Adjuvant Chemotherapy in Children With Enucleated Retinoblastoma and Histopathologic High-Risk Features: Survival...

Retinoblastoma is the most common intraocular malignancy in children. Although primary enucleation continues to be a standard treatment for advanced disease, specific histopathologic high-risk features substantially increase the likelihood of extraocular dissemination. Adjuvant chemotherapy aims to reduce this risk; however, evidence from middle-income countries remains limited.

To determine the prevalence of histopathologic high-risk features in enucleated retinoblastoma and to assess relapse risk and event-free survival (EFS) among patients treated with adjuvant chemotherapy.

We conducted a retrospective analytical study of children with unilateral retinoblastoma treated with primary enucleation and of those with bilateral disease in whom the more affected eye was enucleated before any therapy, between January 2008 and December 2018. Patients presenting high-risk histopathologic features received adjuvant chemotherapy with vincristine, etoposide, and carboplatin (VEC). EFS was estimated using the Kaplan-Meier method and compared using the log-rank test.

A total of 101 patients were included; 74 (73%) had unilateral disease. The mean age at diagnosis was 2.1 years. Most eyes demonstrated advanced intraocular involvement (International Classification of Intraocular Retinoblastoma (ICRB) Group E: 82, 81.2%; Group D: 13, 12.9%). Histopathologic high-risk features were common: choroidal invasion occurred in 42 (41.6%) (17, 40.4% massive ≥3 mm), postlaminar optic nerve invasion in 11 (26.2%), and positive optic nerve margin in 16 (38%). Scleral invasion was identified in 20 (21.5%), and anterior chamber invasion in 14 (14%). Thirteen patients (13%) relapsed, all with fatal outcomes. Ten-year EFS was 83.3%. Massive choroidal invasion, scleral invasion, and postlaminar optic nerve invasion were the strongest predictors of poor outcome, and their coexistence was associated with the highest relapse risk.

Histopathologic high-risk features are common among children undergoing enucleation for advanced retinoblastoma. Adjuvant chemotherapy is warranted in cases with massive choroidal invasion, scleral infiltration, or postlaminar optic nerve involvement, given their strong association with metastatic relapse.