Treatment developments and the unfolding of the quality of life discussion in childhood medulloblastoma: a review

National multicentered retrospective review of clinical and intraoperative factors associated with the development of cerebellar mutism after pediatric posterior fossa tumor resection

BACKGROUND

Cerebellar mutism (CM) is characterized by a significant loss of speech in children following posterior fossa (PF) surgery. The biological origin of CM remains unclear and is the subject of ongoing debate. Significant recovery from CM is less likely than previously described despite rigorous multidisciplinary neuro-rehabilitational efforts.

METHODS

A national multi-centered retrospective review of all children undergoing PF resection in four midsized Canadian academic pediatric institutions was undertaken. Patient, tumor and surgical factors associated with the post-operative development of CM were reviewed. Retrospective identification of PF surgery patients including those developing and those that did not (internal control).

RESULTS

The study identified 258 patients across the 4 centers between 2010 and 2020 (mean age 6.73 years; 42.2% female). Overall, CM was experienced in 19.5% of patients (N = 50). Amongst children who developed CM histopathology included medulloblastoma (35.7%), pilocytic astrocytoma (32.6%) and ependymoma (17.1%). Intraoperative impression of adherence to the floor of the 4th ventricle was positive in 36.8%. Intraoperative abrupt changes in blood pressure and/or heart rate were identified in 19.4% and 17.8% of cases. The clinical resolution of CM was rated to be complete, significant resolution, slight improvement, no improvement and deterioration in 56.0%, 8.0%, 20.0%, 14.0% and 2.0%, respectively. In the cohort of children who experienced post-operative CM as compared to their no-CM counterpart, proportionally more tumors were felt to be adherent to the floor of the 4th ventricle (56.0% vs 49.5%), intraoperative extent of resection was a GTR (74% vs 68.8%) and changes in heart rate were noted (≥ 20% from baseline) (26.0% vs 15.9%). However, a multiple regression analysis identified only abrupt changes in HR (OR 5.97, CI (1.53, 23.1), p = 0.01) to be significantly associated with the development of post-operative CM.

CONCLUSION

As a devastating surgical complication after posterior fossa tumor surgery with variable clinical course, identifying and understanding the operative cues and revising intraoperative plans that optimizes the child's neurooncological and clinical outcome are essential.

Evolution of neurosurgical advances and nuances in medulloblastoma therapy

Medulloblastoma, the most common malignant brain tumor in children, presents a complex treatment challenge due to its propensity for infiltrative growth within the posterior fossa and its potential attachment to critical anatomical structures. Central to the management of medulloblastoma is the surgical resection of the tumor, which is a key determinant of patient prognosis. However, the extent of surgical resection (EOR), ranging from gross total resection (GTR) to subtotal resection (STR) or even biopsy, has been the subject of extensive debate and investigation within the medical community. Today, the impact of neurosurgical EOR on the prognosis of medulloblastoma patients remains a complex and evolving area of investigation. The conflicting findings in the literature, the challenges posed by critical surrounding anatomical structures, the potential for surgical complications and neurologic morbidity, and the nuanced interactions with molecular subgroups all contribute to the complexity of this issue. As the field continues to advance, the imperative to strike a delicate balance between maximizing resection and preserving quality of life remains central to the management of medulloblastoma patients.

Concordance of informant and self-reported ratings on the Frontal Systems Behavior Scale in adult survivors of pediatric brain tumor

OBJECTIVE

It has been theorized that pediatric brain tumor survivors may have reduced insight into their executive functioning. Agreement between informants and survivors has been used to probe this theory, but findings have been inconsistent. This study sought to expand on prior work by examining the relationship between participant role and ratings on the Frontal Systems Behavior Scale (FrSBe) among 73 adult survivors and their informants. This study also sought to test whether agreement on scores varied as a function of tumor treatment.

METHOD

Dyadic mixed effects models examined the relationship between participant ratings on FrSBe subscales and the role of a participant (survivor or informant). Intraclass correlations (ICC) were used to calculate reliable change indices to evaluate significant divergence in self and informant agreement.

RESULTS

Dyadic mixed effects models showed an insignificant relationship between participant role and ratings on the FrSBe apathy and executive dysfunction subscales. Participant role was related to ratings on the disinhibition subscale of the FrSBe. The ICC for apathy was ICC = .583, for disinhibition ICC = .420, and for executive dysfunction ICC = .373. Significant divergence in scores did not vary by history of chemoradiation.

CONCLUSIONS

Results demonstrate an effect of role on one FrSBe subscale and weak to moderate agreement between survivor and informant scores, which suggests that agreement between informants and survivors varies by FrSBe domain. The strongest relationship between survivors and informants was seen on apathy, which suggests that apathy is a shared concern for survivors and their families.

Robustness and dosimetric verification of hippocampal-sparing craniospinal pencil beam scanning proton plans for pediatric medulloblastoma

Background and Purpose

Hippocampal-sparing (HS) is a method that can potentially reduce late cognitive complications for pediatric medulloblastoma (MB) patients treated with craniospinal proton therapy (PT). The aim of this study was to investigate robustness and dosimetric plan verification of pencil beam scanning HS PT.

Materials and Methods

HS and non-HS PT plans for the whole brain part of craniospinal treatment were created for 15 pediatric MB patients. A robust evaluation of the plans was performed. Plans were recalculated in a water phantom and measured field-by-field using an ion chamber detector at depths corresponding to the central part of hippocampi. All HS and non-HS fields were measured with the standard resolution of the detector and in addition 16 HS fields were measured with high resolution. Measured and planned dose distributions were compared using gamma evaluation.

Results

The median mean hippocampus dose was reduced from 22.9 Gy (RBE) to 8.9 Gy (RBE), while keeping CTV V95% above 95 % for all nominal HS plans. HS plans were relatively robust regarding hippocampus mean dose, however, less robust regarding target coverage and maximum dose compared to non-HS plans. For standard resolution measurements, median pass rates were 99.7 % for HS and 99.5 % for non-HS plans (p < 0.001). For high-resolution measurements, median pass rates were 100 % in the hippocampus region and 98.2 % in the surrounding region.

Conclusions

A substantial reduction of dose in the hippocampus region appeared feasible. Dosimetric accuracy of HS plans was comparable to non-HS plans and agreed well with planned dose distribution in the hippocampus region.

Integrated analysis of multiple methods reveals characteristics of the immune microenvironment in medulloblastoma

To explore the characteristics of the immune microenvironment (IME) of medulloblastoma (MB) by four methods: flow cytometry (FCM), immunohistochemical (IHC), bulk RNA expression and single cell RNA sequencing (scRNA-seq), we collected the intraoperative specimens of MB, ependymoma (EPN), high-grade glioma (HGG), and low-grade glioma (LGG) to make a cross-cancer comparison. The specimens were subjected to FCM and IHC respectively, and deconvolution from bulk RNA expression data and scRNA-seq analysis were performed in MB from the GEO database. FCM and IHC analysis found that the proportion of lymphocytes (LC) and T cells between MB and other brain tumors were significantly different. The deconvolution of bulk RNA expression data showed that only the proportion of cell types in MCPCOUNTER changed greatly. scRNA-seq found that the proportion of various immune cells in the IME of MB differed between different subtypes. Techniques such as FCM, IHC, bulk RNA expression, and scRNA-seq can sort out different immune cell subsets to a certain extent and quantify their proportions. The four methods have their own strengthens and limitations, but for highly heterogeneous tumor such as MB, integrated analysis of multiple methods is a better choice.

Improved prediction of postoperative paediatric cerebellar mutism syndrome using an artificial neural network

Background

Postoperative paediatric cerebellar mutism syndrome (pCMS) is a common but severe complication which may arise following the resection of posterior fossa tumours in children. Two previous studies have aimed to preoperatively predict pCMS, with varying results. In this work, we examine the generalisation of these models and determine if pCMS can be predicted more accurately using an artificial neural network (ANN).

Methods

An overview of reviews was performed to identify risk factors for pCMS, and a retrospective dataset collected as per these defined risk factors from children undergoing resection of primary posterior fossa tumours. The ANN was trained on this dataset and its performance evaluated in comparison to logistic regression and other predictive indices via analysis of receiver operator characteristic curves. Area under the curve (AUC) and accuracy were calculated and compared using a Wilcoxon signed rank test, with p&lt;0.05 considered statistically significant.

Results

204 children were included, of whom 80 developed pCMS. The performance of the ANN (AUC 0.949; accuracy 90.9%) exceeded that of logistic regression (p&lt;0.05) and both external models (p&lt;0.001).

Conclusion

Using an ANN, we show improved prediction of pCMS in comparison to previous models and conventional methods.

Brain network hubs and cognitive performance of survivors of childhood infratentorial tumors

BACKGROUND

Childhood infratentorial tumor patients frequently suffer from long-term cognitive deficits. As each constituent of their treatment can lead to neurotoxicity, cascade effects can lead to profound reorganization of the underlying brain network, the so-called 'connectome'. However, to date, few studies have assessed the relationship between brain network topology, the functional role of network hubs (i.e. highly connected regions), and neurocognitive outcomes in adult survivors of childhood infratentorial tumors.

METHODS

In this cross-sectional study, childhood infratentorial tumor survivors (n = 21: pilocytic astrocytoma (n = 8), ependymoma (n = 1) and medulloblastoma (n = 12)) and healthy controls (n = 21) were recruited. Using multishell diffusion-weighted MRI, microstructural organization and topology of supratentorial white matter was investigated; using a voxel-based approach, a fixel-based analysis, and a graph theoretical approach. In addition, neurocognitive subscales of the WAIS-IV intelligence test, and their relationship with nodal strength and network efficiency metrics were assessed.

RESULTS

Similar to earlier studies, we observed widespread decreases in fractional anisotropy (FA) in patients compared to controls, based on voxel-based analyses. In addition, the fixel-based analyses dissociated macro- from microstructural changes, which were encountered in in infratentorial versus supratentorial brain areas, respectively. Finally, regional reorganization (i.e. differences in local efficiency) occurred mainly in hubs, which suggests a specific vulnerability of these areas. These hubs were not only mostly affected, but also most strongly correlated with the intelligence subscales.

CONCLUSION

This study suggests that network hubs are functionally important for intellectual outcomes in infratentorial tumor survivors. Furthermore, these regions could be the primary targets of treatment toxicity. Validation of this specific hypothesis in larger samples is required.

Circ-SKA3 upregulates ID3 expression by decoying miR-326 to accelerate the development of medulloblastoma

Medulloblastoma (MB), the most common malignant childhood brain tumor, is a serious threat to life. Circular RNA (circRNA) is involved in the development of various cancers, including MB. We aimed to explore the role of circRNA spindle and kinetochore associated complex subunit 3 (circ-SKA3) in MB progression. Circ-SKA3 expression was elevated in MB tissues and cells. Depleted expression of circ-SKA3 inhibited MB cell proliferation, migration and invasion and induced apoptosis and cell cycle arrest, and circ-SKA3 knockdown inhibited MB growth in vivo. Mechanism analyses revealed that circ-SKA3 directly targeted miR-326 that could bind to ID3, and circ-SKA3 decoyed miR-326 to increasing ID3 expression. Rescue experiments showed that miR-326 inhibition reversed the effects of circ-SKA3 knockdown, and ID3 overexpression recovered MB cell proliferation, migration and invasion blocked by miR-326 restoration. In conclusion, circ-SKA3 functioned as an oncogene to promote the development of MB by increasing ID3 expression via decoying miR-326, hinting that circ-SKA3 might be a therapeutic target of MB.

Aggressive Medulloblastoma-Derived Exosomal miRNAs Promote In Vitro Invasion and Migration of Tumor Cells Via Ras/MAPK Pathway

Medulloblastomas (MBs) are currently divided into 4 molecular subgroups: WNT, SHH, Group 3, and Group 4. Among them, Group 3 MB has the worst prognosis, and 40%-50% of Group 3 cases are already metastatic at the time of diagnosis. Emerging evidence indicates that exosomes drive tumor invasion, but very little is known about exosomes in MBs. In this study, we initially discovered that exosomes isolated from Group 3 MB cell lines altered in vitro behaviors of a less invasive SHH MB cell line and yielded a much more aggressive phenotype. RNA-sequencing analysis revealed 7 exosomal miRNAs with markedly different expression levels between the SHH and Group 3 MB cell lines. They were all predicted to be related to the Ras/MAPK pathway according to the Kyoto Encyclopedia of Genes and Genomes data analysis. Increased expression of miR-181a-5p, miR-125b-5p, and let-7b-5p was further confirmed in Group 3 MB cells with real-time PCR and was shown to increase in vitro invasion and migratory abilities of tumor cells through the activation of ERK in Ras/MAPK pathway. Collectively, our findings suggest that exosomal miRNAs have a critical role in MB progression in vitro and might serve as diagnostic biomarkers and therapeutic targets.

The reliability of the health related quality of life questionnaire PedsQL 3.0 cancer module in a sample of Swedish children

Background

The Pediatric Quality of Life Inventory (PedsQL) is a modular instrument, designed to integrate generic and disease specific measures, and includes both self- and proxy-reports. The aim of the study was to assess the reliability and limited validity of the Swedish version of the disease specific Pediatric Quality of Life Inventory 3.0 Cancer Module Scales (PedsQL 3.0), in a sample of Swedish children diagnosed with cancer.

Method

A total of 94 families at The Queen Silvia Children’s Hospital, Sahlgrenska University participated in the study. The Pediatric Quality of Life Inventory 4.0 Generic Core Scales (PedsQL 4.0) and the PedsQL 3.0 were administered to 63 children (aged 5–18 years) with cancer and to 94 parents of children with cancer aged 2–18 years.

Results

The internal consistency of the PedsQL 3.0, reached or exceeded Cronbach’s alpha values of 0.70 for both -self- and proxy-reports. The PedsQL 4.0 and PedsQL 3.0 were highly correlated (r = 0.94 for proxy-reports and r = 0.91 for self-reports), indicating convergent validity.

Conclusion

PedsQL 3.0 Cancer Module Scales can be used as a valuable tool for measuring cancer-specific HRQOL in child populations, both in research and in clinical practice.

Long-term outcome of posterior fossa medulloblastoma in patients surviving more than 20 years following primary treatment in childhood

The aim of the study was to analyze the long-term outcome (>20 years) after treatment of posterior fossa medulloblastoma (MB) in childhood. We analyzed data from patients treated for posterior fossa MB between 1974 (introduction of the first international treatment protocol in Norway) and 1987 (when use of radiotherapy was abandoned in children under 4 years of age). Out of 47 children, 24 survived >20 years. At the time of analysis, 16 patients (median age 41 years, range 32–52) were alive (median follow-up 34 years, range 30–42), while 8 patients died 22–41 years (median 31 years) after primary treatment: one late death (after 22 years) was due to tumor recurrence whilst other 7 deaths (after 23 to 41 years) were related to the detrimental effects of the treatment (secondary tumors, stroke, severe epilepsy and depression). Observed 20- and 30-year survival rates were 51% and 44%, respectively. Despite successful treatment of MB in childhood and satisfactory tumor control during the first 20 years following primary treatment, our data indicates that even long-term survivors may die from tumor recurrence. However, the main factors causing late mortality and morbidity in long-term survivors seem to be the complications related to radiotherapy given in childhood.

Posterior Fossa Society Consensus Meeting 2018: a synopsis

PURPOSE

The Posterior Fossa Society (PFS) was founded 4 years ago to systematically gather and exchange information on the post-operative (CMS) and cerebellar cognitive affective syndrome (CCAS). With its consensus meetings, the PFS orchestrates research studies in the field of cerebellar injury and progresses the knowledge of post-operative pediatric cerebellar mutism syndrome (CMS). In this article, we captured the 3-day program of presentations, group discussions, interactive workshops, and dialogue, highlighting the key topic areas of CMS and its research advances.

METHODS

This synopsis is based on the third consensus meeting which was held in Reykjavik, Iceland, in August 2018.

RESULTS

Three working groups have been defined to drive the future research priorities on post-surgical CMS: (i) refining definition and symptoms scoring of CMS; (ii) understanding the pathogenesis and enhancing risk-stratification strategies; and (iii) developing rehabilitation approaches and protocols.

CONCLUSIONS

The third consensus meeting highlighted a unanimous desire for data-driven information to advance the knowledge and guide future research efforts. The PFS constitutes an established and expanding network of multi-disciplinary expertise that can facilitate the development of collaborative studies and produce official guidelines on the topic.

Cerebellar mutism syndrome: current approaches to minimize risk for CMS

PURPOSE

Cerebellar mutism syndrome (CMS) is a serious source of morbidity following posterior fossa surgery in the pediatric population. However, methods for effectively decreasing its incidence and impact remain unclear. It is our aim to examine the impact of adjusting surgical factors, namely the use of a telovelar approach and avoidance of cavitronic ultrasonic aspirator, on the incidence of CMS in our population as well as outlining potential pre-, intra-, and postoperative factors that may contribute to its development.

METHODS

Retrospective review was performed to identify patients undergoing posterior fossa surgery for resection of a medulloblastoma. Demographic, surgical, and postoperative data were collected. These data were analyzed for possible correlations to the risk of developing CMS via univariate analysis. For factors found to be significant, a multivariate analysis was performed to assess their independence.

RESULTS

Seven of 65 patients (10.8%) developed CMS postoperatively. Factors found to be significantly associated with a higher risk of CMS were the degree of retraction utilized during the procedure (p = 0.0000) and incision of the vermis (p = 0.0294). Although they did not reach the threshold of statistical significance, tumor vascularity (p = 0.19), adoption of a transvermian approach (p = 0.19), and lack of intraoperative imaging (p = 0.17) exhibited strongly suggestive trends towards a correlation with CMS.

DISCUSSION

In an effort to reduce the incidence and severity of CMS in our population, our institution adopted surgical practices that minimize tissue trauma and mitigate postoperative edema. This included the use of a telovelar over a transvermian approach to obviate the need for vermian incision, avoidance of the CUSA, and minimization of heavy retraction during surgery. This was successful in reducing the incidence of CMS from 39% in our medulloblastoma patients to 10.8%. The development of CMS after posterior fossa surgery appears to be a "two-hit" phenomenon requiring a combination of existing predisposition, surgical injury, and postoperative exacerbation. Therefore, it is critical to identify the factors involved at each stage and investigate treatments to target them appropriately.

Childhood medulloblastoma-a single institution's historical perspective on survival and functional morbidity

PURPOSE

To compare results from a third (1995-2010) cohort of children with medulloblastoma with two previous series (J Neurosurg 86:13-21, 1997; Arch Dis Child 54:200-203, 1979) to analyse the effects of management changes aimed at improving both overall and event-free survivals (OS and EFS) and functional outcomes.

METHODS

Review of neuro-oncology and imaging databases and previously published results.

RESULTS

There was no statistically significant improvement in the 5-year OS for 104 children diagnosed 1995-2010, 61.5% (95% CI, 52.9, 71.6), compared with 50% of the 80 children presenting 1980-1990 (J Neurosurg 86:13-21, 1997) (difference 11.5%; 95% CI, 2.8, 25.4). Five-year OS for 96 children suitable for risk-stratification was overall 66% (95% CI, 57.9, 75.8); standard risk 77.8% (95% CI, 67.4, 89.7); high risk < 3 years 50.0% (95% CI, 32.3, 77.5); high risk ≥ 3 years 54.5% (95% CI, 37.2, 79.9); 5-year EFS were standard risk 68.5% (95% CI, 57.2, 82.1); high risk < 3 years 40.0% (95% CI, 23.4, 68.4); and high risk ≥ 3 years 36.4% (95% CI, 20.9, 63.2); overall 55.2% (95% CI, 46.1, 66.1). Of 62/63 ≥ 5-year survivor, 9 died later from tumour relapse and 4 from second malignancy. Functional outcomes of 62 of the 63 ≥ 5-year survivors: 67.7% had educational issues requiring remedial input; 18% restricted mobility indoors and outdoors; 59.7% hearing impairment (42% prescribed aids).

CONCLUSIONS

1. Comparison of this single-institution series with its predecessor found that revised chemotherapy and RT protocols and greater accuracy of risk stratification did not result in statistically significant improvements in either survival or treatment-related functional disability. 2. Extended (> 5-year) follow-up is essential if 20% of late deaths from relapse and second malignancies are not to be overlooked.

Intelligence and posterior fossa tumors in Brazilian youth

Central nervous system tumors are the most frequent solid neoplasms in childhood and are frequently located in posterior fossa (PF). In Brazil, this diagnosis is associated to high mortality rates and this context is increasingly worrisome outside of large urban centers in which delayed diagnosis and defaulting from treatment compromise survivorship. Moreover, the lesion and therapeutic toxicity compromise cognitive domains. This study investigated the impact of PF tumors and their treatments on the intellectual capacity of 37 children and adolescents aged 6 to 16, divided into two groups: patients with low grade tumors, submitted only to neurosurgery (G1) and with tumors of higher malignancy submitted to neurosurgery, chemotherapy, and/or radiotherapy (G2). Using the Wechsler Intelligence Scales for Children, data reveal that G1 presented preserved mean performance, while G2 presented low average performance. Cluster-type analysis divided the participants into two groups regarding intelligence, clinical and sociodemographic variables. Inferential statistical analysis highlighted the influence of antineoplastic treatment on nonverbal domains. Mother's schooling demonstrated influence on verbal domains, revealing an important dissociation pattern. The results suggest the relevance of sociocultural factors on the expression of the damage, as well as the administration of radiotherapy at critical neurodevelopmental stages.

Longitudinal assessment of late-onset neurologic conditions in survivors of childhood central nervous system tumors: a Childhood Cancer Survivor Study report

Background

Survivors of childhood central nervous system (CNS) tumors experience high rates of treatment-related neurologic sequelae. Whether survivors continue to be at increased risk for new events as they age is unknown.

Methods

Adverse neurologic health conditions in 5-year survivors of CNS tumors from the Childhood Cancer Survivor Study (n = 1876) were evaluated longitudinally at a median 23.0 years from diagnosis (range, 5.1-38.9), median age at last evaluation 30.3 years (range, 6.1-56.4). Multivariable regression estimated hazard ratios (HRs) and 95% CIs.

Results

From 5 to 30 years post diagnosis, cumulative incidence increased for seizures from 27% to 41%, motor impairment 21% to 35%, and hearing loss 9% to 23%. Risks were elevated compared with siblings (eg, seizures HR: 12.7; 95% CI: 9.6-16.7; motor impairment HR: 7.6; 95% CI: 5.8-9.9; hearing loss HR: 18.4; 95% CI: 13.1-25.9). Regional brain doses of radiation therapy were associated with development of new deficits (eg, frontal ≥50 Gy and motor impairment HR: 2.0; 95% CI: 1.2-3.4). Increased risk for motor impairment was also associated with tumor recurrence (HR: 2.6; 95% CI: 1.8-3.8), development of a meningioma (HR: 2.3; 95% CI: 0.9-5.4), and stroke (HR: 14.9; 95% CI: 10.4-21.4). Seizure risk was doubled by recurrence (HR: 2.3; 95% CI: 1.6-3.2), meningioma (HR: 2.6; 95% CI: 1.1-6.5), and stroke (HR: 2.0; 95% CI: 1.1-3.4).

Conclusions

CNS tumor survivors remain at risk for new-onset adverse neurologic events across their lifespans at a rate greater than siblings. Cranial radiation, stroke, tumor recurrence, and development of meningioma were independently associated with late-onset adverse neurologic sequelae.

Childhood Medulloblastoma: Current Therapies, Emerging Molecular Landscape and Newer Therapeutic Insights

Background:

Medulloblastoma is the most common malignant brain tumor in children, currently treated uniformly based on histopathology and clinico-radiological risk stratification leading to unpredictable relapses and therapeutic failures. Identification of molecular subgroups have thrown light on the reasons for these and now reveals clues to profile molecularly based personalized therapy against these tumors.

Methods:

Research and online contents were evaluated for pediatric medulloblastoma which included latest information on the molecular subgroups and their clinical relevance and update on efforts to translate them into clinics.

Results:

Scientific endeavors over the last decade have clearly identified four molecular variants (WNT, SHH, Group 3, and Group 4) and their demographic, genomic, and epigenetic profile. Latest revelations include significant heterogeneity within these subgroups and 12 different subtypes of MB are now identified with disparate outcomes and biology. These findings have important implications for stratification and profiling future clinical trials against these formidable tumors.

Conclusion:

With the continued outpouring of genomic/epigenomic data of these molecular subgroups and evolution of further subtypes in each subgroup, the challenge lies in comprehensive evaluation of these informations. Current and future endeavors are now needed to profile personalized therapy for each child based on the molecular risk stratification of medulloblastoma, with a hope to improve survival outcome and reduce relapses.

Impact of miRNA-mRNA Profiling and Their Correlation on Medulloblastoma Tumorigenesis

Medulloblastoma (MB) is a clinically challenging, childhood brain tumor with a diverse genetic makeup and differential miRNA profile. Aiming to identify deregulated miRNAs in MB, the miRNA expression profile of human MB samples was compared to that of normal cerebellar tissues. As a result, 8 upregulated and 64 downregulated miRNAs were identified in MB samples. Although various algorithms have been developed to predict the interaction between miRNA-mRNA pairs, the complexity and fidelity of miRNA-mRNA remain a concern. Therefore, to identify the signatures of miRNA-mRNA interactions essential for MB pathogenesis, miRNA profiling, RNA sequencing, and ingenuity pathway analysis (IPA) were performed in the same primary human MB samples. Further, when miR-217 was inhibited, a significant upregulation of predicted target genes SIRT1, ROBO1, FOXO3, and SMAD7 in HDMB03 cells was observed, confirming the validity of our approach. Functional analysis revealed that the inhibition of miR-217 in HDMB03 cells suppresses colony formation, migration, invasion, promoted apoptosis, and arrested cell population in S phase, indicating that manipulation of miR-217 may have a therapeutic potential for MB patients. Therefore, our study provides an essential platform for future investigations of specific miRNAs responsible for MB pathogenesis.

Management and outcomes of treating pediatric medulloblastoma: an eight years' experience in an Iranian pediatric center

PURPOSE

The clinical management of pediatric medulloblastoma requires a multidisciplinary approach, which can be challenging, especially in low- and middle-income countries. The aim of this study was to identify current challenges and describe the treatment and outcomes of Iranian pediatric patients with medulloblastoma who were referred to our center in Tehran, Iran.

METHODS

Our retrospective review included 126 patient records from April 2007 to May 2015. The records were analyzed for epidemiologic features, treatment modalities, overall survival, and progression-free survival. Data were analyzed using SPSS 22.0 software.

RESULTS

Median age at diagnosis was 6 years (male:female ratio, 2.3:1). At the time of diagnosis, 7 patients were 2 years or younger, and 76 (60.3%) were categorized as having high-risk disease. Overall, 100 patients had gross or near-total surgical resection. Cerebral spinal fluid involvement was detected in 22.2% of the patients tested, and spinal involvement was detected in 25% of the patients who underwent spinal MRI. Metastasis stages at the time of diagnosis were as follows: M0: 48.4% patients, M1: 16.7%, M2: 5.5%, and M3: 21.4%. Median times of follow-up and progression-free survival were 16 and 12 months, respectively. Probability of 7-year overall survival and progression-free survival were 59 and 53.8%, respectively.

CONCLUSIONS

Results of the current retrospective study emphasize the need for implementing measures to improve outcome for our patients with medulloblastoma. Such measures include a multidisciplinary approach, unified national treatment guidelines, better disease and metastasis staging, twinning initiatives, and seeking a second opinion when needed.

Cerebellar mutism syndrome

Cerebellar mutism most commonly, but not exclusively, develops in children after surgery for midline cerebellar or intraventricular tumors in the posterior fossa, typically medulloblastoma. Cerebellar mutism syndrome (CMS) comprises a complex set of neurologic and neurocognitive signs and symptoms, the cardinal and central component of which is an initially profound but usually reversible speech disorder. As such, CMS is currently recognized as an extreme form of the so-called cerebellar cognitive affective syndrome (Schmahmann syndrome). The putative cause of CMS is a substantial surgical injury to the proximal components of the bilateral efferent cerebellar pathways, disrupting cerebellar input to the supratentorial brain. The resultant cerebellocerebral diaschisis may lead to supratentorial cortical perfusion depression with frontal predominance. The speech disorder is, therefore, likely an apraxia. As our understanding of the mechanism and the clinical spectrum of CMS evolves, clinically useful preoperative risk stratification schemes, adjustments to surgical strategies and techniques, and possible early therapeutic-rehabilitative measures are being sought and developed to reduce the burden of this severe and particularly handicapping chronic morbidity on affected individuals and their families.

Quality of life in long-term survivors treated for metastatic medulloblastoma with a hyperfractionated accelerated radiotherapy (HART) strategy

PURPOSE

An intensive therapeutic strategy for metastatic medulloblastoma was launched in 1998 in our Institution. The aim of this study was to examine the long-term quality of life (QoL) in survivor patients at least 3 years after the end of the treatment.

METHODS

Patients were asked to complete self-administered QoL questionnaires. An index of physical impairment (IPI) was scored (range 0-100; the lower the score the better) based on clinical objective observations. Patients were divided into two groups (lower IPI group, and higher IPI group) and descriptively compared accordingly.

RESULTS

The study was completed by 25/33 eligible patients. Despite patients with a higher IPI reported worse perceived health condition, they had better emotional and psychological scores than those with a lower IPI in all QoL questionnaires.

CONCLUSION

In our sample, patients with more severe objective and perceived physical impairments reported a better psychosocial QoL, possibly because the greater attention paid to them by society and family contributes to a better adjustment in long-term survivors. On this base, it should be recommended that all survivors receive a strong support as the most impaired patients.

Detection of lower levels of SNAP25 using multiple microarray systems and its functional significance in medulloblastoma

Medulloblastoma (MB) is the most common pediatric malignant brain tumor and patients with high-risk or recurrent MB respond poorly to current therapies, and have a higher related mortality. For this reason, potential molecules related to MB need be identified in order to develop targets for the development of novel therapeutics. In the present study, we compared MB microarray data obtained using different microarray systems and significant targets were selected by gene annotation and enrichment analysis. Genes for soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) annotated with the function 'vesicle' were identified and one of these proteins, synaptosomal-associated protein 25 (SNAP25), was found to have significantly lower expression levels in MB. In addition, SNAP25 was detected in a very low number of MB cells as shown by western blot analysis and immunohistochemical analyses of archived and formalin-fixed/paraffin-embedded human MB specimens. We found that SNAP25 altered the morphology and the chemotherapeutic effects of arabinofuranosyl cytidine (Ara-C) on SNAP25-expressing MB cells. On the whole, our data indicate that the expression of SNAP25 is crucial for dendrite formation and is associated with the effects of targeted chemotherapy. The detection of SNAP25 expression in MB cells may thus be essential for the chemotherapeutic application of Ara-C.

Demographics, patterns of care, and survival in pediatric medulloblastoma

We evaluated the American College of Surgeon's National Cancer Data Base (NCDB) to describe current hospital-based epidemiologic frequency, survival, and patterns of care of pediatric medulloblastoma. We analyzed NCDB 1998-2011 data on medulloblastoma for children ages 0-19 years using logistic and poisson regression, Kaplan-Meier survival estimates, and Cox proportional hazards models. 3647 cases of medulloblastoma in those aged 0-19 years were identified. Chemotherapy was received by 79 and 74% received radiation, with 65% receiving both therapies. Those who received radiation were more likely to be older than four, while those who received chemotherapy were more likely to be age four and younger. Variables associated with receipt of neither radiation nor chemotherapy included age at diagnosis of <1 year, female gender, being of race other than black or white, having no insurance, and living in a residential area with a low level of high school graduates. Better overall survival was observed as age at diagnosis increased, in females, and having received radiation. Compared to medulloblastoma, NOS, better survival was observed for those with demoplastic medulloblastoma, with worse survival in those with large cell medulloblastoma. Majority received multi- disciplinary therapy and radiation had the greatest effect on survival. Ages four and under were most likely to receive chemotherapy and least likely to receive radiation. Suboptimal treatment included 17.8% that did not receive chemotherapy, of which 11.8% received neither chemotherapy nor radiation. Disparities associated with medical access were characteristics for not receiving standard treatment, which resulted in poor outcome.

Integrated Proteomic and Transcriptomic-Based Approaches to Identifying Signature Biomarkers and Pathways for Elucidation of Daoy and UW228 Subtypes

Medulloblastoma (MB) is the most common malignant pediatric brain tumor. Patient survival has remained largely the same for the past 20 years, with therapies causing significant health, cognitive, behavioral and developmental complications for those who survive the tumor. In this study, we profiled the total transcriptome and proteome of two established MB cell lines, Daoy and UW228, using high-throughput RNA sequencing (RNA-Seq) and label-free nano-LC-MS/MS-based quantitative proteomics, coupled with advanced pathway analysis. While Daoy has been suggested to belong to the sonic hedgehog (SHH) subtype, the exact UW228 subtype is not yet clearly established. Thus, a goal of this study was to identify protein markers and pathways that would help elucidate their subtype classification. A number of differentially expressed genes and proteins, including a number of adhesion, cytoskeletal and signaling molecules, were observed between the two cell lines. While several cancer-associated genes/proteins exhibited similar expression across the two cell lines, upregulation of a number of signature proteins and enrichment of key components of SHH and WNT signaling pathways were uniquely observed in Daoy and UW228, respectively. The novel information on differentially expressed genes/proteins and enriched pathways provide insights into the biology of MB, which could help elucidate their subtype classification.

Cerebellar Mutism Syndrome following Midline Posterior Fossa Tumor Resection in Children: An Institutional Experience

Aim:

Cerebellar mutism (CM) syndrome is a well-known and annoying complication of posterior fossa surgery in the pediatric age group. Risk factors such as the type of tumor, size, involvement of posterior fossa structures and hydrocephalus, and postoperative cerebellar swelling for CM were investigated in this study.

Materials and Methods:

A consecutive series of 33 children with midline posterior fossa tumors were operated at the SMS Medical College and Hospital, Department of Neurosurgery, Jaipur India, between September 2015 and December 2016. Their speech and neuroradiological studies were systematically analyzed both preoperatively and postoperatively.

Results:

CM syndrome (CMS) developed in six children (18.18%) in the early postoperative period. The pre- and post-operative irritability, medulloblastoma histology, maximum size more than 45 mm, involvement of superior cerebellar peduncles, and vermian incision were significant single independent risk factors. In addition, male gender also associated with a higher risk for CMS. The latency for the development of mutism ranged from 1 to 12 days (mean 3.5 days). The speech returned to normal in all patients. All cases with CMS accompanied by cerebellar ataxia.

Conclusion:

The medulloblastoma, irritability, maximum size more than 45 mm, involvement of superior cerebellar peduncles, and vermian incision were significant single independent risk factors for postoperative pediatric CMS. Mutism after posterior fossa tumor resection is also accompanied with ataxia. CM usually has a self-limiting course and a favorable prognosis.

Changes in Imaging and Cognition in Juvenile Rats After Whole-Brain Irradiation

PURPOSE

In pediatric cancer survivors treated with whole-brain irradiation (WBI), long-term cognitive deficits and morbidity develop that are poorly understood and for which there is no treatment. We describe similar cognitive defects in juvenile WBI rats and correlate them with alterations in diffusion tensor imaging and magnetic resonance spectroscopy (MRS) during brain development.

METHODS AND MATERIALS

Juvenile Fischer rats received clinically relevant fractionated doses of WBI or a high-dose exposure. Diffusion tensor imaging and MRS were performed at the time of WBI and during the subacute (3-month) and late (6-month) phases, before behavioral testing.

RESULTS

Fractional anisotropy in the splenium of the corpus callosum increased steadily over the study period, reflecting brain development. WBI did not alter the subacute response, but thereafter there was no further increase in fractional anisotropy, especially in the high-dose group. Similarly, the ratios of various MRS metabolites to creatine increased over the study period, and in general, the most significant changes after WBI were during the late phase and with the higher dose. The most dramatic changes observed were in glutamine-creatine ratios that failed to increase normally between 3 and 6 months after either radiation dose. WBI did not affect the ambulatory response to novel open field testing in the subacute phase, but locomotor habituation was impaired and anxiety-like behaviors increased. As for cognitive measures, the most dramatic impairments were in novel object recognition late after either dose of WBI.

CONCLUSIONS

The developing brains of juvenile rats given clinically relevant fractionated doses of WBI show few abnormalities in the subacute phase but marked late cognitive alterations that may be linked with perturbed MRS signals measured in the corpus callosum. This pathomimetic phenotype of clinically relevant cranial irradiation effects may be useful for modeling, mechanistic evaluations, and testing of mitigation approaches.

Medulloblastoma

Medulloblastoma accounts for nearly 10% of all childhood brain tumors. These tumors occur exclusively in the posterior fossa and have the potential for leptomeningeal spread. Treatment includes a combination of surgery, radiation therapy (in patients >3 years old). Patients >3 years old are stratified based on the volume of postoperative residual tumor and the presence or absence of metastases into "standard risk" and "high risk" categories with long-term survival rates of approximately 85% and 70%, respectively. Outcomes are inferior in infants and children younger than 3 years with exception of those patients with the medulloblastoma with extensive nodularity histologic subtype. Treatment for medulloblastoma is associated with significant morbidity, especially in the youngest patients. Recent molecular subclassification of medulloblastoma has potential prognostic and therapeutic implications. Future incorporation of molecular subgroups into treatment protocols will hopefully improve both survival outcomes and posttreatment quality of life.

A School Passport as Part of a Protocol to Assist Educational Reintegration After Medulloblastoma Treatment in Childhood

BACKGROUND

Medulloblastoma is the most common malignant brain tumour in children and is treated with a combination of surgery, radiotherapy and chemotherapy. These children frequently experience long-term cognitive, social and physical sequelae, which significantly affect school reintegration.

AIM

This study aimed to explore school-return experiences to create a more structured school reintegration protocol for children postmedulloblastoma.

METHODS

A cohort of nine patients who had completed treatment and for whom full neuropsychometric data were available was included in the study (median time since diagnosis 8 years). Data were collected using qualitative parental questionnaires, semistructured interviews with teachers (n = 12) and healthcare professionals (HCPs) (n = 6) involved in their school reintegration. Thematic analysis was employed. A focus group with five HCPs was then used for data validation.

RESULTS

This study uncovered the following four main subjects: (1) Information sharing; (2) education and empowerment (of educational professionals (EP) and parents); (3) communication between parents, HCPs and EPs; and (4) long-term difficulties.

DISCUSSION

Implementation of a standardised protocol delivered within the structure of a school passport document would aid uniform follow-up. The proposed multistage protocol includes early communication and reintegration planning followed by meetings at school re-entry. Follow-up meetings are suggested to reduce information loss and reassess the child's needs. Hospital support at school transitions, inclusion of school data in long-term clinical follow-up and long-term rehabilitation are also recommended. Each stage would be supported by school passport documentation and would facilitate school and parental empowerment, paramount to the long-term sustainability of successful schooling.

Consensus paper on post-operative pediatric cerebellar mutism syndrome: the Iceland Delphi results

INTRODUCTION

Confusion has surrounded the description of post-operative mutism and associated morbidity in pediatric patients with cerebellar tumors for years. The heterogeneity of definitions and diagnostic features has hampered research progress within the field, and to date, no international guidelines exist on diagnosis, prevention, treatment, or follow-up of this debilitating condition. An international group of clinicians and researchers from multiple relevant disciplines recently formed a cohesive panel to formulate a new working definition and agree upon standardized methods for diagnosis and follow-up.

METHODS

Consensus was obtained using the modified nominal group technique, involving four rounds of online Delphi questionnaires interspersed with a structured consensus conference with lectures, group work, and open discussion sessions.

RESULTS

A new, proposed definition of "post-operative pediatric CMS" was formed, preliminary recommendations for diagnostic and follow-up procedures were created, two working groups on a new scoring scale and risk prediction and prevention were established, and areas were identified where further information is needed.

DISCUSSION

The consensus process was motivated by desire to further research and improve quality of life for pediatric brain tumor patients. The Delphi rounds identified relevant topics and established basic agreement, while face-to-face engagement helped resolve matters of conflict and refine terminology. The new definition is intended to provide a more solid foundation for future clinical and research work. It is thought as a consensus for moving forward and hopefully paves the way to developing a standard approach to this challenging problem with the advent of better scoring methods and ultimate goal of reducing the risk of CMS.

Psychosocial profile of pediatric brain tumor survivors with neurocognitive complaints

PURPOSE

With more children surviving a brain tumor, neurocognitive consequences of the tumor and its treatment become apparent, which could affect psychosocial functioning. The present study therefore aimed to assess psychosocial functioning of pediatric brain tumor survivors (PBTS) in detail.

METHODS

Psychosocial functioning of PBTS (8-18 years) with parent-reported neurocognitive complaints was compared to normative data on health-related quality of life (HRQOL), self-esteem, psychosocial adjustment, and executive functioning (one-sample t tests) and to a sibling control group on fatigue (independent-samples t test). Self-, parent-, and teacher-report questionnaires were included, where appropriate, providing complementary information.

RESULTS

Eighty-two PBTS (mean age 13.4 years, SD 3.2, 49 % males) and 43 healthy siblings (mean age 14.3, SD 2.4, 40 % males) were included. As compared to the normative population, PBTS themselves reported decreased physical, psychological, and generic HRQOL (d = 0.39-0.62, p < 0.008). Compared to siblings, increased fatigue-related concentration problems (d = 0.57, p < 0.01) were reported, although self-reported self-esteem and psychosocial adjustment seemed not to be affected. Parents of PBTS reported more psychosocial (d = 0.81, p < 0.000) and executive problems (d = 0.35-0.43, p < 0.016) in their child than parents of children in the normative population. Teachers indicated more psychosocial adjustment problems for female PBTS aged 8-11 years than for the female normative population (d = 0.69, p < 0.025), but they reported no more executive problems.

CONCLUSIONS

PBTS with parent-reported neurocognitive complaints showed increased psychosocial problems, as reported by PBTS, parents, and teachers.

IMPLICATIONS FOR CANCER SURVIVORS

Systematic screening of psychosocial functioning is necessary so that tailored support from professionals can be offered to PBTS with neurocognitive complaints.

Antioxidative enzymes in irradiated rat brain-indicators of different regional radiosensitivity

PURPOSE

Previously, we examined manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), and catalase (CAT) activities in rat brain irradiated with 2 or 3 Gy of γ-rays. The results indicated that lower MnSOD activity and inducibility found in hippocampus might explain higher radiosensitivity of this brain region. Thus, in this study, we wanted to determine changes of MnSOD, CuZnSOD, and CAT activities after dose of 5 Gy and to find out if differences in MnSOD activity are caused by changes in its expression.

METHODS

Heads of 4-day-old female rats were irradiated with γ-rays, using (60)Co. Animals were sacrificed 1/24 h after exposure. Hippocampus and cortex tissues were prepared for enzyme activity measurements and Western blot analysis.

RESULTS

One hour after exposure, γ-rays significantly decreased MnSOD activity in both examined brain regions. Twenty-four hours later, MnSOD recovery showed dose and regional dependence. It was weaker at higher doses and in hippocampal region. MnSOD expression changed in the similar manner as MnSOD activity only at lower doses of γ-rays. In both examined brain regions, gamma radiation significantly decreased CuZnSOD activity and did not change activity of CAT.

CONCLUSIONS

Our results confirmed that MnSOD plays an important role in different regional radiosensitivity but also showed that depending on dose, radiation affects MnSOD level by utterly different mechanisms. Postradiation changes of CuZnSOD and CAT are not regionally specific and therefore, cannot account for the different radiosensitivity of the hippocampus and cortex.

Evolving molecular era of childhood medulloblastoma: time to revisit therapy

Currently medulloblastoma is treated with a uniform therapeutic approach based on histopathology and clinico-radiological risk stratification, resulting in unpredictable treatment failure and relapses. Improved understanding of the biological, molecular and genetic make-up of these tumors now clearly identifies it as a compendium of four distinct subtypes (WNT, SHH, group 3 and 4). Advances in utilization of the genomic and epigenomic machinery have now delineated genetic aberrations and epigenetic perturbations in each subgroup as potential druggable targets. This has resulted in endeavors to profile targeted therapy. The challenge and future of medulloblastoma therapeutics will be to keep pace with the evolving novel biological insights and translating them into optimal targeted treatment regimens.

Strategies to improve the quality of survival for childhood brain tumour survivors

BACKGROUND

Tumours of the central nervous system (CNS) are the most frequent solid tumours and the second most frequent type of cancer in children and adolescents. Overall survival has continuously improved in Germany, since an increasing number of patients have been treated according to standardised, multicentre, multimodal treatment recommendations, trials of the German Paediatric Brain Tumour Consortium (HIT-Network) or the International Society of Paediatric Oncology-Europe (SIOP-E) during the last decades. Today, two out of three patients survive. At least 8000 long-term childhood brain tumour survivors (CBTS) are currently living in Germany. They face lifelong disease- and treatment-related late effects (LE) and associated socioeconomic problems more than many other childhood cancer survivors (CCS).

METHOD

We review the LE and resulting special needs of this particular group of CCS.

RESULTS

Despite their increasing relevance for future treatment optimisation, neither the diversity of chronic and cumulative LE nor their pertinent risk factors and subsequent impact on quality of survival have yet been comprehensively addressed for CBTS treated according to HIT- or SIOP-E-protocols. Evidence-based information to empower survivors and stakeholders, as well as medical expertise to manage their individual health care, psychosocial and educational/vocational needs must still be generated and established.

CONCLUSION

The establishment of a long-term research- and care network in Germany shall contribute to a European platform, that aims at optimising CBTSs' transition into adulthood as resilient individuals with high quality of survival including optimal levels of activity, participation and acceptance by society.

Clinical implications of medulloblastoma subgroups: incidence of CSF diversion surgery

OBJECT

While medulloblastoma was initially thought to comprise a single homogeneous entity, it is now accepted that it in fact comprises 4 discrete subgroups, each with its own distinct demographics, clinical presentation, transcriptomics, genetics, and outcome. Hydrocephalus is a common complication of medulloblastoma and not infrequently requires CSF diversion. The authors report the incidence of CSF diversion surgery in each of the subgroups of medulloblastoma (Wnt, Shh, Group 3, and Group 4).

METHODS

The medical and imaging records for patients who underwent surgery for medulloblastoma at The Hospital for Sick Children were retrospectively reviewed. The primary outcome was the requirement for CSF diversion surgery either before or within 60 days of tumor resection. The modified Canadian Preoperative Prediction Rule for Hydrocephalus (mCPPRH) was compared among subgroups.

RESULTS

Of 143 medulloblastoma patients, treated from 1991 to 2013, sufficient data were available for 130 patients (15 with Wnt, 30 with Shh, 30 with Group 3, and 55 with Group 4 medulloblastomas). Of these, 28 patients (22%) ultimately underwent CSF diversion surgery: 0% with Wnt, 29% with Shh, 29% with Group 3, and 43% with Group 4 tumors. Patients in the Wnt subgroup had a lower incidence of CSF diversion than all other patients combined (p = 0.04). Wnt patients had a lower mCPPRH score (lower risk of CSF diversion, p = 0.045), were older, had smaller ventricles at diagnosis, and had no leptomeningeal metastases.

CONCLUSIONS

The overall rate of CSF diversion surgery for Shh, Group 3, and Group 4 medulloblastomas is around 30%, but no patients in the present series with a Wnt medulloblastoma required shunting. The low incidence of hydrocephalus in patients with Wnt medulloblastoma likely reflects both host factors (age) and disease factors (lack of metastases). The absence of hydrocephalus in patients with Wnt medulloblastomas likely contributes to their excellent rate of survival and may also contribute to a higher quality of life than for patients in other subgroups.