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diffuse_intrinsic_pontine_glioma

Diffuse intrinsic pontine glioma

see also Diffuse midline glioma H3 K27M-mutant.

Diffuse midline glioma H3 K27M-mutant includes tumors previously referred to as diffuse intrinsic pontine glioma (DIPG). The identification of this phenotypically and molecularly defined set of tumors provides a rationale for therapies directed against the effects of these mutations.

Epidemiology

Approximately 300 children are diagnosed with diffuse intrinsic pontine gliomas (DIPG) each year, usually between the ages of 5 and 9.

They account for 10% to 25% of pediatric brain tumors.

The majority of DIPGs are astrocytic, infiltrative, and localized to the pons.

Etiology

The majority of the tumors were positive for GFAP (24/24), MIB1 (23/24), OLIG2 (22/24), p16 (20/24), p53 (20/24), SOX2 (19/24), EGFR (16/24), and BMI1 (9/24). The results suggest that dysregulation of EGFR and p53 may play an important role in the development of DIPGs. The majority of DIPGs express stem cell markers such as SOX2 and OLIG2, consistent with a role for tumor stem cells in the origin and maintenance of these tumors 1).

Results suggest that dual targeting of NOTCH and MYCN in DIPG may be an effective therapeutic strategy in DIPG and that adding a γ-secretase inhibitor during radiation therapy may be efficacious initially or during reirradiation 2).

Clinical Features

The symptoms of DIPG usually develop very rapidly prior to diagnosis, reflecting the fast growth of these tumors. Most patients start experiencing symptoms less than three months—and often less than three weeks—before diagnosis. The most common symptoms include:

Rapidly developing problems controlling eye movements, facial expressions, speech, chewing, and swallowing (due to problems in the cranial nerves) Weakness in the arms and legs

Problems with walking and coordination.

Diagnosis

Frameless robotic assisted biopsy of DIPG in pediatric population is an easier, effective, safe and highly accurate method to achieve diagnosis 3).


After the start of the era of biopsy, DIPGs bearing Histone H3K27 mutations have been reclassified into a novel entity, diffuse midline glioma, based on the presence of this molecular alteration. However, it is not well established how clinically diagnosed DIPG overlap with H3 K27-mutated diffuse midline gliomas, and whether rare long-term survivors also belong to this group 4).


Platelet-derived growth factor receptor A is altered by amplification and/or mutation in diffuse intrinsic pontine glioma (DIPG).

A retrospective review of magnetic resonance imaging (MRI) scanning in a pure population of DIPG was undertaken. Baseline diagnostic MRI findings included; local tumour extension in upper medulla (74%) or midbrain (62%), metastatic disease (3%), basilar artery encasement (82%), necrosis (33%), intratumoural haemorrhage (26%), hydrocephalus (23%) and dorsal exophytic component (18%). Post-treatment MRI scans demonstrated increases in; leptomeningeal metastatic disease (16%), cystic change/necrosis (48%), enhancement (72%) and intratumoural haemorrhage (32%). Response rates were calculated according to both RECIST (4%) and WHO (24%) criteria. No MRI parameter in either the diagnostic or response scans had prognostic significance 5).


Accurately determining diffuse intrinsic pontine glioma (DIPG) tumor volume is clinically important.

Eight patients from a Phase I clinical trial testing convection-enhanced delivery (CED) of a therapeutic antibody were included in the study. Pre-CED, post-radiation therapy axial T2-weighted images were analyzed using 2 methods requiring high degrees of subjective judgment (picture archiving and communication system [PACS] polygon and Volume Viewer auto-contour methods) and 1 method requiring a low degree of subjective judgment (k-means clustering segmentation) to determine tumor volumes. Lin's concordance correlation coefficients (CCCs) were calculated to assess interobserver agreement. RESULTS The CCCs of measurements made by 2 observers with the PACS polygon and the Volume Viewer auto-contour methods were 0.9465 (lower 1-sided 95% confidence limit 0.8472) and 0.7514 (lower 1-sided 95% confidence limit 0.3143), respectively. Both were considered poor agreement. The CCC of measurements made using k-means clustering segmentation was 0.9938 (lower 1-sided 95% confidence limit 0.9772), which was considered substantial strength of agreement.

The poor interobserver agreement of PACS polygon and Volume Viewer auto-contour methods highlighted the difficulty in consistently measuring DIPG tumor volumes using methods requiring high degrees of subjective judgment. k-means clustering segmentation, which requires a low degree of subjective judgment, showed better interobserver agreement and produced tumor volumes with delineated borders 6).

Biopsy

The place of stereotactic biopsy in the management of Diffuses Intrinsic Pontine Gliomas (DIPG) in children has changed over the years.

Due to the improvement of neurosurgical technics, it regained credit. Moreover, the era of targeted therapy with molecular and genomic discoveries paved the way to research protocol that requires a biopsy to include the patient. Nonetheless, stereotactic biopsy remains a surgical procedure with its risks. A complication has never been reported in case of a biopsy of a DIPG : metastatic seeding along the tract of the biopsy. Beuriat et al report the first two cases in the literature 7).

Nevertheless, most neurosurgical teams are reluctant to perform biopsy in pediatric patients, citing potential risks and lack of direct benefit. Yet, in reviewing 90 patients with and the published data on brainstem biopsy, these procedures have a diagnostic yield and morbidity and mortality rates similar to those reported for other brain locations. In addition, the quality and quantity of the material obtained confirm the diagnosis and inform an extended molecular screen, including biomarker study-information important to designing next-generation trials with targeted agents. Stereotactic biopsies can be considered a safe procedure in well-trained neurosurgical teams and could be incorporated in well-defined protocols for patients with DIPG 8).

Treatment

Outcome

Complications

1)
Ballester LY, Wang Z, Shandilya S, Miettinen M, Burger PC, Eberhart CG, Rodriguez FJ, Raabe E, Nazarian J, Warren K, Quezado MM. Morphologic characteristics and immunohistochemical profile of diffuse intrinsic pontine gliomas. Am J Surg Pathol. 2013 Sep;37(9):1357-64. doi: 10.1097/PAS.0b013e318294e817. PubMed PMID: 24076776; PubMed Central PMCID: PMC3787318.
2)
Taylor IC, Hütt-Cabezas M, Brandt WD, Kambhampati M, Nazarian J, Chang HT, Warren KE, Eberhart CG, Raabe EH. Disrupting NOTCH Slows Diffuse Intrinsic Pontine Glioma Growth, Enhances Radiation Sensitivity, and Shows Combinatorial Efficacy With Bromodomain Inhibition. J Neuropathol Exp Neurol. 2015 Jun 25. [Epub ahead of print] PubMed PMID: 26115193.
3)
Coca HA, Cebula H, Benmekhbi M, Chenard MP, Entz-Werle N, Proust F. Diffuse intrinsic pontine gliomas in children: Interest of robotic frameless assisted biopsy. A technical note. Neurochirurgie. 2016 Dec;62(6):327-331. doi: 10.1016/j.neuchi.2016.07.005. PubMed PMID: 28120771.
4)
Porkholm M, Raunio A, Vainionpää R, Salonen T, Hernesniemi J, Valanne L, Satopää J, Karppinen A, Oinas M, Tynninen O, Pentikäinen V, Kivivuori SM. Molecular alterations in pediatric brainstem gliomas. Pediatr Blood Cancer. 2017 Aug 9. doi: 10.1002/pbc.26751. [Epub ahead of print] PubMed PMID: 28792659.
5)
Hargrave D, Chuang N, Bouffet E. Conventional MRI cannot predict survival in childhood diffuse intrinsic pontine glioma. J Neurooncol. 2008 Feb;86(3):313-9. Epub 2007 Oct 2. PubMed PMID: 17909941.
6)
Singh R, Zhou Z, Tisnado J, Haque S, Peck KK, Young RJ, Tsiouris AJ, Thakur SB, Souweidane MM. A novel magnetic resonance imaging segmentation technique for determining diffuse intrinsic pontine glioma tumor volume. J Neurosurg Pediatr. 2016 Jul 8:1-8. [Epub ahead of print] PubMed PMID: 27391980.
7)
Beuriat PA, Szathmari A, Di Rocco F, Kanold J, Mottolese C, Frappaz D. Diffuse Intrinsic Pontine Glioma in children : document or treat ? World Neurosurg. 2016 Jul 12. pii: S1878-8750(16)30533-2. doi: 10.1016/j.wneu.2016.07.011. [Epub ahead of print] PubMed PMID: 27422681.
8)
Puget S, Blauwblomme T, Grill J. Is biopsy safe in children with newly diagnosed diffuse intrinsic pontine glioma? Am Soc Clin Oncol Educ Book. 2012:629-33. doi: 10.14694/EdBook_AM.2012.32.629. PubMed PMID: 24451809.
diffuse_intrinsic_pontine_glioma.txt · Last modified: 2019/08/03 17:52 by administrador