Gamma Knife Radiosurgery for Low-Grade Gliomas: Clinical Results at Long-Term Follow-Up of Tumor Control and Patients' Quality of Life

Pleomorphic Xanthoastrocytoma: Multi-Institutional Evaluation of Stereotactic Radiosurgery

BACKGROUND AND OBJECTIVES

Pleomorphic xanthoastrocytoma (PXA) is a rare low-grade glial tumor primarily affecting young individuals. Surgery is the primary treatment option; however, managing residual/recurrent tumors remains uncertain. This international multi-institutional study retrospectively assessed the use of stereotactic radiosurgery (SRS) for PXA.

METHODS

A total of 36 PXA patients (53 tumors) treated at 11 institutions between 1996 and 2023 were analyzed. Data included demographics, clinical variables, SRS parameters, tumor control, and clinical outcomes. Kaplan-Meier estimates summarized the local control (LC), progression-free survival, and overall survival (OS). Secondary end points addressed adverse radiation effects and the risk of malignant transformation. Cox regression analysis was used.

RESULTS

A total of 38 tumors were grade 2, and 15 tumors were grade 3. Nine patients underwent initial gross total resection, and 10 received adjuvant therapy. The main reason for SRS was residual tumors (41.5%). The median follow-up was 34 months (range, 2-324 months). LC was achieved in 77.4% of tumors, with 6-month, 1-year, and 2-year LC estimates at 86.7%, 82.3%, and 77.8%, respectively. Younger age at SRS (hazard ratios [HR] 3.164), absence of peritumoral edema (HR 4.685), and higher marginal dose (HR 6.190) were significantly associated with better LC. OS estimates at 1, 2, and 5 years were 86%, 74%, and 49.3%, respectively, with a median OS of 44 months. Four patients died due to disease progression. Radiological adverse radiation effects included edema (n = 8) and hemorrhagic change (n = 1). One grade 3 PXA transformed into glioblastoma 13 months after SRS.

CONCLUSION

SRS offers promising outcomes for PXA management, providing effective LC, reasonable progression-free survival, and minimal adverse events.

Unveiling the Efficacy of Gamma Knife Radiosurgery for Tectal Plate Gliomas

BACKGROUND AND OBJECTIVES

Tectal plate gliomas (TPGs) are midbrain tumors that grow slowly and have a benign clinical course. Most TPGs are low-grade astrocytomas, but they can encompass various histological tumor types. Gamma Knife radiosurgery (GKRS) is being explored as a potentially safe and effective treatment option for TPGs, although research in this area is limited. This study aims to evaluate GKRS's efficacy and safety in patients with TPG and provide a comprehensive review of existing literature on the topic.

METHODS

This retrospective, single-center study included 48 patients with consecutive TPG who underwent GKRS between September 2005 and June 2022. Patients diagnosed with TPGs based on radiological or tissue-based criteria and who had a minimum follow-up period of 12 months were eligible for inclusion. The primary end points were local control and the absence of GKRS-associated or tumor-associated mortality and morbidity.

RESULTS

During a median follow-up of 28.5 months (range, 12-128), the radiological assessment showed tumor control in all cases, with 16.7% achieving a complete response and 68.8% achieving a partial response. Pseudoprogression occurred in 6.2% of cases, with onset ranging from 3 to 8 months. Clinical outcomes revealed no permanent neurological deterioration, with symptoms improving in 14.6% of patients and remaining stable in the others. One patient in the pseudoprogression group experienced transient Parinaud syndrome. One patient died during follow-up because of unrelated causes. The mean survival time after GKRS was 123.7 months. None of the clinical, radiological, or radiosurgical variables showed a correlation with partial/complete response, clinical improvement, or overall survival.

CONCLUSION

There is limited research available on the management of TPGs, and this study presents the largest patient cohort treated with GKRS, along with a substantial follow-up duration. Despite its limitations, this study demonstrates the efficacy and low-risk profile of GKRS for TPGs.

Unruptured anterior Inferior cerebellar artery aneurysm following stereotactic irradiation for vestibular schwannoma: Case report and literature review

Background

The clinical features and therapeutic measures of vestibular schwannoma (VS) radiation-related aneurysm (RRA) have not been well described. We reported the first VS RRA case admitted for acute anterior inferior cerebella artery (AICA) ischemic symptoms. Literature was reviewed to present the research fruits about VS RRAs, and some therapeutic advices were given.

Materials and methods

A 54-year-old woman who had undergone GKS 10 years previously for a right VS was admitted to our hospital in 2018 because of sudden onset of severe vertigo and vomiting, accompanied with unsteady gait. During tumor resection, a dissecting aneurysm arose from the main trunk of AICA was encountered accidently within the tumor. The aneurysm was successfully treated with direct clip ligation, sparing the parent vessel. Data about this case were combined with those of other 11 radiation-related AICA aneurysm cases retrieved from the current literature. The following parameters were evaluated: Age, Sex, Diagnostic method, Location of aneurysm, Age of radiotherapy (Years)/Latency, Rupture, x-ray dosage, Type of radiotherapy, History of surgical resection of VS, Aneurysm Type, Morphology, Number, Treatment, Operative complications, Sequela, Outcome. VS RRAs mainly occurred in women (75%) with a median age of 62.5 years and were mainly located on AICA. Ruptured aneurysms accounted for 75.0% of the total cases. This paper reported the first VS case admitted with acute AICA ischemic symptoms. Cases with sacciform-like, irregular and fusiform-shaped aneurysms accounted for 50.0%, 25.0% and 25.0% of the total, respectively. After surgical treatment, 75.0% patients recovered, except for 3 patients who developed new ischemic consequence.

Conclusion

Patients should be informed of the risk of RRAs after receiving radiotherapy for VS. In these patients, RRAs should be suspected when subarachnoid hemorrhage or AICA ischemic symptoms occurred. Active intervention should be conducted considering the high instability and bleeding rate of VS RRAs.

Low grade gliomas

Low grade gliomas concern grade I and grade II tumors. The only grade one tumor is the pilocytic astrocytoma. This is a well-defined tumor with characteristic histology, often accompanied by a cyst. GKNS has been used in surgically inaccessible tumors since 1994. More recently it has been demonstrated that the tumors are more treatment resistant in adults than in children. Grade II tumors include oligodendrogliomas and grade II diffuse astrocytomas. The standard treatment for oligodendrogliomas us total removal followed by fractionated radiotherapy. GKNS has been shown to be of benefit in smaller tumors which have not responded to other treatment. It may also have a role as an ancillary treatment in smaller Grade II astrocytomas.

Gamma Knife radiosurgery as primary treatment of low-grade brainstem gliomas: A systematic review and metanalysis of current evidence and predictive factors

The current standard of care for surgically inaccessible low-grade brainstem gliomas (BS-LLGs) is external-beam radiotherapy (RT). Developments toward more innovative conformal techniques have focused on decreasing morbidity, by limiting radiation to surrounding tissues. Among these Gamma Knife radiosurgery (SRS-GK) has recently gained an increasingly important role in the treatment of these tumors. Although SRS-GK has not yet been compared with conventional RT in patients harboring focal BS-LGGs, clinical practice has been deeply influenced by trials performed on other tumors. This is the first meta-analysis on the topic, systematically reviewing the most relevant available evidence, comparing RT and SRS-GK as primary treatments of BS-LGGs, focusing on survival, clinical outcome, oncological control, and complications. Predictive factors have been systematically evaluated and analyzed according to statistical significance and clinical relevance.

Gamma Knife radiosurgery as salvage therapy for gangliogliomas after initial microsurgical resection

INTRODUCTION

Gangliogliomas (GG) are considered WHO grade I rare tumors. While they commonly manifest as temporal lobe epilepsy, they can be located anywhere in the brain. Primary treatment is complete microsurgical resection. Remnant or recurrent GG can benefit from radiation therapy. Here, we present a series of GG who received Gamma Knife radiosurgery (GKR) after initial microsurgery.

METHODS

Between October 2009 and February 2020, four patients benefitted from such approach. The median age at surgery was 16 years (mean 17, 11-25) and at the time of GKR was 22.5 years (mean 23, 19-28). Initial clinical symptom was epilepsy in 3 cases and incidental in one. Biopsy was firstly performed in one case. One patient had stereotactic electroencephalography. The respective anatomical locations were right parieto-occipital, sylvian, left paraventricular and left inferior parietal.

RESULTS

Gamma Knife radiosurgery was performed after a median time of 3.5 years after initial gross total microsurgical resection (GTR). The median follow-up after GKR was 54 months (mean 58.5, 6-120). The median marginal dose was 18 Gy (mean 17.5, 16-18). The median target volume was 0.5 mL (mean 0.904, 0.228-2.3). The median prescription isodose volume was 0.6 mL (mean 0.9, 0.3-2.4). At last follow-up, GG majorly decreased in 3 patients, remained stable in one.

CONCLUSION

Gamma Knife radiosurgery is safe and effective for remnant GG after GTR. Primary treatment remains microsurgical resection, especially in cases with symptomatic mass effect or with epilepsy. Single fraction GKR can be a valuable option for remnant or recurrent tumors after initial resection.

Concise review of stereotactic irradiation for pediatric glial neoplasms: Current concepts and future directions

Brain tumors, which are among the most common solid tumors in childhood, remain a leading cause of cancer-related mortality in pediatric population. Gliomas, which may be broadly categorized as low grade glioma and high grade glioma, account for the majority of brain tumors in children. Expectant management, surgery, radiation therapy (RT), chemotherapy, targeted therapy or combinations of these modalities may be used for management of pediatric gliomas. Several patient, tumor and treatment-related characteristics including age, lesion size, grade, location, phenotypic and genotypic features, symptomatology, predicted outcomes and toxicity profile of available therapeutic options should be considered in decision making for optimal treatment. Management of pediatric gliomas poses a formidable challenge to the physicians due to concerns about treatment induced toxicity. Adverse effects of therapy may include neurological deficits, hemiparesis, dysphagia, ataxia, spasticity, endocrine sequelae, neurocognitive and communication impairment, deterioration in quality of life, adverse socioeconomic consequences, and secondary cancers. Nevertheless, improved understanding of molecular pathology and technological advancements may pave the way for progress in management of pediatric glial neoplasms. Multidisciplinary management with close collaboration of disciplines including pediatric oncology, surgery, and radiation oncology is warranted to achieve optimal therapeutic outcomes. In the context of RT, stereotactic irradiation is a viable treatment modality for several central nervous system disorders and brain tumors. Considering the importance of minimizing adverse effects of irradiation, radiosurgery has attracted great attention for clinical applications in both adults and children. Radiosurgical applications offer great potential for improving the toxicity profile of radiation delivery by focused and precise targeting of well-defined tumors under stereotactic immobilization and image guidance. Herein, we provide a concise review of stereotactic irradiation for pediatric glial neoplasms in light of the literature.

Chemotherapy-induced changes in tumor consistency can allow gross total resection of previously unresectable brainstem pilocytic astrocytoma

Background

Low-grade gliomas (LGG) are described by the World Health Organization as Grades I and II. Among LGGs, the most common primary brain tumor is pilocytic astrocytoma (PA) and carries an excellent prognosis when treated with complete surgical resection. Cases, in which this is not possible, are associated with less favorable outcomes and worse progression-free survival.

Case Description

This report describes a case of a 22-year-old male, who presented with progression of a primary brainstem tumor previously treated with stereotactic radiosurgery and chemotherapy. Patient underwent surgical exploration and was diagnosed with juvenile PA, but debulking was limited by the very dense and fibrous tumor. Complete surgical resection was not possible at this time. Despite efforts to treat with chemotherapy, the patient presented a year later with clinical deterioration and severe neurologic deficits, prompting surgical re-exploration. During the second operation, the tumor was found to have undergone very significant softening in consistency, allowing for gross total resection (GTR).

Conclusion

Aggressive treatment of brainstem LGG should be pursued whenever possible, given its generally favorable prognosis. Repeat microsurgical resection, even with a different approach, might be reasonable and safe. Finally, chemotherapy may be associated with changes in the tumor consistency that can render previously unresectable lesions amenable to successful aggressive resection.

Radiotherapy in the Management of Paediatric Low-Grade Gliomas

Paediatric low-grade (World Health Organization grade I-II) gliomas (LGGs) represent a spectrum of primary central nervous system tumours. Local tumour control is the cornerstone in the general management of childhood gliomas. Surgery is the primary treatment of choice in the majority. Non-surgical treatments are recommended for progressive or symptomatic inoperable disease. Although chemotherapy is increasingly used as first non-surgical treatment, radiotherapy remains standard as salvage treatment or as primary treatment in selected cases in which surrounding normal tissue can be optimally preserved. The role of targeted therapies is currently under investigation in clinical trials. Modern high-precision radiotherapy techniques, including proton therapy, have the potential to improve long-term toxicities. There is therefore an urgent need for prospective studies to compare the efficacy and safety of modern radiotherapy with systemic treatment in children with LGGs. New information on molecular genetic patterns in LGGs may also have an impact on the selection and sequencing of radiotherapy.

Gamma knife radiosurgery for recurrent gliomas

Objective

In recent years, gamma knife radiosurgery (GKRS) has become increasingly more popular as a salvage treatment modality for patients diagnosed with recurrent gliomas. The goal of GKRS for recurrent glioma patients is to improve survival rates with minimal burden for these patients. The emphasis of this report is on local tumor control (TC), clinical outcome and survival analysis.

Methods

We performed a retrospective analysis of prospectively collected data of all patients who underwent GKRS for gliomas at the Gamma Knife Center Tilburg between 23-09-2002 and 21-05-2015. In total, 94 patients with glioma were treated with GKRS. Two patients were excluded because GKRS was used as a first stage treatment. The other 92 patients were included for analysis.

Results

TC was 37% for all tumors (TC was 50% in LGGs and 27% in HGGs). Local progression (LP) was 46% for all tumors (LP was 31% in LGGs and 58% in HGGs). New distant lesions were seen in 18% of all patients (in 5% of LGG patients and 31% of HGG patients). Median progression-free and overall survival (PFS and OS) for all patients were 10.5 and 34.4 months, respectively. Median PFS was 50.1 and 5.7 months for low and high grade tumors, respectively. Median OS was 86.6 and 12.8 months for low and high grade tumors, respectively. No serious adverse events were noted post-GKRS.

Conclusion

GKRS can safely be used as salvage treatment for recurrent glioma and seems to improve survival rates in (high grade) glioma patients with minimal burden.