Real-world implementation of optic pathway glioma surveillance in children with neurofibromatosis type 1: a 20-year cohort study

Background/aims Current guidelines recommend baseline ophthalmological assessment at neurofibromatosis type 1 (NF1) diagnosis or suspicion, at least annual ophthalmological surveillance until age 8 years, and no routine baseline MRI. We evaluated real-world implementation of this surveillance pathway and characterised the use, indications and diagnostic yield of first and repeat brain-and-orbit MRI performed during follow-up in a paediatric NF1 referral network. Methods Retrospective single-centre cohort study of children with NF1 between January 2004 and January 2024. Adherence was defined as at least one ophthalmology visit within 12 months of NF1 diagnosis and then at least annually through age 8 years. First-MRI indications were categorised as optic pathway glioma (OPG)-directed, MRI for another documented NF1-related indication, or without documented indication. Diagnostic yield was assessed for first and repeat MRI. For repeat MRI, second studies after a prior negative MRI were described as either prompted by ophthalmologic, neurologic or endocrinologic concerns or performed without specific documented OPG-related signs. Results Among 156 children, ophthalmology records were retrievable for 122; and MRI for 150. Adherence to ophthalmic surveillance was 41.8% (51/122; 95% CI 33.4% to 50.7%). Of these 150 children, 98 (65.3%) underwent at least one brain-and-orbit MRI; 21/150 (14.0%; 95% CI 9.3% to 20.5%) had an OPG. 20/21 OPGs (95.2%) were detected on the first MRI. Diagnostic yield was 20.4% (20/98; 95% CI 13.6% to 29.4%) for first MRI. At the patient level, 1/31 children undergoing repeat MRI after a prior MRI without OPG were diagnosed with OPG (3.2%; 95% CI 0.6% to 16.2%). Conclusion Documented ophthalmological surveillance was incomplete and examination content was heterogeneous. Ophthalmological findings were the leading trigger among OPG-directed first MRIs that detected OPG, while patient-level yield of repeat MRI after a prior MRI without OPG was low. These findings support ophthalmological surveillance and indication-driven repeat MRI.