Impact of Race on the Outcomes of Retinoblastoma Treated With Primary Enucleation: A Global Study of 1426 Patients.

Background: To evaluate the clinical presentation, pathological features and outcomes of retinoblastoma based on the race of origin in a global cohort of patients.

Methods: Retrospective collaborative study of 1426 patients who underwent primary enucleation for retinoblastoma.

Results: Patients were grouped into Caucasians (n = 231, 16%), Asians (n = 841, 59%), Hispanics (n = 226, 16%), Arabs (n = 96, 7%) and Others (Africans, African Americans, Indigenous Australians; n = 32, 2%) cohorts. On histopathology, massive choroidal invasion was higher in Asians (30%) and Hispanics (26%) than Caucasians (15%, p < 0.001). Post-laminar optic nerve invasion was higher in Asians (28%), Hispanics (20%) and Others (9%) than Caucasians (11%, p < 0.001). At a mean follow-up of 41 months (median, 35 months; range, < 1-149 months), tumour recurrence and metastasis-related death was higher in Hispanics (9% and 12%, respectively), Asians (4% and 13%, respectively) and Others (6% and 6%, respectively). Multivariate Cox proportional hazards analysis of outcomes based on race with 8th edition AJCC pT stage and adjuvant therapy as covariates revealed 6.8 times greater risk for orbital tumour recurrence in Hispanics compared to Caucasians (p = 0.010) and 3.2 times risk hazards for metastasis-related death in Hispanics and Asians compared to Caucasians (p = 0.028 and p = 0.038, respectively).

Conclusion: The histopathological features in primarily enucleated eyes with retinoblastoma vary with race. Despite adjusting for tumour staging and adjuvant treatment, race remains an independent predictor of outcomes, including orbital tumour recurrence and metastasis-related death. A stringent follow-up and a more aggressive treatment approach is recommended in Asians and Hispanics who manifest high-risk histopathological features.