Primary Enucleation for Intraocular Unilateral Retinoblastoma Can Save Life in Lower-Income Settings.

OBJECTIVE: To investigate the outcomes of primary enucleation and adjuvant systemic chemotherapy, when deemed appropriate, on a cohort of children with unilateral intraocular Rb (AJCC 8th edition, cT2 and cT3) from diverse economic groupings. METHODS: A prospective analysis including treatment-naïve Rb patients were presented to 11 centers from 10 countries from January 1 to December 31, 2019, and were followed-up thereafter. Only children with unilateral intraocular Rb that underwent primary enucleation were included in the present analysis. Systemic metastasis and survival were investigated. RESULTS: Of the 692 children with Rb, 191 (27.6%) were included in the study cohort. Among them, 24 (12.6%) were from low-income countries (LICs), 89 (46.6%) from lower-middle-income countries (LMICs), 59 (30.9%) from upper-middle-income countries (UMICs), and 19 (9.9%) from high-income countries (HICs). High-risk histopathological features were observed in 110 eyes (57.6%) following enucleation, and 102 of these children (92.7%) received adjuvant intravenous chemotherapy. The three-year survival rate for the entire cohort was 95.0%. Stratified by economic grouping, survival rates were 87.5% (LIC), 96.6% (LMIC), 93.2% (UMIC), and 100% (HIC). Children from LICs demonstrated a higher prevalence of HRHF compared to HICs. Residing in a lower-income country was associated with a higher risk of systemic metastasis and poorer outcomes. CONCLUSION: In the present multinational cohort of children with unilateral intraocular Rb who underwent upfront enucleation coupled with adjuvant chemotherapy as needed, overall survival was favorable, especially for children from low-income countries. Prompting early diagnosis, while the tumor remains intraocular can be life-saving, particularly in low-resource settings where primary enucleation and adjuvant chemotherapy can cure unilateral Rb.