Role of additional topotecan injections (plus two) in reducing recurrence rate in retinoblastoma of group D and group E patients: a retrospective study.

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.