High-risk histopathological features of retinoblastoma: A global study of 1426 patients from 5 continents

Abstract

Purpose : To evaluate the high-risk histopathological features (HRHF) following primary enucleation of eyes with retinoblastoma (RB) and assess the patient outcomes across continents

Methods : Retrospective study of 1426 patients from 5 continents during the study period of 2011 to 2020

Results : Of the 1426 primarily enucleated RB eyes, 923 (65%) were from Asia, 27 (2%) from Australia, 120 (8%) from Europe, 162 (11%) from North America, and 194 (14%) from South America. Based on International Classification of Intraocular Retinoblastoma, the eyes belonged to group C (n=2, <1%), D (n=264, 19%), or E (n=1046, 73%). Based on continent (Asia vs Australia vs Europe vs North America vs South America), the histopathology features included massive choroidal invasion (31% vs 7% vs 13% vs 19% vs 27%, p=0.001), post-laminar optic nerve invasion (27% vs 0% vs 16% vs 21% vs 19%, p=0.0006), scleral infiltration (5% vs 0% vs 4% vs 2% vs 7%, p=0.13), and microscopic extrascleral infiltration (4% vs 0% vs <1% vs <1% vs 4%, p=0.68). Adjuvant chemotherapy with/without orbital radiotherapy was given in 761 (53%) patients. Based on Kaplan-Meier estimates in different continents (Asia vs Australia vs Europe vs North America vs South America), the 6 year risk of orbital tumor recurrence was 5% vs 2% vs 0% vs 0% vs 12% (p<0.001), systemic metastasis was 8% vs 5% vs 2% vs 0% vs 13% (p=0.001), and death was 10% vs 3% vs 2% vs 0% vs 11% (p<0.001).

Conclusions : There is a wide variation in the infiltrative histopathology features of RB across continents resulting in variable outcomes. South America and Asia had higher risk of orbital tumor recurrence, systemic metastasis and death compared to Australia, Europe, and North America.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.