Retinoblastoma Vitreous Seed Clouds (Class 3)

Purpose To compare the efficacy and toxicity of treating class 3 retinoblastoma vitreous seeds with ophthalmic artery chemosurgery (OAC) alone versus OAC with intravitreous chemotherapy. Design Retrospective cohort study. Participants Forty eyes containing clouds (class 3 vitreous seeds) of 40 retinoblastoma patients (19 treated with OAC alone and 21 treated with OAC plus intravitreous and periocular chemotherapy). Methods Ocular survival, disease-free survival and time to regression of seeds were estimated with Kaplan-Meier estimates. Ocular toxicity was evaluated by clinical findings and electroretinography: 30-Hz flicker responses were compared at baseline and last follow-up visit. Continuous variables were compared with Student t test, and categorical variables were compared with the Fisher exact test. Main Outcome Measures Ocular survival, disease-free survival, and time to regression of seeds. Results There were no disease- or treatment-related deaths and no patient demonstrated externalization of tumor or metastatic disease. There was no significant difference in the age, laterality, disease, or disease status (treatment naive vs. previously treated) between the 2 groups. The time to regression of seeds was significantly shorter for eyes treated with OAC plus intravitreous chemotherapy (5.7 months) compared with eyes treated with OAC alone (14.6 months; P P = 0.05). The 36-month Kaplan-Meier estimates of ocular survival were 83.3% (95% confidence interval, 56.7%–94.3%) for the OAC alone group and 100% for the OAC plus intravitreous chemotherapy group ( P = 0.16). The mean change in electroretinography responses was not significantly different between groups, decreasing by 11 μV for the OAC alone group and 22 μV for the OAC plus intravitreous chemotherapy group ( P = 0.4). Conclusions Treating vitreous seed clouds with OAC and intravitreous and periocular chemotherapy, compared with OAC alone, resulted in a shorter time to regression and was associated with fewer recurrences requiring additional treatment and fewer enucleations. The toxicity to the retina does not seem to be significantly worse in the OAC plus intravitreous chemotherapy group.