Long‐term visual outcome after chemotherapy for optic pathway glioma in children: Site and age are strongly predictive

Abstract

BACKGROUND: Optic pathway gliomas (OPGs) are commonly noted in pediatric oncology services. Radiotherapy is effective at controlling tumors, but has many undesirable late effects, especially in patients with neurofibromatosis. Chemotherapy is commonly used to preserve vision and delay or eliminate the need for radiotherapy. Despite visual threat being a common reason to initiate chemotherapy in patients with OPG, reports of visual outcome after chemotherapy are not common and reports of long-term visual outcome are even scarcer. METHODS: In a single institution, all patients with OPG who had received chemotherapy or radiotherapy between 1996 and 2013 were identified from hospital databases. Visual, treatment, and radiological data were recorded. Categorized visual acuity was the primary outcome measure. RESULTS: Of 43 patients identified, visual data were available for 42 patients. Approximately 14% of patients experienced an improvement in visual acuity during therapy, 9% of patients experienced a deterioration, and the remainder were stable. At a mean follow-up of 78 months, 26% of patients were legally blind. Children aged <2 years and patients with a chiasmatic/hypothalamic tumor site were overrepresented in this category. An intraconal location was predictive of poor visual outcome for that eye but was unilateral with normal vision in the contralateral eye. CONCLUSIONS: Risk factors for long-term visual deterioration are young age, chiasmatic/hypothalamic tumor site, and intraconal tumor site for the involved eye. The most common visual outcome for children with OPG after treatment with chemotherapy is stability. This stability is maintained over the long term for >90% of children without these risk factors. Cancer 2015;121:4190-6.

Optic pathway glioma volume predicts retinal axon degeneration in neurofibromatosis type 1

“…Previous studies have suggested that OPG involvement in the optic chiasm vs the optic tract carries a higher risk of vision loss. 3,5,14,[26][27][28] Despite the optic tracts demonstrating a statistically significant increased risk of vision loss compared to the optic chiasm in these studies, the positive predictive value is less than chance. 3 Our data do not support increased risk of vision loss from optic tract involvement, but instead suggest that OPG and AVP volume along with total brain volume are highly predictive of damage to the visual pathway.…”

Optic Pathway Gliomas

“…For children with NF1-associated OPGs, there are conflicting reports whether OPGs involving isolated optic nerves and or chiasm have a better clinical prognosis than gliomas that involve structures posterior to the chiasm (i.e., optic tracts/ optic radiations) although more recently several studies favor posterior pathway involvement to have poorer visual outcome. 8,32,40,[76][77][78] In the NF1-associated OPGs with posterior pathway involvement, additional hypothalamic involvement did not confer a poorer visual prognosis in a later study. 32 Sporadic OPGs with posterior involvement also show poorer visual outcomes.…”

Optic Nerve Glioma : Case Report

“…Radiation therapy can be used before and after surgery (9) . After treatment of ONGs Long-term side effects may occur, such as: learning disabilities, cognitive difficulties and impairments in growth (10) .…”