An Exploratory Analysis of the Conditional Neurocognitive Function Failure Risk in Patients Receiving Whole Brain Radiotherapy for Brain Metastases on NRG Oncology CC001: Conditional Neurocognitive Toxicity Risk.

PURPOSE: We sought to estimate the conditional risk of development of neurocognitive function failure (NCFF) after whole brain radiotherapy (WBRT) for patients with brain metastases (BM) on NRG Oncology CC001. In addition, we aimed to determine if factors prognostic of NCFF at time of treatment remained relevant over time. MATERIALS/METHODS: We performed a post hoc analysis of 518 patients enrolled on NRG CC001 in which patients with BM were randomly assigned to WBRT + memantine or hippocampal-avoidant (HA-WBRT) + memantine. Life table method was used to calculate conditional monthly hazard rates and cumulative incidence was used to estimate rates of NCFF. Risk factors associated with NCFF were analyzed using cause-specific multivariable Cox proportional hazards modeling. RESULTS: The cumulative risk of development of NCFF by 6 months was 64.0% for the entire cohort. The greatest conditional monthly hazard rate of development of neurocognitive toxicity was 2-3 months post radiation (0.97, 95% CI 0.85-1.10); this rate significantly declined and then plateaued to 0.036 (95% CI: 0-0.11) by 8 months post treatment. For 2-month survivorship without cognitive failure, HA-WBRT (HR 0.74, P=0.033) and age ≤ 61 (HR 0.62, P=0.003) continued to be protective against cognitive toxicity. In addition, conditional cumulative incidence of development of NCFF was significantly reduced with HA techniques for patients living ≥ 2 months free of cognitive dysfunction (P=0.047). CONCLUSIONS: Our data highlight that the greatest risk for development of neurocognitive toxicity is within the first 3 months after treatment, and therefore strategies to mitigate toxicities should focus on this initial period. Moreover, the conditional risk of neurocognitive impairment significantly declines the longer patients live with preserved cognition. Importantly, these data can be used to inform patients on how their risks of development of NCFF can change over time.

Stereotactic Radiosurgery for 1-10 Brain Metastases to avoid Whole-Brain Radiotherapy - Results of the CYBER-SPACE Randomized Phase 2 Trial.

BACKGROUND: Stereotactic Radiosurgery (SRS) is an emerging alternative to whole-brain radiotherapy (WBRT) for treating multiple brain metastases (BM), reducing toxicity and improving tumor control. The CYBER-SPACE trial compared SRS based on either SPACE or MPRAGE MRI sequence for avoiding or delaying WBRT in patients with 1-10 BM. METHODS: Patients with 1-10 untreated BM were randomized 1:1 to receive SRS of all lesions based on either SPACE or MPRAGE MRI sequences. If subsequently new BM occurred, SRS was repeated. WBRT was indicated upon occurrence of >10 new BM, leptomeningeal disease or exhausted SRS-radiotolerance. The primary outcome was freedom from WBRT indication (WBRTi). Secondary outcomes included overall survival (OS), safety, and quality of life. RESULTS: 202 patients were randomized; SPACE n=99, MPRAGE n=103. 12-month WBRTi-free survival was 77.1% (95%-CI: 69.5%-83.1%) overall, 78.5% (95%-CI: 66.7%-86.5%) for SPACE, and 76.0% (95%-CI: 65.2%-83.9%) for MPRAGE (HR=0.84, 95%-CI: 0.43-1.63, p=0.590). Patients with 5-10 BM had shorter WBRTi-free survival (HR=3.13, 95%-CI: 1.53-6.40, p=0.002). Median OS was 13.1 months overall, 10.5 months for SPACE, and 15.2 months for MPRAGE (HR=1.10, 95%-CI: 0.78-1.56, p=0.585). Neurologic death rate was 10.1%. Predictors for longer OS included Karnofsky Performance Status >80% (HR=0.51, 95%-CI: 0.33-0.77, p=0.002) and concurrent immunotherapy (HR=0.34, 95%-CI: 0.23-0.52, p<0.001). CONCLUSIONS: The more sensitive SPACE sequence did not improve outcomes over MPRAGE. SRS with thorough monitoring and immediate re-treatment for new lesions decreases the need for WBRT and achieves low neurologic death rates. SRS should be considered a favorable alternative to WBRT for patients with 1-10 BM.

Enhancing Hierarchical Transformers for Whole Brain Segmentation with Intracranial Measurements Integration.

Whole brain segmentation with magnetic resonance imaging (MRI) enables the non-invasive measurement of brain regions, including total intracranial volume (TICV) and posterior fossa volume (PFV). Enhancing the existing whole brain segmentation methodology to incorporate intracranial measurements offers a heightened level of comprehensiveness in the analysis of brain structures. Despite its potential, the task of generalizing deep learning techniques for intracranial measurements faces data availability constraints due to limited manually annotated atlases encompassing whole brain and TICV/PFV labels. In this paper, we enhancing the hierarchical transformer UNesT for whole brain segmentation to achieve segmenting whole brain with 133 classes and TICV/PFV simultaneously. To address the problem of data scarcity, the model is first pretrained on 4859 T1-weighted (T1w) 3D volumes sourced from 8 different sites. These volumes are processed through a multi-atlas segmentation pipeline for label generation, while TICV/PFV labels are unavailable. Subsequently, the model is finetuned with 45 T1w 3D volumes from Open Access Series Imaging Studies (OASIS) where both 133 whole brain classes and TICV/PFV labels are available. We evaluate our method with Dice similarity coefficients(DSC). We show that our model is able to conduct precise TICV/PFV estimation while maintaining the 132 brain regions performance at a comparable level. Code and trained model are available at: https://github.com/MASILab/UNesT/wholebrainSeg.

Mapping functional traces of opioid memories in the rat brain.

Addiction to psychoactive substances is a maladaptive learned behaviour. Contexts surrounding drug use integrate this aberrant mnemonic process and hold strong relapse-triggering ability. Here, we asked where context and salience might be concurrently represented in the brain during retrieval of drug-context paired associations. For this, we developed a morphine-conditioned place preference protocol that allows contextual stimuli presentation inside a magnetic resonance imaging scanner and investigated differences in activity and connectivity at context recall. We found context-specific responses to stimulus onset in multiple brain regions, namely, limbic, sensory and striatal. Differences in functional interconnectivity were found among amygdala, lateral habenula, and lateral septum. We also investigated alterations to resting-state functional connectivity and found increased centrality of the lateral septum in a proposed limbic network, as well as increased functional connectivity of the lateral habenula and hippocampal 'cornu ammonis' 1 region, after a protocol of associative drug-context. Finally, we found that pre- conditioned place preference resting-state connectivity of the lateral habenula and amygdala was predictive of inter-individual conditioned place preference score differences. Overall, our findings show that drug and saline-paired contexts establish distinct memory traces in overlapping functional brain microcircuits and that intrinsic connectivity of the habenula, septum, and amygdala likely underlies the individual maladaptive contextual learning to opioid exposure. We have identified functional maps of acquisition and retrieval of drug-related memory that may support the relapse-triggering ability of opioid-associated sensory and contextual cues. These findings may clarify the inter-individual sensitivity and vulnerability seen in addiction to opioids found in humans.

Emergence of metastability in frustrated oscillatory networks: the key role of hierarchical modularity.

Oscillatory complex networks in the metastable regime have been used to study the emergence of integrated and segregated activity in the brain, which are hypothesised to be fundamental for cognition. Yet, the parameters and the underlying mechanisms necessary to achieve the metastable regime are hard to identify, often relying on maximising the correlation with empirical functional connectivity dynamics. Here, we propose and show that the brain's hierarchically modular mesoscale structure alone can give rise to robust metastable dynamics and (metastable) chimera states in the presence of phase frustration. We construct unweighted 3-layer hierarchical networks of identical Kuramoto-Sakaguchi oscillators, parameterized by the average degree of the network and a structural parameter determining the ratio of connections between and within blocks in the upper two layers. Together, these parameters affect the characteristic timescales of the system. Away from the critical synchronization point, we detect the emergence of metastable states in the lowest hierarchical layer coexisting with chimera and metastable states in the upper layers. Using the Laplacian renormalization group flow approach, we uncover two distinct pathways towards achieving the metastable regimes detected in these distinct layers. In the upper layers, we show how the symmetry-breaking states depend on the slow eigenmodes of the system. In the lowest layer instead, metastable dynamics can be achieved as the separation of timescales between layers reaches a critical threshold. Our results show an explicit relationship between metastability, chimera states, and the eigenmodes of the system, bridging the gap between harmonic based studies of empirical data and oscillatory models.

Lymphopenia associated with whole-brain radiotherapy and its effects on clinical outcomes of patients with brain metastases.

There is increasing awareness of radiotherapy's potential side effects, such as lymphopenia. Therefore, this study aimed to establish the association between WBRT and the development of lymphopenia in patients with brain metastases undergoing brain radiotherapy (RT), along with evaluating the corresponding clinical outcomes. Including 116 patients with brain metastases undergoing brain radiotherapy, the study collected the absolute lymphocyte counts (ALC) within 2 weeks before brain radiotherapy (pre-radiotherapy, pre-RT), as well as ones at 1 and 2 months after completing RT (post-RT). Univariate and multivariate analyses were performed to identify associations between radiation modality and post-RT ALC. The relationships between post-RT ALC and overall survival were evaluated with Kaplan-Meier analysis and a multivariate Cox regression model. The median ALC definitely decreased at 1 month post-RT, but at 2 months post-RT, gradually rose but not to the pre-RT ALC. The multivariate analysis identified WBRT and lower pre-RT ALC as independent risk factors associated with the decrease in post-RT ALC at 1 month. It also revealed more than 4 brain metastases, G3-4 lymphopenia at 1 month and lower post-RT ALC at 2 months exhibited significantly worse prognosis regardless of the radiation modality. However, there was indeed an independent correlation between radiation modality and the outcome of intracranial progression-free survival (PFS). To approach the feasibility and reasonableness of treatment, clinicians should carefully consider various factors to achieve long-term survival of patients.

AB080. High-dose methotrexate with and without intra-thecal methotrexate and whole-brain radiotherapy for primary central nervous system lymphoma: a systematic review.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) requires effective & well-tolerated treatment strategies. The use of high-dose methotrexate (HD-MT) with or without intra-thecal methotrexate (IT-MT) and whole-brain radiotherapy (WBRT) has emerged as a prominent approach for PCNSL. This systematic review aims to assess the efficacy and safety of these treatment modalities. METHODS: A comprehensive search strategy identified relevant studies from PubMed, EMBASE, and Cochrane Library. The following search terms were used: "high-dose methotrexate", "primary central nervous system lymphoma", "intra-thecal methotrexate", and "whole-brain radiotherapy". We included randomized controlled trials (RCTs), cohort studies & case-controlled studies evaluating the use of HD-MT with or without IT-MT and whole-brain radiotherapy in the treatment of confirmed PCNSL. Data extraction & quality assessment was conducted by two independent reviewers. Primary outcomes include overall survival (OS), progression-free survival (PFS) & treatment-related adverse events (TRAEs). Secondary outcomes were neurological function and quality of life (QOL) assessments. The risk of bias in individual studies was assessed using the Cochrane Risk of Bias Tool for randomized trials and the Newcastle-Ottawa Scale for observational studies. RESULTS: We identified 5 studies, consisting of 1 RCT, 3 cohort studies, and 1 case-controlled study. Pooled analysis revealed that HD-MT with or without IT-MT and whole-brain radiotherapy significantly improved both OS and PFS compared to other treatment modalities but we found no significant difference between patients who received HD-MT with or without IT-MT. Combination therapy was generally well-tolerated, with manageable TRAE. Subgroup analyses stratified by age, disease stage, and other relevant factors demonstrated consistent efficacy and safety profiles across different patient populations. The risk of bias assessment indicated that the majority of the included studies had low-moderate risk of bias. CONCLUSIONS: There was no significant difference between patients who received HD-MT with or without IT-MT plus radiotherapy, emphasizing the comparable efficacy of these treatment modalities. Combination therapy was generally well-tolerated, with manageable TRAE. This highlights the favourable safety profile of HD-MT with fewer side effects compared with the combination of IT-MT.

AB079. Whole-brain radiotherapy versus high dose chemotherapy with autologous stem-cell transplantation for consolidation therapy in primary central nervous system lymphoma.

BACKGROUND: Whole brain radiotherapy (WBRT) is commonly used as consolidation therapy in primary central nervous system lymphoma (PCNSL). However, high-dose chemotherapy followed by autologous stem cell transplantation (HD-ASCT) has emerged as an alternative approach for PCNSL. This systematic review aims to assess the efficacy and safety of both treatment modalities. METHODS: The systematic review follows PRISMA guidelines. A comprehensive search strategy identified relevant studies from PubMed, Europe PMC, and Cochrane Library. The following search terms were used: "primary central nervous system lymphoma", "Autologous Stem Cell Transplantation", and "whole-brain radiotherapy". We included randomized controlled trials (RCTs) cohort studies evaluating the use of whole-brain radiotherapy and high-dose chemotherapy followed by autologous stem cell transplantation in the treatment of histologically-confirmed PCNSL. Publications included were limited to English language full texts that were published in the past 10 years. Data extraction & manuscript quality assessment was done by two independent reviewers with a third reviewer to resolve any discrepancy. Primary outcomes include overall survival (OS), progression-free survival (PFS) & treatment related toxicity (TRT). Secondary outcomes were clinical neurological function and performance score assessments. Individual studies were assessed using the Jadad Scale and the Newcastle-Ottawa Scale for observational studies. RESULTS: We identified 5 studies, consisting of 2 RCTs and 3 cohort studies. After all studies considered, analysis revealed that consolidation therapy with HD-ASCT had a better overall PFS and OS compared to whole-brain radiotherapy (P<0.005). Both groups showed similar TRT with mostly haematological toxicity. Holistically clinical cognitive functions are found to be improved in HD-ASCT Patients and poorer results are exhibited by WBRT patients primarily in executive functions. Performance statuses are scored differently across all studies with slightly preferable results shown in patients treated with HDC-ASCT. CONCLUSIONS: Based on the findings of this systematic review, HDC-ASCT might be a preferable choice of consolidative therapy as shown with better OS, PFS with similar TRT. While WBRT are more feasible and cost-efficient, risks of cognitive impairment and reduced performance status after WBRT should be considered for further treatment choices. Further randomized clinical trials with a similar scoring system are needed.

Biostasis: A Roadmap for Research in Preservation and Potential Revival of Humans.

Human biostasis, the preservation of a human when all other contemporary options for extension of quality life are exhausted, offers the speculative potential for survival via continuation of life in the future. While provably reversible preservation, also known as suspended animation, is not yet possible for humans, the primary justification for contemporary biostasis is the preservation of the brain, which is broadly considered the seat of memories, personality, and identity. By preserving the information contained within the brain's structures, it may be possible to resuscitate a healthy whole individual using advanced future technologies. There are numerous challenges in biostasis, including inadequacies in current preservation techniques, methods to evaluate the quality of preservation, and potential future revival technologies. In this report, we describe a roadmap that attempts to delineate research directions that could improve the field of biostasis, focusing on optimizing preservation protocols and establishing metrics for querying preservation quality, as well as pre- and post-cardiac arrest factors, stabilization strategies, and methods for long-term preservation. We acknowledge the highly theoretical nature of future revival technologies and the importance of achieving high-fidelity brain preservation to maximize the potential of future repair technologies. We plan to update the research roadmap biennially. Our goal is to encourage multidisciplinary communication and collaboration in this field.

High segregation and diminished global integration in large-scale brain functional networks enhances the perceptual binding of cross-modal stimuli.

Speech perception requires the binding of spatiotemporally disjoint auditory-visual cues. The corresponding brain network-level information processing can be characterized by two complementary mechanisms: functional segregation which refers to the localization of processing in either isolated or distributed modules across the brain, and integration which pertains to cooperation among relevant functional modules. Here, we demonstrate using functional magnetic resonance imaging recordings that subjective perceptual experience of multisensory speech stimuli, real and illusory, are represented in differential states of segregation-integration. We controlled the inter-subject variability of illusory/cross-modal perception parametrically, by introducing temporal lags in the incongruent auditory-visual articulations of speech sounds within the McGurk paradigm. The states of segregation-integration balance were captured using two alternative computational approaches. First, the module responsible for cross-modal binding of sensory signals defined as the perceptual binding network (PBN) was identified using standardized parametric statistical approaches and their temporal correlations with all other brain areas were computed. With increasing illusory perception, the majority of the nodes of PBN showed decreased cooperation with the rest of the brain, reflecting states of high segregation but reduced global integration. Second, using graph theoretic measures, the altered patterns of segregation-integration were cross-validated.