Stereotactic Radiosurgery Treatment Research Articles

Pre-operative Stereotactic Radiosurgery for Patients with One to Four Brain Metastases: A Single-Arm Phase 2 Trial Outcome Analysis (NCT03398694)

Abstract 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 pre-operative radiosurgery where the target is well defined may be superior, however, the efficacy of pre-operative SRS has not yet been tested in a clinical trial. Methods We conducted a phase II, single-arm trial of pre-operative 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 gamma knife or linear accelerator as per RTOG-9005 dosing criteria24 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, primary endpoint of 6-month LC was 100% (95% CI: 0.891-1.000; p=0.005). 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 pre-operative SRS when compared to historical controls. Further study with a larger randomized cohort of patients is warranted to fully understand the benefits of pre-operative SRS.

Improving the efficiency of single-isocenter multiple metastases stereotactic radiosurgery treatment

PurposeMultiple brain metastases can be treated efficiently with Stereotactic Radio Surgery (SRS) using a Single Isocenter Dynamic Conformal Arc (SIDCA) technique. Currently plans are manually optimized, which may lead to unnecessary table angles and arcs being used. This study aimed to evaluate an automatic 4π-optimization SIDCA algorithm for treatment efficiency and plan quality.Methods and MaterialsAutomatic 4π-optimized SIDCA plans were created and compared to the manually optimized clinical plans for 54 patients who received single-fraction SRS to 2-10 metastases. The number of table angles and arcs were compared with a paired t-test using a Bonferroni-corrected significance level of p<0.05/4=0.0125. The reduction in treatment time was estimated from the difference in the number of table angles and arcs. Plan quality was assessed through the volume-averaged inverse Paddick Conformity Index (CI) and Gradient Index (GI), and the volume of normal brain surrounding each metastasis receiving 12 Gy (local V12 Gy). For a five-patient subset the automatic plans were manually adjusted further. CI and GI were assessed for non-inferiority using a one-sided t-test with the non-inferiority limit equal to the 95% inter-observer reproducibility limit from a separate planning study (corrected significance level p<0.05/(4−1)=0.017).ResultsThe automatic plans significantly improved treatment efficiency with a mean reduction in the number of table angles and arcs of −0.5±0.1 and −1.3±0.2 respectively (± standard error, both p<0.001). Estimated treatment time saving was −2.7±0.5minutes, 14% of the total. The volume-averaged CI and GI were non-inferior to the clinical plans (both p<0.001), although there was a small systematic shift in CI of 0.07±0.01. The resulting difference in local V12 Gy, 0.25±0.04cm3, was not clinically significant. Minor manual adjustment of the automatic plans removed these slight differences whilst preserving the improved treatment efficiency.ConclusionsAutomatic 4π-optimization can generate SIDCA SRS plans with improved treatment efficiency and non-inferior plan quality.

Stereotactic radiosurgery for brain metastasis from cholangiocarcinoma.

Accounting for approximately 15% of primary liver cancers and 3% of gastrointestinal malignancies, cholangiocarcinoma (CCA) poses a serious health concern given its high mortality rate. Managing brain metastases (BMs) from CCA is challenging because of their rarity and poor prognosis, with little guidance on treatment from the literature. In this study, the authors aimed to evaluate the safety and efficacy of stereotactic radiosurgery (SRS) in managing BMs from CCA. This multicenter retrospective study included 13 CCA patients with 41 BMs treated with SRS from October 2006 to April 2022 at eight institutions affiliated with the International Radiosurgery Research Foundation. Inclusion criteria were a CCA diagnosis, an age over 18 years, no other malignancies, single-fraction SRS treatment for BMs, and at least one follow-up image. Data on demographics, tumor characteristics, treatment details, and outcomes were collected. The primary endpoints were local control (LC), intracranial progression-free survival (PFS), and overall survival (OS). The secondary endpoint was the development of adverse radiation effects (AREs). The median radiological follow-up was 5 months (range 1-18 months). At the last follow-up, LC was achieved in 39 (95.1%) of 41 BMs. New distant metastases were observed in 3 patients (23.1%), and the mean intracranial PFS was 9.4 months (95% CI 6.5-12.3 months). Six-month and 1-year OS rates were 38.5% and 11.5%, respectively, and the median OS was 6 months (95% CI 4.9-7.2 months). Concurrent immunotherapy was associated with a high risk of local failure (HR 29.665, 95% CI 1.799-489.206, p = 0.018), and the absence of systemic chemotherapy before SRS was linked to reduced OS (HR 6.658, 95% CI 1.173-37.776, p = 0.032). Regarding AREs, only 1 patient (7.7%) experienced right hemiparesis and was treated with corticosteroid therapy. SRS is an effective option for managing BMs in CCA patients, showing promise in LC and a high safety profile.

SRTRP-Net: A multi-task learning network for segmentation and prediction of stereotactic radiosurgery treatment response in brain metastases

Before the Stereotactic Radiosurgery (SRS) treatment, it is of great clinical significance to avoid secondary genetic damage and guide the personalized treatment plans for patients with brain metastases (BM) by predicting the response to SRS treatment of brain metastatic lesions. Thus, we developed a multi-task learning model termed SRTRP-Net to provide prior knowledge of BM ROI and predict the SRS treatment response of the lesion. In dual-encoder tumor segmentation Network (DTS-Net), two parallel encoders encode the original and mirrored multi-modal MRI images. The differences in the dual-encoder features between foreground and background are enhanced by the symmetrical visual difference block (SVDB). In the bottom layer of the encoder, a transformer is used to extract local contextual features in the spatial and depth dimensions of low-resolution images. Then, the decoder of DTS-Net provides the prior knowledge for predicting the response to SRS treatment by performing BM segmentation. SRS response prediction network (SRP-Net) directly utilizes shared multi-modal MRI features weighted by the signed distance map (SDM) of the masks. The bidirectional multi-dimensional feature fusion module (BMDF) fuses the shared features and the clinical text information features to obtain comprehensive tumor information for characterizing tumors and predicting SRS treatment response. Experiments based on internal and external clinical datasets have shown that SRTRP-Net achieves comparable or better results. We believe that SRTRP-Net can help clinicians accurately develop personalized first-time treatment regimens for BM patients and improve their survival.

Comparison of Repeat Versus Initial Stereotactic Radiosurgery for Intracranial Arteriovenous Malformations: A Retrospective Multicenter Matched Cohort Study

BACKGROUND AND OBJECTIVES: Studies comparing neurological and radiographic outcomes of repeat to initial stereotactic radiosurgery (SRS) intracranial arteriovenous malformations are scarce. Our aim was to perform a retrospective matched comparison of patients initially treated with SRS with those undergoing a second radiosurgical procedure. METHODS: We collected data from arteriovenous malformations managed in 21 centers that underwent initial and repeated radiosurgery from 1987 to 2022. Based on arteriovenous malformations volume, margin dose, deep venous drainage, deep, and critical location, we matched 1:1 patients who underwent an initial SRS for treatment-naive arteriovenous malformations and a group with repeated SRS treatment. RESULTS: After the selection process, our sample consisted of 328 patients in each group. Obliteration in the initial SRs group was 35.8% at 3 and 56.7% at 5 years post-SRS, while the repeat SRS group showed obliteration rates of 33.9% at 3 years and 58.6% at 5 years, without statistically significant differences (P = .75 and P = .88, respectively). There were no statistically significant differences between the 2 groups for obliteration rates (hazard ratio = 0.93; 95% CI, 0.77-1.13; P = .5), overall radiation-induced changes (RIC) (OR = 1.1; 95% CI, 0.75-1.6; P = .6), symptomatic RIC (OR = 0.78; 95% CI, 0.4-1.5; P = .4), and post-SRS hemorrhage (OR = 0.68; 95% CI; P = .3). CONCLUSION: In matched cohort analysis, a second SRS provides comparable outcomes in obliteration and RIC compared with the initial SRS. Dose reduction on repeat SRS may not be warranted.

A Population-Based Analysis of Brain Metastasis Burden and Management in 8705 Small Cell Lung Cancer Patients

INTRODUCTION: Patients with small cell lung cancer (SCLC) have historically been characterised by poor overall survival (OS) and high risk for intracranial metastatic disease (IMD), but large-scale real-world evidence on clinical presentation and treatment in this population is lacking. These patients traditionally receive whole brain radiation therapy (WBRT) for IMD, however, a recent systematic review has indicated that OS following stereotactic radiosurgery (SRS) may be non-inferior compared with WBRT. METHODS: We included all patients diagnosed with SCLC between April 2007 and March 2018 identified through a provincial health administrative database. Information on patient and treatment characteristics, incidence and time to IMD, and OS from time of SCLC diagnosis were collected and analyzed using R. RESULTS: A total of 8705 patients were included. Median age was 68 years (range 18-103). Most patients presented with extensive disease (n = 5625) and were diagnosed after 2011 (n = 5768). Patients who received chemotherapy (n = 5563) had significantly longer OS than those who did not (median 10.64 vs 1.58 mo, HR 0.36, 95% CI 0.34-0.37). 6662 patients received brain imaging at the time of primary diagnosis (CT: 5126, MRI: 1536), and 88% of patients surviving longer than 6 mo received more than one follow-up brain scan. 31% developed IMD (synchronous: 1175, asynchronous: 1511) with median intracranial progression-free survival of 5.65 mo. Median OS of patients with IMD was 9.76 mo, 29 and 1300 received SRS and WBRT as first treatment for their IMD, respectively. OS was in favour of SRS over WBRT (median 20.47 vs 8.74 mo, HR 0.57, 95% CI 0.39-0.84), which remained significant in multivariate analysis (p &lt; 0.001). CONCLUSIONS: OS for patients with SCLC remains poor and many patients present with IMD. Some patients with SCLC may benefit from SRS treatment.

Trans-radial cerebral angiography for stereotactic radiosurgery treatment of arteriovenous malformations

ObjectivesThe popularity of trans-radial access (TRA) for cerebral angiography is growing. Potential benefits of TRA over traditional trans-femoral access (TFA) are multitude. This study aimed to evaluate discharge outcomes and patient opinion of TRA compared to TFA in patients undergoing cerebral angiography prior to stereotactic radiosurgery (SRS) treatment for cerebral arteriovenous malformations. MethodsConsecutive patients treated at the ONLY < BLINDED FOR REVIEW>) over a 22-month period were included. All patients underwent cerebral angiography with either TRA or TFA as part of treatment planning prior to SRS. TRA patients who had previously undergone TFA in other centres were surveyed for their experience of cerebral angiography using a questionnaire. SRS staff at our centre were approached for their opinion. Results492 patients were included (median age = 43 years, 57.5% male, median lesions treated = 1). More patients underwent angiography with TFA (75.2%) than TRA (24.8%). No difference was found in accumulated dose for angiography between the groups (p>0.05). There was 17.6% reduction in overnight stay between TRA and TRF, the proportion of patients requiring overnight admission was higher for the TFA (35.2%) than TRA (17.6%, p<0.05). 101 patients were surveyed, with a response rate of 47%. Most respondents (79%) indicated preference for TRA over TFA. ConclusionsUse of TRA in pre-SRS cerebral angiography is feasible and improves both patient and staff experience. The adoption of TRA could have important implications for department resources and costs by reducing the proportion of overnight admissions.

Novel frameless LINAC radiosurgery solution for uveal melanoma.

Radiation treatment has replaced enucleation as an organ-preservation treatment for patients with uveal melanoma (UM). We developed a novel non-invasive, frameless LINAC based solution for fractionated stereotactic radiosurgery (fSRS) treatment. We designed and constructed the a stereotactic ocular localization box that can be attached and indexed to a stereotactic LINAC tabletop. It contains adjustable LED lights as a gaze focus point and CCD camera for monitoring of the patient's eye position. The device also has 6 infrared spheres compatible with the ExacTRAC IGRT system. Treatment plans were developed using iPLAN Dose version 4.5, with conformal dynamic arcs and 6MV photon beam in flattening filter free mode, dosed to 50Gy in 5 fractions. During treatment, patients were instructed to stare at the light when a radiation beam is prepared and ready for delivery. Eye movement was tracked throughout treatment. Residual setup errors were recorded for evaluation. The stereotactic ocular localization box was 3D-printed with polylactic acid material and attached to the stereotactic LINAC tabletop. 10 patients were treated to evaluate the feasibility, tolerability and setup accuracy. Median treatment time for each arc is 17.3 ± 2.4 seconds (range: 13.8-23.4). After ExacTRAC setup, the residual setup errors are -0.1 ± 0.3mm laterally, -0.1 ± 0.3mm longitudinally, and 0 ± 0.2mm vertically. The residue rotational errors are -0.1 ± 0.3 degree pitch, 0.1 ± 0.2 degree roll, and 0 ± 0.2 degree couch rotation. All patients received treatment successfully. We successfully developed a novel non-invasive frameless mask-based LINAC solution for SRS for uveal melanoma, or other ocular tumors. It is well tolerated with high set up accuracy. Future directions for this localization box would include a multi-center trial to assess the efficacy and reproducibility in the fabrication and execution of such a solution for UM therapy.

Abstract 6465: A population-based analysis of brain metastasis burden and management in 8705 small cell lung cancer patients

Abstract Introduction: Patients with small cell lung cancer (SCLC) have historically been characterized by poor overall survival (OS) and high risk for brain metastases (BM), but large-scale real-world evidence on clinical presentation and treatment in this population is lacking. Methods: The aim of this study was to describe the clinical characteristics and outcomes of patients with SCLC and BM in Ontario, Canada. This retrospective cohort study included all patients in Ontario, Canada, who were diagnosed with SCLC between April 2010 and March 2018. Data were analyzed between June 2022 and July 2023. Kaplan-Meier and multivariable Cox regression analyses were performed to compare overall survival (OS) between patient cohorts stratified by disease stage, BM diagnosis, or first-line intracranial treatment modality. Results: 8705 patients were included. Median age at diagnosis was 68 years (range 18-103). Median OS of all patients was 7.46 months (95% confidence interval, CI, 7.23-7.69). 32% (n=2686) of patients developed BM (synchronous, 43.7%; asynchronous, 56.3%) and had median OS of 9.76 months (95% CI, 9.36-10.22). 102, 1654, and 880 patients received stereotactic radiosurgery (SRS), whole brain radiation therapy (WBRT), and no treatment, respectively, for their BM in the first-line setting or after prophylactic cranial irradiation (PCI). In propensity score-matched analyses, OS was equivocal between SRS- and WBRT-treated cohorts among patients who did not receive PCI (hazard ratio, HR, 1.18, 95% CI, 0.75-1.81) and those who received PCI prior to BM development (HR, 0.77, 95% CI, 0.53-1.13). Conclusions: Survival for patients with SCLC remains poor, and many patients present with BMs. With careful selection, patients with SCLC may benefit from SRS treatment. Citation Format: Karolina Gaebe, Anders W. Erickson, Sarah Chen, Arjun Sahgal, Benjamin H. Lok, Kelvin K. Chan, Sunit Das. A population-based analysis of brain metastasis burden and management in 8705 small cell lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6465.

Long-term survival in patients with brain-only metastatic non-small cell lung cancer undergoing upfront intracranial stereotactic radiosurgery and definitive treatment to the thoracic primary site

Background and purposeTo evaluate modern clinical outcomes for patients with brain-only metastatic non-small cell lung cancer (NSCLC) treated with intracranial stereotactic radiosurgery (SRS) with or without definitive treatment of the primary site. Materials and methodsPatients with synchronously diagnosed NSCLC and brain-only metastatic disease treated with intracranial SRS at a single institution were retrospectively identified. Patients were stratified based on whether they did (A) or did not (B) receive definitive primary site treatment. Patient characteristics and clinical outcomes were compared. ResultsFrom 2008 to 2022, 103 patients were identified, 53 of whom received definitive primary site treatment. Median follow-up was 2.1 y (A) and 0.8 y (B) (p < 0.001). 28 (53 %) patients in Group A received immune checkpoint inhibitor (ICI) therapy versus 19 (38 %) in Group B (p = 0.13) and there were no other statistically significant baseline or treatment characteristic differences between the groups. 5-year local-PFS was 34.5 % (A) versus 0 % (B) (p < 0.001). 5-year regional-PFS was 33.0 % (A) versus 0 % (B) (p < 0.001). 5-year distant body-PFS was 34.0 % (A) versus 0 % (B) (p < 0.001). 5-year CNS-PFS was 14.7 % (A) versus 0 % (B) (p = 0.12). 5-year OS was 40.2 % (A) versus 0 % (B) (p = 0.001). 5-year CSS was 67.6 % (A) versus 0 % (B) (p = 0.002). On multivariable analysis, lack of definitive treatment to the primary site (HR = 2.40), AJCC T3-4 disease (HR = 2.73), and lack of ICI therapy (HR = 2.86) were significant predictors of death. ConclusionDefinitive treatment to the thoracic primary site in patients with brain-only metastatic NSCLC after intracranial radiosurgery was associated with slower progression of disease and improved survival.

Radiotherapy Hyperfractionated 3DIsodosezones Planning Optimization Method forLung Tumors withBED Pareto-Multiobjective Model

3D Isodoselines and Isodosezones were presented in previous publication. Isodosezones were put out and applied on prostate tumors. In this further improvement, 3D Isodosezones are got with programming innovation with new software-engineering programming for lung cancer. BED model for radiotherapy hypofractionated treatment planning optimization is used. Interior Optimization (IO) for lung tumor BED model hyperfractionated Treatment Planning Optimization (TPO) application is further demonstrated. The implemented data was got with additional-dual constrained evolutionary algorithm for BED-LQ model (Biological Effective Dose) in this cancer type. Results for TPO with 3D IO-Graphical Optimization show a number of surfactal IO 3D Isodoselines/zones with proven accuracy-feasibility of the novelty of the technique. Programming software for surfactal-isodoselines/zones methods solutions show a series of 3D IO graphs for TPO. Applications for lung tumors radiotherapy and stereotactic radiosurgery treatments are briefed.

Stereotactic radiosurgery for brain metastases arising from gynecological malignancies: A retrospective treatment outcome analysis

BackgroundThis retrospective study aims to assess the efficacy of stereotactic radiosurgery (SRS) in the treatment of brain metastases (BM) originating from gynecological cancers. It focuses on local control (LC), distant tumor control (DTC), and overall survival (OS). MethodsThe analysis comprised 18 individuals with gynecological-origin BM treated with SRS at the Hadassah Medical Center from 2004 to 2021. Statistical analyses evaluate factors impacting LC, DTC, and OS. ResultsA total of 36 BM of gynecological origin underwent SRS. The median age at the first SRS treatment was 60 years, with a median time of 24.5 months from the primary malignancy diagnosis to BM detection. The 12-month LC rate per patient was 84.6 %, and 5.6 % per BM. Only two instances of local recurrence were observed. The DTC at 12 months was 75 %, with a 29 % overall. Non-significant trends indicating a correlation with distant brain failure with increased cumulative volume and the occurrence of craniotomy before SRS. The median OS of the cohort was 16.5 months from SRS treatment. The 6, 12, 18, and 24-month survival rates were 77.8 %, 66.7 %, 50 %, and 22.2 % respectively. Higher number of BM was associated with lower OS (p = 0.046). On multivariate analysis, age was a significant factor for OS (p = 0.03), demonstrating that older age was associated with a more favorable prognosis. ConclusionThis study supports SRS effectiveness for treating BM from gynecological cancers and suggests similar outcomes to more common malignancies.

Adjuvant Stereotactic Radiosurgery for Clear Cell Meningiomas

ObjectiveClear cell meningiomas (CCM) are an uncommon meningioma subtype marked by aggressive growth and high rates of recurrence despite initial resection. The present study evaluates the adjuvant benefit of stereotactic radiosurgery (SRS) for residual or recurrent tumors. MethodsAfter review of our prospectively maintained data base, we identified 6 patients (3 female) with histologically confirmed Grade 2 CCMs. The median age of the patients at the time of SRS was 45 years. Five patients had undergone prior gross total surgical resection and 1 patient had subtotal resection before SRS. The median SRS treatment volume was 4.7 cc and the median radiosurgical margin dose was 13 Gy (range: 10 – 15 Gy). ResultsThe median follow-up time was 35.5 months (range 6 – 168 months). Three patients achieved tumor control after the first SRS procedure. Three patients experienced tumor progression at 4, 22, and 32 months after initial SRS. Tumor control was obtained in 2 of these patients after additional SRS. One patient with multiple SRS procedures had suspected adverse radiation effect that was successfully treated with corticosteroids followed by bevacizumab. ConclusionsTumor control was maintained in 5 of 6 patients after one or more SRS procedures. SRS should be considered for early intervention after surgical resection of CCM. To maximize the tumor control rate, patients with diagnosed CCM should be treated more generously and higher margin dose should be prescribed. Patients with CCM should be counselled that more than one SRS may be necessary to provide sustained tumor control.

Incidence and imaging characteristics of difficult to detect retrospectively identified brain metastases in patients receiving repeat courses of stereotactic radiosurgery.

During stereotactic radiosurgery (SRS) planning for brain metastases (BM), brain MRIs are reviewed to select appropriate targets based on radiographic characteristics. Some BM are difficult to detect and/or definitively identify and may go untreated initially, only to become apparent on future imaging. We hypothesized that in patients receiving multiple courses of SRS, reviewing the initial planning MRI would reveal early evidence of lesions that developed into metastases requiring SRS. Patients undergoing two or more courses of SRS to BM within 6months between 2016 and 2018 were included in this single-institution, retrospective study. Brain MRIs from the initial course were reviewed for lesions at the same location as subsequently treated metastases; if present, this lesion was classified as a "retrospectively identified metastasis" or RIM. RIMs were subcategorized as meeting or not meeting diagnostic imaging criteria for BM (+ DC or -DC, respectively). Among 683 patients undergoing 923 SRS courses, 98 patients met inclusion criteria. There were 115 repeat courses of SRS, with 345 treated metastases in the subsequent course, 128 of which were associated with RIMs found in a prior MRI. 58% of RIMs were + DC. 17 (15%) of subsequent courses consisted solely of metastases associated with + DC RIMs. Radiographic evidence of brain metastases requiring future treatment was occasionally present on brain MRIs from prior SRS treatments. Most RIMs were + DC, and some subsequent SRS courses treated only + DC RIMs. These findings suggest enhanced BM detection might enable earlier treatment and reduce the need for additional SRS.

Plan quality assessment of modern radiosurgery technologies in the treatment of multiple brain metastases

Stereotactic radiosurgery (SRS) of multiple brain metastases has evolved over the last 40 years allowing centres to treat an increasing number of brain metastases in a single treatment fraction. HyperArcTM planning optimisation technique is one such development that streamlines the treatment of multiple metastases with a single isocentre. Several studies have investigated the plan quality of HyperArc compared to CyberKnife or Gamma Knife, however there are limited number of studies that include all three modalities. It is the aim of this study to provide an assessment of plan quality between the three SRS platforms across ten patients with multiple brain metastases ranging from three to eight metastases per patient. Strict planning workflows were established to avoid bias towards any particular treatment platform. Plan quality was assessed through dose to organs at risk, Paddick conformity index (PCI), gradient index (GI), global efficiency index (Gη) and dose to normal brain tissue. Results from this study found mean PCI observed across Gamma Knife plans was significantly lower than HyperArc and CyberKnife. HyperArc plans observed significantly shorter beam-on times which were 10 to 20 times faster than CyberKnife and Gamma Knife plans. Gamma Knife and CyberKnife were found to produce plans with significantly superior GI, global efficiency index and the volume of healthy brain receiving greater than 12 Gy (V12Gy) when compared to HyperArc plans. Lesion volume was seen to influence the relative difference in dose metrics between systems. The study revealed that all three treatment modalities produced high quality plans for the SRS treatment of multiple brain metastases, each with respective benefits and limitations.

Two is better than one: longitudinal detection and volumetric evaluation of brain metastases after Stereotactic Radiosurgery with a deep learning pipeline.

Close MRI surveillance of patients with brain metastases following Stereotactic Radiosurgery (SRS) treatment is essential for assessing treatment response and the current disease status in the brain. This follow-up necessitates the comparison of target lesion sizes in pre- (prior) and post-SRS treatment (current) T1W-Gad MRI scans. Our aim was to evaluate SimU-Net, a novel deep-learning model for the detection and volumetric analysis of brain metastases and their temporal changes in paired prior and current scans. SimU-Net is a simultaneous multi-channel 3D U-Net model trained on pairs of registered prior and current scans of a patient. We evaluated its performance on 271 pairs of T1W-Gad MRI scans from 226 patients who underwent SRS. An expert oncological neurosurgeon manually delineated 1,889 brain metastases in all the MRI scans (1,368 with diameters > 5mm, 834 > 10mm). The SimU-Net model was trained/validated on 205 pairs from 169 patients (1,360 metastases) and tested on 66 pairs from 57 patients (529 metastases). The results were then compared to the ground truth delineations. SimU-Net yielded a mean (std) detection precision and recall of 1.00±0.00 and 0.99±0.06 for metastases > 10mm, 0.90±0.22 and 0.97±0.12 for metastases > 5mm of, and 0.76±0.27 and 0.94±0.16 for metastases of all sizes. It improves lesion detection precision by 8% for all metastases sizes and by 12.5% for metastases < 10mm with respect to standalone 3D U-Net. The segmentation Dice scores were 0.90±0.10, 0.89±0.10 and 0.89±0.10 for the above metastases sizes, all above the observer variability of 0.80±0.13. Automated detection and volumetric quantification of brain metastases following SRS have the potential to enhance the assessment of treatment response and alleviate the clinician workload.

Trigeminal neuralgia pain outcomes following microsurgical resection versus stereotactic radiosurgery for petroclival meningiomas: a systematic review and meta-analysis.

Petroclival meningiomas (PCMs) are challenging lesions to treat because of their deep location and proximity to critical neurovascular structures. Patients with these lesions commonly present because of local mass effect. A symptom that proves challenging to definitively manage is trigeminal neuralgia (TN), which occurs in approximately 5% of PCM cases. To date, there is no consensus on whether microsurgical resection or stereotactic radiosurgery (SRS) leads to better outcomes in the treatment of TN secondary to PCM. In this systematic review and meta-analysis, the authors aimed to evaluate the available literature on the efficacy of microsurgical resection versus SRS for controlling TN secondary to PCM. The Embase, MEDLINE, Scopus, and Cochrane databases were queried from database inception to May 17, 2022, using the search terms "(petroclival AND meningioma) AND (trigeminal AND neuralgia)." Study inclusion criteria were as follows: 1) reports on patients aged ≥ 18 years and diagnosed with TN secondary to PCM, 2) cases treated with microsurgical resection or SRS, 3) cases with at least one posttreatment follow-up report of TN pain, 4) cases with at least one outcome of tumor control, and 5) publications describing randomized controlled trials, comparative or single-arm observational studies, case reports, or case series. Exclusion criteria were 1) literature reviews, technical notes, conference abstracts, or autopsy reports; 2) publications that did not clearly differentiate data on patients with PCMs from data on patients with different tumors or with meningiomas in different locations (other intracranial or spinal meningiomas); 3) publications that contained insufficient data on treatments and outcomes; and 4) publications not written in the English language. References of eligible studies were screened to retrieve additional relevant studies. Data on pain and tumor outcomes were compared between the microsurgical resection and SRS treatment groups. The DerSimonian-Laird random-effects model with Hartung-Knapp-Sidik-Jonkman variance correction was used to pool estimates from the included studies. Two comparative observational studies and 6 single-arm observational studies describing outcomes after primary intervention were included in the analyses (138 patients). Fifty-seven patients underwent microsurgical resection and 81 underwent SRS for the management of TN secondary to PCM. By the last follow-up (mean 71 months, range 24-149 months), the resection group had significantly higher rates of pain resolution than the SRS group (82%, 95% CI 50%-100% vs 31%, 95% CI 18%-45%, respectively; p = 0.004). There was also a significantly longer median time to tumor recurrence following resection (43.75 vs 16.7 months, p < 0.01). The resection group showed lower rates of pain persistence (0%, 95% CI 0%-6% vs 25%, 95% CI 13%-39%, p = 0.001) and pain exacerbation (0% vs 12%, 95% CI 3%-23%, p = 0.001). The most common postintervention Barrow Neurological Institute pain score in the surgical group was I (66.7%) compared with III (27.2%) in the SRS group. Surgical reintervention was less frequently required following primary resection (1.8%, 95% CI 0%-37% vs 19%, 95% CI 1%-48%, p < 0.01). Microsurgical resection is associated with higher rates of TN pain resolution and lower rates of pain persistence and exacerbation than SRS in the treatment of PCM. SRS with further TN management is a viable alternative in patients who are not good candidates for microsurgical resection.

Analysis of upfront resection or stereotactic radiosurgery for local control of solid and cystic cerebellar hemangioblastomas.

The purpose of this study was to identify rates of and risk factors for local tumor progression in patients who had undergone surgery or radiosurgery for the management of cerebellar hemangioblastoma and to describe treatments pursued following tumor progression. The authors conducted a retrospective single-center review of patients who had undergone treatment of a cerebellar hemangioblastoma with either surgery or stereotactic radiosurgery (SRS) between 1996 and 2019. Univariate and multivariate regression analyses were performed to examine factors associated with local tumor control. One hundred nine patients met the study inclusion criteria. Overall, these patients had a total of 577 hemangioblastomas, 229 of which were located in the cerebellum. The surgical and SRS cohorts consisted of 106 and 123 cerebellar hemangioblastomas, respectively. For patients undergoing surgery, tumors were treated with subtotal resection and gross-total resection in 5.7% and 94.3% of cases, respectively. For patients receiving SRS, the mean target volume was 0.71 cm3 and the mean margin dose was 18.0 Gy. Five-year freedom from lesion progression for the surgical and SRS groups was 99% and 82%, respectively. The surgical and SRS cohorts contained 32% versus 97% von Hippel-Lindau tumors, 78% versus 7% cystic hemangioblastomas, and 12.8- versus 0.56-cm3 mean tumor volumes, respectively. On multivariate analysis, factors associated with local tumor progression in the SRS group included older patient age (HR 1.06, 95% CI 1.03-1.09, p < 0.001) and a cystic component (HR 9.0, 95% CI 2.03-32.0, p = 0.001). Repeat SRS as salvage therapy was used more often for smaller tumor recurrences, and no tumor recurrences of < 1.0 cm3 required additional salvage surgery following repeat SRS. Both surgery and SRS achieve high rates of local control of hemangioblastomas. Age and cystic features are associated with local progression after SRS treatment for cerebellar hemangioblastomas. In cases of local tumor recurrence, salvage surgery and repeat SRS are valid forms of treatment to achieve local tumor control, although resection may be preferable for larger recurrences.

Evaluation of improvements in plan quality with Photon Optimizer v16.1 for single brain lesion SRS treatment.

The purpose of this study is to compare the performance of the Photon Optimizer (PO) version 16.1 algorithm with its earlier version PO v13.6 and with Progressive Resolution Optimizer (PRO) version 13.6 algorithms. 20 patients with single brain lesions treated with the stereotactic radiosurgery (SRS) technique were retrospectively selected for this study. Initially, for all patients volumetric modulated arc therapy (VMAT) SRS plans were generated with the PRO v 13.6 algorithm. Then, all the plans were re-generated with two versions 13.6 and 16.1 of PO algorithm using the same setup and dose-volume optimization objectives as that of PRO with a similar planning approach. The quality of the generated plans was analysed using ICRU 91 plan evaluation parameters and also using dice similarity co-efficient (DSC), centre of mass distance (CMD) between target and prescription isodose line, Monitor units (MU) and brain-gross tumor volume (GTV) 12 Gy volume. Paired Student t-test was used for statistical analysis with 0.05 as a significant value. PO v16.1 improved all the dosimetric parameters studied compared to PO 13.6, the difference is statistically significant for all the parameters (p < 0.05), except for median dose and brain-GTV 12 Gy volume. PO v16.1 also showed statistically significant improvement for all the dosimetric parameters evaluated, except DSC and conformity index (CI), compared to PRO v13.6. The PO v16.1 generated plans are dosimetrically superior to PO v13.6 and PRO v13.6 in terms of target dose coverage and dose gradient with lesser beam modulation and plan complexity for single brain lesion SRS.

Artificial-intelligence-driven measurements of brain metastases'response to SRS compare favorably with current manual standards of assessment.

Evaluation of treatment response for brain metastases (BMs) following stereotactic radiosurgery (SRS) becomes complex as the number of treated BMs increases. This study uses artificial intelligence (AI) to track BMs after SRS and validates its output compared with manual measurements. Patients with BMs who received at least one course of SRS and followed up with MRI scans were retrospectively identified. A tool for automated detection, segmentation, and tracking of intracranial metastases on longitudinal imaging, MEtastasis Tracking with Repeated Observations (METRO), was applied to the dataset. The longest three-dimensional (3D) diameter identified with METRO was compared with manual measurements of maximum axial BM diameter, and their correlation was analyzed. Change in size of the measured BM identified with METRO after SRS treatment was used to classify BMs as responding, or not responding, to treatment, and its accuracy was determined relative to manual measurements. From 71 patients, 176 BMs were identified and measured with METRO and manual methods. Based on a one-to-one correlation analysis, the correlation coefficient was R2 = 0.76 (P = .0001). Using modified BM response classifications of BM change in size, the longest 3D diameter data identified with METRO had a sensitivity of 0.72 and a specificity of 0.95 in identifying lesions that responded to SRS, when using manual axial diameter measurements as the ground truth. Using AI to automatically measure and track BM volumes following SRS treatment, this study showed a strong correlation between AI-driven measurements and the current clinically used method: manual axial diameter measurements.