Brain Imaging in Pediatric Cancer Survivors: Correlates of Cognitive Impairment

Metabolic Profile of Cerebellum in Posterior Fossa Tumor Survivors: Correlation With Memory Impairment

AIMS

The cerebellum is a key structure in working and procedural memory. The aim of the present prospective exploratory study was to investigate, the metabolic characteristics of the cerebellum in posterior fossa tumor (PFT) survivors using 3D proton magnetic resonance spectroscopy imaging (3D MRSI), to determine whether metabolites could be useful biomarkers of memory impairment.

MATERIALS AND METHODS

Sixty participants were included in the IMPALA study, divided into three groups: 22 irradiated PFT, 17 nonirradiated PFT, and 21 healthy controls matched with irradiated PFT for age, sex, and handedness. PFT survivors were treated at least 5 years ago, either by surgery or a combination of surgery, chemotherapy, and radiotherapy. All participants underwent working and procedural memory tests and multimodal MRI including a 3D MRSI sequence. N-acetylaspartate (NAA), choline (Cho), creatine (Cr), and lactate (Lac) metabolite values were extracted from the cerebellum for comparisons between groups, correlations with neurocognitive test scores, and radiotherapy doses.

RESULTS

Median (range) age at neurocognitive tests was 18 (7-26) years. Median Cho, Cr, NAA, and Lac values, and the ratio of NAA to the sum of metabolites were significantly lower for PFT survivors than for healthy controls (p < 0.05). Scores on working and procedural memory tests were significantly lower for PFT survivors (p < 0.004) and correlated with median and maximum Cho and NAA values (0.28

CONCLUSION

Results revealed changes in cerebellar metabolic values in PFT survivors that were closely correlated with memory deficits, suggesting that some metabolites could be used as markers of cognitive decline, but this will require validation on a larger sample size.

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Key Words

• Cerebellum
• Memory
• Metabolic
• Paediatric posterior fossa tumor
• Radiotherapy
• Spectroscopy imaging

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Affiliation(s)

F Tensaouti Radiation Oncology Department, Oncopole Claudius Regaud- Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France; ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France.
N Courbière ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
B Cabarrou Biostatistics & Health Data Science Unit, Oncopole Claudius Regaud/Institut Universitaire du Cancer de Toulouse - Oncopôle, Toulouse, France
L Pollidoro ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
M Roques Radiology Department, Toulouse University Hospital, Toulouse, France
A Sévely Radiology Department, Toulouse University Hospital, Toulouse, France
P Péran ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France
E Baudou ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France; Pediatric Neurology Department, Children's Hospital, Toulouse University Hospital, Toulouse, France
A Laprie Radiation Oncology Department, Oncopole Claudius Regaud- Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France; ToNIC, Toulouse NeuroImaging Center, Université de Toulouse, Inserm, UPS, France

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Advancing presurgical non-invasive molecular subgroup prediction in medulloblastoma using artificial intelligence and MRI signatures

Global investigation of medulloblastoma has been hindered by the widespread inaccessibility of molecular subgroup testing and paucity of data. To bridge this gap, we established an international molecularly characterized database encompassing 934 medulloblastoma patients from thirteen centers across China and the United States. We demonstrate how image-based machine learning strategies have the potential to create an alternative pathway for non-invasive, presurgical, and low-cost molecular subgroup prediction in the clinical management of medulloblastoma. Our robust validation strategies-including cross-validation, external validation, and consecutive validation-demonstrate the model's efficacy as a generalizable molecular diagnosis classifier. The detailed analysis of MRI characteristics replenishes the understanding of medulloblastoma through a nuanced radiographic lens. Additionally, comparisons between East Asia and North America subsets highlight critical management implications. We made this comprehensive dataset, which includes MRI signatures, clinicopathological features, treatment variables, and survival data, publicly available to advance global medulloblastoma research.

Concurrent brain structural and functional alterations in the thalamus of adult survivors of childhood brain tumors: a multimodal MRI study

Adult survivors of childhood brain tumors often present with cognitive deficits that affect their quality of life. Studying brain structure and function in brain tumor survivors can help understand the underlying mechanisms of their cognitive deficits to improve long-term prognosis of these patients. This study analyzed voxel-based morphometry (VBM) derived from T1-weighted MRI and the amplitude of low-frequency fluctuation (ALFF) from resting-state functional magnetic resonance imaging (rs-fMRI) to examine the structural and functional alterations in 35 brain tumor survivors using 35 matching healthy individuals as controls. Compared with healthy controls, brain tumor survivors had decreased gray matter volumes (GMV) in the thalamus and increased GMV in the superior frontal gyrus. Functionally, brain tumor survivors had lower ALFF values in the inferior temporal gyrus and medial prefrontal area and higher ALFF values in the thalamus. Importantly, we found concurrent but negatively correlated structural and functional alterations in the thalamus based on observed significant differences in GMV and ALFF values. These findings on concurrent brain structural and functional alterations provide new insights towards a better understanding of the cognitive deficits in brain tumor survivors.

Multimodal imaging with magnetization transfer and diffusion tensor imaging reveals evidence of myelin damage in children and youth treated for a brain tumor

Background

The microstructural damage underlying compromise of white matter following treatment for pediatric brain tumors is unclear. We use multimodal imaging employing advanced diffusion tensor imaging (DTI) and magnetization transfer imaging (MTI) MRI methods to examine chronic microstructural damage to white matter in children and adolescents treated for pediatric brain tumor. Notably, MTI may be more sensitive to macromolecular content, including myelin, than DTI.

Methods

Fifty patients treated for brain tumors (18 treated with surgery ± chemotherapy and 32 treated with surgery followed by cranial-spinal radiation; time from diagnosis to scan ~6 years) and 45 matched healthy children completed both MTI and DTI scans. Voxelwise and region-of-interest approaches were employed to compare white matter microstructure metrics (magnetization transfer ratio (MTR); DTI- fractional anisotropy [FA], radial diffusivity [RD], axial diffusivity [AD], mean diffusivity [MD]) between patients and healthy controls.

Results

MTR was decreased across multiple white matter tracts in patients when compared to healthy children, P < .001. These differences were observed for both patients treated with radiation and those treated with only surgery, P < .001. We also found that children and adolescents treated for brain tumors exhibit decreased FA and increased RD/AD/MD compared to their healthy counterparts in several white matter regions, Ps < .02. Finally, we observed that MTR and DTI metrics were related to multiple white matter tracts in patients, Ps < .01, but not healthy control children.

Conclusions

Our findings provide evidence that the white matter damage observed in patients years after treatment of pediatric posterior fossa tumors, likely reflects myelin disruption.

Cerebral blood flow and structural connectivity after working memory or physical training in paediatric cancer survivors - Exploratory findings

Paediatric cancer survivors often suffer from cognitive long-term difficulties. Consequently, strengthening cognition is of major clinical relevance. This study investigated cerebral changes in relation to cognition in non-brain tumour paediatric cancer survivors after working memory or physical training compared to a control group. Thirty-four children (≥one-year post-treatment) either underwent eight weeks of working memory training (n = 10), physical training (n = 11), or a waiting period (n = 13). Cognition and MRI, including arterial spin labelling and diffusion tensor imaging, were assessed at three time points (baseline, post-training, and three-month follow-up). Results show lower cerebral blood flow immediately after working memory training (z = -2.073, p = .038) and higher structural connectivity at the three-month follow-up (z = -2.240, p = .025). No cerebral changes occurred after physical training. Short-term changes in cerebral blood flow correlated with short-term changes in cognitive flexibility (r = -.667, p = .049), while long-term changes in structural connectivity correlated with long-term changes in working memory (r = .786, p = .021). Despite the caution given when interpreting data from small samples, this study suggests a link between working memory training and neurophysiological changes. Further research is needed to validate these findings.

Unraveling the relations between post-traumatic stress symptoms, neurocognitive functioning, and limbic white matter in pediatric brain tumor patients

Background

Pediatric brain tumor patients are at risk of developing neurocognitive impairments and associated white matter alterations. In other populations, post-traumatic stress symptoms (PTSS) impact cognition and white matter. This study aims to investigate the effect of PTSS on neurocognitive functioning and limbic white matter in pediatric brain tumor patients.

Methods

Sixty-six patients (6-16 years) completed neuropsychological assessment and brain MRI (1-year post-diagnosis) and parents completed PTSS proxy questionnaires (CRIES-13; 1-3 months and 1-year post-diagnosis). Mean Z-scores and percentage impaired (>1SD) for attention, processing speed, executive functioning, and memory were compared to normscores (t-tests, chi-square tests). Multi-shell diffusion MRI data were analyzed for white matter tractography (fractional anisotropy/axial diffusivity). Effects of PTSS on neurocognition and white matter were explored with linear regression models (FDR correction for multiple testing), including age at diagnosis, treatment intensity, and tumor location as covariates. Neurocognition and limbic white matter associations were explored with correlations.

Results

Attention (M = -0.49, 33% impaired; P < .05) and processing speed (M = -0.57, 34% impaired; P < .05) were significantly lower than healthy peers. PTSS was associated with poorer processing speed (β = -0.64, P < .01). Treatment intensity, age at diagnosis, and tumor location, but not PTSS, were associated with limbic white matter metrics. Neurocognition and white matter metrics were not associated.

Conclusions

Higher PTSS was associated with poorer processing speed, highlighting the need for monitoring, and timely referrals to optimize psychological well-being and neurocognitive functioning. Future research should focus on longitudinal follow-up and explore the impact of PTSS interventions on neurocognitive performance.

Methylphenidate improves cognitive function and health-related quality of life in survivors of childhood brain tumours

OBJECTIVES

The growing population of survivors of childhood brain tumors present the challenge of long-term quality of survival. The domains most affected by tumor and treatment are those implicated in development of typical intellectual functions: attention, working memory, and processing speed, with consequent effects upon function and quality of life. In this paper we present service evaluation data on the 12-month effect upon processing speed, visual and auditory attentional domains in 29 patients receiving methylphenidate aged 5-16 years (Mean=10.6).

METHODS

Patients received immediate-release methylphenidate and were converted to modified-release as appropriate. Mean optimal dose of immediate-release methylphenidate was 0.34 mg/kg per dose (range 0.2-0.67).

RESULTS

Patients showed a significant positive impact of methylphenidate on attention in all tests of selective visual attention from the Test of Everyday Attention for Children 2. A significant improvement was also shown on response time. Significant change was not found on psychometric measures of sustained auditory or visual attention, or selective auditory attention. Ratings of Health-Related Quality of Life showed a positive benefit of methylphenidate at 12 months. Side effects were minimal and not statistically significant.

CONCLUSIONS

Survivors of childhood brain tumor with attentional and processing speed deficit show clinical benefit from methylphenidate.

Improving quality and quantity of life for childhood cancer survivors globally in the twenty-first century

The contributions of cooperative groups to performing large-cohort clinical trials and long-term survivorship studies have facilitated advances in treatment, supportive care and, ultimately, survival for patients with paediatric cancers. As a result, the number of childhood cancer survivors in the USA alone is expected to reach almost 580,000 by 2040. Despite these substantial improvements, childhood cancer survivors continue to have an elevated burden of chronic disease and an excess risk of early death compared with the general population and therefore constitute a large, medically vulnerable population for which delivery of high-quality, personalized care is much needed. Data from large survivorship cohorts have enabled the identification of compelling associations between paediatric cancers, cancer therapy and long-term health conditions. Effectively translating these findings into clinical care that improves the quality and quantity of life for survivors remains an important focus of ongoing research. Continued development of well-designed clinical studies incorporating dissemination and implementation strategies with input from patient advocates and other key stakeholders is crucial to overcoming these gaps. This Review highlights the global progress made and future efforts that will be needed to further increase the quality and quantity of life-years gained for childhood cancer survivors.

Patient-reported neurocognitive function in adult survivors of childhood and adolescent osteosarcoma and Ewing sarcoma

PURPOSE

Little is known regarding long-term neurocognitive outcomes in osteosarcoma and Ewing sarcoma (EWS) survivors despite potential risk factors. We evaluated associations among treatment exposures, chronic health conditions, and patient-reported neurocognitive outcomes in adult survivors of childhood osteosarcoma and EWS.

METHODS

Five-year survivors of osteosarcoma (N = 604; median age 37.0 years) and EWS (N = 356; median age 35.0 years) diagnosed at < 21 years from 1970 to 1999, and 697 siblings completed the Childhood Cancer Survivor Study Neurocognitive Questionnaire and reported chronic health conditions, education, and employment. Prevalence of reported neurocognitive difficulties were compared between diagnostic groups and siblings. Modified Poisson regression identified factors associated with neurocognitive difficulties.

RESULTS

Osteosarcoma and EWS survivors, vs. siblings, reported higher prevalences of difficulties with task efficiency (15.4% [P = 0.03] and 14.0% [P = 0.04] vs. 9.6%, respectively) and emotional regulation (18.0% [P < 0.0001] and 15.2% [P = 0.03] vs. 11.3%, respectively), adjusted for age, sex, and ethnicity/race. Osteosarcoma survivors reported greater memory difficulties vs. siblings (23.5% vs. 16.4% [P = 0.01]). Comorbid impairment (i.e., ≥ 2 neurocognitive domains) was more prevalent in osteosarcoma (20.0% [P < 0.001]) and EWS survivors (16.3% [P = 0.02]) vs. siblings (10.9%). Neurological conditions were associated with worse task efficiency (RR = 2.17; 95% CI = 1.21-3.88) and emotional regulation (RR = 1.88; 95% CI = 1.01-3.52), and respiratory conditions were associated with worse organization (RR = 2.60; 95% CI = 1.05-6.39) for EWS. Hearing impairment was associated with emotional regulation difficulties for osteosarcoma (RR = 1.98; 95% CI = 1.22-3.20). Patient report of cognitive difficulties was associated with employment but not educational attainment.

CONCLUSIONS

Survivors of childhood osteosarcoma and EWS are at increased risk for reporting neurocognitive difficulties, which are associated with employment status and appear related to chronic health conditions that develop over time.

IMPLICATIONS FOR CANCER SURVIVORS

Early screening, prevention, and treatment of chronic health conditions may improve/prevent long-term neurocognitive outcomes.

Social affective outcomes and brain injury in children and adolescents treated for brain tumours

In this Review we critically evaluate the empirical literature investigating the effect of paediatric brain tumours and their treatment on social affective function. We focus specifically on relations between social affective function and compromised brain structure and function associated with treatment for a paediatric brain tumour. We concentrate on emotion recognition and regulation, because these are core components of social affective function. First, we provide an overview of the literature in typically developing children and discuss the underlying brain networks thought to subserve emotion (ie, limbic system and supporting white matter microstructure). We then focus on how damage to brain structure and function after treatment for a paediatric brain tumour might be related to compromised emotion recognition and regulation-as well as broader social affective outcomes. On the basis of our review of the literature across typically developing children and those with a paediatric brain tumour, we suggest that structural changes to fronto-limbic tracts might interrupt social network neural communication in children and adolescents treated for brain tumours. A critical analysis of the reviewed literature suggests a relationship between social affective dysfunction and childhood-acquired injury to white matter microstructure. We argue that the knowledge synthesised regarding paediatric brain tumours could extend to other neurological disorders. Finally, we identify considerations for future investigation and recommend research practices to be adopted in forthcoming studies to establish causal links between brain structure and function to social affective processes.

Cancer neuroscience: State of the field, emerging directions

The nervous system governs both ontogeny and oncology. Regulating organogenesis during development, maintaining homeostasis, and promoting plasticity throughout life, the nervous system plays parallel roles in the regulation of cancers. Foundational discoveries have elucidated direct paracrine and electrochemical communication between neurons and cancer cells, as well as indirect interactions through neural effects on the immune system and stromal cells in the tumor microenvironment in a wide range of malignancies. Nervous system-cancer interactions can regulate oncogenesis, growth, invasion and metastatic spread, treatment resistance, stimulation of tumor-promoting inflammation, and impairment of anti-cancer immunity. Progress in cancer neuroscience may create an important new pillar of cancer therapy.

Impact of Anesthetic Exposures on the Neurocognitive Profiles of Pediatric Brain Tumor Survivors: A New Direction for Research and Multidisciplinary Collaboration

Primary brain tumors are the most commonly diagnosed solid tumors in children, and pediatric brain tumor survivors experience lasting, pervasive deficits of neurocognitive functioning. Repeated exposure to anesthetic drugs is a necessary component not only of surgical resection but also of multimodal cancer care for the youngest patients with brain tumors. The potential for anesthetic neurotoxicity to worsen neurocognitive outcomes in this vulnerable group, therefore, warrants our attention and further study through multi-disciplinary collaboration. This review discusses neurocognitive functioning in pediatric brain tumor survivors, highlighting the findings of a recent study of children with tumors of the posterior fossa which identified treatment-related risk factors for neurocognitive difficulties, with those undergoing multimodal therapies (eg, chemotherapy and irradiation) experiencing the greatest deficits compared with healthy controls. The role of anesthetic neurotoxicity in long-term outcomes among pediatric brain tumor survivors is also reviewed.

Risk factors and screening for neurocognitive impacts of therapy

Long-term survivors of pediatric hematologic malignancies are at elevated risk for neurocognitive impairment. Such impairment manifests in different ways at different times during survivorship, with deficits in processing speed, attention, and memory often appearing before deficits in executive function, intelligence, and academics. Survivors exposed to therapies that directly target the central nervous system (CNS), as is the case in acute lymphoblastic leukemia, may demonstrate subtle deficits during frontline therapy, and these deficits may grow and evolve over time. Survivors who do not receive CNS-directed therapies (eg, Hodgkin lymphoma) are also at elevated risk for neurocognitive impairment, although the influence on brain function is indirect through cancer therapy impact on systemic organ function vital to brain health (eg, cardiopulmonary morbidity). Over the course of the survivor's life span, the presence and impact of neurocognitive deficits will be determined by a complex interaction between premorbid development and environment, cancer therapy and clinical care, and posttreatment recovery and health. The timing and type of these treatment and health events will dictate the approach to screening and monitoring for neurocognitive impairment.

Processing efficiency in pediatric cancer survivors: A review and operationalization for outcomes research and clinical utility

OBJECTIVE

Childhood cancer and cancer-related treatments disrupt brain development and maturation, placing survivors at risk for cognitive late effects. Given that assessment tools vary widely across researchers and clinicians, it has been daunting to identify distinct patterns in outcomes across diverse cancer types and to implement systematic neurocognitive screening tools. This review aims to operationalize processing efficiency skill impairment-or inefficient neural processing as measured by working memory and processing speed abilities-as a worthwhile avenue for continued study within the context of childhood cancer.

METHODS

A comprehensive literature review was conducted to examine the existing research on cognitive late effects and biopsychosocial risk factors in order to conceptualize processing efficiency skill trends in childhood cancer survivors.

RESULTS

While a frequently reported pattern of neurobiological (white matter) and cognitive (working memory and processing speed) disruption is consistent with processing efficiency skill impairment, these weaknesses have not yet been fully operationalized in this population. We offer a theoretical model that highlights the impacts of a host of biological and environmental factors on the underlying neurobiological substrates of cancer survivors that precede and may even predict long-term cognitive outcomes and functional abilities following treatment.

CONCLUSION

The unified construct of processing efficiency may be useful in assessing and communicating neurocognitive skills in both outcomes research and clinical practice. Deficits in processing efficiency may serve as a possible indicator of cognitive late effects and functional outcomes due to the unique relationship between processing efficiency skills and neurobiological disruption following cancer treatment. Continued research along these lines is crucial for advancing childhood cancer outcomes research and improving quality of life for survivors.

Cross-translational models of late-onset cognitive sequelae and their treatment in pediatric brain tumor survivors

Pediatric brain tumor treatments have a high success rate, but survivors are at risk of cognitive sequelae that impact long-term quality of life. We summarize recent clinical and animal model research addressing pathogenesis or evaluating candidate interventions for treatment-induced cognitive sequelae. Assayed interventions encompass a broad range of approaches, including modifications to radiotherapy, modulation of immune response, prevention of treatment-induced cell loss or promotion of cell renewal, manipulation of neuronal signaling, and lifestyle/environmental adjustments. We further emphasize the potential of neuroimaging as a key component of cross-translation to contextualize laboratory research within broader clinical findings. This cross-translational approach has the potential to accelerate discovery to improve pediatric cancer survivors' long-term quality of life.

Characterizing academic performance in pediatric acute lymphoblastic leukemia with population-based achievement tests

BACKGROUND

Recent shifts from radiation to chemotherapy-based treatment for acute lymphoblastic leukemia (ALL) have contributed to reduced long-term morbidity. Despite this, ALL survivors remain at increased risk for long-term cognitive impairments.

AIM

To identify demographic and treatment factors associated with school performance in pediatric survivors of ALL.

METHODS

We collected standardized test scores for reading, math, and science obtained in a school setting from grades 3-11 in 63 ALL survivors (46.0% boys). Most participants were assessed across multiple grades (median number of grades n = 5, range 1-7), and 269 observations were considered in the analyses. Treatment exposures were extracted from medical records. Socio-economic status was estimated using participation in free/reduced lunch programs at school. Mixed effects linear regression models were conducted to determine factors associated with school performance.

RESULTS

ALL survivors' scores were comparable to state norms on reading, math, and science performances. On multivariable analysis, participation in free/reduced lunch programs was significantly associated with lower reading scores (β = -12.52; 95% CI -22.26:-2.77, p = .01). Exposure to radiation during treatment was also associated with lower reading test scores (β = -30.81, 95% CI -52.00:-9.62, p = .01). No significant associations between demographics and treatment parameters were observed for math and science test scores.

CONCLUSIONS

We utilized population-based achievement tests conducted from grades 3-11 to characterize school performance in ALL survivors. Our results imply that survivors with low socio-economic status and those exposed to radiation during treatment could benefit from early monitoring and intervention to maximize academic success.

Structural Neuroimaging Findings Related to Adult Non-CNS Cancer and Treatment: Review, Integration, and Implications for Treatment of Cognitive Dysfunction

Cancer- and treatment-related cognitive dysfunction (CRCD) is a common challenge faced by patients diagnosed with non-central nervous system (CNS) cancer. It has become increasingly recognized that multiple factors likely play a role in these symptoms, including the cancer disease process, systemic treatments (e.g., chemotherapy and endocrine therapies), and risk factors that may predispose an individual to both cancer and cognitive dysfunction. As the field has evolved, advanced neuroimaging techniques have been applied to better understand the neural correlates of CRCD. This review focuses on structural neuroimaging findings related to CRCD in adult non-CNS cancer populations, including examination of gray matter volume/density and white matter integrity differences between cancer patients and comparison groups, as well as emerging findings regarding structural network abnormalities. Overall, this literature has demonstrated consistent findings of reduced gray matter volume/density and white matter integrity in cancer patients relative to comparison groups. These are most prominent in individuals treated with chemotherapy, though alterations have also been noted in those treated with anti-estrogen and androgen-deprivation therapies. Alterations in gray and white matter structural network connectivity have also been identified. These structural abnormalities have been observed most prominently in frontal and temporal brain regions, and have been shown to correlate with subjective and objective cognitive function, as well as with physiological and clinical variables, helping to inform understanding of CRCD mechanisms. To date, however, structural neuroimaging techniques have not been utilized in systematic studies of potential CRCD treatments, suggesting a potentially fruitful avenue for future research.