NF1 optic pathway glioma. Analysing risk factors for visual outcome and indications to treat.

BACKGROUND The aim of the project was to identify risk factors associated with visual progression and treatment indications in pediatric patients with Neurofibromatosis type 1 associated optic pathway gliomas (NF1-OPG). METHODS A multi-disciplinary expert group consisting of ophthalmologists, pediatric neuro-oncologists, neurofibromatosis specialists and neuro-radiologists involved in therapy trials assembled a cohort of children with NF1-OPG from six European countries with complete clinical, imaging and visual outcome datasets. Using methods developed during a consensus workshop, visual and imaging data were reviewed by the expert team and analyzed to identify associations between factors at diagnosis with visual and imaging outcomes. RESULTS 83 patients (37 males, 46 females, mean age 5.1±2.6 years; 1-13.1 years) registered in the European treatment-trial SIOP LGG-2004 (recruited 2004-2012) were included. They were either observed or treated (at diagnosis/ after follow-up).In multivariable analysis, factors present at diagnosis associated with adverse visual outcomes included: multiple visual signs and symptoms (adjOR 8.33, 95%CI 1.9-36.45); abnormal visual behavior (adjOR 4.15, 95%CI 1.20-14.34); new onset of visual symptoms (adjOR 4.04, 95%CI 1.26-12.95) and optic atrophy (adjOR 3.73, 95%CI 1.13-12.53). Squint, posterior visual pathway tumor involvement, and bilateral pathway tumor involvement, showed borderline significance. Treatment appeared to reduce tumor size but improved vision in only 10/45 treated patients. Children with visual deterioration after primary observation are more likely to improve with treatment than children treated at diagnosis. CONCLUSIONS The analysis identified the importance of symptomatology, optic atrophy and history of vision loss as predictive factors for poor visual outcomes in children with NF1-OPG.