**13. Chemotherapy**

High-dose chemotherapy with or without support by autologous stem cell transplantation, especially in children below the age of 3 years [25].

Palliative chemotherapy:


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**Table 3.**

complex 1 [34].

**14.2 High grade glioma**

clinical characteristics:

Pilocytic astrocytoma

Pilomyxoid astrocytoma Diffuse astrocytoma

Subependymal giant cell astrocytoma

Pleomorphic xanthoastrocytoma

*WHO grades of pediatric astrocytic tumours [28].*

*An Overview of Pediatric CNS Malignancies DOI: http://dx.doi.org/10.5772/intechopen.88189*

**14. Special tumor types astrocytic tumor**

**14.1 Genomic alterations low grade glioma**

localized predominantly in the posterior fossa and brainstem [27].

activation of *BRAF* and the ERK/MAPK pathway [29]

survival (PFS) and overall survival (OS) [31].

Astrocytomas are the most common pediatric brain tumors, accounting for 7–8% of all childhood cancers [26]. Approximately 40% of all pediatric brain tumours are low grade astrocytoma, whereas most common primary CNS malignancy in adults being high grade astrocytoma [7]. Pediatric brain tumors are typically infratentorial,

Pediatric astrocytic tumours are further sub-classified by WHO grades (**Table 3**).

1.Most common genomic modification in cases of pilocytic astrocytoma involves

2.Alternative *BRAF* gene fusions, *RAF1* rearrangements, *RAS* mutations, and *BRAF* V600E point mutations are less commonly observed in such cases [30].

3.Presence of the *BRAF-KIAA1549* fusion gene shows better progression-free

4.Other pediatric low-grade gliomas (e.g., pilomyxoid astrocytoma) are also associated with *BRAF* activation through the *BRAF-KIAA1549* fusion [32].

5.In 53% pediatric grade II diffuse astrocytomas, the most common alterations reported are rearrangements in the MYB family of transcription factors [33].

Children having mutation in one of two tuberous sclerosis genes (*TSC1*/ hamartin or *TSC2*/tuberin) are at a risk of developing Subependymal giant cell astrocytomas, cortical tubers, and subependymal nodules, as either of these mutations results in activation of the mammalian target of rapamycin (mTOR)

The following pediatric high-grade glioma subgroups were identified on the basis of their DNA methylation patterns, and they show distinctive molecular and

1.Histone K27-mutation: **H3.3 (***H3F3A***) and H3.1 (***HIST1H3B* **and, rarely,**  *HIST1H3C***) mutation at K27**. These cases occur predominantly in mid

**Astrocytic tumour Grade**

Anaplastic astocytoma III Glioblastoma giant glioblastoma gliosarcoma IV

I

II

*Current Cancer Treatment*

• Tumor debulking

**12. Radiotherapy**

pediatric brain development.

**13. Chemotherapy**

Palliative chemotherapy:

• May induce transient remission

• Increases the quality of life

eration of the toxicities

radiotherapy without increasing the side effects [24].

• Diversion of CSF (shunting)

• Complete tumor resection [5]

In the literature, overall surgical morbidity rates vary from 10 to 54%. The rates highly depend on the location of the tumour, grade and propensity to disseminate [21].

Radiotherapy plays an important role in the management of pediatric brain tumours. It can be used either as adjuvant treatment in case of resectable tumours

The most common long term side effect of radiotherapy in pediatric age group is neurocognitive dysfunction and upto 20–60% patients suffer from neurocognitive deficit as a long term sequelae of radiotherapy [23]. Sophisticated radiotherapy techniques are warranted for to avoid future negative impacts of radiation on

Use of better immobilization and more suitable imaging techniques like highresolution brain imaging with computed tomography (CT) and magnetic resonance imaging (MRI) to accurately define the tumour limits and precisely assess the normal brain structures has greatly improved the degree of efficacy achieved by

Technological advancements like use of conformal radiotherapy allows high radiation dose distributions within targeted tissues while simultaneously attempting to reduce dose to surrounding normal tissues. Conformal radiotherapy can be accomplished through a variety of techniques, including intensity-modulated radiotherapy (IMRT), stereotactic radiotherapy and proton beam therapy.

IMRT has shown promise in the treatment of a number of disease sites and is now being investigated in the use of pediatric tumors to reduce long-term toxicity. Stereotactic technique has the ability to reduce the treatment volume as it delivers highly conformal radiation to brain tumours and minimum dose to surrounding brain tissue. It can be delivered as stereotactic radiosurgery in which the entire dose is delivered as a single fraction or as fractionated stereotactic radiotherapy (FSRT) in which the treatment is delivered over weeks with multiple daily fractions. Only small margins of several millimeters are used for brain tumors, greatly reducing the

volume of normal brain parenchyma receiving high doses of radiation.

transplantation, especially in children below the age of 3 years [25].

High-dose chemotherapy with or without support by autologous stem cell

• The benefits of chemotherapy or other treatments must be balanced by consid-

or as a definitive management option in case of unresectable tumours [22].

**156**
