External beam radiotherapy in retinoblastoma - Tumor control and comparison of 2 techniques

Objective: To investigate eye conservation, local control, and complication rates among children with retinoblastoma treated with 2 different external beam radiotherapy (EBR) techniques. Methods: Fifty-eight eyes in 42 patients received EBR as the primary treatm ent modality for retinoblastoma (median follow-up, 37 months). The EER tech nique was relative lens-sparing (RLS) in 26 eyes and modified lateral beam (MLB) in 32 eyes. Both groups were comparable in Reese-Ellsworth retinoblas toma classification. If necessary, patients received focal salvage therapy. Results: At 24 months, eye conservation rates were 88.5% and 89.1% among ey es treated with RLS and MLB, respectively (P = .40); tumor control rates wi thout salvage therapy were 84.6% and 53.3% (P = .02), respectively. Among e yes with Reese-Ellsworth stage IV and V disease, eye conservation rates wer e 88% +/- 8% and 83% +/- 9% at 36 months in the RLS and MLB groups, respect ively, and local tumor control rates were 81% +/- 10% and 51% +/- 12%. Perc entages of eyes without cataract at 36 months were 83.1% and 63.0%, respect ively (P = .40). Among patients observed for at least 18 months, midfacial hypoplasia developed in 38.5% and 29.4%, respectively (P = .70). Conclusions: The EER technique was associated with high eye conservation an d local control rates. Salvage therapy was performed significantly less fre quently in the RLS group compared with the MLB group, and complication rate s in both groups were similar.