Ocular and Orbital Malignancies
Radiotherapy for low-grade gliomas in children has always been controversial due to the high control rates and long potential timeline for the development of late toxicities.
The use of effective cytotoxic regimens like carboplatin and vincristine , thioguanine, procarbazine, lomustine, and vincristine (TPCV) , and single-agent vinblastine [3, 4] means that radiotherapy may often be delayed to a more favorable age allowing for continued normal development.
Many children who are not surgical cases will ultimately need radiotherapy for disease control, and thus conformal treatment methods are required.
Merchant et al. demonstrated reduced target margin (1 cm CTV) radiotherapy for low-grade gliomas results in excellent disease control and acceptable rates of vasculopathy . ACNS0221 is evaluating the use of 0.5 cm CTV margins for low-grade gliomas, but has not yet been reported.
Optic pathway gliomas (OPGs) represent a special case of low-grade glioma and often require treatment due to threatened vision. The response rate of OPGs with vision symptoms is substantial, with greater than 75% having either stabilization or improvement in vision with radiotherapy .
Radiotherapy is potentially curative in 80–90% of low-grade gliomas; however, given the potential for late effects, radiotherapy is often used as a last resort after progression following multiple chemotherapy or targeted therapy regimens or when vision is threatened.
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