Intracameral Chemotherapy (Melphalan) for Aqueous Seeding in Retinoblastoma: Bicameral Injection Technique and Related Toxicity in a Pilot Case Study

Background: The anterior chamber has been shown by pharmacokinetic studies to represent a sanctuary never achieving a tumoricidal dose with the present administration routes, such as systemic, intra-arterial, or intravitreal injections.

Method: A novel intracameral chemotherapy technique is described to control aqueous seeding in a pilot unilateral group E retinoblastoma case with primary aqueous seeding. Anterior segment toxicity was carefully monitored.

Results: Control of the retinal tumor and vitreous seeding was achieved by intra-arterial and intravitreal chemotherapies. Sterilization of the aqueous was achieved after a first cycle of 7 melphalan injections in the anterior chamber, but relapse was noted 3.5 months later. This relapse was finally controlled with a second cycle of 6 intracameral injections targeting the posterior chamber. Corneal endothelial cell density remained stable over the injection period. Heterochromia and a progressive cataract developed, which required cataract surgery. At 5 years' follow-up, the patient is tumor free with normal vision (20/20 in both eyes), full binocularity, and no metastasis.

Conclusions: The present bicameral injection technique appears to be safe and effective with limited toxicity. Melphalan-induced side effects were noted on the iris and lens but with no impact on the final visual function.