rates of adverse radiation events (ARE) have been reported when combining American Society for Radiation Oncology (ASTRO)-guideline-suggested dose (SD) stereotactic radiosurgery (SRS) with immunotherapy or targeted therapy for melanoma brain metastases. The objective of this study is to expl...

Purpose To report patient outcomes and local tumor control rates in a cohort of patients with biopsy-proven HER-2 positive breast cancer treated with stereotactic radiosurgery (SRS) for brain metastases (BM). Methods This international, retrospective, multicenter study, included 195 female patients with 1706 SRS-treated BM. Radiologic and clinical...

BACKGROUND AND OBJECTIVES Gamma knife radiosurgery (GKRS) is a safe and effective treatment option for hypothalamic hamartomas (HH), but there is no consensus opinion on its timing, dosage, and follow-up. The aim of this study was to define the safety, efficacy, outcome, and complication profile of GKRS in this patient population. METHODS This ret...

Purpose To report patient outcomes and local tumor control rates in a cohort of patients with biopsy-proven HER-2 positive breast cancer treated with stereotactic radiosurgery (SRS) for brain metastases (BM). Methods This international, retrospective, multicenter study, included 195 female patients with 1706 SRS-treated BM. Radiologic and clinical...

BACKGROUND AND OBJECTIVES Studies comparing neurological and radiographic outcomes of repeat to initial stereotactic radiosurgery (SRS) intracranial arteriovenous malformations are scarce. Our aim was to perform a retrospective matched comparison of patients initially treated with SRS with those undergoing a second radiosurgical procedure. METHODS...

Objective Brain metastases (BM) are associated with poor prognosis and increased mortality rates, making them a significant clinical challenge. Studying BMs can aid in improving early detection and monitoring. Systematic comparisons of anatomical distributions of BM from different primary cancers, however, remain largely unavailable. Methods To te...

INTRODUCTION Oligodendrogliomas are primary brain tumors classified as IDH-mutant and 1p19q co-deleted in the 2021 WHO Classification. Surgery, fractionated radiotherapy and chemotherapy are well established treatments for these tumors, but there are few studies evaluating the efficacy of stereotactic radiosurgery (SRS). As these tumors are less in...

INTRODUCTION Repeat stereotactic radiosurgery (SRS) for persistent cerebral arteriovenous malformation (AVM) has generally favorable patient outcomes. However, reporting studies are limited by small patient numbers and single-institution biases. METHODS This multicenter, retrospective cohort study included patients treated with repeat, single-frac...

INTRODUCTION There is conflicting evidence on the significance of adrenocorticotrophic hormone (ACTH) staining in the prognosis of nonfunctioning pituitary neuroendocrine tumors (NFpitNETs). METHODS This retrospective, multicenter study included patients managed with SRS for NFpitNET residuals. The patients were divided into two cohorts: 1) silent...

OBJECTIVE Recent studies have suggested that biologically effective dose (BED) is an important correlate of pain relief and sensory dysfunction after Gamma Knife radiosurgery (GKRS) for trigeminal neuralgia (TN). The goal of this study was to determine if BED is superior to prescription dose in predicting outcomes in TN patients undergoing GKRS as...

Introduction: Brainstem cerebral cavernous malformations (CCM) are clinically more aggressive compared to superficial CCMs. Due to their location, resection can be challenging, making stereotactic radiosurgery (SRS) an attractive alternative for symptomatic patient. Method: Brainstem CCM patients (n=170) were treated with Gamma Knife SRS at 11 radi...

OBJECTIVE The purpose of this study was to describe the long-term outcomes and associated risks related to repeat stereotactic radiosurgery (SRS) for persistent arteriovenous malformations (AVMs) in pediatric patients. METHODS Under the auspices of the International Radiosurgery Research Foundation, this retrospective multicenter study analyzed pe...

OBJECTIVE Cerebral cavernous malformations (CCMs) are the second most common vascular anomaly affecting the CNS in children. Although stereotactic radiosurgery (SRS) has been proposed as an alternative to microsurgery in the management of selected cases in adults, there is a paucity of studies focusing on pediatric patients. The aim of this study w...

BACKGROUND AND OBJECTIVES There are no studies evaluating the efficacy and safety of more than 2 stereotactic radiosurgery (SRS) procedures for cerebral arteriovenous malformations (AVM). The aim of this study was to provide evidence on the role of third single-session SRS for AVM residual. METHODS This multicenter, retrospective study included pa...

OBJECTIVE There are few reports of outcomes following stereotactic radiosurgery (SRS) for the management of cerebral cavernous malformations (CCMs) of the basal ganglia or thalamus. Therefore, the authors aimed to clarify these outcomes. METHODS Centers participating in the International Radiosurgery Research Foundation were queried for CCM cases...

OBJECTIVE Patients with deep-seated arteriovenous malformations (AVMs) have a higher rate of unfavorable outcome and lower rate of nidus obliteration after primary stereotactic radiosurgery (SRS). The aim of this study was to evaluate and quantify the effect of AVM location on repeat SRS outcomes. METHODS This retrospective, multicenter study invo...

OBJECTIVE The goal of this study was to characterize local tumor control (LC), overall survival (OS), and safety of stereotactic radiosurgery for colorectal brain metastasis (CRBM). METHODS Ten international institutions participating in the International Radiosurgery Research Foundation provided data for this retrospective case series. This study...

ABBREVIATIONS AVM = arteriovenous malformation; RIC = radiation-induced change; SDH = subdistribution hazard; SRS = stereotactic radiosurgery. OBJECTIVE Patients with deep-seated arteriovenous malformations (AVMs) have a higher rate of unfavorable outcome and lower rate of nidus obliteration after primary stereotactic radiosurgery (SRS). The aim of...

Background: Cerebral cavernous malformations (CCMs) frequently manifest with haemorrhages. Stereotactic radiosurgery (SRS) has been employed for CCM not suitable for resection. Its effect on reducing haemorrhage risk is still controversial. The aim of this study was to expand on the safety and efficacy of SRS for haemorrhagic CCM. Methods: This...

BACKGROUND AND OBJECTIVES There is conflicting evidence on the significance of adrenocorticotrophic hormone (ACTH) staining in the prognosis of nonfunctioning pituitary neuroendocrine tumors (NFpitNETs). The objective of this study was to define the effect of ACTH immunostaining on clinical and radiographic outcomes of stereotactic radiosurgery (SR...

Objective Stereotactic radiosurgery (SRS) has been proposed as an alternative to resection for epilepsy control in patients with cerebral cavernous malformations (CCM) located in critical areas. Methods This multicentric, retrospective study evaluated seizure control in patients with a solitary CCM and a history of at least one seizure prior to SR...

Background: Repeat stereotactic radiosurgery (SRS) for persistent cerebral arteriovenous malformation (AVM) has generally favorable patient outcomes. However, reporting studies are limited by small patient numbers and single-institution biases. The purpose of this study was to provide the combined experience of multiple centers, in an effort to fu...

Background and objectives: Meningiomas in children are uncommon, with distinct characteristics that set them apart from their adult counterparts. The existing evidence for stereotactic radiosurgery (SRS) in this patient population is limited to only case series. The objective of this study was to evaluate the safety and efficacy of SRS in managing...

Background: Clival chordomas are challenging because of their proximity to critical neurovascular structures. Stereotactic radiosurgery (SRS) has been proven effective with minimal adverse effects. Objective: To compare the outcomes of histologically confirmed primary clival chordomas in adults who underwent SRS alone (SRS group) vs SRS after fr...

INTRODUCTION Koos IV vestibular schwannoma (VS) are preferably treated by surgery. However, SRS can be an alternative for patients with contraindications or who refuse surgery. SRS for Koos IV patient younger than 45 years old has not been previously studied and could be associated with more complications. METHODS This is a retrospective multicent...

Meningiomas are thought to originate from the meningothelial cells of the arachnoid mater and are the most common primary brain tumor in adults. Histologically confirmed meningiomas occur with an incidence of 9.12/100,000 population and account for 39% of all primary brain tumors and 54.5% of all non-malignant brain tumors. Risk factors for meningi...

Background: There are limited data regarding outcomes for patients with gastrointestinal (GI) primaries and brain metastases treated with stereotactic radiosurgery (SRS). Objective: To examine clinical outcomes after SRS for patients with brain metastases from GI primaries and evaluate potential prognostic factors. Methods: The International R...

Background Surgery is the preferred treatment for large vestibular schwannomas (VS). Good tumor control and cranial nerve outcomes were described in selected Koos IV VS after single-session stereotactic radiosurgery (SRS), but outcomes in elderly patients have never been specifically studied. The aim of this study is to report clinical and radiolog...

Background: Intraventricular metastases (IVMs) are uncommon, and their optimal management remains debatable. Objective: The aim is to define the safety and efficacy of stereotactic radiosurgery (SRS) in the treatment of IVMs. Methods: This retrospective, multicenter study included patients managed with SRS for IVMs. SRS-induced adverse events,...

OBJECTIVE Radiological progression occurs in 50%–60% of residual nonfunctioning pituitary adenomas (NFPAs). Stereotactic radiosurgery (SRS) is a safe and effective management option for residual NFPAs, but there is no consensus on its optimal timing. This study aims to define the optimal timing of SRS for residual NFPAs. METHODS This retrospective...

OBJECTIVE Stereotactic radiosurgery (SRS) is an effective treatment for intracranial metastatic disease, but its role in triple-negative breast cancer requires further study. Herein, the authors report overall survival (OS) and local tumor control in a multiinstitutional cohort with triple-negative breast cancer metastases treated with SRS. METHOD...

Purpose Surgery is the treatment of choice for large vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has been suggested as an alternative to resection in selected patients. However, the safety and efficacy of SRS in Koos grade IV patients ≤ 45 years old has not been evaluated. The aim of this study is to describe the clinical and radio...

Purpose Surgery is the treatment of choice for large vestibular schwannomas (VS). Stereotactic radiosurgery (SRS) has been suggested as an alternative to resection in selected patients. However, the safety and efficacy of SRS in Koos grade IV patients ≤45 years old has not been evaluated. The aim of this study is to describe the clinical and radiol...

OBJECTIVE The purpose of this retrospective, single-institution study was to evaluate radiological and clinical outcomes of patients managed with repeat stereotactic radiosurgery (SRS) for residual cerebral arteriovenous malformation (AVM) after prior SRS. METHODS The authors evaluated the clinical and radiological outcomes of consecutive patients...

OBJECTIVE Though stereotactic radiosurgery (SRS) is an established safe treatment for small- and medium-sized vestibular schwannomas (VSs), its role in the management of Koos grade IV VS is still unclear. In this retrospective multicenter study, the authors evaluated tumor control and the patient outcomes of primary, single-session SRS treatment fo...

Objective The role of stereotactic radiosurgery (SRS) in the management of recurrent and residual intracranial primary melanocytomas (PMC) remains unclear. The aim of this study is to evaluate the safety and efficacy of SRS in the management of these rare tumors. Methods One patient treated with SRS in our institution for an intracranial PMC was r...

INTRODUCTION The optimal management of patients with an incidental meningiomas remains unclear. The aim of this study was to characterize the radiologic and neurological outcomes of expectant and SRS management of asymptomatic meningioma patients. METHODS Using data from 14 centers across 10 countries, the study compares SRS outcomes to active sur...

Hypoglossal schwannomas (HS) are extremely rare neoplasms. Surgical resection has historically been the treatment of choice but carries a significant risk of postoperative neurological deficits and mortality. Stereotactic radiosurgery (SRS) is a minimally invasive approach that may afford long-term tumour growth. However, literature to determine th...

Background Surgical removal has been performed as the first line treatment for symptomatic or enlarging hypoglossal schwannomas (HS). Stereotactic radiosurgery (SRS) offers a minimally invasive approach that may afford long-term tumor control for patients with HS particularly those who refuse or are unfit for surgery. This study evaluates outcomes...

Background: The optimal management of asymptomatic, presumed WHO grade I meningiomas remains controversial. Objective: To define the safety and efficacy of stereotactic radiosurgery (SRS) compared with active surveillance for the management of patients with asymptomatic parafalcine/parasagittal (PFPS) meningiomas. Methods: Data from SRS-treate...

Objective: The optimal treatment for recurrent and residual gangliogliomas remains unclear. The aim of this study was to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) in the management of patients with recurrent or residual intracranial ganglioglioma. Methods: This retrospective multicenter study involved patients managed w...

Simple Summary Meningioma, a type of brain tumor, is a common incidental finding on brain imaging. The best management approach for patients with an incidental meningioma remains unclear. This retrospective multi-center study investigated the outcomes of patients with an incidental meningioma in a frontobasal location, who were managed with active...

Background The optimal treatment strategy of asymptomatic, convexity meningiomas, remains unclear. Objective The purpose of this study was to define the safety and efficacy of stereotactic radiosurgery (SRS) in the management of patients with asymptomatic convexity meningiomas. Methods Data of SRS-treated patients from 14 participating centers an...

Objective The optimal management of asymptomatic, skull-based meningiomas is not well defined. The aim of this study is to compare the imaging and clinical outcomes of patients with asymptomatic, skull-based meningiomas managed either with upfront stereotactic radiosurgery (SRS) or active surveillance. Methods This retrospective, multicenter study...

IntroductionGlioma remains incurable and a life limiting disease with an urgent need for effective therapies. Sonodynamic therapy (SDT) involves systemic delivery of non-toxic chemical agents (sonosensitizers) that accumulate in tumor cells or environment and are subsequently activated by exposure to low-frequency ultrasound to become cytotoxic age...

Background The optimal management of asymptomatic, petroclival meningiomas remains incompletely defined. The purpose of this study was to evaluate the safety and efficacy of upfront stereotactic radiosurgery (SRS) for patients with asymptomatic, petroclival region meningiomas.Methods This retrospective, international, multicenter study involved pat...

Objectives: Early identification of patients who will experience delayed-onset pain relief after GKRS for trigeminal neuralgia (TN) will allow optimal patient management, and avoidance of unnecessary procedures. A non-invasive tool to identify late responders to GKRS is currently unavailable. We sought to evaluate MRI based diffusivity metrics obt...

Objective Isocitrate dehydrogenase (IDH) mutation status is recommended used for diagnosis and prognostication of glioblastoma patients. We studied efficacy and safety of stereotactic radiosurgery (SRS) for patients with recurrent IDH-wt glioblastoma.Methods Consecutive patients treated with SRS for IDH-wt glioblastoma were pooled for this retrospe...

Background The management of craniopharyngiomas is challenging, usually requiring multidisciplinary care. We evaluated the long-term clinical and radiologic outcomes of Gamma Knife radiosurgery (GKRS) for craniopharyngiomas. Methods This retrospective study involved patients managed with GKRS for a craniopharyngioma during the period of 1989 to 20...

OBJECTIVE Molecular profiles, such as isocitrate dehydrogenase (IDH) mutation and O ⁶ -methylguanine-DNA methyltransferase (MGMT) methylation status, have important prognostic roles for glioblastoma patients. The authors studied the efficacy and safety of stereotactic radiosurgery (SRS) for glioblastoma patients with consideration of molecular tumo...

Background The initial management of asymptomatic, incidentally discovered, cavernous sinus (CS) meningiomas remains incompletely defined. This study evaluated the safety and efficacy of stereotactic radiosurgery for patients presenting with an asymptomatic CS meningioma. Methods This is an international, retrospective study included patients trea...

Objective: The optimal management of asymptomatic, skull-based meningiomas is not well defined. The aim of this study is to compare the imaging and clinical outcomes of patients with asymptomatic, skull-based meningiomas managed either with upfront stereotactic radiosurgery (SRS) or active surveillance. Methods: This retrospective, multicenter stud...

OBJECTIVE The object of this study was to evaluate the safety, efficacy, and long-term outcomes of stereotactic radiosurgery (SRS) in the management of intracranial chordomas. METHODS This retrospective multicenter study involved consecutive patients managed with single-session SRS for an intracranial chordoma at 10 participating centers. Radiolog...

Background: Brain metastases represent a major indication for stereotactic radiosurgery (SRS), but further study is needed regarding repeat SRS (SRS2) after local or marginal recurrence after prior SRS (SRS1). We report local tumor control (LC) after SRS2 and identify predictors of radiation necrosis (RN) and symptomatic RN (SRN). Methods: Patie...

PurposeResection of clinoid meningiomas can be associated with significant morbidity. Experience with stereotactic radiosurgery (SRS) for clinoid meningiomas remains limited. We studied the safety and effectiveness of SRS for clinoid meningiomas.Methods From twelve institutions participating in the International Radiosurgery Research Foundation, we...

OBJECTIVE As novel therapies improve survival for men with prostate cancer, intracranial metastatic disease has become more common. The purpose of this multicenter study was to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) in the management of intracranial prostate cancer metastases. METHODS Demographic data, primary tumor ch...

Objective The optimal management of intraventricular metastases remains debatable. The aim of this study is to define the safety and efficacy of Gamma-Knife radiosurgery in the treatment of intraventricular metastases. Methods This retrospective, single-center study involved patients that were treated with stereotactic radiosurgery (SRS) for intra...

Background: Gamma Knife radiosurgery (GKRS) is a safe and effective treatment option for trigeminal neuralgia (TN). However, there is no objective, non-invasive, tool to identify non-responders or late responders to GKRS and to facilitate longitudinal patient management. We hypothesized that diffusivity metrics obtained three months after GKRS may...

Background: Brain metastases (BM) from differentiated thyroid cancer are rare. Stereotactic radiosurgery (SRS) is commonly used for the treatment of BMs; however, the experience with SRS for thyroid cancer BMs remains limited. The goal of this international, multi-centered study was to evaluate the efficacy and safety of SRS for thyroid cancer BMs....

Abstract Background Intra-thecal baclofen pump has been proven a safe and effective treatment of spasticity. Subdural hematoma has been rarely described following intra-thecal drug delivery device insertion. Case presentation We report on the rare case of a 45-year-old male with multiple sclerosis who presented with symptoms of intra-cranial hypote...

Background Very delayed aneurysmal rupture represents a rare, poorly understood, catastrophic complication of intracranial aneurysm flow diversion (FD) treatment. Case Description A 48-year-old woman presented to the neurosurgical clinic for an elective admission 6-month post-FD treatment with a single pipeline embolization device (PED) treatment o...

Intracranial tumors are rare in pregnancy and may present a diagnostic and therapeutic challenge. We report on a 34-year-old female who presented with new-onset partial seizures hours following delivery due to a left frontal space occupying lesion. Urgent surgical resection of the lesion was performed and histopathologic evaluation revealed anaplas...

Background/Objectives: The use of flow-diverter devices (FD) is considered a reliable tool for the treatment of complex intracranial aneurysms. They promote thrombosis of the sac through diversion of the blood flow. In the present study we report the clinical and angiographic results of the use of FD in our clinic. Methods: We retrospectively revie...

Background/Objectives: Endovascular treatment of intracranial arteriovenous malformations (AVMs) is considered an adjunctive procedure in their treatment. However, sometimes embolization can result incomplete angiographic obliteration of the AVM, without the need for further treatment. We present our series regarding complete obliteration of AVMs w...