Objective: The purpose of the study is to investigate chemoreduction and adjuvant treatment (AT) for retinoblastoma and its effect on complete retinal tumor control, vitreous seed control, and subretinal seed control.
Design: The study design was a prospective, nonrandomized clinical trial.
Participants: There were 130 intraocular retinoblastomas in 52 eyes of 32 consecutive patients observed for at least 1 year after initiation of treatment.
Intervention: Treatment with chemoreduction using vincristine, etoposide, and carboplatin (VEC) and adjuvant treatment (+ AT) (cryotherapy, laser photocoagulation, thermotherapy, chemothermotherapy, plaque radiation therapy, or external beam radiation therapy) were assessed.
Main outcome measures: The effect of chemoreduction for 6 cycles (VEC x 6) versus fewer than 6 cycles (VEC x <6) on retinoblastoma control was analyzed. Furthermore, the impact of adjuvant treatment (+ AT) versus no adjuvant treatment (no AT) on retinoblastoma control was analyzed.
Results: Retinal tumors showed favorable initial regression with chemoreduction. Adjuvant treatment was applied to 93% of the retinal tumors after chemoreduction and only 2% recurred over the mean follow-up of 17 months (range 13-27 months). Vitreous seeds and subretinal seeds showed initial regression and often complete disappearance with chemoreduction. In those eyes with seeds before treatment, the addition of AT to VEC for 6 cycles decreased the vitreous seed recurrence from 75% to 0% (P = 0.04) and also decreased the subretinal seed recurrence from 67% to 0% (P = 0.003). More important, when considering that enucleation or external beam radiation therapy was the only other treatment option for these 52 eyes, the authors were successful in avoiding these methods in 42% of cases. Of the 36 eyes classified as Reese-Ellsworth group 5, there was 78% ocular salvage, and external beam radiation therapy was avoided in 25% of these eyes. There was a 100% ocular salvage in the group 5 eyes that received VEC for 6 cycles + AT to retinal tumors and seeds.
Conclusions: Chemoreduction and AT to intraocular retinoblastoma and its seeds provides good retinal tumor control, even in eyes with advanced disease. Chemoreduction alone generally is not adequate to achieve complete tumor seed control. Cautious follow-up of affected patients is recommended because the risk for recurrent vitreous and subretinal seeds is substantial and proper treatment is critical for salvaging the eye.