Outcomes of a radiation sparing approach in medulloblastoma by subgroup in young children: an institutional review.

OBJECTIVE: To describe disease outcomes including overall survival and relapse patterns by subgroup in young pediatric patients treated for medulloblastoma with a radiation-sparing approach. METHODS: Retrospective analysis of clinical outcomes includes treatment, relapse, and salvage therapy and late effects in children treated for medulloblastoma with a radiation-sparing approach at British Columbia Children's Hospital (BCCH) between 2000 and 2020. RESULTS: There were 30 patients (median age 2.8 years, 60% male) treated for medulloblastoma with a radiation-sparing approach at BCCH. Subgroups included Sonic Hedgehog (SHH) (n = 14), group 3 (n = 7), group 4 (n = 6), and indeterminate status (n = 3). Three- and 5-year event-free survival (EFS) were 49.0% (30.2-65.4%) and 42.0% (24.2-58.9%) and overall survival (OS) 66.0% (95% CI 46.0-80.1%) and 62.5% (95% CI 42.5 and 77.2%), respectively, with a median follow-up of 9.5 years. Relapse occurred in 12/25 patients following a complete response, of whom six (group 4: n = 4; group 3: n = 1; unknown: n = 1) were successfully salvaged with craniospinal axis (CSA) RT and remain alive at a median follow-up of 7 years. Disease/treatment-related morbidity included endocrinopathies (n = 8), hearing loss n = 16), and neurocognitive abnormalities (n = 9). CONCLUSIONS: This radiation sparing treatment approach for young patients with medulloblastoma resulted in a durable cure in most patients with SHH subgroup medulloblastoma. In those patients with groups 3 and 4 medulloblastoma, relapse rates were high; however, most group 4 patients were salvaged with RT.

A randomized control intervention trial to improve social skills and quality of life in pediatric brain tumor survivors.

BACKGROUND: To determine if a group social skills intervention program improves social competence and quality of life (QOL) in pediatric brain tumor survivors (PBTS). METHODS: We conducted a randomized control trial in which PBTS (8-16 years old, off therapy for over 3 months) were allocated to receive social skills training (eg, cooperation, assertion, using social cognitive problem solving strategies, role playing, games, and arts and crafts) in 8 weekly 2-hour sessions, or an attention placebo control (games and arts and crafts only). Outcomes were self-reported, proxy-reported (caregiver), and teacher-reported using the Social Skills Rating System (SSRS), to measure social competence, and the Pediatric Quality of Life (PedsQL4.0, generic) to measure QOL at baseline, after intervention, and at 6 months follow-up. At baseline, SSRS were stratified into low and high scores and included as a covariate in the analysis. RESULTS: Compared to controls (n = 48), PBTS in the intervention group (n = 43) reported significantly better total and empathy SSRS scores, with improvements persisting at follow-up. The PBTS in the intervention group who had low scores at baseline reported the greatest improvements. Proxy and teacher reports showed no intervention effect. CONCLUSIONS: Participating in group social skills intervention can improve self-reported social competence that persisted to follow up. The PBTS should be given the opportunity to participate in social skills groups to improve social competence.

Determinants of social competence in pediatric brain tumor survivors who participated in an intervention study.

PURPOSE: This prospective study describes disease/treatment, personal characteristics, and social/family contextual variables as risk and resilience factors that predict social competence in pediatric brain tumor survivors (PBTS). METHODS: Ninety-one PBTS (51% male, mean age 11.21 years, off-treatment, attending a regular classroom >50% of the time) participated. PBTS and their primary caregivers (proxy) completed the Social Skills Rating System (SSRS) to assess social competence at baseline, 2, and 8 months follow-up. At baseline, medical information (e.g., tumor type and location, cranial irradiation therapy (CIT)), personal characteristics (e.g., child's age and gender, intelligence, executive function, attention, and memory), and social/family factors (family income and ethnicity) were obtained. RESULTS: Using mixed model multivariable analyses with a longitudinal component, tumor type (medulloblastoma) (p < 0.01) and poor executive function, specifically, emotional control, were the best predictors of low total and assertion self-reported SSRS scores (p < 0.02). Receiving CIT was associated with low proxy-reported assertion (p = 0.035), and cooperation score (p = 0.02). Poor emotional control was associated with low proxy-reported total (p = 0.032), assertion (p = 0.023), and self-control scores (p = 0.007). Being non-White was associated with low proxy-reported total (p = 0.016), self-control (p = 0.040), responsibility (p = 0.035), and cooperation scores (p = 0.002). There were no significant changes over time. CONCLUSIONS: This study supports a multifactorial model of insult and non-insult factors (medical, personal, and social context) as determinants of social competence in PBTS. Data from both informants identify determinants of social competence. These factors need to be considered in future interventions to help children better improve their social competence.

Determinants of quality of life outcomes for survivors of pediatric brain tumors.

INTRODUCTION: To describe the quality of life (QOL) of pediatric brain tumor survivors (PBTSs) prospectively and to identify potential medical, personal and family contextual factors associated with QOL. METHODS: Ninety-one PBTSs (8-16 years) who were off treatment and attending a regular classroom participated. Self- and caregiver-proxy-reported on QOL at baseline, 2 and 8 months. At baseline, cognitive, executive function, attention and memory, medical and demographics information were attained. RESULTS: Significant improvements over time in PBTS's emotional QOL were self- and proxy-reported (P < 0.01) and global QOL proxy-reported (P = 0.04). Receiving cranial irradiation therapy (CIT) and poor behavioral regulation predicted poor global QOL scores reported by both informants (P < 0.017). Poor behavioral regulation also predicted poor self-reported school functioning, and poor proxy-reported emotional and social QOL (P < 0.037). Boys reported better emotional QOL (P = 0.029), and PBTSs over 11 years old were reported to have better emotion and school-related QOL. Finally, being non-White and having low income predicted poor self-reported global and emotional QOL (P = 0.041). CONCLUSIONS: Receiving CIT, having poor behavioral regulation, being a female, under 11 years old and coming from low-income, non-White families place PBTSs at risk for poor QOL.

White matter and information processing speed following treatment with cranial-spinal radiation for pediatric brain tumor.

OBJECTIVE: We compared the structure of specific white matter tracts and information processing speed between children treated for posterior fossa tumors with cranial-spinal radiation (n = 30), or with surgery +/- focal radiation (n = 29), and healthy children (n = 37). METHOD: Probabilistic diffusion tensor imaging (DTI) tractography was used to delineate the inferior longitudinal fasciculi, optic radiation, inferior frontal occipital fasciculi, and uncinate fasciculi bilaterally. Information processing speed was measured using the coding and symbol search subtests of the Wechsler Intelligence Scales, and visual matching, pair cancellation, and rapid picture naming subtests of the Woodcock-Johnson Test of Cognitive Ability, 3rd revision. We examined group differences using repeated measures MANOVAs and path analyses were used to test the relations between treatment, white matter structure of the tracts, and information processing speed. RESULTS: DTI indices of the optic radiations, the inferior longitudinal fasciculi, and the inferior fronto-occipital fasciculi differed between children treated with cranial-spinal radiation and children treated with surgery +/- focal radiation, and healthy controls (p = .045). Children treated with cranial-spinal radiation also exhibited lower processing speed scores relative to healthy control subjects (p = .002). Notably, we observed that group differences in information processing speed were related to the structure of the right optic radiation (p = .002). CONCLUSION: We show that cranial-spinal radiation may have a negative impact on information processing speed via insult to the right optic radiations. (PsycINFO Database Record

White matter compromise predicts poor intellectual outcome in survivors of pediatric low-grade glioma.

BACKGROUND: While the impact of cranial radiation on white matter following treatment for pediatric brain tumor has been the focus of many recent studies, the effect of treatment in the absence of radiation has received little attention. The relations between white matter and cognitive outcome have not been explored in patients who have undergone radiation-free treatment. As most patients treated without cranial radiation survive long after their diagnosis, it is critical to identify factors that may impact structural and neurocognitive outcomes. METHODS: Using diffusion tensor imaging, we examined white matter structure in 32 patients with pediatric low-grade glioma (PLGG) (19 with subtentorial location and 13 with supratentorial location) and 32 healthy participants. Indices of intellectual functioning were also evaluated. Radiation was not used to treat this cohort, aged 8-19 years. RESULTS: We detected evidence of deficits in IQ and compromised supra- and subtentorial white matter in patients relative to healthy children (P < .05). Compromise of supratentorial white matter mediated the impact of treatment for PLGG on IQ. Greater white matter compromise was observed in patients who presented without multiple symptoms, were treated with biopsy/no surgery, had positive neurofibromatosis 1 status, were younger age at diagnosis, and whose parents had lower levels of education (P < .05). CONCLUSIONS: Our findings provide evidence of increased risk of intellectual and white matter compromise in patients treated for PLGG without radiation. We identify a neural origin of cognitive deficit useful for predicting outcome and mitigating long-term adverse effects in pediatric brain tumor patients treated without cranial radiation.

Changes to memory structures in children treated for posterior fossa tumors.

Children treated for medulloblastoma (MB) exhibit long-term impairments in declarative memory, but the pathophysiology underlying this is unclear. Previous studies report declines in global white matter volume, but have failed to link this to declines in memory performance. We examined the effects of treatment on measures of global brain structure (i.e., total white and gray matter volume) and specific memory structures (i.e., hippocampus and uncinate fasciculus). We used volumetric MRI and diffusion tensor imaging in pediatric survivors of MB and one survivor of astrocytoma treated with cranial-spinal radiation (n = 20), and healthy controls (n = 13). Compared to controls, the survivor group exhibited reduced white matter volume, damage to the uncinate fasciculus, and a smaller right hippocampus. Critically, reduced hippocampal volume was not related to differences in brain volume, suggesting that the hippocampus may be especially vulnerable to treatment effects. A subset of the survivors (n = 10) also underwent memory testing using the Children's Memory Scale (CMS). Performance on the general index of the CMS was significantly correlated with measures of hippocampal volume and uncinate fasciculus. The examination of treatment effects on specific brain regions provides a better understanding of long-term cognitive outcome in children with brain tumors, particularly medulloblastoma.

Clinical and neuroanatomical predictors of cerebellar mutism syndrome.

Cerebellar mutism syndrome (CMS) is an important medical challenge in the management of pediatric posterior fossa brain tumors, because it occurs in a subset of children following tumor resection. A definitive clinical profile and neuroanatomical substrate associated with CMS remains unclear. We investigated the relationship between presurgical and clinical variables and the incidence of CMS, along with diffusion tensor imaging, to characterize the integrity of cerebello-thalamo-cerebral white matter pathways. Seventeen children with posterior fossa tumors and CMS, 34 children with posterior fossa tumors without CMS, and 28 healthy children were enrolled in this study. Bilateral cerebello-thalamo-cerebral pathways were delineated and segmented into anatomical regions. Mean integrity measures for each region were compared among children with CMS, children without CMS, and healthy children. Left-handedness, medulloblastoma histology, and larger tumor size distinguished between patients with CMS and patients without CMS (P < .04). Right cerebellar white matter within the cerebello-thalamo-cerebral pathway was compromised in children with CMS relative to children without CMS and healthy children (P < .02). We provide a potential schema for CMS risk among children treated for posterior fossa tumors. Left-handed children treated for medulloblastoma may be the most at risk for CMS, and unilateral, localized damage within the cerebello-thalamo-cerebral pathway at the level of the right cerebellum is implicated in the presentation of CMS. This disruption in communication between the right cerebellum and left frontal cortex may contribute to speech-language problems observed in children with CMS. Our findings may be relevant for surgical planning and speech-language therapy to mitigate symptoms of CMS.

Cerebello-thalamo-cerebral connections in pediatric brain tumor patients: impact on working memory.

Brain tumors are the leading cause of death and disability from childhood disease in developed countries. Pediatric posterior fossa tumors are often effectively controlled with a combination of surgery, radiation, and chemotherapy, depending on tumor type. White matter injury following resection of tumor and radiation treatment is associated with cognitive declines, including working memory deficits. We investigated how brain injury following treatment for posterior fossa tumors results in deficits in working memory. We used diffusion tensor imaging and probabilistic tractography to examine the structural integrity of cerebello-thalamo-cerebral tracts in patients and healthy children. We also compared working memory outcome in patients versus controls, and related this function to integrity of cerebello-thalamo-cerebral tracts. Bilateral cerebello-thalamo-cerebral tracts were delineated in all participants. Patients treated with a combination of surgery and radiation had lower mean anisotropy and higher mean radial diffusivity within the cerebellar regions of the cerebello-thalamo-cerebral tract compared to patients treated with surgery only and healthy controls. Poorer working memory scores were observed for the cranial radiation group relative to controls. Reduced anisotropy and higher radial diffusivity within the entire cerebello-thalamo-cerebral pathway predicted lower working memory. Our finding that working memory function is related to the integrity of cerebello-thalamo-cerebral connections is a novel contribution to the understanding of cerebral-cerebellar communication. Identifying differences in the structural integrity of white matter for specific pathways is an essential step in attempting to localize the effects of posterior fossa tumors and their treatment methods.