Pediatric glioblastoma

Glioblastoma in children, when compared with adults, is relatively rare.

Despite this rarity, it is apparent from the limited number of publications that pediatric glioblastoma is quite distinct from their adult counterparts. The differences pertain to the molecular genetics, effectiveness of the adjuvant therapies, and possibly the prognosis after treatment. With a plethora of path-breaking translational research coming through in recent times, a host of new information is now available on pediatric glioblastomas that holds great promise as far as the future treatment options are concerned 1)

In contrast to adult GBM, few molecular prognostic markers for the pediatric counterpart have been established.


Some anaplastic pleomorphic xanthoastrocytomas (PXA) were reported to have extremely poor prognosis which showed a type of pediatric glioblastoma (GBM) molecular profile. Recent integrated molecular classification for primary central nervous system tumors proposed some differences between histological and molecular features. Herein, in a genome-wide molecular analysis, Nakamura et al., showed an extreme aggressive anaplastic PXA that resulted in a pediatric GBM molecular profile. A full implementation of the molecular approach is the key to predict prognosis and decide the treatment strategy for anaplastic PXA 2).


Korshunov et al. investigated the prognostic significance of genomic and epigenetic alterations through molecular analysis of 202 pedGBM (1-18 years) with comprehensive clinical annotation. Routinely prepared formalin-fixed paraffin-embedded tumor samples were assessed for genome-wide DNA methylation profiles, with known candidate genes screened for alterations via direct sequencing or FISH. Unexpectedly, a subset of histologically diagnosed GBM (n = 40, 20 %) displayed methylation profiles similar to those of either low-grade gliomas or pleomorphic xanthoastrocytomas (PXA). These tumors showed a markedly better prognosis, with molecularly PXA-like tumors frequently harboring BRAF V600E mutations and 9p21 (CDKN2A) homozygous deletion. The remaining 162 tumors with pedGBM molecular signatures comprised four subgroups: H3.3 G34-mutant (15 %), H3.3/H3.1 K27-mutant (43 %), IDH1-mutant (6 %), and H3/IDH wild-type (wt) GBM (36 %). These subgroups were associated with specific cytogenetic aberrations, MGMT methylation patterns and clinical outcomes. Analysis of follow-up data identified a set of biomarkers feasible for use in risk stratification: pedGBM with any oncogene amplification and/or K27M mutation (n = 124) represents a particularly unfavorable group, with 3-year overall survival (OS) of 5 %, whereas tumors without these markers (n = 38) define a more favorable group (3-year OS ~70 %).Combined with the lower grade-like lesions, almost 40 % of pedGBM cases had distinct molecular features associated with a more favorable outcome. This refined prognostication method for pedGBM using a molecular risk algorithm may allow for improved therapeutic choices and better planning of clinical trial stratification for this otherwise devastating disease 3)

Treatment

Total resection and receiving chemotherapy adjuvant to radiation or chemoradiation (CRT) are most closely associated with improved progression free survival (PFS) and overall survival (OS). For higher risk incompletely resected patients, temozolomide use and treatment intensification with concurrent CRT, adjuvant chemotherapy, and higher radiation dose were associated with improved outcomes 4).

Bevacizumab and irinotecan are a promising regimen for pediatric cases of recurrent glioblastoma after gross-total resection, although the optimal treatment schedule must be determined on a patient-by-patient basis 5).

Case reports

A rare case of primary pediatric glioblastoma multiforme in a 7-year-old girl with Turner’s syndrome is reported, and various aspects regarding clinical and pathophysiological issues have been discussed. Although Turner’s syndrome is not one of the congenital chromosomal abnormalities which demand routine CNS screening, neurological assessment may be of value in those with relevant clinical findings 6).

1)

Das KK, Kumar R. Pediatric Glioblastoma. In: De Vleeschouwer S, editor. Glioblastoma [Internet]. Brisbane (AU): Codon Publications; 2017 Sep 27. Chapter 15. Available from http://www.ncbi.nlm.nih.gov/books/NBK469983/ PubMed PMID: 29251872.
2)

Nakamura T, Fukuoka K, Nakano Y, Yamasaki K, Matsushita Y, Yamashita S, Ikeda J, Udaka N, Tanoshima R, Shiba N, Tateishi K, Yamanaka S, Yamamoto T, Hirato J, Ichimura K. Genome-wide DNA methylation profiling shows molecular heterogeneity of anaplastic pleomorphic xanthoastrocytoma. Cancer Sci. 2019 Jan 4. doi: 10.1111/cas.13903. [Epub ahead of print] PubMed PMID: 30609203.
3)

Korshunov A, Ryzhova M, Hovestadt V, Bender S, Sturm D, Capper D, Meyer J, Schrimpf D, Kool M, Northcott PA, Zheludkova O, Milde T, Witt O, Kulozik AE, Reifenberger G, Jabado N, Perry A, Lichter P, von Deimling A, Pfister SM, Jones DT. Integrated analysis of pediatric glioblastoma reveals a subset of biologically favorable tumors with associated molecular prognostic markers. Acta Neuropathol. 2015 Mar 10. [Epub ahead of print] PubMed PMID: 25752754.
4)

Walston S, Hamstra DA, Oh K, Woods G, Guiou M, Olshefski RS, Chakravarti A, Williams TM. A multi-institutional experience in pediatric high-grade glioma. Front Oncol. 2015 Feb 18;5:28. doi: 10.3389/fonc.2015.00028. eCollection 2015. PubMed PMID: 25741472; PubMed Central PMCID: PMC4332307.
5)

Umeda K, Shibata H, Saida S, Hiramatsu H, Arakawa Y, Mizowaki T, Nishiuchi R, Adachi S, Heike T, Watanabe K. Long-term efficacy of bevacizumab and irinotecan in recurrent pediatric glioblastoma. Pediatr Int. 2015 Feb;57(1):169-71. doi: 10.1111/ped.12414. PubMed PMID: 25711258.
6)

Hanaei S, Habibi Z, Nejat F, Sayarifard F, Vasei M. Pediatric Glioblastoma Multiforme in Association with Turner’s Syndrome: A Case Report. Pediatr Neurosurg. 2015 Feb 25. [Epub ahead of print] PubMed PMID: 25720952.

Dravet Syndrome

Dravet syndrome, previously known as severe myoclonic epilepsy of infancy (SMEI), is a type of epilepsy with seizures that are often triggered by hot temperatures or fever.

Dravet and Bureau in 1981 described “benign myoclonic epilepsy in infancy” in 7 normal children with onset of myoclonic seizures in the first 3 years of life 1). The syndrome was defined as including myoclonic seizures only, except rare simple febrile seizures, with good prognosis regarding response to therapy and cognitive functions.

Dravet Syndrome (DS) is a severe epileptic encephalopathy of childhood involving intractable seizures, recurrent status epilepticus and cognitive decline. Because DS is a rare disease, available data is limited and evidence-based treatment guidelines are lacking.

Both VNS and corpus callosotomy (CC) can be effective at reducing seizure frequency. Patients with DS may benefit from earlier and more aggressive surgical intervention. Studies using larger patient cohorts will help clarify the role that surgery may play in the multidisciplinary approach to controlling seizures in DS. Further studies will help determine the appropriate timing of and type of surgical intervention 2).

Loss of function in the Scn1a gene leads to Dravet syndrome (DS). Reduced excitability in cortical inhibitory neurons is thought to be the major cause of DS seizures.

Ritter-Makinson et al., showed enhanced excitability in thalamic inhibitory neurons that promotes the non-convulsive seizures that are a prominent yet poorly understood feature of DS. In a mouse model of DS with a loss of function in Scn1a, reticular thalamic cells exhibited abnormally long bursts of firing caused by the downregulation of calcium-activated potassium SK channels. The study supports a mechanism in which loss of SK activity causes the reticular thalamic neurons to become hyperexcitable and promote non-convulsive seizures in DS. They propose that reduced excitability of inhibitory neurons is not global in DS and that non-GABAergic mechanisms such as SK channels may be important targets for treatment 3).


Vagus nerve stimulation (VNS) is an established neurostimulation treatment for intractable epilepsy, however little evidence is published on its efficacy in patients with DS.

Dibué-Adjei et al., performed a meta-analysis of all peer-reviewed English language studies reporting seizure outcomes of patients with DS treated with adjunctive vagus nerve stimulation. The primary and secondary outcome measures were ≥50% reduction of seizures or of the most-debilitating seizure type and seizure reduction per patient.

13 studies comprising 68 patients met the inclusion criteria of which 11 were single-center retrospective case series, one was a multi-center retrospective analysis and one was a case report. 52.9% of patients experienced a ≥50% reduction of seizures and the average seizure reduction, which could only be assessed in n=28 patients was 50.8%. 7 out of 13 studies reported additional benefits of VNS, however this could not be assessed systematically.

Vagus nerve stimulation appears to reduce seizure frequency in patients with DS. Based on this preliminary analysis, controlled trials of VNS in this rare condition using patient-centric outcome measures are indicated 4).

1)

Dravet C, Bureau M. [The benign myoclonic epilepsy of infancy (author’s transl)]. Rev Electroencephalogr Neurophysiol Clin. 1981 Dec;11(3-4):438-44. French. PubMed PMID: 6808601.
2)

Dlouhy BJ, Miller B, Jeong A, Bertrand ME, Limbrick DD Jr, Smyth MD. Palliative epilepsy surgery in Dravet syndrome-case series and review of the literature. Childs Nerv Syst. 2016 Sep;32(9):1703-8. doi: 10.1007/s00381-016-3201-4. Epub 2016 Jul 27. Review. PubMed PMID: 27465677.
3)

Ritter-Makinson S, Clemente-Perez A, Higashikubo B, Cho FS, Holden SS, Bennett E, Chkaidze A, Eelkman Rooda OHJ, Cornet MC, Hoebeek FE, Yamakawa K, Cilio MR, Delord B, Paz JT. Augmented Reticular Thalamic Bursting and Seizures in Scn1a-Dravet Syndrome. Cell Rep. 2019 Jan 2;26(1):54-64.e6. doi: 10.1016/j.celrep.2018.12.018. PubMed PMID: 30605686.
4)

Dibué-Adjei M, Fischer I, Steiger HJ, Kamp MA. Efficacy of adjunctive vagus nerve stimulation in patients with Dravet syndrome: A meta-analysis of 68 patients. Seizure. 2017 Aug;50:147-152. doi: 10.1016/j.seizure.2017.06.007. Epub 2017 Jun 17. Review. PubMed PMID: 28666193.

Biodegradable wafer

One of the therapeutic options for Glioblastoma multiforme includes placing biodegradable wafers releasing BCNU (Gliadel®) into the tumor bed at the time of surgical removal of the tumor. Due to the significant benefit this polymer technology has had clinically, Shapira-Furman et al., from Johns Hopkins Hospital have prepared wafers releasing Temozolomide (TMZ), TMZ delivered via polymer wafer could be used as a complementary treatment with or as an alternative to Gliadel®. TMZ is an alkylating agent which is water soluble. To remain comparable with the preclinical studies that led to Gliadel® the same size of wafers were formulated with TMZ. Wafers were loaded with 50% w/w TMZ in poly(lactic acid-glycolic acid) (PLGA) and showed reliable release of high dose TMZ for a period of 4 weeks. To achieve this 30-day release of the highly water soluble drug, they developed an encapsulation method, where the drug powder was first coated with the polymer to form core-shell particles in which the coating shell served as a rate controlling membrane for the drug particles. Wafers were also made with a co-loading of TMZ and BCNU. All wafers were tested in vivo by treating an intracranial 9L gliosarcoma model in F344 rats. Rats that were either untreated or treated with blank wafer died within 11 days while the median survival for rats treated with systemic TMZ was 18 days. The group that received the BCNU alone wafer had a median survival of 15 days, the group that received the TMZ wafer alone had a median survival of 19 days, and the group treated with the BCNU-TMZ wafer had a median survival of 28 days with 25% of the animals living long term (p < .0038 vs. Control; p < .001 vs. Blank Polymer). These findings demonstrate the potential of this newly designed wafer for treating GBM. Moreover, this concept, can pave the way for other drug combinations that may improve the clinical application of numerous agents to treat solid tumors 1).

1)

Shapira-Furman T, Serra R, Gorelick N, Doglioli M, Tagliaferri V, Cecia A, Peters M, Kumar A, Rottenberg Y, Langer R, Brem H, Tyler B, Domb AJ. Biodegradable wafers releasing Temozolomide and Carmustine for the treatment of brain cancer. J Control Release. 2018 Dec 31. pii: S0168-3659(18)30753-3. doi: 10.1016/j.jconrel.2018.12.048. [Epub ahead of print] PubMed PMID: 30605703.
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