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.

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.

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.

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.

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.

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.

A single-session stereotactic radiosurgery for vagal paraganglioma: Effective tumor reduction and innovative treatment option.

Background: Vagal paragangliomas (VPs) are rare tumors in the upper cervical region. Although surgical resection is the standard treatment for these tumors, it carries significant risks due to the tumor's high vascularity and proximity to vital structures. Stereotactic radiosurgery (SRS) for skull base paraganglioma could be a minimally invasive alternative. Case Description: We report the case of a 47-year-old man with a large, asymptomatic VP who was successfully treated with SRS with Gamma Knife Icon, which was performed in the parapharyngeal space (volume: 25.7 mL) using a marginal dose of 14 Gy to the 45% isodose line. This case illustrates the successful treatment of a lesion near the conventional limits (lower limit of C2 vertebral body) using noninvasive mask fixation. Excellent tumor control without neurological deficits was achieved for 25 months after SRS. The tumor volume decreased by 70% (final volume: 7.6 mL). Conclusion: This study demonstrates the utility of Gamma Knife Icon, which facilitates optimal SRS for upper cervical lesions, including VPs.

Mitigating radiation-induced cognitive toxicity in brain metastases: More questions than answers.

The emergence of advanced systemic therapies added to the use of cranial radiation techniques has significantly improved outcomes for cancer patients with multiple brain metastases (BM), leading to a considerable increase in long-term survivors. In this context, the rise of radiation-induced cognitive toxicity (RICT) has become increasingly relevant. In this critical narrative review, we address the controversies arising from clinical trials aimed at mitigating RICT. We thoroughly examine interventions such as memantine, hippocampal avoidance irradiation during BM treatment or in a prophylactic setting, and the assessment of cognitive safety in stereotactic radiosurgery (SRS). Our focus extends to recent neuroscience research findings, emphasizing the importance of preserving not only the hippocampal cortex but also other cortical regions involved in neural dynamic networks and their intricate role in encoding new memories. Despite treatment advancements, effectively managing patients with multiple BM and determining the optimal timing and integration of radiation and systemic treatments remain areas requiring further elucidation. Future trials are required to delineate optimal indications and ensure SRS safety. Additionally, the impact of new systemic therapies and the potential effects of delaying irradiation on cognitive functioning also need to be addressed. Inclusive trial designs, encompassing patients with multiple BM and accounting for diverse treatment scenarios, are essential for advancing effective strategies in managing RICT and the treatment of BM patients.

The Role of Surgery in Metastatic Renal Cell Carcinoma in 2024.

Renal cell carcinoma (RCC) is the most common solid tumour of the kidney and accounts for 3% of all cancers. While immune checkpoint inhibitor (ICI)-based combination therapies have emerged as the first-line treatment for metastatic renal cell carcinoma (mRCC), the role of surgery has become more controversial. This review summarizes the evidence, current role and future directions for surgery in mRCC management. The survival benefits of cytoreductive nephrectomy (CN) shown in the interferon era have encountered increasing disputes in the tyrosine-kinase inhibitor (TKI) and ICI eras. Undoubtedly, several systematic reviews based on retrospective data have supported the survival benefits of CN. Nevertheless, 2 prospective trials, CARMENA and SURTIME, proved that sunitinib as the upfront therapy resulted in noninferior survival outcomes compared with immediate CN. The safety of CN does have solid ground in the current literature. Several studies suggested that preoperative systemic therapy did not seem to aggravate perioperative complications or mortality rates, in experienced centres. Meticulous patient selection is the rule of thumb in the modern management of mRCC patients. The limitations of the existing prognostication models, however, must be acknowledged. Clinicians should adopt a multidisciplinary and holistic approach and contemplate all patient, disease, surgeon and socio-economical factors, before deciding who should go for surgery. The advent of metastasis-directed therapy (MDT) and survival benefits of adjuvant pembrolizumab shown in the oligometastatic subgroup, where complete metastasectomy could be achieved (M1 NED), calls for more comparative studies against upfront ICI combinations. In summary, CN brings survival benefits to well-selected good-to-intermediate-risk mRCC patients. Individualized and multidisciplinary care is pivotal.

Patient reported outcomes and short-term adjustment trajectories following gamma knife radiosurgery for benign brain tumor.

PURPOSE: Patient reported outcomes (PROs) in the context of Gamma Knife Stereotactic Radiosurgery (GKSRS) for benign brain tumor have been under-researched. This study examined changes in PROs and adjustment trajectories post-GKSRS. METHOD: 50 adults (54% female) aged on average 53.18 (SD = 14.76) years with benign brain tumor were assessed 1 week before GKSRS, 1-2 weeks post-GKSRS, and at 3-month follow-up. Telephone-based questionnaires of anxiety and depressive symptoms, cognitive function, symptom burden, and health-related quality of life (HRQoL) were completed. RESULTS: Significant improvements in HRQoL, perceived cognitive ability, anxiety, and total brain tumor symptoms were evident between pre-GKSRS and 3-month follow-up. Conversely, there was a significant short-term increase in depressive symptoms at post-GKSRS; however, levels did not differ from pre-GKSRS at follow-up. No significant changes were evident on PROs of headaches or fatigue. About half of the participants (46-51%) experienced reliable improvement in global HRQoL, and one-third (31-34%) reported improved anxiety symptoms. Increased depressive symptoms was seen in 34% of participants post-GKSRS and 18% at follow-up. CONCLUSIONS: At 3 months post-GKSRS, improvements in HRQoL, anxiety, perceived cognitive ability, and total brain tumor symptoms were evident. Routine monitoring and support for pre-GKSRS anxiety and depressive symptoms post-GKSRS is recommended.

Individuals receiving Gamma Knife radiosurgery for benign brain tumor experience positive impacts on global, emotional, and physical HRQoL, perceived cognitive ability, anxiety, and overall brain tumor symptoms following treatment.Due to heightened levels of anxiety observed prior to treatment, routine screening and support for anxiety are recommended before individuals receive Gamma Knife radiosurgery.Symptoms of depression may increase following Gamma Knife radiosurgery, therefore routine monitoring and management of mood symptoms is recommended after treatment.Evidence-based psychological interventions are needed for healthcare professionals to support individuals undergoing Gamma Knife radiosurgery.

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.

Surgical resection versus stereotactic radiosurgery for the treatment of brain metastases in the motor cortex; a meta-analysis and systematic review.

Brain metastasis in the motor cortex is a challenging condition to treat. Surgical resection or stereotactic radiosurgery (SRS)/hypofractionated stereotactic radiotherapy (hypoSRT) are valuable options up to now. Due to its unique location and potential for neurologic deficits, neither treatment is entirely satisfactory. There is still a lack of data on the treatment result of motor cortex metastasis. This study provides a comprehensive review and meta-analysis comparing surgery and SRS/hypoSRT for treating brain metastasis in the motor cortex. Core databases, including PubMed, Embase, and the Cochrane Library, were systematically searched for brain metastasis in the motor cortex, demonstrating the clinical outcomes of both surgery and SRS/hypoSRT. Motor power outcome and treatment-associated complication rates were thoroughly evaluated. Twenty-five articles were listed for full-text review. Among them, 13 articles were eligible for inclusion criteria: retrospective cohort studies comparing surgery and SRS/hypoSRT. There are 323 patients in the surgery group and 220 in the SRS/hypoSRT group. The motor outcome is better in surgery group, but without statistical significance (0.49 vs 0.37, p = 0.3937) and treatment-related complication is lower in surgery group with statistical significance (0.09 vs 0.26, p = 0.0218). Treatment modality should be tailored by the patient's performance status, history of radiation, presence of ongoing chemotherapy, or extracranial progression status.

Preoperative stereotactic radiosurgery for patients with 1-4 brain metastases: A single-arm phase 2 trial outcome analysis (NCT03398694).

Background: Stereotactic radiosurgery (SRS) following surgical resection is the standard of care for patients with symptomatic oligo brain metastasis (BM), however, it is associated with 10-15% local failure. Targeting a resection cavity is imprecise, thus preoperative radiosurgery where the target is well-defined may be superior, however, the efficacy of preoperative SRS has not yet been tested in a clinical trial. Methods: We conducted a phase 2, single-arm trial of preoperative SRS followed by surgical resection in patients with 1-4 symptomatic oligo BMs (NCT03398694) with the primary objective of measuring 6-month local control (LC). SRS was delivered to all patients utilizing a gamma knife or linear accelerator as per RTOG-9005 dosing criteria [Shaw E, Scott C, Souhami L, et al. Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05. Int J Radiat Oncol Biol Phys. 2000;47(2):291-298] based on tumor diameter with the exception that the largest lesion diameter treated was 5 cm with 15 Gy with all SRS treatment given in single fraction dosing. Results: The trial screened 50 patients, 48 patients were treated under the protocol and 32 patients completed the entire follow-up period. Of all the patients who completed the follow-up period, the primary endpoint of 6-month LC was 100% (95% CI: 0.891-1.000; P = .005). Secondary endpoints, presented as medians, were overall survival (17.6 months), progression-free survival (5.3 months), distant in-brain failure (40.8% at 1 year), leptomeningeal failure (4.8% at 1 year), and radiation necrosis (7.7% at 1 year). Conclusions: Our data confirms superior local control in patients who received preoperative SRS when compared to historical controls. Further study with a larger randomized cohort of patients is warranted to fully understand the benefits of preoperative SRS.

Treatment Reproducibility in Brain Stereotactic Radiotherapy Using a Shim Mask Versus a Standard Mask.

Introduction This study aimed to evaluate the setup accuracy of the new shim mask with mouth bite compared to the standard full brain mask in stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments for brain metastases or tumors. Method A combined retrospective and prospective design was employed, involving 40 patients treated at our center. Patients previously treated using standard head masks formed the retrospective cohort, while those treated with the Shim mask and mouth bite formed the prospective cohort. Daily cone-beam computed tomography (CBCT) scans were obtained before each treatment session to ensure patient setup accuracy. Key metrics included absolute shifts in translational and rotational directions, the number of repeat CBCTs, and the time interval between CBCTs. Results The Shim mask significantly reduced the mean setup errors in the lateral translation (p=0.022) from 0.17 cm (SD=0.10) to 0.10 cm (SD=0.10), and in X-axis rotation (p=0.030) from 0.79° (SD=0.43) to 0.47° (SD=0.47). By considering cutoff points of 1 mm in translational and 1° in rotational directions, the Shim mask was significantly more accurate in the lateral direction (p=0.004). Moreover, while 70% of patients in the standard group required repeat CBCT scans, none in the Shim group did, resulting in an average time saving of 10.4 minutes per patient. Conclusion The Shim mask with mouth bite offers enhanced immobilization accuracy in SRT/SRS treatments, leading to time and potential cost savings by reducing the need for repeat CBCT scans. This underscores the importance of adopting innovative immobilization techniques to optimize patient outcomes.

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.

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.

Stereotactic radiosurgery for medically refractory non-lesional epilepsy: A case-based Radiosurgery Society (RSS) practice review.

INTRODUCTION: Medically refractory epilepsy (MRE) occurs in about 30 % of patients with epilepsy, and the treatment options available to them have evolved over time. The classic treatment for medial temporal lobe epilepsy (mTLE) is anterior temporal lobectomy (ATL), but an initiative to find less invasive options has resulted in treatments such as neuromodulation, ablative procedures, and stereotactic radiosurgery (SRS). SRS has been an appealing non-invasive option and has developed an increasing presence in the literature over the last few decades. This article provides an overview of SRS for MRE with two example cases, and we discuss the optimal technique as well as the advantages, alternatives, and risks of this therapeutic option. CASES: We present two example cases of patients with MRE, who were poor candidates for invasive surgical treatment options and underwent SRS. The first case is a 65-year-old female with multiple medical comorbidities, whose seizure focus was localized to the left temporal lobe, and the second case is a 19-year-old male with Protein C deficiency and medial temporal lobe sclerosis. Both patients underwent SRS to targets within the medial temporal lobe, and both achieve significant improvements in seizure frequency and severity. DISCUSSION: SRS has generally been shown to be inferior to ATL for seizure reduction in medically refractory mTLE. However, there are patients with epilepsy for which SRS can be considered, such as patients with medical comorbidities that make surgery high risk, patients with epileptogenic foci in eloquent cortex, patients who have failed to respond to surgical management, patients who choose not to undergo surgery, and patients with geographic constraints to epilepsy centers. Patients and their physicians should be aware that SRS is not risk-free. Patients should be counseled on the latency period and monitored for risks such as delayed cerebral edema, visual field deficits, and radiation necrosis.

Stereotactic radiosurgery for anterior cranial fossa dural arteriovenous fistulas.

OBJECTIVE: Anterior cranial fossa (ACF) dural arteriovenous fistulas (DAVFs) are notoriously malignant vascular abnormalities, and their drainage into the cortical vein poses a high risk of intracranial hemorrhage (ICH). Stereotactic radiosurgery (SRS) is increasingly seen as an alternative to microsurgery or embolization for the treatment of DAVFs; however, researchers have yet to report on its applicability to ACF DAVFs. This paper summarizes the authors' experience in the use of SRS for ACF DAVFs. The authors' objective was to gain a preliminary overview of SRS outcomes in the treatment of ACF DAVFs. METHODS: This retrospective study examined all patients who underwent SRS for ACF DAVFs at a single academic medical center between November 2000 and November 2023. Demographic data, DAVF characteristics, and clinical outcomes were obtained from medical records. RESULTS: A total of 12 patients diagnosed with ACF DAVFs were treated using SRS. One patient was lost to follow-up. The mean age was 54.8 years and men comprised 82% of the cohort. The most common presenting symptoms included headache (n = 5), ocular symptoms (n = 3), seizure (n = 2), anosmia (n = 1), and tinnitus (n = 1). Two patients were asymptomatic. Four patients (36%) initially presented with ICH. Nine patients exhibited DAVF Cognard type IV, and 2 patients exhibited Cognard type III. DAVF obliteration in 7 of the 11 patients (64%) was confirmed by brain MR angiography (n = 4) or digital subtraction angiography (n = 3). No post-SRS episodes of ICH were reported. Most of the patients (10 of 11) reported improvements in clinical symptoms. CONCLUSIONS: SRS appears to be a viable alternative treatment for ACF DAVFs, particularly for patients who are not suitable candidates for surgery or those with an unfavorable angioarchitecture.