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

Purpose: To explore the safety of high-dose intravitreal topotecan (HD-IvitTopo) for recurrent retinoblastoma management in human eyes.

Methods: 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.

Results: 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.

Conclusions: 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.