High-risk retinoblastoma based on age at primary enucleation: a study of 616 eyes

PURPOSE: To study the high-risk histopathology features of retinoblastoma based on age at primary enucleation. METHODS: Retrospective study of 616 patients. RESULTS: The mean age at presentation and primary enucleation for retinoblastoma was 34 months (median, 28 months; range, 4 years of age at the time of enucleation. Bilateral retinoblastoma (34%; p 4 years. Based on 8th edition American Joint Committee on Cancer staging system, pT3 was less common in children ≤1 year of age (13%; p 4 years of age. Post-laminar optic nerve infiltration (6%; p = 0.02) and massive choroidal infiltration (9%; p = 0.04) was least common in children ≤1 year of age. Over a mean follow-up period of 52 months (median, 36 months; range