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

Abstract

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.

Keywords: Anterior chamber fluid; Aqueous seeding; Chemotherapy; Intracameral chemotherapy; Intravitreal injection; Melphalan; Pathology of the anterior segment; Retinoblastoma.

Fig. 1

a Biomicroscopy and gonioscopy at presentation: pseudohypopyon (white triangle); iris nodules at 6 and 9 o'clock and nodules in the angle over 270° (white arrows). b Ultrasonic biomicroscopy (35 mHz) at presentation: circular invasion of the posterior chamber, including the canals of Petit and Hannover, but no involvement of the ciliary body, iris, or Schlemm's canal.

Fig. 2

a Fundus montage at presentation: inferiorly located vitreous seeding type III (cloud) masking the primary peripheral tumor. b, c Ultrasonic biomicroscopy (35 mHz) of the primary peripheral tumor under the vitreous base (b) and tumor invasion of the posterior chamber (c) at presentation. d Fundus montage at full remission. e Ultrasonic biomicroscopy at complete remission: tumor-free posterior chamber. f, g Gonioscopy at first remission (f) and at relapse (g).

Fig. 3

Technique of intracameral injection. a, a’ Long-needle passage (34 G) across peripheral clear cornea. b Complete aspiration of the aqueous volume contained in the anterior and posterior chambers. This maneuver is facilitated by indenting the eye with a scleral depressor (not illustrated) just posteriorly to the limbus (see online suppl. video). c Syringe exchange with melphalan at a concentration of 15 μg/mL. d Melphalan injection of 1/3 (paracentesis volume minus the volume to be injected into the vitreous) into the anterior chamber. e Perforation of the iris root at a tumor-free meridian selected by ultrasonic biomicroscopy to position the needle in the posterior chamber. f Transiridal injection into the posterior chamber of the remaining 2/3 (paracentesis volume minus the volume to be injected into the vitreous) with anterior chamber retrofilling. In total, the mean intracameral injection volume was 0.35 mL. g Triple freeze and thaw cryo-application at the entry site.

Fig. 4

Monitoring of tumor response in the anterior chamber by cytopathological analysis (a-c) and cell culture (d-g). a Isolated, small- to medium-sized malignant cells with granular chromatin and scant cytoplasm. Some apoptotic nuclei are present in the background (liquid-based cytology, Papanicolaou staining, ×400). b Bright-field micrograph (×400) of 1 out of 5 aggregates detected in culture after the first sampling (January 9, 2012). c A group of malignant cells express the immunocytochemical marker synaptophysin (clone 27G12, dilution 1:100, Leica Biosystems), consistent with retinoblastoma cells (liquid-based cytology, ×400). d-g Quantification of the number of aggregates (d), cells per aggregate (e), individual cells (f), and dying cells (Trypan blue positive) (g) calculated on samples harvested before each intracameral injection. 20120109, 20120119, 20120130, 20120209, 20120628, day of sampling (year/month/day). *** p < 0.001.

Fig. 5

Iris and lens toxicity. a, b Biomicroscopic views of the iris with hypochromic heterochromia. c, d Biomicroscopic views of cortical opacification of the lens. e, f Scheimpflug photography of cortical opacification of the lens.