Outcomes of five cases of retinoblastoma with optic nerve invasion on imaging

Purpose To investigate the timing of enucleation, treatment course, and outcome for retinoblastoma (RB) with optic nerve (ON) invasion on imaging. Study design Retrospective clinical study. Methods Of the 160 patients with RB who presented to the National Center for Child Health and Development in Japan between 2005 and 2022, ON invasion on imaging at the initial presentation was seen in five patients. The clinical, computed tomography (CT), and magnetic resonance imaging (MRI) findings, and treatment courses were reviewed retrospectively. Results MRI showed ON invasion in all five patients (three with unilateral RB, 2 with bilateral RB); in two patients CT detected no invasion. Enucleation was performed in four patients, three of whom underwent neoadjuvant therapy and one had a positive ON resection margin following the enucleation as initial treatment. One patient did not undergo enucleation due to cerebrospinal fluid dissemination. All enucleated patients underwent adjuvant chemotherapy. Four patients underwent radiotherapy. During follow-up (mean, 89.4 months), four patients survived and one died. Conclusion MRI is recommended to evaluate ON invasion and determine the timing of enucleation for RB. The appropriate choice of neoadjuvant or adjuvant therapy would be helpful to avoid radiotherapy for RB with ON invasion on imaging.