LGG-37. Long-term Outcome, Visual Morbidity and Prognostic Factors in Infants and Young Children with Optic Pathway Glioma from the Great Ormond Street Hospital (GOSH) LGG - Cohort

INTRODUCTION: The treatment aim of childhood optic pathway glioma (OPG) is visual preservation. However, long-term outcomes and prognostic factors implicated remain largely unknown. METHODS: We undertook a retrospective study of infants and young children (IYC) ≤3 years with OPG and logMAR visual acuity (VA) at baseline/follow-up. We derived Overall- (OS), Progression-free (PFS), Radiotherapy-free (RTFS) and Visual event-free survival (vEFS) curves and analysed prognostic factors for visual deterioration and WHO defined blindness (>1.3 logMAR both eyes). RESULTS: Of 81 IYC-OPG (147 evaluable eyes) baseline vision was below 5%ile for age in 33 (41%) and 27 (33%) in one or both eyes respectively, within normal range in 21 (26%). After observation (11), chemotherapy (66) or RT (4), radiological progression occurred in 47 (58%), multiple times in 34.6% (range 2 - 8) and 10yr-PFS was 39.8%. Twenty had RT after 4.2 years from diagnosis (10yr-RTFS 72.4%) and 12% died (10yr-OS 89%). After 8.9 years VA was better/stable/ worse in 36%/32%/32% of subjects, with median time to visual event of 1.7 years (range 0.16 - 12) and 10yr-vEFS 41.3%. Final VA was reduced (>0.2 logMAR) in 23 (28.4%) and 43 (53.1%) in only one or both eyes respectively. Amongst those with unilateral impairment 13/23 affected eyes had no useful vision (light/no light perception). Amongst those with bilateral impairment best eye VA was > 1.0 log MAR in 22/43 (LP/NLP in 10). Infants < 1 year had significantly inferior 10-yrPFS (5.6%), post-chiasmatic involvement was associated with visual deterioration (HR 2.91, 95%CI=1.1- 7.7), and baseline bilateral abnormal for age vision predicted WHO blindness at follow-up (OR 17.9, 95%CI=3.2 – 101.1). CONCLUSIONS: Many IYC-OPG suffer multiple progressions with significant long-term visual morbidity. Predictive factors such as age, tumor location and baseline age-adjusted vision allow patients’ selection for early sight rehabilitation and consideration for experimental strategies preventing visual loss.