ID #617 Is radiation therapy always necessary for brain tumors in children?

We present 2 cases of treatment strategy and outcomes for patients with LGG chiasmatic-sellar region(CSR), similar in age, tumour volume and neurological status at the time of diagnosis.

1st patient, received proton RT at 3 y.o. as part of a combined approach, after 8 years of stable disease developed a severe long-term complications: persistent cognitive dysfunction, diabetes insipidus, severe cerebrovascular disease with angiographic findings of Moya-Moya Syndrome (MMS) IV stage with episodes of ischaemic stroke necessitating microsurgical intervention: extra-intracranial end-to-side microvascular anastomosis (bypass creation for cortical blood supply) and myoperinosteosynangiosis (additional vascularization by placing temporalis muscle and periosteum on the cortex). These complications significantly impacted the patient’s quality of life and required regular inpatient monitoring.

2d patient, received CHT without RT, 7 years of stable disease without long-term complications. The child is socialized, studied in school, and does not require specialised medical support.

Conclusions

Among children with CSR tumors who undergo RT, MMS occurs in 5–18% of cases within 3–4.5 years, and 20–30% develop ischemic stroke in the long term. For pediatric low-grade glioma, the stroke risk is dose-dependent: approximately 5% per Gy.

Despite the high conformability of proton RT compared to photon RT, its use, particularly in the suprasellar and prepontine regions close to the circle of Willis, is associated with a higher risk of developing MMS. Children irradiated under 5 years of age and those with NF1 are reported to be at increased risk.

These findings underscore the need for a balanced approach when selecting treatment strategies for diencephalic tumors in children, considering the high sensitivity of critical structures (optic chiasm, hypothalamus, circle of Willis vessels) to radiation. In the context of a favorable survival prognosis, emphasis should shift toward minimizing therapeutic sequelae, including avoidance of RT when not absolutely indicated.