Outcomes of systematic screening for optic pathway tumors in children with Neurofibromatosis Type 1

Abstract

Optic pathway tumors (OPT) occur in about 15% of individuals with Neurofibromatosis Type 1 (NF1) and may effect substantial visual loss. Because their growth is not predictable at the time of discovery, neuroimaging for OPT in asymptomatic NF1 patients remains controversial. We evaluated the outcomes of systematic screening by both MRI and ophthalmic examinations for OPT in young children with NF1 seen at multi-disciplinary clinics for Neurofibromatosis and Genetics at one institution between 1996 and 2001. We report on 84 children who presented with NF1 under age 6 years, of whom 13 children presented with either known OPT or abnormal MRI findings and 11 children had OPTs identified by neuroimaging, including two children with abnormal eye examinations at presentation (one with strabismus and one with optic atrophy). Nine OPTs were detected in asymptomatic subjects with normal ophthalmic examinations. Three children with chiasmal lesions enlarging on subsequent MRI were treated with carboplatin and vincristine. After treatment, the vision in each involved eye was intact. In contrast, the 13 children with OPT diagnosed outside of screening guidelines included five children with substantial visual loss. Our observations suggest that early recognition of NF1 promotes appropriate surveillance and allows early intervention to reduce complications of OPT. This analysis supports prospective studies to compare the outcomes of systematic screening with neuroimaging to screening with ophthalmic examinations alone in children with NF1.

Screening children with NF1 for optic pathway glioma – No

“…8 Where screening using MRI is reported in the literature, there is a high frequency of clinically insignificant 'anomalies' detected on screening images causing anxiety to parents and requiring additional clinical time to explain their significance and neuroimaging for monitoring. 9 Summary: The test of 'visual acuity testing' fails the screening criteria on many points, but most importantly it is not specific or sensitive. MRI screening is both sensitive and specific, but has not been shown to alter outcomes.…”

Screening children with NF1 for optic pathway glioma – Yes

“…There is evidence that children identified early through a screening programme have reduced complications from their OPG. 8 Children can develop visual problems as a result of secondary raised intracranial pressure and can benefit hugely from a third ventriculostomy. Children managed by a multi-disciplinary team (MDT) involving paediatric neurosurgeons are likely to be dealt with more efficiently.…”

Lisch and the Importance of His Nodules

“…Optic pathway tumours (OPT) occur in about 15% of individuals with NF1 and can result in visual loss and even morbidity in young children (14,15). They are usually found Lisch Nodules in Neurofibromatosis 1 …”