Abstract
Purpose:
The presence of primary or secondary aqueous seeding in retinoblastoma (rb) represents a universal indication for enucleation. All previous attempts at conservative treatment have been associated with 100% failure rate. Here we present a novel technique of in situ chemotherapy specifically developped to eradicate aqueous seeding.
Methods:
Retrospective review of two patients presenting with primary (patient#1) and secondary (patient# 2) aqueous seeding respectively. Combined injections of melphalan were given in the vitreous (200 μg/mL) and in both posterior (PC) and anterior (AC) chambers (15 μg/mL). The intra-cameral procedure consisted of 5 successive steps: 1) long needle passage (34G) across the peripheral clear cornea, 2) aqueous aspiration of of both AC and PC volumes, 3) melphalan injection of 1/3 of the paracentesis volume in AC, 4) trans-iridal injection into the PC of the last 2/3 and AC retrofilling, 5) triple freeze and thaw cryo-application at the entry site. Per-operative intra-venous acetazolamide is administred to suppress aqueous secretion.
Results:
Patient#1 was diagnosed with unilateral group E anterior diffuse rb at 11 years of age. Following first line intra-arterial chemotherapy, she received 10 intravitreal and 12 intra-cameral injections. Complete regression was achieved with an event-free follow-up of 27 months. The patient is binocular with visual acuity of 20/20 OU.<br /> Patient#2 was diagnosed with bilateral rb, group D OD and group E OS at 6 months of age. Following first line systemic chemotherapy and intra-arterial injections in OS, he developed secondary anterior seeding in OD at 25 months of age. He received 4 intravitreal and 5 intra-cameral injections. Complete regression was obtained with an event-free follow-up of 7 months since the last injection. The patient has good fixation without nystagmus.
Conclusions:
This is the first study to report globe salvage in case of anterior chamber seeding using a new intra-cameral injection technique. Moreover, both eyes retained normal visual function including binocularity in patient#1. We would like to stress that this approach is safe and efficient provided that 1) careful 35mHz ultrasonic biomicroscopy have excluded invasion of the ciliary body, iris and Schlemm's canal, 2) the injection is performed in the PC with retofilling of the AC, 3) pharmacologic suppression of aqueous secretion is observed.