Chemotherapy for Retinoblastoma: Impact of Intravitreal Chemotherapy

Chemotherapy is now the primary treatment of retinoblastoma in eyes with visual potential or those that are considered not advanced for retinoblastoma. In addition to intravenous chemotherapy (IVC), drugs delivered via alternative routes such as intra-arterial and intravitreal administration have emerged as promising options for management of retinoblastoma. Various studies have shown excellent results in salvaging nearly 100% of groups A-C eyes; however, intra-arterial chemotherapy (IAC) seems to offer superior local control rates as compared with IVC for advanced intraocular retinoblastoma (groups D and E eyes). Intravitreal chemotherapy (IVitC), that delivers the highest concentration of drug in the vitreous cavity while minimizing systemic drug concentration, has emerged in recent years (2012) as an effective treatment for refractory or persistent vitreous seeding. The role of concomitant and subsequent therapies is an important consideration, particularly the use of IVitC in combination with IAC. As IVitC became acceptable during the era of IAC, most of the patients treated previously with IVC did not receive IVitC. Therefore, it is possible that some of the IVC failures could have been avoided with the use of IVitC. We provide our perspective of published data that seems to be skewed by evolving practice patterns that project enhanced efficacy of IAC when compared with historic control rates achieved with IVC. In absence of better-quality data or randomized controlled trials, it is hard to establish superiority of one treatment over the other.