Retinoblastoma Outcomes in the Americas: a prospective analysis of 491 children with retinoblastoma from 23 American countries

Purpose Globally, disparities exist in retinoblastoma treatment outcomes between high- and low-income countries, but independent analysis of American countries is lacking. We report outcomes of American retinoblastoma patients and explore factors associated with survival and globe salvage. Design Subanalysis of prospective cohort study data. Methods Multicenter analysis at 57 American treatment centers in 23 countries of varying economic levels (low income=LIC, lower-middle=LMIC, upper-middle=UMIC, high=HIC) of 491 treatment-naïve retinoblastoma patients diagnosed in 2017 and followed through 2020. Survival and globe salvage rates analyzed with Kaplan-Meier analysis and Cox proportional hazard models. Results Of patients, 8 (1.6%), 58 (11.8%), 235 (47.9%) and 190 (38.7%) were from LIC, LMIC, UMIC and HIC, respectively. Three-year survival rates in LICs were 60.0% (95% CI, 12.6-88.2) compared to 99.2% (94.6-99.9) in HICs. Death was less likely in patients older than four years (vs. four or younger, HR=0.45 [95% CI, 0.27 – 0.78], P=0.048). Patients with more advanced tumors (e.g., cT3 vs. cT1, HR= 4.65 × 109 [95% CI, 1.25 × 109 – 1.72 × 1010], P<0.001) and females (vs. males, HR=1.98 [1.27-3.10], P=0.04) were more likely to die. Three-year globe salvage rates were 13.3% (95% CI, 5.1-25.6) in LMICs and 46.2% (38.8-53.3) in HICs. At three years, 70.1% of cT1 eyes (95% CI, 54.5-81.2) versus 8.9% of cT3 eyes (5.5-13.3) were salvaged. Advanced tumor stage was associated with higher enucleation risk (e.g., cT3 vs. cT1, SHR=4.98 [95% CI, 2.36-10.5), P<0.001). Conclusions Disparities exist in survival and globe salvage in American countries based on economic level and tumor stage demonstrating a need for childhood cancer programs.