A phase II trial of carboplatin for intraocular retinoblastoma

Retinoblastoma patients with RB1 germline mutations are at risk of developing second malignancies and external beam radiation therapy increases the risk. Carboplatin-containing chemotherapy regimens in conjunction with local therapies have been investigated for intraocular retinoblastoma, but the lack of data regarding the efficacy of single agent intravenous carboplatin prompted this phase II study.

Twenty-five patients (43 eyes) were treated with intravenous carboplatin (18.7 mg/kg for patients < 12 kg, 560 mg/m(2) for patients >/= 12 kg). Patients received a median of two cycles of carboplatin (range one to five cycles) beginning at a median age of 5 months (range 14 days to 22 months).

All patients were extraocular disease free during the follow-up period (median 76.3 months). Responses were noted in 33 of 36 evaluable eyes (92%). The 5-year overall ocular and ocular event-free survivals were 93.3% (95% CI, 84.4-100%) and 43.5% (95% CI, 25.8-61.3%) for eyes treated for Reese-Ellsworth (RE) group 1-3 disease and 25.0% (95% CI, 1.0-50.0%) and 8.3% (95% CI, 0-24.0%) for RE group 4-5 disease, respectively. No non-hematopoietic serious or permanent toxicities related to the chemotherapy were observed.

When used as a neoadjuvant agent, carboplatin usually leads to objective responses of intraocular retinoblastoma. The 5-year ocular event-free survival appears inferior to other protocols using more extensive chemotherapy, but with greater radiation therapy usage, overall ocular survival rate for RE group 1-3 eyes was excellent.