[Evaluation the risk of optic nerve invasion associated with optic nerve obscuration in advanced retinoblastoma]

Objective: To evaluate the potential association between optic nerve invasion and optic nerve obscuration during treatment of advanced retinoblastoma. Methods: Retrospective case series study. Medical records of 77 patients (77 eyes) with advanced retinoblastoma (Group D/E) who were treated with primary or secondary enucleation in the Ophthalmology Department of Peking University People's Hospital from January 1^st 2012 to December 31^th 2015 were retrospectively reviewed. RetCam photographs under general anesthesia at diagnosis and each subsequent follow-up were evaluated for complete obscuration of the optic nerve. The primary endpoints included prelaminar invasion, postlaminar invasion and optic nerve transection invasion. Group difference was calculated with chi-square. Results: There were 46 boys and 31 girls in the study. The mean age at the first diagnosis was (27.1±22.1) months. The optic nerve was obscured in 62 eyes (80.5%) at the first diagnosis and 61 eyes (79.2%) at the last ocular examination prior to enucleation. Twenty-nine eyes (37.7%) underwent primary enucleation. Forty-eight eyes (62.3%) were treated with eye-preserving therapy, followed by enucleation. Fourteen eyes (18.2%) were in Group D and 63 eyes (81.8%) were in Group E. Histopathologic analysis of enucleated eyes without optic nerve obscuration (16 eyes) showed prelaminar invasion in 7 eyes, postlaminar invasion in 2 eyes and optic nerve transection invasion in 0 eyes. Histopathologic analysis of enucleated eyes with optic nerve obscuration (61 eyes) showed prelaminar invasion in 26 eyes, postlaminar invasion in 9 eyes and optic nerve transection invasion in 4 eyes. The difference between two groups did not achieve statistical significance (P=0.935, 1.000, 0.296). Histopathologic analysis of enucleated eyes with persistent complete obscuration of the optic nerve showed a high risk factor in 10 eyes (10/40), while in 1 eye (1/8) the optic nerve was visible at the initial presentation and obscured before secondary enucleation (P=0.529). Conclusion: Optic nerve obscuration at the last examination prior to enucleation may not be associated with postlaminar optic nerve invasion in advanced retinoblastoma. (Chin J Ophthalmol, 2020, 56: 681-687).