Secondary Ophthalmic Artery Chemotherapy for Bilateral Retinoblastoma After Incomplete Response to Intravenous Chemotherapy: Initial Prospective Experience from a Resource-Limited Setting.

Background: Ophthalmic artery chemotherapy (OAC) is increasingly used for globe salvage in retinoblastoma, but prospective evidence from low- and middle- income countries is scarce. We evaluated short-term outcomes of secondary OAC after insufficient response to intravenous chemotherapy (IVC) with/without focal therapy in a resource- limited setting. Materials & Methods: In this prospective study (January 2023-June 2025), 21 eyes (5 group B, 5 group C, 8 group D, 3 group E) from 20 children with bilateral retinoblastoma were included; 19 had prior unilateral enucleation. Thirteen eyes underwent bridging OAC after partial IVC response, and eight received rescue OAC for failure or recurrence. Primary endpoints were globe salvage, tumor control, and complications. Results: The cohort included 12 males (60%); median age at diagnosis was 11 months (IQR: 4-18) and at OAC initiation 27 months (IQR: 17-36.5). Eighty-one OAC sessions were delivered (median 4 per eye, IQR: 3-5). After median follow-up of 19 months, overall globe salvage was 76.2% (16/21). Kaplan-Meier analysis showed eye preservation >80% at 12 months and ~70% at 24 months. Complications with permanent sequelae occurred in only one case (5%), with no mortality. Recurrence was observed in 23.5%. Exploratory subgroup analysis showed higher observed globe salvage with among eyes receiving bridging OAC than with among those receiving rescue OAC (100% vs. 37.5%); . However, this finding should be interpreted cautiously because of differences in the two groups differed in baseline disease characteristics, behavior, treatment indication, and underlying chemosensitivity between groups, and the observed association may reflect these factors rather than the timing of OAC alone. Lack of a favorable response after the first OAC cycle was associated with subsequent enucleation (RR = 6.00, 95% CI 1.03-35.91, p=0.001). Conclusions: This prospective single-center study suggests that secondary OAC is a feasible globe-preserving treatment after incomplete response to IVC with/without focal thrapy in a resource-limited setting. Exploratory subgroup analyses suggested higher observed globe salvage with bridging OAC and an association between lack of response after the first OAC session and subsequent enucleation; however, findings should be interpreted cautiously because of small sample size and potential confounding by treatment indication and baseline tumor biology. Larger multicenter studies with longer follow-up are needed to validate these findings.