The efficacy of surgery over stereotactic radiosurgery in the management of tumor-related trigeminal neuralgia.

Tumor-related trigeminal neuralgia (TN) is a deeply debilitating condition that severely impacts patient quality of life. Two principal treatment methods in use are open surgical resection of the causative tumor or the use of stereotactic radiosurgery (SRS). In this letter, we aim to evaluate the use of both treatment methods and highlight that in patients with commensurate anatomy, open surgical resection continues to provide greater rates of symptomatic relief, lower rates of recurrence, and complication compared to stereotactic radiosurgery.

Return to work in younger patients with brain metastases who survived for 2 years or more.

PURPOSE: The study's purpose was to analyze return to work and other long-term outcomes in younger patients with newly diagnosed brain metastases, treated before they reached legal retirement age, i.e. younger than 65 years. METHODS: We included patients who survived greater than 2 years after their first treatment, regardless of approach (systemic therapy, neurosurgical resection, whole-brain or stereotactic radiotherapy). The primary endpoint was the proportion of patients who worked 2 years after their initial treatment for brain metastases. Outcomes beyond the 2-year cut-off were also abstracted from comprehensive electronic health records, throughout the follow-up period. RESULTS: Of 455 patients who received active therapy for brain metastases, 62 (14%) survived for > 2 years. Twenty-eight were younger than 65 years. The actuarial median survival was 81 months and the 5-year survival rate 53%. For patients alive after 5 years, the 10-year survival rate was 54%. At diagnosis, 25% of patients (7 of 28) were permanently incapacitated for work/retired. Of the remaining 21 patients, 33% did work 2 years later. However, several of these patients went on to receive disability pension afterwards. Eventually, 19% continued working in the longer run. Younger age, absence of extracranial metastases, presence of a single brain metastasis, and Karnofsky performance status 90-100 were common features of patients who worked after 2 years. CONCLUSION: Long-term survival was achieved after vastly different therapeutic approaches, regarding both upfront and sequential management. Many patients required three or more lines of brain-directed treatment. Few patients continued working in the longer run.

Stereotactic radiosurgery for recurrent/residual nonfunctioning pituitary adenoma: a single-arm systematic review and meta-analysis.

BACKGROUND: Nonfunctioning pituitary adenomas (NFPAs) are a significant subtype of pituitary tumors, accounting for 30% of all pituitary tumors and 10-20% of intracranial tumors. The primary treatment for NFPAs is resection, but complete resection is often challenging due to the tumor's proximity to critical structures, leading to frequent recurrences. Stereotactic radiosurgery (SRS) has emerged as a viable treatment option for recurrent or residual NFPAs, but its long-term efficacy and safety profile require further investigation. METHODS: This systematic review followed PRISMA guidelines and included studies published up to February 2024. We searched MEDLINE, Embase, and Cochrane databases for studies evaluating SRS for recurrent/residual NFPAs. Inclusion criteria focused on studies reporting outcomes and complications of SRS, while exclusion criteria omitted case reports, case series, and non-English studies. Data extracted included demographic details, dosimetry parameters, and follow-up durations. The risk of bias was assessed using the ROBINS-I tool, and statistical analyses were performed using single-arm meta-analyses. RESULTS: A total of 24 studies involving 3,781 patients were included. The mean follow-up duration was 60 months. Tumor control was achieved in approximately 92.3% of patients. The risk of developing hypopituitarism post-SRS was 13.62%, while the risk for panhypopituitarism was 2.55%. New visual field deficits occurred in 3.94% of patients. Cranial nerve deficits were rare, with event rates below 1% for CN III, CN V, and CN VI. CONCLUSION: SRS is effective in managing recurrent or residual NFPAs, achieving high tumor control rates. However, the risk of hypopituitarism remains a significant concern, necessitating regular endocrinological monitoring. While generally safe, the potential for new visual field deficits and other cranial nerve deficits must be considered. SRS remains a valuable treatment option, but clinicians should be aware of its potential complications.

Detecting endolymphatic hydrops in patients with cranial nerve VIII schwannoma using hydrops MR examination.

PURPOSE: This study utilized Hydrops MRI in patients with cranial nerve (CN) VIII schwannoma to assess the concomitance with endolymphatic hydrops (EH), aiming to elucidate the mechanism of hydrops formation in these patients. METHODS: Twenty-six patients diagnosed as CN VIII schwannoma including vestibular schwannoma (VS) in 24 and intracochlear schwannoma (ICS) in 2 were enrolled. Fifteen patients received radiosurgery and 11 patients opted for a wait-and-scan approach. All patients underwent an inner ear test battery, followed by Hydrops MRI. Based on Hydrops MRI, 6 patients (23%) with positive EH were assigned to Group A, while the other 20 patients showing negative EH were assigned to Group B. RESULTS: The abnormality rates of inner ear test battery in Group A ran from the audiometry (100%), cervical vestibular-evoked myogenic potential (cVEMP) test (83%), ocular VEMP (oVEMP) test (67%) to the caloric test (33%), exhibiting a significantly declining sequence. This declining sequence is consistent with the decreasing order in the prevalence of EH from the cochlea (83%), saccule (50%) to utricle (50%). However, Group B did not show such decreasing trend, indicating that Groups A and B did not share the common mechanism. The mean tumor size prior to radiosurgery was 1.91 ± 0.89 cm, which significantly reduced to 1.53 ± 0.60 cm at a mean interval of 6 years following radiosurgery. In contrast, tumor size remained unchanged in those opted for a wait-and-scan approach. CONCLUSION: It is recommended to utilize Hydrops MRI for patients with CN VIII schwannoma during annual follow-up, particularly those experienced episodic vertigo and/or deteriorated hearing. The Hydrops MRI can not only monitor tumor size, but also detect the presence of EH, so as to guide treatment decision.

Stereotactic radiosurgery for arteriovenous malformations in pediatric patients: an updated systematic review and meta-analysis.

OBJECTIVE: Intracranial arteriovenous malformations are the most common cause of intracranial hemorrhages in pediatric patients. Stereotactic radiosurgery (SRS) has been used extensively to treat these lesions. The authors conducted a systematic review and meta-analysis to report treatment outcomes and long-term complications. METHODS: This study follows the PRISMA and MOOSE guidelines, with the search spanning electronic databases up to February 6, 2024. The outcome measures included obliteration rate, hemorrhage in the latency period, symptomatic radiation-induced changes (RICs), cyst formation, and radiation-induced tumorigenesis. RESULTS: A total of 1493 patients across 24 studies were included. The pooled complete obliteration after single-fraction SRS was 64.7% (95% CI 58%-69%). The pooled post-SRS hemorrhage rate at the final follow-up was 6.2% (95% CI 5%-8%). The overall incidence rate of RIC was 31.3% (267/854 patients), and the incidence of symptomatic RIC was 8.8% (114/1289 patients). For permanent symptomatic RIC, the pooled incidence was 4.8% (62/1283 patients). At final follow-up, 17 cases of radiation-induced necrosis were documented among 654 patients (2.6%). Similarly, cyst formation was reported in 1.3% of cases (17/1265 patients) and radiation-induced tumors occurred in 0.15% of cases (2/1342 patients). CONCLUSIONS: SRS can be considered an effective intervention for appropriately selected pediatric patients with arteriovenous malformations. Long-term complication rates appear to be low but additional longitudinal studies are required to better define the long-term outcomes.

Pediatric Cranial Stereotactic Radiosurgery: Meta-Analysis and International Stereotactic Radiosurgery Society Practice Guidelines.

BACKGROUND: There are limited data on the use of stereotactic radiosurgery (SRS) for pediatric patients. The aim of this systematic review was to summarize indications and outcomes specific to pediatric cranial SRS to inform consensus guidelines on behalf of the International Stereotactic Radiosurgery Society (ISRS). METHODS: A systematic review, using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), analyzed English-language articles on SRS, published between 1989 and 2021, that included outcomes for at least 5 pediatric patients. MEDLINE database terms included tumor types and locations, and radiosurgical and age-specific terms. We excluded nonclinical reports, expert opinions, commentaries, and review articles. Meta-regressions for associations with local control were performed for medulloblastoma, craniopharyngioma, ependymoma, glioma, and arteriovenous malformation (AVM). RESULTS: Of the 113 articles identified for review, 68 met the inclusion criteria. These articles described approximately 400 pediatric patients with benign and malignant brain tumors and 5119 with AVMs who underwent cranial SRS. The rates of local control for benign tumors, malignant tumors, and AVMs were 89% (95% CI, 82%-95%), 71% (95% CI, 59%-82%), and 65% (95% CI, 60%-69%), respectively. No significant associations were identified for local control with patient-, tumor-, or treatment-related variables. CONCLUSIONS: This review is the first to summarize outcomes specific to SRS for pediatric brain tumors and AVMs. Although data reporting is limited for pediatric patients, SRS appears to provide acceptable rates of local control. We present ISRS consensus guidelines to inform the judicious use of cranial SRS for pediatric patients.

Well calculated is better than quickly calculated: Comparison of Pencil beam and Monte Carlo algorithms according to the number of lesions and fractionation in radiosurgery of multiple brain metastases.

PURPOSE: In this work we compared pencil beam (PB) and Monte Carlo (MC) algorithms in single isocenter plans of multiple brain metastases radiosurgery (SIMM-SRS) plans using the quality indices reported for SRS. METHOD: The plans were evaluated concerning the prescribed dose, fractions and the number of metastases. The quality indices studied were mean dose (Dmean), D95, Paddick conformity index (PCI), Radiation Therapy Oncology Group (RTOG) homogeneity (HIRTOG) and quality of coverage indices (QRTOG), gradient index (GI), efficiency index for targets (Gη12Gy) and organs at risk (OARη12Gy) and V12-V18 for brain. RESULTS: The D95 for plans calculated with PB algorithm increased and differences were statistically significant (p < 0.001). For Dmean no differences were observed (p > 0.194). The PCI for the single-fraction cases showed statistical significant differences (p < 0.039). The PCI for the three-fraction cases did not show statistical significant difference (p < 0.569). However, the mean value of the index for all cases did not differ significantly between PB (0.84) and MC (0.81). The GI showed statistically significant differences, only for the plans with more than 10 metastases for a single-fraction (p = 0.0001). The Gη12Gy values reported are within the interval of 0.26-0.80, and for all cases, there were no statistically significant differences. CONCLUSION: Considering that MC is more accurate for small volumes and heterogeneities, and computational time is reasonable for clinical use, it should be selected in all cases for SIMM-SRS plans. We introduced the potential of novel indices as Gη12Gy, and OARη12Gy for clinical evaluation that potentially serve as optimization factor.

How safe and effective is irradiating radiation-induced meningiomas? Single-center experience in primary and salvage Gamma-Knife Radiosurgery, systematic review, and metanalysis of current evidence on the topic.

This is a single-center experience and metanalysis of the safety and efficacy measures of Gamma-knife stereotactic radiosurgery (SRS-GK) for radiation-induced meningiomas (RIMs). This study comprised a single-center analysis of SRS-GK for RIMs at IRCCS San Raffaele Hospital, Milan, Italy, and a systematic literature review and meta-analysis to address the actuarial local control (LC), distant control (DC), progression-free survival (PFS), and toxicity. The original series comprised 13 patients harboring 30 RIMs. Partial response was observed in 26 %, stability in 52 %, and progression in 22 %. The 5-year LC and DC rates were 71 % and 67 %. One patient developed radionecrosis, and an additional 2 presented edema. Metanalysis comprised 4 papers and data from the original series, comprising 146 patients and 308 RIMs. The 5-year LC was 84 %, the DC 67 %, and radionecrosis in 1.4 %. SRS-GK has an efficacy profile falling between that observed for radiologically suspected sporadic meningiomas and confirmed higher-grade lesions.

Diagnostic and therapeutic dilemmas of asymptomatic intracranial AVMs: A case report and evidence-based review.

First described by Virchow in the 19th century, intracranial arteriovenous malformations (AVMs) are complex, tangle-shaped vascular lesions with a number of associated neuroparenchymal, hemodynamic, and angio-architectural changes. However, the clinical description of extracranial AVMs dates back to the Ebers Papyrus (c. 1500 BC), with a still unknown definitive underlying etiology thus far. AVMs are rare lesions, with approximately 0.15% incidence and 0.001-0.5% prevalence, but of high importance as they tend to affect young patients who are frequently otherwise healthy. In the majority of cases, AVMs present as sudden intracranial hemorrhages that require immediate intervention, but incidentally-detected unruptured AVMs are only found in ∼15% of cases, leaving a confusing dilemma regarding the appropriate next step, particularly given the several therapeutic interventions available and clinical trials that were vulnerable to follow-up criticism. Herein, we present a case of an incidentally detected asymptomatic AVM in a 15-year-old boy via advanced imaging techniques that was initially misinterpreted as a post-traumatic subarachnoid hemorrhage on routine imaging studies. In providing a comprehensive overview of pathological classification schemes and the currently available diagnostic options for these silent dilemmatic AVMs, we highlight three management techniques: microsurgical resection, endovascular embolization, and stereotactic surgery, with the best option depends mostly on addressing lesion resection properly with minimal associated mortality and morbidity.

Validation of the prognostic index for spine metastasis (PRISM) for stratifying survival in patients treated with spinal stereotactic body radiation.

PURPOSE: The Prognostic Index for Spinal Metastasis (PRISM) is a scoring system derived from prospective data from a single institution that stratifies patients undergoing spine stereotactic radiosurgery (SSRS) for spinal metastases into subgroups by overall (OS). We sought to further demonstrate its generalizability by performing validation with a large dataset from a second high-volume institution, Mayo Clinic. METHODS AND MATERIALS: Eight hundred seventy-nine patients-424 from Mayo Clinic and 455 from MD Anderson Cancer Center (MDACC)-who received SSRS between 2007 and 2019 were identified. Patients were stratified by PRISM criteria, and overall survival (OS) for the PRISM groups for each cohort was compared using Kaplan-Meier estimations and univariate Cox proportional analyses. Model calibration and concordance indices (C-indices) were calculated for each cohort to assess the quality of the scoring system. RESULTS: Patient and tumor characteristics varied significantly between both cohorts including histology, sex, performance status, and number of organs involved (all P < 0.001). Median OS was 30.3 and 22.1 months for the Mayo and MDACC cohorts, respectively. Kaplan-Meier survival curves revealed robust separation between prognostic groups within both cohorts. The Mayo cohort showed median OS of 57.1, 37.0, 23.7, and 8.8 months for Groups 1, 2, 3, and 4, respectively. Univariate analysis revealed hazard ratios of 3.0 (95 % confidence interval [CI], 1.9-4.9), 5.2 (95 % CI, 3.2-8.3), and 12.9 (95 % CI, 7.8-21.4) for groups 2, 3 and 4, respectively all P < 0.001). The C-indices were 0.69 and 0.66 for the unstratified and stratified scores for the Mayo cohort, and 0.70 and 0.68 for the MDACC cohort, respectively. CONCLUSION: These data demonstrate robust validation of the PRISM score to stratify OS in patients treated with SSRS by a large external cohort, despite substantial differences among the cohorts. Overall, the PRISM scoring may help guide optimal treatment selection for patients with spine metastases.

Brain Metastatic Prostate Adenocarcinoma: Avoiding Mistaken Identities.

Brain metastatic carcinoma is a rare occurrence among prostate cancer metastases. 68Gallium prostate-specific membrane antigen PET-CT ([68Ga]PSMA PET/CT) is commonly used for prostate cancer staging and detection of biochemical recurrences. However, various CNS tumors exhibit activity on [68Ga]PSMA PET/CT and may often be included in the differential diagnosis. Herein, we present a case of brain metastatic prostate cancer successfully treated with surgical resection and adjuvant stereotactic Gamma Knife radiosurgery (GKRS) followed by androgen deprivation therapy (ADT) to emphasize the need for histologic confirmation. A 70-year-old male with a history of very high-risk prostatic adenocarcinoma presented with biochemical recurrence following radical prostatectomy and irradiation of the prostatic fossa. [68Ga]PSMA PET/CT and MRI identified a solitary lesion in the left occipital lobe; differential diagnosis included prostate metastasis, meningioma, or a new metastatic primary lesion. The patient underwent surgical resection, and immunohistochemical staining confirmed the lesion as brain metastatic prostate adenocarcinoma. One month after resection, the patient underwent GKRS to the tumor bed and two additional metastases, followed by ADT. Repeated imaging 15 months after GKRS revealed stable posttreatment changes with no evidence of new metastases, thus demonstrating durable, effective local and systemic control. Brain metastatic prostate adenocarcinoma without nodal or osseous metastases is a rare phenomenon. The affinity of [68Ga]PSMA PET/CT for non-prostate histologies such as meningioma introduces uncertainty into the diagnostic process. This case demonstrates the durable local control conferred by GKRS toward these lesions and emphasizes the need for clinical, radiographic, and histopathologic data to identify disease presentations and facilitate appropriate treatment regimens.

Endoscope-assisted treatment for delayed cystic radiation necrosis after stereotactic radiosurgery for metastatic brain tumors: illustrative cases.

BACKGROUND: Cystic formation due to radiation necrosis in metastatic brain tumors is a rare condition. Surgical intervention is necessary if symptoms develop. Additionally, excising radiation necrosis lesions within the cyst is essential to prevent recurrence. Neuroendoscopic surgery is a minimally invasive method suitable for treating cystic diseases and accessing deep lesions in the brain. The authors herein present a method for removing radiation necrotic tissue from deep lesions of cystic radiation necrosis using neuroendoscopy. OBSERVATIONS: Endoscopic surgery was performed in two patients with symptomatic cystic radiation necrosis. Both cases involved multilocular cysts, with radiation necrosis located deep within the cyst. The authors performed a small craniotomy of approximately 3 cm and opened the cyst. After removing its contents, an endoscope was used to closely observe the interior of the cyst. Removal of the septum within the cyst allowed the endoscope to be inserted deeply. The authors identified and excised the nodular lesion diagnosed as radiation necrosis in the deep tissue. Following the surgery, the cyst shrank rapidly, and symptoms disappeared. Both patients showed no recurrence of the lesions. LESSONS: The authors performed minimally invasive surgery and achieved good outcomes. Endoscopic surgery was considered beneficial for treating cystic radiation necrosis. https://thejns.org/doi/10.3171/CASE24250.

Radiation Therapy for Brain Tumors in Dogs and Cats.

External beam radiation therapy (RT) has become the standard of care for non-resectable or post-operative incompletely excised brain tumors in dogs and cats due to its relatively low side effect profile and increasing availability. This article reviews the indications for, expected outcomes of and possible toxicities associated with RT, follow-up care recommendations after RT, and publications about specific tumor types in dogs and cats with brain tumors.

Stereotactic radiosurgery for patients with spinal metastases from prostate cancer.

PURPOSE: Spinal metastases may result in intractable pain, neurological deficit, and vertebral body collapse. There are only a few studies describing outcomes following spine stereotactic radiosurgery (SRS) specifically for prostate cancer metastases. METHODS: A prospectively collected database of patients with prostate cancer spinal metastases treated at the University of Pittsburgh Medical Center from 2003 to 2023 was analyzed. The primary outcome was local control (LC). Secondary outcomes were overall survival (OS), pain resolution, and adverse radiation effects (AREs). RESULTS: Thirty-seven patients and 51 lesions were identified. Fifteen lesions (29%) were previously resected and 34 lesions (67%) were previously irradiated. The median tumor volume was 37.0 cc (range: 2.9-263.3). A majority of lesions (71%) were treated in a single fraction (median 20 Gy, range: 14-22.5); multi-fractionated treatment consisted of 21-30 Gy in 2-5 fractions. Median follow-up was 12 months (range: 1-146). The 6-month, 1-year, and 2-year LC rates were 97%, 91%, and 91%, respectively. No tested prognostic factors were associated with LC, including hormone sensitivity. The 6-month, 1-year, and 2-year OS rates were 71%, 56%, and 32%; age > 70 years (p = 0.048) and tumor volume > 30 cc (p = 0.03) were associated with inferior rates of OS. Complete or partial pain response was observed in 58% of patients. There were 8 instances (16%) of AREs, 2 of which were vertebral compression fractures (4%). CONCLUSION: Radiosurgery as a primary or adjuvant treatment modality for prostate cancer spinal metastases confers durable LC and moderate pain relief with minimal toxicity. Further studies are warranted to optimize management in this patient population.

Hearing preservation and quality of life in small to medium sized vestibular schwannomas after a wait and scan approach or stereotactic radiosurgery: a systematic review and meta-analysis.

BACKGROUND: The management of vestibular schwannomas (VS) encompasses a choice between conservative "wait-and-scan" (WAS) approach, stereotactic radiosurgery (SRS) or open microsurgical resection. Currently, there is no consensus on the optimal management approach for small to medium sized VS. This study aims to compared outcomes related to hearing in patients with small and medium sized VS who underwent initial treatment with WAS versus SRS. METHODS: A systematic review of the available literature was conducted using PubMed/MEDLINE, Embase, and Cochrane up December 08, 2023. Meta-analysis was performed using a random-effect model to calculate mean difference (MD) and relative risk (RR). A leave-one-out analysis was conducted. The risk of bias was assessed via the Risk of Bias in Non-randomized Studies-Interventions (ROBINS-I) and Cochrane Risk of Bias assessment tool (RoB-2). Ultimately, the certainty of evidence was evaluated using the GRADE assessment. The primary outcomes were serviceable hearing, and pure-tone average (PTA). The secondary outcome was the Penn Acoustic Neuroma Quality of Life Scale (PANQOL) total score. RESULTS: Nine studies were eligible for inclusion, comprising a total of 1,275 patients. Among these, 674 (52.86%) underwent WAS, while 601 patients (47.14%) received SRS. Follow-up duration ranged from two to eight years. The meta-analysis indicated that WAS had a better outcome for serviceable hearing (0.47; 95% CI: 0.32 - 0.68; p < 0.001), as well as for postoperative functional measures including PTA score (MD 13.48; 95% CI 3.83 - 23.13; p < 0.01), and PANQOL total score (MD 3.83; 95% CI 0.42 - 7.25; p = 0.03). The overall certainty of evidence ranged from "very low" to "moderate". CONCLUSIONS: Treating small to medium sized VS with WAS increases the likelihood of preserving serviceable hearing and optimized PANQOL overall postoperative score compared to SRS. Nevertheless, the limited availability of literature and the methodological weakness observed in existing studies outline the need for higher-quality studies.

Stereotactic radiosurgery alone for brain arteriovenous malformations: a single-institute experience.

OBJECTIVE: Brain arteriovenous malformations (BAVMs) represent an ongoing clinical challenge because of their complex nature. The long-term outcomes of BAVMs patients treated with stereotactic radiosurgery (SRS) alone are unclear. METHODS: We conducted a retrospective analysis of 201 patients treated for BAVMs from January 2010 to December 2019. The identified predictors of obliteration or hemorrhage in the multivariate analysis were estimated by odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: A total of 201 patients treated with gamma knife radiosurgery (GKRS) alone as the primary treatment for BAVMs were included. The mean age at GKRS treatment was 31.4 ± 1.1 years, and 61.2% of the patients were male. Multivariate logistic regression revealed that a higher radiosurgery-based AVM score (OR 1.847, 95% CI = 1.292-2.641; p = 0.001) was significantly associated with worse obliteration, and a higher margin dose significantly favored obliteration (OR 0.352, 95% CI = 0.189-0.658; p = 0.001). Multivariate analysis revealed that an increased lesion volume of 1 cm3 (OR 1.279, 95% CI = 1.023-1.600; p = 0.031) and a high margin dose (OR 0.363, 95% CI = 0.134-0.983; p = 0.046) were significant prognostic factors for post-SRS hemorrhage. CONCLUSIONS: In conclusion, our study investigated the available clinical and radiological prognostic factors for BAVMs and revealed that a higher margin dose significantly improved both the obliteration rate and nonhemorrhagic outcomes. Currently, the most appropriate candidates, Spetzler-Martin grade, and optimal radiation dose are still being defined by prospective trials.

Judicious and evidence-based use of radiosurgery - recommendations for low-middle income countries.

Surgical removal remains the primary treatment for most brain tumours. However, radiosurgery presents an effective, less invasive alternative or additional treatment for certain types. Our goal was to explore radiosurgery's roles in treating various brain tumours, focussing on its application in low- and middle-income countries (LMICs). We reviewed all relevant systematic reviews, metaanalyses, and guidelines to determine the most effective radiosurgical approaches. Additionally, we consulted a panel of experts with over ten years of experience in LMICs, such as Pakistan. For brain tumours, stereotactic radiosurgery should generally follow a confirmed histopathological diagnosis. Exceptions include tumours identified through Magnetic Resonance Imaging (MRI), like Vestibular Schwannoma (VS), pre-diagnosed Neurofibromatosis type 2 (NF2), multiple typical meningiomas, and metastases with a known histology from another site. While radiosurgery is gaining traction as a primary and adjunct treatment in some LMICs, the lack of regional guidelines, trained personnel, and collaboration among specialists hinders its wider adoption. Addressing these gaps is crucial for expanding radiosurgical care in these regions.

Dynamics of tumor evolution after Gammaknife radiosurgery for sporadic vestibular schwannoma: defining volumetric patterns characterizing individual trajectory.

BACKGROUND: Definition of tumor control and treatment failure after Gammaknife radiosurgery (GKRS) for vestibular schwannoma (VS) is still debated. The lack of knowledge on the dynamics of tumor evolution can lead to misinterpretation and subsequent inappropriate second treatment. The aim of this study was to evaluate the post-GKRS dynamics of evolution of tumor volume, and characterize volumetric patterns. METHODS: We included patients with sporadic VS treated by GKRS with an MRI follow-up of minimum 3 years. A clustering in 2 steps was performed: definition of the patterns of evolution based on a subset of patients with the most comprehensive follow-up, then assignment of the remaining patients on a best fit basis. The minimum length of follow-up was assessed by measuring the consistency of the clusters over time (Adjusted Rand Index and Normalized Mutual Information). An analysis of the discriminant variables was finally performed. RESULTS: 1,607 patients were included (median follow-up: 67 months). Five patterns were defined with one pattern gathering almost all cases of treatment failure. The clustering at 5 years afforded the highest consistency with long-term follow-up. Discriminant variables for clusters were: sex, initial symptoms, delay of diagnosis, Koos grading, fundus invasion, and number of isocenters. CONCLUSIONS: The definition of these robust distinct patterns is likely to help tremendously the physicians to distinguish tumor control from potential failure. We advocate for no retreatment decision before 5 years post-GKRS. Further investigations are required to decide if the dynamics of evolution can be predicted at GKRS on an individual basis.

Progress of intracranial metastases during the interval before stereotactic radiosurgery, a retrospective cohort analysis.

INTRODUCTION: The incidence of intracranial metastatic disease is increasing worldwide. As a valuable treatment modality, stereotactic radiosurgery requires detailed imaging, and this study evaluated the differences between imaging obtained on the day of treatment compared to historical or referral imaging. MATERIALS AND METHODS: A retrospective cohort study was performed, evaluating all the patients presenting with eligible referral imaging in a 13-month period and comparing this imaging to the imaging taken on the day of treatment. Numbers of additional metastases, volumes and volume differences among the images were compared. RESULTS: There was a median interval of 19 days between the acquisition of the diagnostic or referral scan and the day of treatment imaging. Even the group that had the shortest interval (up to 2 weeks) showed at least one additional deposit in 50 % of the patients. Volume was increased in 75 % of this group. Longer intervals were associated with higher increases in volume. CONCLUSION: These results demonstrate the increase in the disease burden in patients with intracranial metastatic disease, in relation to number and volume, in the interval between the referral and treatment imaging. This has significant implications for planning pathways, to ensure that metastatic deposits are not missed or undertreated.

KEAP1-mutant atypical meningioma: illustrative case.

BACKGROUND: While genetic testing of tumors is commonly used to inform the selection of systemic therapies, there is limited evidence for the application of radiotherapy for brain cancer. Recent studies have shown that Kelch-like ECH-associated protein 1 (KEAP1), a key regulator of cellular responses to oxidative and electrophilic stress, is associated with radioresistance in multiple cancer types. Several studies have reported the clinical significance of KEAP1 mutation in brain metastasis; however, the effect of KEAP1 mutations on radioresponse in meningioma has never been reported. OBSERVATIONS: The authors present the case of a 40-year-old female with a KEAP1 mutation-positive atypical meningioma that was initially treated with resection followed by intensity-modulated radiation therapy (IMRT). Recurrence was observed at 15 months, requiring reoperation and adjuvant stereotactic radiosurgery (SRS). An excellent treatment response was observed at 7 months post-SRS with an improvement in reported symptoms, although bevacizumab was required for the resolution of radiation necrosis observed 2 months post-SRS. LESSONS: To the authors' knowledge, this is the first report of KEAP1-mutant meningioma, including its clinical course after comprehensive management. Notably, treatment included multimodal radiotherapy with IMRT followed by SRS. SRS led to an excellent treatment response at the 7-month follow-up. However, radiation necrosis developed after both radiotherapy treatments, suggesting that radiological modification can be beneficial in patients with KEAP1 mutations. https://thejns.org/doi/10.3171/CASE24387.