Chemoreduction plus focal therapy for retinoblastoma: factors predictive of need for treatment with external beam radiotherapy or enucleation.

PURPOSE: To report the results of chemoreduction and focal therapy for retinoblastoma with determination of factors predictive of the need for treatment with external beam radiotherapy or enucleation.
DESIGN: Interventional case series.
METHODS: One-hundred three patients with retinoblastoma (158 eyes with 364 tumors) at the Ocular Oncology Service at Wills Eye Hospital of Thomas Jefferson University in conjunction with the Division of Oncology at Children's Hospital of Philadelphia from June 1994 to August 1999 were enrolled for this prospective clinical trial. The patients received treatment for retinoblastoma with six planned cycles (one cycle per month) of chemoreduction using vincristine, etoposide, and carboplatin combined with focal treatments (cryotherapy, thermotherapy, or plaque radiotherapy). The two main outcome measures after chemoreduction and focal therapy were the need for external beam radiotherapy and the need for enucleation. The clinical features at the time of patient presentation were analyzed for impact on the main outcome measures using a series of Cox proportional hazards regressions.
RESULTS: Using Reese-Ellsworth (RE) staging for retinoblastoma, there were nine (6%) eyes with group I disease, 26 (16%) eyes with group II disease, 16 (10%) eyes with group III disease, 32 (20%) eyes with group IV disease, and 75 (48%) eyes with group V retinoblastoma. All eyes showed initial favorable response with tumor regression. The median follow-up was 28 months (range, 2-63 months). Failure of chemoreduction and need for treatment with external beam radiotherapy occurred in 25% of eyes at 1 year, 27% at 3 years, and no further increase at 5 years. More specifically, external beam radiotherapy was necessary at 5 years in 10% of RE groups I-IV eyes and 47% of RE group V eyes. Multivariate factors predictive of treatment with external beam radiotherapy included non-Caucasian race, male sex, and RE group V disease. Failure of chemoreduction and the need for treatment with enucleation occurred in 13% eyes at 1 year, 29% at 3 years, and 34% at 5 years. More specifically, enucleation was necessary in 15% of RE groups I-IV eyes at 5 years and in 53% of RE group V at 5 years. Multivariate factors predictive of treatment with enucleation included patient age older than 12 months, single tumor in eye, and tumor proximity to foveola within 2 mm. Overall, of the 158 eyes, 50% required external beam radiotherapy or enucleation and 50% were successfully managed without these treatments. No patient developed retinoblastoma metastasis, pinealoblastoma, or second malignant neoplasms over the 5-year follow up.
CONCLUSIONS: Chemoreduction offers satisfactory retinoblastoma control for RE groups I-IV eyes, with treatment failure necessitating additional external beam radiotherapy in only 10% of eyes and enucleation in 15% of eyes at 5-year follow-up. Patients with RE group V eyes require external beam radiotherapy in 47% and enucleation in 53% at 5 years.