Focal periocular carboplatin chemotherapy avoids systemic chemotherapy for unilateral, progressive retinoblastoma

Purpose: The purpose of this study was to report a case of a boy with unilateral, multifocal retinoblastoma who was successfully treated with periocular carboplatin injections for a tumor that progressed despite focal laser ablation. Methods: This is an interventional case report. A boy with a paternal history of retinoblastoma and in utero identification of an RB1 mutation was monitored beginning at 2 weeks of age. When the patient was 6 months old, the first tumor was detected and treatment with a direct, ablative, large spot-size diode laser was initiated. During a 38-month period of follow-up, the patient received 23 laser treatments and 3 periocular carboplatin injections (20 mg in 2 mL) to treat 3 tumors in 1 eye. Results: Initially, diode laser ablation of the tumors produced a favorable involutional response of the tumors, associated with a decrease in size and vascularity. Despite aggressive treatment with 12 consecutive laser treatments for 9.7 months, progressive tumor growth was observed in the superonasal tumor, whereas the other 2 tumors remained quiescent. At that time, a series of three focal periocular injections of carboplatin were administered in combination with continued laser ablation. The tumor regressed with type 4 chorioretinal scarring. No systemic chemotherapy or radiation was required. Conclusion: This case of unilateral, multifocal retinoblastoma was successfully treated solely with diode laser ablation and rescue periocular injections of carboplatin after the failure of laser alone. A trial of periocular carboplatin with laser may be considered in cases of unilateral retinoblastoma that are resistant to laser ablation therapy alone.