Gliomas that affect the optic pathways are for the most part low-grade
neoplasms that often, but not always, have good prognoses. Optimal treatment and management of optic pathway
gliomas remains unclear and the decision hinges upon several factors including patient age,
tumor location, and visual symptoms. We favor a treatment approach that is dependent on the location of
tumor within anterior, chiasmal or posterior/hypothalamic visual pathways. In children who are minimally or not symptomatic, we recommend observation rather than early treatment intervention. Most of these patients will have
neurofibromatosis type 1 (NF1) based on the natural history and their
pilocytic astrocytoma histology. Serial magnetic resonance imaging studies and formal neuro-ophthalmology testing should enable close observation of these patients, with intervention being reserved for when
tumor progression results in significant visual loss or
proptosis.
Chemotherapy is an accepted first line treatment, and a number of effective medications are available, although no agent has proven clearly superior. If progression is accompanied by the complete loss of vision, surgery can be utilized to help alleviate structural issues (ie,
proptosis). Minimally symptomatic chiasmal or
hypothalamic tumors that arise in the setting of NF1 can also be observed initially because of their favorable prognosis. Children with NF1 and chiasmal or posterior visual
tumors who progress either on imaging or clinical grounds (ie, development of significant visual deficits) should be treated first with
chemotherapy rather than
radiation therapy to minimize the effects on the developing central nervous system. Individuals without NF1 presenting with a chiasmal or hypothalamic mass are candidates for biopsy to determine the underlying pathology of the lesion. Symptomatic patients with
pilocytic astrocytoma should first receive
chemotherapy. In contrast, other histologies including malignant optic pathway
gliomas should be treated similar to other
gliomas that occur in other locations with appropriate doses of radiation and
chemotherapy.