Evolving criteria for group E retinoblastoma: impact on outcomes.

ABSTRACT

OBJECTIVE: To assess the impact of evolving criteria for group E retinoblastoma on ocular survival outcomes. DESIGN: A retrospective observational study. METHODS: Single-institution consecutive case series of patients with advanced intraocular retinoblastoma (groups D and E) were classified based on International Intraocular Retinoblastoma Classification (IIRC) and International Classification of Retinoblastoma (ICRB) criteria. The main outcomes measured were ocular survival, frequency of histopathologic risk factors (HRF), and the need for adjuvant therapy. RESULTS: A total of 332 eyes of 298 patients were classified into group D (150, 45%) and E eyes (182, 55%) based on IIRC criteria. ICRB classification resulted in upstaging of 57 group D eyes (17%) to group E. Eyes that were upstaged to group E from D in the ICRB classification (E1) differed significantly, with a greater proportion undergoing primary enucleation (17 of 57, 30%) than those that were not (10 of 93, 11%) (p = 0.003). Similar significant differences were observed between group E2 and E3 eyes (p < 0.0001). Ocular survival according to Kaplan-Meier estimates at 12 months of 79%, 59%, 49%, and 1% differed significantly between all groups (ICRB D, E1, E2, and E3, respectively). CONCLUSION: Proposed new subgrouping of group E eyes into E1, E2, and E3 based on clinical criteria is based upon natural history of tumor progression and is predictive of ocular survival. Preservation of the existing lower boundaries for group E by ICRB and IIRC offers the possibility of reanalyzing existing published data.