Periocular chemotherapy drug may reduce small-volume intraocular retinoblastoma

Mallipatna AC. Arch Ophthalmol. 2011;129(6):738-745.

High-dose periocular topotecan in fibrin sealant may reduce small-volume intraocular retinoblastoma, enabling successful focal therapy, a study found.

The retrospective assessment reviewed the medical records of 10 eyes that received one to four injections of topotecan in fibrin sealant, with or without accompanying laser and/or pre-chemotherapy cryotherapy and with a median interval of 23 days between injections. Median dosage was 3.72 mg/m², and median follow-up was 11 months.

Eight eyes that responded to treatment had small discrete tumors, with an International Intraocular Retinoblastoma Classification of group A or B. The two that did not respond were group D eyes with recurrent disease.

Of eyes that responded, the primary prior treatment was laser for three eyes, systemic chemotherapy with focal laser for two eyes and periocular topotecan for three eyes. In four of the treated eyes, tumor regression allowed for effective focal therapy; however, the other four required long-term control using systemic chemotherapy.

Toxic effects were negligible at a maximum dosage of 3.75 mg/m². According to the study authors, effects are typically observed at the topotecan dosages given in this study, suggesting that periocular administration results in low and slow systemic absorption. They encouraged a prospective trial with dose escalation to define the maximum tolerated dose.

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