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