Outcomes of Group D Retinoblastoma With Resistant Vitreous Seeds After Integration of Intravitreal Chemotherapy to the Treatment Protocol

Introduction: A major therapeutic challenge in the salvage of Group D retinoblastoma eyes is the poor response of vitreous seeds to intravenous chemotherapy. The novel use of intravitreal melphalan has greatly impacted the salvage of such eyes; however, concerns regarding its safety and toxicity still exist, particularly in dark-eyed children. This study aims to evaluate our experience and determine the visual and anatomical outcomes of intravitreal melphalan in group D retinoblastoma with resistant vitreous seeds. Method: All patients, from August 2018 to February 2020, with group D retinoblastoma harboring vitreous seeds refractory to first-line chemo reduction regimen with vincristine, etoposide, and carboplatin for six cycles plus local consolidation with thermotherapy or cryotherapy were evaluated. Fifteen eyes of 15 patients that fulfilled the eligibility criteria and received intravitreal melphalan were retrospectively reviewed for demographics, iris color, treatments offered, seed inactivation, globe survival, visual acuity, and complications. Result: Mean age at presentation was 22 months for bilateral disease and 36 months for unilateral disease. A total of 77 injections were administered (mean, five injections per eye) with doses ranging from 20 µg to 30 µg. Complete seed control was seen in 13 of 15 (87%) eyes, and globe salvage was possible in 11 of 15 (73%) eyes. Eyes with macular tumor had visual acuity ranging from 6/36 (0.8) to 6/60 (1.0). SIx of eight eyes (75%) with extra macular tumors had vision 0.4 or better. Conclusion: Intravitreal melphalan seems like a promising treatment modality in group D retinoblastoma with resistant vitreous seeds having dark eyes. Amblyopia therapy may play an important role in attaining maximal visual benefits in these children.