Intravitreal melphalan for persistent or recurrent retinoblastoma vitreous seeds: preliminary results

Recurrent or persistent vitreous seeds following treatment of retinoblastoma poses difficult management and often leads to enucleation.

To describe the technique and evaluate the efficacy and complications of intravitreal melphalan for vitreous seeding from retinoblastoma.

This retrospective noncomparative analysis was conducted at a tertiary referral center. The study included 11 consecutive eyes of 11 patients with viable persistent or recurrent vitreous seeds following treatment of retinoblastoma.

All eyes received intravitreal melphalan injection (20-30 µg) by transconjunctival pars plana route with concomitant triple-freeze cryotherapy at the injection site during needle withdrawal for prevention of extraocular seeding. Each patient was offered planned 6 monthly cycles.

Vitreous seed control and complications of therapy.

The mean patient age at vitreous injection was 37 months (median, 27 months; range, 16-82 months). Viable vitreous seeds involved 2 (n = 1), 3 (n = 4), or 4 (n = 6) quadrants. The solid intraretinal retinoblastoma and subretinal seeds showed regression in all eyes following intravenous chemotherapy (n = 6) or intra-arterial chemotherapy (n = 5). There were a total of 55 injections, with a mean number per patient of 5 (median, 6; range, 2-6). Fewer than 6 injections (n = 5) were delivered owing to complete vitreous seed control and parental desire to avoid more injections. By a mean of 9 months' follow-up (median, 9 months; range, 6-16 months), therapeutic success with complete vitreous seed regression was achieved in all 11 cases (100%). Globe salvage was attained in all cases (100%). Further vitreous seed development did not occur in any case. Complications included focal retinal pigment epithelial mottling near the site of chemotherapy injection (2 eyes) and nonaxial posterior lens opacity (2 eyes). There was no case of extraocular tumor extension, hypotony, or phthisis bulbi.

These preliminary short-term results suggest that intravitreal melphalan injection for persistent or recurrent vitreous retinoblastoma seeding can provide tumor control with minimal toxicity and complications.