30 RETINA TODAY | OCTOBER 2016 OCULAR ONCOLOGY Intravitreal and intraarterial administration of chemotherapy are important and effective methods of treatment, but they must be used with caution. BY HILARY M. GRAY, BA; KAREEM SIOUFI, MD; AND CAROL L. SHIELDS, MD INTRAVITREAL CHEMOTHERAPY FOR VITREOUS SEEDING CAUSED BY RETINOBLASTOMA Vitreous seeding is one of the primary reasons for treatment failure following conserva- tive management of retinoblastoma. 1,2 In our hands, until early 2006, most children with recurrent vitreous seeding were managed with plaque radiotherapy, external beam radiotherapy, or enucleation. 1,2 In 2006, following the initial experience of Kaneko and Suzuki in Japan, 3 we performed the first intravitreal injection of melphalan for the management of retinoblastoma vitreous seeds in the United States. 4 Quite cautiously, we sequentially injected the affected eyes of three patients with previously treated retinoblastoma and extensive recurrent vitreous seeding. Our initial experience was that all three cases showed dramatic response with rapid seed regres- sion. However, due to the low chemotherapy dose (8 μg/0.1 cc melphalan) used at that time, seed recurrence was a problem. Since then, melphalan dose escalation to between 20 μg/0.1 cc and 30 μg/0.1 cc has allowed reliably improved results, with vitreous seed control in nearly every case. 5,6 Today, vitreous seeds no longer readily necessitate enucle- ation, as these cases can be managed safely and reliably with intravitreal chemotherapy (IVitC). 4-6 In 2012, Ghassemi and Shields 4 and Munier et al 7 each reported on the safety and efficacy of IVitC for vitreous seeds. Munier et al noted that IVitC was no longer prohibited for retinoblastoma manage- ment. 7 This approach has now been adopted at almost all major retinoblastoma centers worldwide. In this article we describe a child with retinoblastoma treated initially with intraarterial chemotherapy (IAC) and then subsequently with intravitreal melphalan for recurrent vitreous seeding. CASE REPORT A 26-month-old male initially presented for evaluation of a lazy eye with leukocoria and was found to have retinoblas- toma. The patient was referred to Wills Eye Hospital Ocular Oncology Service for an opinion. On examination, visual acuity was fix and follow in the right eye (OD), and no fix or follow in the left eye (OS). Intraocular pressures were normal in both eyes. OD was healthy, but OS showed obvious leukocoria (Figure 1). On funduscopy, there was total retinal detachment up against the back of the lens, with exophytic retinoblastoma classi- fied as group D and measuring 16.0 mm in basal dimension and 10.6 mm in thickness (Figure 2A). Both vitreous and subretinal seeds were noted. Ultrasonography and magnetic resonance imaging using T1- and T2-weighted scans showed • Vitreous seeding is an important cause of treatment failure following conservative management of retinoblastoma. • Intravitreal chemotherapy (IVitC) and intraarterial chemotherapy are effective approaches to managing patients with retinoblastoma and should be selected based on clinical examination, previous treatments, and tumor manifestations. • The main indications for IVitC include patients with vitreous seeds unresponsive to standard therapy or recurrent vitreous seeds after previous standard therapy. AT A GLANCE