Background: Access to intra-arterial chemotherapy for retinoblastoma in low- and middle-income countries (LMICs) is limited. There is a need to optimize the efficacy of systemic chemotherapy for advanced intraocular retinoblastoma, particularly in LMICs. The aim was to compare the efficacy of standard versus higher dose carboplatin-based intravenous chemotherapy for group D and E retinoblastoma.
Methods: The single-center, single-blinded, randomized study was conducted during 2019-2021. Patients with newly diagnosed group D or E retinoblastoma were randomized to receive vincristine, etoposide, and standard versus higher dose (<36 months: 18.6 vs. 28 mg/kg; ≥36 months: 560 vs. 840 mg/m2 ) carboplatin. Examination under anesthesia and ultrasonography was performed at diagnosis and following three cycles of chemotherapy. Group E eyes with poor likelihood of globe/vision salvage at diagnosis were excluded.
Results: Thirty-two eyes of 30 patients were analyzed: 17 group D and 15 group E eyes. The tumor response to chemotherapy with regards to regression pattern (p = .72), tumor shrinkage (diameter: p = .11, height: p = .96), subretinal seeds (p = .91), and vitreous seeds (p = .9) were comparable between the two treatment arms. The globe salvage (group D [82% vs. 67%; p = .58]; group E [12.5% vs. 29%; p = .57]) and salvage of meaningful vision (group D [100% vs. 75%; p = .13]; group E [100% vs. 50%; p = .48]) were comparable between standard and higher dose arms. No excess treatment-related toxicity was observed in the higher dose arm.
Conclusions: Higher dose carboplatin-based intravenous chemotherapy did not result in superior globe or vision salvage in group D or E retinoblastoma.
Keywords: abandonment; enucleation; melphalan; ophthalmic artery chemosurgery; topotecan; vitreous seed.
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