Central nervous system injury and neurobiobehavioral function in children with brain tumors: a review of the literature

Nutritional status and inflammatory markers as survival predictors in pediatric central nervous system tumors

BACKGROUND & AIMS

Central nervous system tumors (CNS) are the second most common malignancies in childhood. Inflammation and changes in nutritional status play an important role and can be used as prognostic markers. Thus, this study aimed to evaluate the predictive ability of nutritional status and inflammatory markers on overall survival (OS) of pediatric patients with CNS.

METHODS

In this retrospective cohort study, 103 patients were followed for 5 years. Clinical, anthropometric, and hematological data were collected. Body mass index for age (BMI/A), neutrophil-to-lymphocyte ratio (NLR) and systemic inflammation response index (SIRI) were calculated. OS curves were calculated using the Kaplan Meier method and evaluated using the Log-Rank test. The Cox proportional hazards model was performed to identify independent variables associated with prognostic factors, generating hazard ratios (HR) and 95% confidence intervals (CI).

RESULTS

Nutritional status did not significantly affect OS. However, patients with NLR ≥2.18 and SIRI ≥1249.18 had significantly lower OS in 5 years. Only treatment and high NLR were identified as independent prognostic factors for worse OS. Treatment with exclusive radiotherapy or chemotherapy (HR: 16.22, 95% CI: 2.19-120.07) and NLR (HR: 1.94, 95% CI: 1.02-3.69) were identified as independent prognostic factors for worse OS at 5 years.

CONCLUSION

High pretreatment NLR was shown to be an independent prognostic factor for OS in pediatric patients with CNS.

Optimizing the Radiation Treatment Planning of Brain Tumors by Integration of Functional MRI and White Matter Tractography

Background

Diffusion tensor imaging (DTI) and functional magnetic resonance imaging (fMRI) present the ability to selectively protect functional regions and fiber tracts of the brain when brain tumors are treated with radiotherapy.

Objective

This study aimed to assess whether the incorporation of fMRI and DTI data into the radiation treatment planning process of brain tumors could prevent the neurological parts of the brain from high doses of radiation.

Material and Methods

In this investigational theoretical study, the fMRI and DTI data were obtained from eight glioma patients. This patient-specific fMRI and DTI data were attained based on tumor location, the patient's general conditions, and the importance of the functional and fiber tract areas. The functional regions, fiber tracts, anatomical organs at risk, and the tumor were contoured for radiation treatment planning. Finally, the radiation treatment planning with and without fMRI & DTI information was obtained and compared.

Results

The mean dose to the functional areas and the maximum doses were reduced by 25.36% and 18.57% on fMRI & DTI plans compared with the anatomical plans. In addition, 15.59% and 20.84% reductions were achieved in the mean and maximum doses of the fiber tracts, respectively.

Conclusion

This study demonstrated the feasibility of using fMRI and DTI data in radiation treatment planning to maximize radiation protection of the functional cortex and fiber tracts. The mean and maximum doses significantly decreased to neurologically relevant brain regions, resulting in reducing the neuro-cognitive complications and improving the patient's quality of life.

Health utilities in pediatric cancer patients and survivors: a systematic review and meta-analysis for clinical implementation

PURPOSE

Health utility (HU) is a useful metric for evaluating cost and utility of cancer therapies or prioritizing healthcare resources. We conducted a meta-analysis to compare HUs in association with clinical parameters and identify missing cancer-related themes from the extant HU measures for pediatric cancer patients and survivors.

METHODS

Studies published in the PubMed, Embase, Web of Science, and Cochrane Library were identified. Meta-analyses were performed to estimate weighted means of HUs assessed by self- and proxy-responses. Mixed-effects meta-regressions were applied to compare HUs between cancer patients/survivors and general populations. Missing themes in the extant measures were identified based on established patient-reported outcomes frameworks.

RESULTS

Of 123 selected studies included pediatric cancer populations, 44% used the Health Utilities Index version 2 (HUI2), and 48% used version 3 (HUI3). Compared to general populations, cancer patients undergoing therapies for acute lymphoblastic leukemia (ALL) had 0.129 (95% CI - 0.183 to - 0.075) and brain tumor had 0.257 (95% CI - 0.354 to - 0.160) lower HUs per proxy-reported HUI3, whereas survivors of ALL had 0.028 (95% CI - 0.062 to 0.007) and brain tumor had 0.188 (95% CI - 0.237 to - 0.140) lower HUs per proxy-reported HUI3. Compared to general populations, cancer patients treated with multimodality therapy and survivors off therapy 2-5 years had significantly poorer HUs (p's < 0.05). Missing cancer-specific contents from the HU measures were identified.

CONCLUSION

Pediatric cancer patients and survivors had poorer HUs than general populations. It is important to select appropriate HUs for economic evaluations, and offer interventions to minimize HU deficits for particular cancer populations.

Autophagy Inhibition Reduces Irradiation-Induced Subcortical White Matter Injury Not by Reducing Inflammation, but by Increasing Mitochondrial Fusion and Inhibiting Mitochondrial Fission

Radiotherapy is an effective tool in the treatment of malignant brain tumors, but irradiation-induced late-onset toxicity remains a major problem. The purpose of this study was to investigate if genetic inhibition of autophagy has an impact on subcortical white matter development in the juvenile mouse brain after irradiation. Ten-day-old selective neural Atg7 knockout (KO) mice and wild-type (WT) littermates were subjected to a single 6-Gy dose of whole-brain irradiation and evaluated at 5 days after irradiation. Neural Atg7 deficiency partially prevented myelin disruption compared to the WT mice after irradiation, as indicated by myelin basic protein staining. Irradiation induced oligodendrocyte progenitor cell loss in the subcortical white matter, and Atg7 deficiency partly prevented this. There was no significant change between the KO and WT mice in the number of microglia and astrocytes in the subcortical white matter after irradiation. Transcriptome analysis showed that the GO mitochondrial gene expression pathway was significantly enriched in the differentially expressed genes between the KO and WT group after irradiation. Compared with WT mice, expression of the mitochondrial fusion protein OPA1 and phosphorylation of the mitochondrial fission protein DRP1 (P-DRP1) were dramatically decreased in KO mice under physiological conditions. The protein levels of OPA1and P-DRP1 showed no differences in WT mice between the non-irradiated group and the irradiated group but had remarkably increased levels in the KO mice after irradiation. These results indicate that inhibition of autophagy reduces irradiation-induced subcortical white matter injury not by reducing inflammation, but by increasing mitochondrial fusion and inhibiting mitochondrial fission.

Infrared spectroscopic imaging study of BV-2 microglia altering tumor cell biological activity and cellular fraction

Tumor brain metastasis is a severe threat to patients' neurological function, in which microglia may be involved in the process of tumor cell metastasis among nerve cells. Our study focused on the interaction between microglia and breast and lung cancer cells. Changes in the proliferation and migration ability of cocultured tumor cells were examined; synchrotron radiation-based fourier transform infrared microspectroscopy (SR-FTIR) was used to detect changes in the structures and contents of biomolecules within the tumor cells. The experimental results showed that the proliferation and migration ability of tumor cells increased after coculture, and the structures and contents of biological macromolecules in tumor cells changed. The absorption peak positions of the amide Ⅱ and amide Ⅰ bands observed for the four kinds of tumor cells changed, and the absorption intensities were significantly enhanced, indicating changes in the secondary structures and contents of proteins in tumor cells, which may be the root cause of the change in tumor cell characteristics. Therefore, the metabolites of microglia may be involved in the progression of tumor cells in the nervous system. In this study, we focused on the interaction between microglia and tumor cells by using SR-FTIR and provided a new understanding of the mechanism of brain metastasis.

Structural neuroimaging

Characterizing the neuroanatomical correlates of brain development is essential in understanding brain-behavior relationships and neurodevelopmental disorders. Advances in brain MRI acquisition protocols and image processing techniques have made it possible to detect and track with great precision anatomical brain development and pediatric neurologic disorders. In this chapter, we provide a brief overview of the modern neuroimaging techniques for pediatric brain development and review key normal brain development studies. Characteristic disorders affecting neurodevelopment in childhood, such as prematurity, attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), epilepsy, and brain cancer, and key neuroanatomical findings are described and then reviewed. Large datasets of typically developing children and children with various neurodevelopmental conditions are now being acquired to help provide the biomarkers of such impairments. While there are still several challenges in imaging brain structures specific to the pediatric populations, such as subject cooperation and tissues contrast variability, considerable imaging research is now being devoted to solving these problems and improving pediatric data analysis.

Serial MRI Scan of Posterior Fossa Tumours Predict Patients at Risk of Developing Neurocognitive Impairment

Background:

Brain tumours are the most common solid tumours in children. More than 50% of these tumours develop in the posterior cranial fossa. Long term survivors of posterior fossa tumours (PFT) suffer from neurocognitive and memory issues. We hypothesized that serial MRI scanning of brain would show differences in hippocampal and ACC volume change in PFT patients treated with and without chemo-radiotherapy.

Material and Methods:

Twelve patients (8 females and 4 males) underwent 76 serial MR imaging examinations before and during treatment for posterior fossa tumours. Seven patients (4 medulloblastoma, 2 as ependymoma and 1 high grade glioma) were treated with maximum surgical resection followed by adjuvant radiotherapy and chemotherapy (Group 1). The other five patients were diagnosed as pilocytic astrocytoma who were treated only with surgery (Group 2). Hippocampal volumes were obtained manually on high-resolution 3Tesla T1-weighted images and normalised to intracranial volume, while ACC thickness and volume were obtained automatically using FreeSurfer software.

Results:

After the treatment period, the change in normalised hippocampal volume from baseline was significantly lower in group 1 patients compared to group 2 (mean change -0.0001470 ± 8.981e-005; Mean ± SEM vs 0.0002765 ± 9.151e-005; Mean ± SEM, respectively, P=0.004). Displayed graphically, the negative hippocampal growth trajectory in group 1 gradually returned to a positive growth pattern. There were no statistically significant changes in ACC volume and thickness. Both groups had similar rates of pre-operative hydrocephalus.

Conclusion:

Compared to PFT patients treated with surgery alone, PFT patients treated with chemo-radiotherapy showed lower hippocampal volumes and altered hippocampal growth trajectory. Serial quantitative MRI measures of brain may provide a neuroanatomical substrate for assessing functional impact on normal brain function following treatment of posterior fossa tumours.

Feasibility and efficacy of an extended trial of home-based working memory training for pediatric brain tumor survivors: a pilot study

BACKGROUND

Impaired working memory appears to play a key role in some of the neurocognitive late effects of pediatric brain tumor treatments, including declines in intellectual and executive functioning. Recent studies of pediatric cancer survivors suggest Cogmed® Working Memory Training is effective at improving working memory, although pediatric brain tumor survivors may demonstrate a less robust response than children with other cancers. The current study sought to determine if an extended course of Cogmed (35 sessions) was both feasible and efficacious for brain tumor survivors and if improvements were observable in near-transfer and far-transfer working memory measures as well as parent rating scores at 6 months post-treatment.

METHODS

Twenty pediatric brain tumor survivors ages 8 to 18 years with working memory deficits completed 35 sessions of Cogmed. Assessments of working memory and academic skills were completed at baseline, completion of training, and 6-month follow-up and parents completed questionnaires at baseline and 6-month follow-up.

RESULTS

Participants showed significant improvements in working memory at training completion and 6-month follow-up and math achievement at 6-month follow-up. Parents reported executive functioning improvements at follow-up as compared with baseline. Participants' program-based working memory skills did not change significantly between sessions 25 and 35, suggesting that extended training did not provide additional benefit.

CONCLUSIONS

This study replicates and extends previous research by: (1) demonstrating that brain tumor survivors at high risk for neurocognitive late effects can complete and benefit from working memory training, (2) identifying a point of diminished returns on training time investment, and (3) demonstrating benefits 6 months post-intervention.

Diffusion Tensor Imaging and Neurobehavioral Outcome in Children With Brain Tumors Treated With Chemotherapy

BACKGROUND

Childhood brain tumor survivors (CBTS) often experience treatment-related neurocognitive deficits affecting quality of life (QOL), but systemic chemotherapy contributions to outcomes are unclear. Our objective was to relate brain tissue changes to neurocognitive and QOL effects after systemic myeloablative chemotherapy with autologous hematopoietic progenitor cell rescue in CBTS.

PROCEDURE

Regional brain volumes and diffusion tensor indices were correlated with neurocognitive, behavioral, and QOL measures, and compared between 8 CBTS (mean age 8.5 years, mean age at diagnosis 32 months), and 9 healthy controls (mean 9.3 years).

RESULTS

Overall QOL, school, and psychosocial functioning were significantly lower in patients (P < .05). Most patients scored within normative ranges on neurocognitive and behavioral assessment. Elevated mean diffusivity and decreased fractional anisotropy, indicating gray and white matter injury, respectively, appeared in memory and executive functioning areas. Low scores on Inhibition on the Neuropsychological Assessment-II were correlated with elevated mean diffusivity in prefrontal cortex.

CONCLUSIONS

Brain injury, decreased QOL, and to a lesser extent, executive functioning deficits appear in CBTS treated with myeloablative chemotherapy and autologous hematopoietic progenitor cell rescue. Early cognitive and psychological assessment and intervention are warranted in this population.