Long-term (20-year) real-world outcomes of intravenous chemotherapy (chemoreduction) for retinoblastoma in 964 eyes of 554 patients at a single centre.

BACKGROUND: Intravenous chemotherapy (IVC) remains an important globe salvage therapy for retinoblastoma.
METHODS: Evaluation of long-term globe salvage at 5, 10, 15 and 20 years following frontline IVC for retinoblastoma.
RESULTS: Of 994 eyes, comparison by International Classification of Retinoblastoma group (A vs B vs C vs D vs E) revealed more advanced group with older mean age at presentation (8 vs 7 vs 10 vs 11 vs 15 months, p<0.001). By clinical features, more advanced group demonstrated greater mean tumour diameter (3.2 vs 6.8 vs 9.4 vs 14.3 vs 16.4, p<0.001) and thickness (2.0 vs 3.7 vs 4.4 vs 7.3 vs 9.3, p<0.001), and greater frequency of vitreous seeds ≥1 quadrant (0% vs 0% vs 44% vs 42% vs 57%, p<0.001) and subretinal seeds (0% vs 0% vs 22% vs 65% vs 54%, p<0.001). By outcomes, less advanced group demonstrated greater tumour control (without need for enucleation or external beam radiotherapy (EBRT)) by year 2 (96% vs 91% vs 91% vs 71% vs 32%, p<0.001), and with minimal change up to 20 years. In order to achieve globe salvage, additional intra-arterial chemotherapy (IAC) or plaque radiotherapy was employed by year 2 (5% vs 26% vs 28% vs 27% vs 19%, p<0.001), with little further need up to 20 years. Pinealoblastoma (2%), metastasis (2%) and death (1%) were infrequent.
CONCLUSION: Frontline IVC (plus additional IAC and/or plaque radiotherapy) for retinoblastoma provided complete tumour control for groups A (96%), B (91%), C (91%), D (71%) and E (32%), avoiding enucleation or EBRT and was lasting for up to 20 years. © Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.