Abstract
OBJECTIVE: To evaluate the effectiveness of administering additional intravitreal topotecan injections (plus two) in reducing the recurrence rate in patients with advanced retinoblastoma (RB). METHODS AND ANALYSIS: This retrospective, non-comparative and interventional study encompassed 26 eyes of 25 patients with RB, treated between January 2019 and April 2024. All eyes in this series had received previous intravenous chemotherapy and/or intra-arterial chemotherapy. Patients received intravitreal topotecan (30 µg/0.1 mL) and/or intravitreal melphalan (20-30 µg/0.1 mL) injections every 3-4 weeks until vitreous seeds regression was achieved. Subsequently, two additional injections of topotecan (30 µg/0.1 mL) were administered after complete regression to consolidate subclinical residuals. The control of vitreous seeds, ocular toxicity assessment and clinical characteristics was observed. RESULTS: The median age of the patients was 26 months, with 57.7% belonging to group D and 42.3% to group E of RB classification. A total of 111 injections were administered in 26 eyes, with a median of 4 injections per eye. Complete vitreous seeds regression was achieved in 100% of eyes, and eye salvage was successful in 24 of 26 eyes (92.3%). There were no recurrences of vitreous seeds. Enucleation was performed in two eyes: one due to phthisis bulbi and one due to optic nerve tumour recurrence. No cases of systemic metastasis or death were reported. CONCLUSION: Administering additional intravitreal topotecan injections (plus two) following the complete regression of vitreous seeds may contribute to reducing the recurrence rate in patients with RB. This approach enhances the long-term efficacy of intravitreal injections, thereby contributing to higher eye salvage rates.However, the retrospective, non-randomised design and small sample size remain limitations. Multicentre prospective studies are warranted to validate these findings and refine treatment protocols.