Lack of Complications of High-Dose Intravitreal Topotecan for Recurrent Retinoblastoma in 81 Consecutive Injections

To explore the safety of high-dose intravitreal topotecan (HD-IvitTopo) for recurrent retinoblastoma management in human eyes. There were 81 consecutive injections of HD-IvitTopo (90 micrograms (µg)/0.18cc-100 µg/0.20cc on a monthly basis) in 25 eyes with recurrent retinoblastoma. Tumor control and injection-related complications were assessed at each visit. Each tissue was reviewed for complication-associated alterations and systemic evaluation for myelosuppression, infection, metastasis, and death was assessed. At the time of injection, the mean patient age was 26 months and in all cases the injection was for recurrent retinoblastoma (n=24 eyes, 100%) involving intraretinal tumor (n=6 eyes, 24%), vitreous seeds (n=3 eyes, 12%), subretinal seeds (n=13 eyes, 52%), or multiple tumor types (n=3 eyes, 12%). The mean intraretinal tumor thickness was 2.2 mm, vitreous seed thickness varied from pinpoint to confluent seeds, and subretinal seed was 0.9 mm. The total number of HD-IvitTopo injections was 81 (mean 3.2 per eye) with 39 (48%) injections given without concurrent chemotherapy and 42 (52%) given with concurrent intravenous or intra-arterial chemotherapy. At mean follow-up of 10 months after first injection, tumor control was achieved in all cases (n=81 injections, 100%) and there was no local or systemic complication in any of the 81 injections. There was no case of extraocular tumor extension, myelosuppression, infection, metastasis, or death. Based on this analysis, HD-IvitTopo is safe and effective in the management of recurrent small retinoblastoma in humans. Further investigation of the limits of this therapy is warranted.