Gamma Knife Stereotactic Radiosurgery Research Articles

SURG-43. PATTERNS OF FAILURE FOLLOWING REIRRADIATION WITH GAMMA KNIFE STEREOTACTIC RADIOSURGERY FOR RECURRENT HIGH-GRADE GLIOMAS

Abstract Re-irradiation with stereotactic radiosurgery (SRS) is an increasingly used treatment for recurrent high-grade glioma (HGG). We analyzed the patterns of failure and outcomes of salvage Gamma Knife SRS for recurrent HGG to better identify which patients would most benefit. We reviewed all patients who received SRS for recurrent HGG from January 2008 to May 2020. Pattern of failure was defined by the distance of recurrence from the SRS isodose line as follows: in-field local, marginal local, regional local, and distant failure. Overall survival (OS), progression-free survival (PFS), and local-failure free survival (LFS) were estimated using Kaplan-Meier methods, and regression model analysis was performed to analyze clinical predictors of failure. A total of 146 patients with HGG underwent SRS treatment to 410 target lesions. The median target volume was 3.3 cm3 and median total dose was 18 Gy. Sixty-one (41.8%) patients developed progression following SRS. PFS at 6 and 12 months were 65.8% and 37.3% respectively. Median OS was 12.4 months from salvage SRS. There were 113 (79.5%) local failures (53.1% in-field, 45.1% marginal, and 1.8% regional), 2 (1.4%) distant, and 27 (19%) concomitant local and distant failures. LFS at 6 and 12 months was 82.9% and 66.6%, respectively. Non-white race (HR = 0.37), SRS dose ≥ 20 Gy (HR = 0.34), age < 60 years (HR = 0.43), and KPS ≥ 70 (HR = 0.44) were associated with longer time to local failure. Non-white race (HR = 5.55) and SRS dose ≥ 20 Gy (HR = 5.62) were associated with more distant failure. No grade 4 or 5 toxicity was observed. In conclusion, the dominant pattern of failure remains local and in-field despite conformal dose distribution with SRS and infiltrative tumor histology. This supports the role of reirradiation with SRS in well selected patients with recurrent HGG.

RADT-43. RADIOSURGERY FOR BRAIN METASTASES FROM GYNECOLOGICAL PRIMARIES: AN INSTITUTIONAL PERSPECTIVE OF 58 METASTATIC LESIONS

Abstract Stereotactic radiosurgery (SRS) is being increasingly employed in the treatment of brain metastases. The evidence of radiological response of metastatic lesions from gynecological primary is lacking in literature. To assess the response rate of metastatic lesions to gamma knife SRS over a longitudinal follow-up period, a single centre prospectively maintained database was analysed retrospectively from 2014 to 2024. Lesion volumes were contoured at each follow up scan using Leksell Gammaplan software. Response assessment in neuro-oncology (RANO) criteria was used to assess radiological tumor response rates. Fifteen patients with 58 lesions were included. Average duration of radiological follow-up available was 16.7 months. The primary gynecological source of brain metastases in patients were cervical(n=4), ovarian(n=7), endometrial(n=3) and vulvar (n=1). Single fraction SRS was used for 49 lesions (range 16-20 Gy) and hypofractionated SRS for 9 lesions (8Gy x 3 to 9Gy x3). Average time to complete response was 9.01 months (range 1-25.7). The average follow-up for lesions with partial response was 12.2 months (range 1 -32) As per RANO criteria, complete response was seen in 33(56.9%) lesions and partial response in 25(43.1%). At 6month follow up, complete response was seen in 58.49% (n=31) of the lesions available(n=53) for assessment and partial response in 41.51%(n=22). At 18-months, complete response was seen in 66.67%(n=22) and partial response in 33.33%(n=11). Within pathological subgroups, endometrial (60%,n=3) primary showed higher rate of complete response at 6months than ovarian (52.7%,n=19), vulvar (50%, n=1) and cervical (40%,n=6) subgroups. Brain metastases from ovarian primary source were most encountered and endometrial metastases showed highest response rates to SRS. Six month and 18-month response rates were better than previously reported literature.

Stereotactic radiosurgery (SRS) for patients with brainstem cerebral cavernous malformations (CCMs): an international, multicentric study

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. Hemorrhagic risk reduction, risk factors of post-SRS hemorrhage, and clinical outcomes were retrospectively analyzed. Most patients had a single (165/170 patients) brainstem CCMs treated; the majority of CCMs (165/181) presented with bleeding. Single-session SRS decreased the risk of repeat hemorrhage in patients with hemorrhagic brainstem CCM (HR: 0.17, p < 0.001) using recurrent multivariate analysis. The annual hemorrhage rate decreased from 14.8 per 100 CCM-years before SRS to 2.3 after treatment. Using univariate Cox-analysis, the probability of a new hemorrhages after SRS was reduced for patient older than 35 years (HR = 0.21, p = 0.002) and increased with a margin dose > 13 Gy (HR = 2.57, p = 0.044). Adverse radiation effect (ARE) occurred in 9 patients (5.3%) and was symptomatic in four (2.4%). At a median follow-up of 3.4 years (Inter-quartile range: 5.4), 13 patients (8.0%) had a worsened clinical status, with the treated CCM being the cause in 5.6% (10) of the patients. Single-session SRS decreased the risk of repeat hemorrhage in patients with hemorrhagic brainstem CCM and conveyed this benefit with a low risk of advrse radiation effects (ARE) and worsening clinical status.

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.

Comparative effectiveness of frame-based and mask-based Gamma Knife stereotactic radiosurgery in brain metastases: A 509 patient meta-analysis.

Stereotactic Radiosurgery (SRS) is the primary treatment for patients with limited numbers of small brain metastases. Head fixation is usually performed with framed-based (FB) fixation; however, mask-based (MB) fixation has emerged as a less invasive alternative. A comparative meta-analysis between both approaches has not been performed. Databases were searched until August 28th, 2023, to identify studies comparing MB and FB SRS in the treatment of brain metastases. Our outcomes of interest included local tumor control (LTC), radiation necrosis (RN), mortality, and treatment time (TT). Mean difference (MD), risk ratio (RR), and hazard ratio (HR) were used for statistical comparisons. From 295 articles initially identified, six studies (1 clinical trial) involving 509 patients were included. LTC revealed comparable RR at 6-months (RR = 0.95[95%CI = 0.89-1.01], p = 0.12) and a marginal benefit in FB SRS at 1-year (RR = 0.87[95%CI = 0.78-0.96], p = 0.005). However, in oligometastases exclusively treated with single-fraction SRS, LTC was similar among groups (RR = 0.92 [95%CI = 0.89-1.0], p = 0.30). Similarly, in patients with oligometastases treated with single-fraction SRS, RN (HR = 1.69; 95%CI = 0.72-3.97, p = 0.22), TT (MD = -29.64; 95%CI = -80.38-21.10, p = 0.25), and mortality were similar among groups (RR = 0.62; 95%CI = 0.22-1.76, p = 0.37). Our findings suggest that FB and MB SRS, particularly oligometastases treated with single-fraction, are comparable in terms of LTC, RN, TT, and mortality. Further research is essential to draw definitive conclusions.

Multistaged Stereotactic Radiosurgery for Complex Large Lobar Arteriovenous Malformations: A Case Series.

Although stereotactic radiosurgery (SRS) has well defined outcomes in the management of smaller-volume arteriovenous malformations (AVM), this report evaluates the outcomes when SRS is used for large-volume (≥10 cc) lobar AVMs. Between 1990 and 2022, a cohort of 1325 patients underwent Leksell Gamma Knife SRS for brain AVMs. Among these, 40 patients (25 women; median age: 37 years) with large lobar AVMs underwent volume-staged SRS followed by additional SRS procedures if needed (2-5 procedures). The patients presented with diverse AVM locations and Spetzler-Martin Grades. Before SRS, 16 patients underwent a total of 43 embolization procedures. Over a median follow-up of 73 months, 20 patients achieved AVM obliteration. The 3, 5, and 10-year obliteration rates were 9.3%, 15.3%, and 53.3%, respectively. During the latency interval between the first SRS procedure and the last follow-up, 11 patients had intracerebral hemorrhages (ICH) and 6 developed new neurological deficits unrelated to ICH. The postoperative hemorrhage risk after the first SRS was 13.8% at 3 years, 16.6% at 5 years, and 36.2% at 10 years. No hemorrhagic event was documented after confirmed obliteration. Compared with the modified Rankin Scale (mRS) scores before SRS, the mRS improved or remained stable in 28 patients. Nine patients died during the observation interval. Five were related to ICH. These outcomes underscore both the potential effectiveness and the limitations of multistage SRS procedures for complex high-risk large volume AVMs in critical brain lobar locations. Most patients retained either stable or improved long-term mRS scores. During the latency interval from the first SRS until obliteration, achieved after two or more procedures, the risk of hemorrhage and treatment-related complications persists.

Severe pneumocranium after gamma knife stereotactic radiosurgery for brain metastasis: A case report and literature review.

Gamma knife stereotactic radiosurgery (GKRS) is a recognized safe and effective treatment for brain metastasis; however, some complications can present significant clinical challenges. This case report highlights a rare occurrence of cerebrospinal fluid (CSF) leakage and pneumocranium following GKRS, emphasizing the need for awareness and prompt management of these complications. A 35-year-old male with a history of malignant neoplasm of the lip in 2015 and perineural spread of malignancy into the left cavernous sinus was treated with GKRS in 2017. The patient was admitted emergently 39 days after discharge due to persistent headache and dizziness. Brain computed tomography (CT) revealed diffuse bilateral pneumocranium alongside an observation of CSF leakage. A surgical procedure involving a left frontal-temporal craniotomy was performed to excise a residual skull base tumor and repair the dura, guided by a navigator system. The conclusive pathological assessment revealed the presence of squamous cell carcinoma markers. The patient exhibited excellent tolerance to the entire procedure and experienced a prompt and uneventful recovery process. After surgery, the symptoms alleviated and CSF leak stopped. The follow-up image showed the pneumocranium resolved. Pneumocranium due to early-stage post-GKRS is uncommon. The rapid tumor shrinkage and timing of brain metastasis spreading through the dura can lead to CSF leak and pneumocranium. We reviewed current treatment options and presented a successful craniotomy-based dura repair case.

Assessment of Gamma Knife Stereotactic Radiosurgery as an Adjuvant Therapy in First-Line Management of Newly Diagnosed Glioblastoma: Insights from Ten Years at a Neuroscience Center

Gamma knife radiosurgery (GKRS), a form of stereotactic radiosurgery (SRS), has gained importance in treating glioblastoma alongside conventional chemotherapy. This study aims to assess the efficacy of combining GKRS with surgery and chemotherapy to enhance treatment outcomes for glioblastoma patients. This prospective clinical study, adhering to STROBE guidelines, assessed 121 glioblastoma patients from June 2008 to December 2022. All patients who had not undergone prior radiotherapy underwent open surgical tumor resection, GKRS, and adjuvant chemotherapy. In the analyzed cohort, the median survival post-diagnosis was 21.2 months (95% CI: 11.4–26.7) and the median progression-free survival was 13.6 months (95% CI: 12.5–28.3). The median time to first recurrence post-treatment was 14.5 months (range: 4–33 months). The median prescribed dose for GKRS was 12 Gy (range: 10–17 Gy), with a median target volume of 6.0 cm3 (range: 1.6–68 cm3). Post GKRS, 92 patients experienced local recurrence, 21 experienced distant recurrence, and 87 received additional treatment, indicating diverse responses and treatment engagement. This study evaluates the use of GKRS for glioblastomas, emphasizing its efficacy and complications in a single-center trial. It suggests integrating GKRS into initial treatment and for recurrences, highlighting the comparable survival rates but underscoring the need for further research.

Deep learning for automatic segmentation of vestibular schwannoma: a retrospective study from multi-center routine MRI.

Automatic segmentation of vestibular schwannoma (VS) from routine clinical MRI has potential to improve clinical workflow, facilitate treatment decisions, and assist patient management. Previous work demonstrated reliable automatic segmentation performance on datasets of standardized MRI images acquired for stereotactic surgery planning. However, diagnostic clinical datasets are generally more diverse and pose a larger challenge to automatic segmentation algorithms, especially when post-operative images are included. In this work, we show for the first time that automatic segmentation of VS on routine MRI datasets is also possible with high accuracy. We acquired and publicly release a curated multi-center routine clinical (MC-RC) dataset of 160 patients with a single sporadic VS. For each patient up to three longitudinal MRI exams with contrast-enhanced T1-weighted (ceT1w) (n = 124) and T2-weighted (T2w) (n = 363) images were included and the VS manually annotated. Segmentations were produced and verified in an iterative process: (1) initial segmentations by a specialized company; (2) review by one of three trained radiologists; and (3) validation by an expert team. Inter- and intra-observer reliability experiments were performed on a subset of the dataset. A state-of-the-art deep learning framework was used to train segmentation models for VS. Model performance was evaluated on a MC-RC hold-out testing set, another public VS datasets, and a partially public dataset. The generalizability and robustness of the VS deep learning segmentation models increased significantly when trained on the MC-RC dataset. Dice similarity coefficients (DSC) achieved by our model are comparable to those achieved by trained radiologists in the inter-observer experiment. On the MC-RC testing set, median DSCs were 86.2(9.5) for ceT1w, 89.4(7.0) for T2w, and 86.4(8.6) for combined ceT1w+T2w input images. On another public dataset acquired for Gamma Knife stereotactic radiosurgery our model achieved median DSCs of 95.3(2.9), 92.8(3.8), and 95.5(3.3), respectively. In contrast, models trained on the Gamma Knife dataset did not generalize well as illustrated by significant underperformance on the MC-RC routine MRI dataset, highlighting the importance of data variability in the development of robust VS segmentation models. The MC-RC dataset and all trained deep learning models were made available online.

Stereotactic Radiosurgery for Patients with Brain Metastases from Hepatopancreaticobiliary Cancers.

The role of stereotactic radiosurgery (SRS) for patients with brain metastases from hepatopancreaticobiliary (HPB) cancers has yet to be established. The authors present a single-institution experience of patients with HPB cancers who underwent SRS when their cancer spread to the brain. We surveyed our Gamma Knife SRS data base of 18,000 patients for the years 1987-2022. In total, 19 metastatic HPB cancer patients (13 male) with 76 brain metastases were identified. The median age at SRS was 61 years (range: 48-83). The primary cancer sites were hepatocellular carcinoma (HCC, 11 patients), cholangiocarcinoma (CCC, 2 patients), and pancreatic carcinoma (PCC, 6 patients). The median Karnofsky Performance Score (KPS) was 80 (range: 50-90). Two patients underwent pre-SRS whole-brain fractionated radiation therapy (WBRT) and eight patients underwent pre-SRS surgical resection. All SRS was delivered in single session. The median margin dose was 18 Gy (range: 15-20). The median cumulative tumor volume was 8.1 cc (range: 1.0-44.2). The median patient overall survival (OS) after SRS was 7 months (range 1-79 months). Four patients had documented local tumor progression after SRS at a median time of 8.5 months (range: 2-15) between SRS and progression. Out of 76 treated tumors, 72 tumors exhibited local control. The local tumor control rate per patient was 78.9%. The local tumor control per tumor was 94.7%. Four patients developed new brain metastases at a median of 6.5 months (range: 2-17) after SRS. No patient experienced adverse radiation effects (AREs). At the last follow-up, 18 patients had died, all from systemic disease progression. Metastatic spread to the brain from HPB cancers occurs late in the course of the primary disease. In this study, all deceased patients ultimately died from primary disease progression. SRS is a non-invasive strategy that maximally preserves quality of life, and our results reported favorable outcomes compared to the existing literature. SRS should be considered as one of the primary management strategies for patients with brain metastatic spread from HPB cancer.

Analysis of the treatment planning metrics and their correlation with morphology of intracranial lesions in Gamma Knife stereotactic radiosurgery.

Gamma Knife Radiosurgery (GKRS) has established a role in treating various benign brain pathologies. The radiosurgery planning necessitates a proper understanding of radiation dose distribution in relation to the target lesion and surrounding eloquent area. The quality of a radiosurgery plan is determined by various planning parameters. Here, we have reviewed various GKRS planning parameters and analyzed their correlation with the morphology of treated brain lesions. A total of 430 treatment plans (71 meningioma, 133 vestibular schwannoma/VS, 150 arteriovenous malformation/AVM, 76 pituitary adenoma/PA treated with GKRS between December 2013 and May 2023) were analyzed for target coverage (TC), conformity index (CI), homogeneity index (HI), and gradient index (GI). The values of CIPaddick and CILomax for PA were lower and differed significantly from meningioma, VS, and AVM. The value of HI for PA was higher and differed significantly when compared with meningioma, VS, and AVM. The values of HI for AVM were also significantly higher than VS and meningioma. The mean GI was 3.02, 2.92, 3.03, and 2.88 for meningioma, VS, AVM, and PA, respectively. The value of GI for meningioma and AVM was significantly higher when compared with the values for VS and PA. The mean TC was 0.94 for meningioma, 0.96 for VS, 0.95 for AVM, and 0.90 for PA. The value TC of PA was lower and differed significantly when compared with VS, AVM, and meningioma. Lesions with a volume of ≤1 cc had poor planning metrics as the spillage of radiation may be higher. The GKRS planning parameters depend on the size, shape, nature, and location of intracranial lesions. Therefore, each treatment plan needs to be evaluated thoroughly and a long-term follow-up is needed to establish their relation with clinical outcome.

1134 A Call to Revise the Thirty-year-old SRS Dose Guidelines for Brain Metastases

INTRODUCTION: Stereotactic Radiosurgery (SRS) currently is the most widely used neurosurgical strategy for treatment of brain metastases. Many centers still rely on 30-year-old dose volume guidelines derived from RTOG 90-05. METHODS: Between 2014 and 2020 330 NSCLC patients (median age = 65 years) with 2910 brain metastases underwent Gamma knife SRS. The number of tumors treated per patient ranged from 1-56 and the total tumor cumulative volume ranged from .05 to 33.09 cc (median = 3.17). The median prescribed tumor margin dose was 18 Gy. RESULTS: Median overall survival after radiosurgery was 15.5 months. Radiological tumor progression was noted 66 out of 2910 tumors (2.27%) in 51 out of 330 patients (15.45%). Tumors were divided into 4 categories based on tumor volumes (&lt;1.5 cc, 1.5-&lt;5 cc, 5-&lt;10 cc, and = 10cc). The effect of margin dose, and % tumor covered in 18 Gy, 20 Gy, and 24 Gy on local tumor control was analyzed for all 4 categories. In tumors with volumes &gt;1.5 cc local tumor control was significantly better (P &lt; 0.05) when =65% of the tumor volume received at least 24 Gy. No relationship was found between tumor control and 75, 90, and 100 % volumes receiving 18 or 20 Gy. CONCLUSIONS: In this study neither conformality of dose delivery nor tumor margin doses were the most important predictors of local tumor control as long as =65% of the tumor volume received at least 24 Gy. This finding can serve as a prescriptive guideline that allows margin doses below the RTOG guidelines, reduces reliance on strict conformality, and improves tumor control.

Uveal melanoma: the value of molecular genetic testing for early detection of metastatic disease. Clinical case

To date, the issue of not only timely diagnosis and treatment of patients with uveal melanoma (UM), but also the prediction of this pathology remains relevant. The technology of fine needle aspiration biopsy (FNAB) makes it possible to assess the risk of developing metastatic disease using tumor specimen in patients undergoing organ-preserving treatment by cytological and molecular genetic testing in the primary intraocular lesion. Here we present a case of newly identified locally advanced (T3a) UM, outline the possibilities of organ-preserving treatment using Gamma Knife stereotactic radiosurgery, and also demonstrate the feasibility of conducting a comprehensive prognostic testing on FNAB material, including cytological and molecular genetic and morphological prognostic factors. The results of this testing have made it possible to recommend a more frequent surveillance monitoring regime for metastatic disease, which ultimately led to the early detection of UM liver metastases, followed by their successful treatment.

Salvage Microsurgery Following Failed Primary Radiosurgery in Sporadic Vestibular Schwannoma

Management of sporadic vestibular schwannoma with radiosurgery is becoming increasingly common globally; however, limited data currently characterize patient outcomes in the setting of microsurgical salvage for radiosurgical failure. To describe the clinical outcomes of salvage microsurgery following failed primary stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT) among patients with sporadic vestibular schwannoma. This was a cohort study of adults (≥18 years old) with sporadic vestibular schwannoma who underwent salvage microsurgery following failed primary SRS/FSRT in 7 vestibular schwannoma treatment centers across the US and Norway. Data collection was performed between July 2022 and January 2023, with data analysis performed between January and July 2023. Salvage microsurgical tumor resection. Composite outcome of undergoing less than gross total resection (GTR) or experiencing long-term facial paresis. Among 126 patients, the median (IQR) age at time of salvage microsurgery was 62 (53-70) years, 69 (55%) were female, and 113 of 117 (97%) had tumors that extended into the cerebellopontine angle at time of salvage. Of 125 patients, 96 (76%) underwent primary gamma knife SRS, while 24 (19%) underwent linear accelerator-based SRS; the remaining patients underwent FSRT using other modalities. Postoperative cerebrospinal fluid leak was seen in 15 of 126 patients (12%), hydrocephalus in 8 (6%), symptomatic stroke in 7 (6%), and meningitis in 2 (2%). Each 1-mm increase in cerebellopontine angle tumor size was associated with a 13% increased likelihood of foregoing GTR (64 of 102 patients [63%]) or long-term postoperative House-Brackmann grade higher than I (48 of 102 patients [47%]) (odds ratio, 1.13; 95% CI, 1.04-1.23). Following salvage microsurgery, tumor growth-free survival rates at 1, 3, and 5 years were 97% (95% CI, 94%-100%), 93% (95% CI, 87%-99%), and 91% (95% CI, 84%-98%), respectively. In this cohort study, more than half of patients who received salvage microsurgery following primary SRS/FSRT underwent less than GTR or experienced some degree of facial paresis long term. These data suggest that the cumulative risk of developing facial paresis following primary SRS/FSRT by the end of the patient's journey with treatment approximates 2.5% to 7.5% when using published primary SRS/FSRT long-term tumor control rates.

Neurosurgery as an opportunity to correct symptoms of mental and behavioural disorders

Neurosurgical treatment for psychiatric disorders has a controversial history. This branch of neurosurgery called by developer of prefrontal leucotomy and Nobel prize laureate Egaz Moniz “psychosurgery”, was initially based not on scientific researches, but on enthusiasm of individuals and pressing social need. The outcome of psychosurgery regardless of its clinical benefits was the negative attitude of the broad masses and medical community, some countries have banned psychosurgery – the era of psychopharmacology has come. However, some patients suffering from severe course of the psychiatric disorder are resistant to conservative treatment.Over the last decades, the novel neuroimaging methods and neurobiological researches have considerably improved understanding of the pathogenesis of psychiatric disorders and scientific validity of the surgical intervention into the neural circuits. In this article, the main stages of the history of the psychiatric neurosurgery are briefly reviewed. Furthermore, the clinical and surgical considerations including the anatomic target localization, outcome and possible complications of the major operations which are still in practice are presented. The new neurosurgical techniques such as deep brain stimulation and gamma knife stereotactic radiosurgery were also considered. The part of the article is devoted to ethical, legal and terminological issues of psychiatric neurosurgery.

Cost of Treatment for Brain Metastases Using Data From a National Health Insurance Provider

In the United States, brain metastases (BMs) affect 10% to 20% of patients with cancer, presenting a significant health care challenge and necessitating intricate, high-cost treatments. Few studies have explored the comprehensive care cost for BMs, and none have used real insurance claims data. Partnering with a northeastern health care insurer, we investigated the true costs of various brain-directed radiation methods, aiming to shed light on treatment expenses, modalities, and their efficacy. We analyzed medical claims from Highmark Health-insured patients in Pennsylvania, Delware, West Virginia, and New York diagnosed with BMs (ICD-10 code C79.31) and treated with radiation from January 1, 2020 to July 1, 2022. Costs for radiation techniques were grouped by specific current procedural terminology claim codes. We subdivided costs into technical and physician components and separated hospital from freestanding costs for some modalities. From January 1, 2020 to July 1, 2022, 1048 Highmark Health members underwent treatment for BMs. Females (n = 592) significantly outnumbered males (n = 456), with an average age of 64.4 years. Each member had, on average, 5.309 claims costing $2015 per claim. Total cost totaled $10,697,749. Per-treatment analysis showed that hippocampal avoidance intensity modulated radiation therapy was the costliest treatment at $47,748, followed by stereotactic radiation therapy at $37,230, linear accelerator stereotactic radiosurgery (SRS) at $30,737, Gamma Knife SRS at $30,711, and whole-brain radiation therapy at $5225. Whole-brain radiation therapy was the least costly radiation technique. Similar per-treatment prices for Gamma Knife and linear accelerator SRS support their use in treating BMs. Stereotactic radiation therapy in general was costlier on a per-use basis than SRS, prompting further scrutiny on its frequent use. Hippocampal avoidance intensity modulated radiation therapy was the costliest radiation therapy on a per-use basis by a moderate amount, prompting further discussion about its comparative cost effectiveness against other radiation modalities. This study underscores the importance of multiple considerations in treating BMs, such as tumor control, survival, side effects, and costs.

O-01 Case report: Temozolomide treatment of refractory prolactinoma

Abstract Introduction Treatment of refractory prolactinoma is challenging. Temozolomide (TMZ), an oral chemotherapeutic agent, has been recommended as an effective drug for refractory pituitary adenomas or carcinomas. Clinical Case We report a 53-year-old male who presented with diplopia, left eye proptosis, conjunctival congestion, and headache. Magnetic resonance imaging (MRI) showed a macroadenoma 20×17 mm in diameter with compression of the optic chiasm and invasion of both cavernous sinuses. Hormonal evaluation revealed hyperprolactinemia of 2382 ug/L, 120x above the upper limit of normal (ULN), with central hypothyroidism and hypogonadism. Cabergoline was recommended as an initial treatment. Despite the maximum cabergoline dose of 1.5 g daily, tumor volume increased with visual disturbances and headaches. Prolactin (PRL) remained 60x above ULN so the patient underwent transsphenoidal surgery. Tumor histology was consistent with an atypical pituitary adenoma, positively stained for prolactin and sporadically for growth hormone, Ki-67 of 6.4%, no mitosis and negative p53. Postoperatively, the PRL level was still high (25x above ULN) with tumor remnants in both cavernous sinuses. Due to the tumor resistance to dopamine agonist treatment and uncomplete surgical resection, patient underwent stereotactic gamma knife radiosurgery (GK prescription dose 22 Gy, isodose 49%) simultaneously with TMZ treatment. After 2 cycles of TMZ (1. cycle TMZ 300mg/5days, 2. cycle TMZ 400 mg/5days), the PRL level decreased significantly (126 ug/L). The plan is to apply a total of 6 cycles of temozolomide. Conclusion Clinical evidence for the efficacy of TMZ in refractory prolactinoma remains limited, but early use of this agent may be helpful in some cases.

Insights into the dosimetric and geometric characteristics of stereotactic radiosurgery for multiple brain metastases: A systematic review.

GammaKnife (GK) and CyberKnife (CK) have been the mainstay stereotactic radiosurgery (SRS) solution for multiple brain metastases (MBM) for several years. Recent technological advancement has seen an increase in single-isocentre C-arm linac-based SRS. This systematic review focuses on dosimetric and geometric insights into contemporary MBM SRS and thereby establish if linac-based SRS has matured to match the mainstay SRS delivery systems. The PubMed, Web of Science and Scopus databases were interrogated which yielded 891 relevant articles that narrowed to 20 articles after removing duplicates and applying the inclusion and exclusion criteria. Primary studies which reported the use of SRS for treatment of MBM SRS and reported the technical aspects including dosimetry were included. The review was limited to English language publications from January 2015 to August 2023. Only full-length papers were included in the final analysis. Opinion papers, commentary pieces, letters to the editor, abstracts, conference proceedings and editorials were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. The reporting of conformity indices (CI) and gradient indices, V12Gy, monitor units and the impact of translational and rotational shifts were extracted and analysed. The single-isocentre technique for MBM dominated recent SRS studies and the most studied delivery platforms were Varian. The C-arm linac-based SRS plan quality and normal brain tissue sparing was comparable to GK and CK and in some cases better. The most used nominal beam energy was 6FFF, and optimised couch and collimator angles could reduce mean normal brain dose by 11.3%. Reduction in volume of the healthy brain receiving a certain dose was dependent on the number and size of the metastases and the relative geometric location. GK and CK required 4.5-8.4 times treatment time compared with linac-based SRS. Rotational shifts caused larger changes in CI in C-arm linac-based single-isocentre SRS. C-arm linac-based SRS produced comparable MBM plan quality and the delivery is notably shorter compared to GK and CK SRS.

A retrospective cohort study of stereotactic radiosurgery for vestibular schwannomas: Comparison of two age groups (75 years or older vs. 65-74 years).

Treatment outcome data of stereotactic radiosurgery (SRS) for vestibular schwannomas (VS) in patients ≥75 years (late elderly) are lacking. Approximately 39% of patients ≥75 years with VS were reported to experience severe facial palsy after surgical removal. This study compared the treatment outcomes post-SRS for VS between patients ≥75 and 65-74 years (early elderly). Of 453 patients who underwent gamma knife SRS for VS, 156 were ≥65 years old. The late and early elderly groups comprised 35 and 121 patients, respectively. The median tumor volume was 4.4 cc, and the median radiation dose was 12.0 Gy. The median follow-up periods were 37 and 56 months in the late and early elderly groups, respectively. Tumor volume control was observed in 27 (88%) and 95 (83%) patients (P = 0.78), while additional procedures were required in 2 (6%) and 6 (6%) patients (P = 1.00) in the late and early elderly groups, respectively. At the 60th and 120th months post-SRS, the cumulative tumor control rates were 87%, 75%, 85%, and 73% (P = 0.81), while the cumulative clinical control rates were 93% and 87%, 95%, and 89% (P = 0.80), in the late and early elderly groups, respectively. In the early elderly group, two patients experienced facial pain, and one experienced facial palsy post-SRS; there were no adverse effects in the late elderly group (both P = 1.00). SRS is effective for VS and beneficial in patients ≥75 years old as it preserves the facial nerve.

Advocacy for Epilepsy Surgery in Africa: Moroccan Experience of 132 Cases

In Africa, epilepsy is a real burden. Temporal lobe epilepsy is the most common drug-resistant focal epilepsy disorder, and temporal lobectomy are the most common effective treatment on patients with drug-resistant epilepsy. We aim to highlight the Moroccan experience in epilepsy surgery and to ascertain its long-term outcome. Through the results of surgical treatment in our series, we expect to raise awareness of the need of epilepsy surgery in Africa and contribute to its development. We present a retrospective study of 132 patients who underwent surgery for epilepsy from January 2005 to December 2021 at our institution. The presurgical evaluation was based on clinical screening, interictal EEG, VEEG, neuropsychological tests, MRI and Pet Scan in some cases. Data are presented as the median and ranges. For all analyses, P-values < 0.05 were considered statistically significant. Our series includes 132 patients (69 males, 52.27%), median age at surgery was 24 years (range: 1-64). One hundred -fifteen patients (87%) were operated for temporal lobe epilepsy, among them, 98 (85%) had anterior temporal lobectomy, and 17 (15%) had a lesionectomy. Seventeen patients (13%) were operated for extratemporal epilepsy, among them, 4 had lesionectomy, 7 functional hemispherotomy, and 5 patients had Gamma Knife Stereotactic Radiosurgery. Our postoperative outcomes 3 months after surgery found 113 patients (85.6%), seizure-free (Engel I), 16 Engel II (12.1%), and 3 Engel III (2.3 %) in temporal lobe epilepsy. In extratemporal lobe epilepsy, 12 (70.5%) were Engel I, seizure-free, 4 Engel II (23.5%) and 1 Engel III (6%). These results confirm that a majority of patients with drug-resistant epilepsy may benefit from surgical treatment without submitting to preoperative invasive explorations. This should help develop epilepsy surgery widely in Africa.