Baseline and Post-NACT Imaging in Retinoblastoma With Optic Nerve Involvement: Can MRI Predict Prognosis?

PURPOSE: To describe a staging system for optic nerve invasion using magnetic resonance imaging (MRI) and report any correlation with survival outcome. METHODS: This was a ambispective study. Twenty-one patients with retinoblastoma who had optic nerve involvement on MRI were staged at baseline based on contrast enhancement and/or thickening and length of involvement. Response to neoadjuvant chemotherapy (NACT) was noted according to proposed response evaluation criteria and results were correlated with survival outcome. RESULTS: Baseline MRI staging was able to predict event-free survival (EFS) (P = .0015) using the log-rank test for trends. Patients with optic nerve enhancement alone showed 100% survival prognosis. Optic nerve thickening cases with complete or partial response to NACT showed better EFS (P > .90) than those with stable disease according to response evaluation criteria. CONCLUSIONS: The modified staging system for optic nerve invasion used in the current study significantly predicted EFS. The study also showed that response to NACT may be affected by baseline staging. The authors recommend that cases with optic nerve enhancement only, irrespective of the length of involvement (stage 0), may be treated with upfront enucleation. Cases with optic nerve thickening may be staged to evaluate the correlation with survival outcome in a larger cohort in future studies. [J Pediatr Ophthalmol Strabismus. 2024;61(2):98-105.].

Can Enhancement Pattern in Normal-Sized Optic Nerves on Magnetic Resonance Imaging Better Predict Tumor Invasion in Retinoblastoma Eyes?

Introduction: Optic nerve (ON) enhancement alone without ON thickening on contrast-enhanced magnetic resonance imaging (CE-MRI) can be associated with post-laminar optic nerve invasion (PLONI) in eyes with group E retinoblastoma. A few case reports and retrospective studies in the literature show a poor correlation between ON enhancement on MRI and ON invasion on histopathological examination (HPE). There is no universal consensus on the management of such cases. It is desirable that the presence and extent of a true ON invasion be reliably picked up before planning upfront enucleation in order to avoid stage II disease. Methods: In a prospective study conducted at a tertiary eye care center in North India, all retinoblastoma patients presenting with ON enhancement on imaging were evaluated. Demographic and imaging details, histopathological findings, and treatment details were recorded. The length and pattern of enhancement noted on MRI were correlated with histopathology. Follow-up was done till the end of the study period. Results: Six group E retinoblastoma eyes were evaluated. 3 eyes (50%) showed solid enhancement, 2 eyes (33.33%) had tram track pattern and 1 eye (16.66%) showed punctate enhancement pattern on CE-MRI. On histopathology, 5 (83.33%) cases showed PLONI and all 6 (100%) had ON head infiltration. The cut end of the ON was free in all cases. On correlating MRI and HPE, all eyes with solid enhancement pattern showed PLONI, of which 2/3 (66.6%) had diffuse ON infiltration. Only 50% of eyes with tram track patterns showed PLONI. The case which showed a punctate enhancement pattern showed focal infiltration by tumor cells with vacuolated cytoplasm on HPE. At the last follow-up, all patients were alive and free of disease. Conclusion: ON enhancement patterns may make it more predictive for PLONI on HPE. Solid enhancement pattern appears to correlate better with the extent of ON invasion on HPE, and longer lengths of solid ON enhancement may be considered for neoadjuvant chemotherapy rather than upfront enucleation.