Retinoblastoma and treatment: A current evaluation of advanced therapy

Retinoblastoma is the most common primary childhood ocular tumor, affecting nearly 3.5 per million children worldwide. A mutation in the RB1 gene, which presents as either germline or sporadic, along with additional mutational events, promote neoplastic growth in the retina. Fortunately, current treatment protocols result in success rates approaching 99% at specialized centers, with many children maintaining useful vision. Overall, treatment is guided by aggressiveness and size, and is classified by systems such as the ReeseEllsworth System and the International Classification of Retinoblastoma. Due to advances in chemotherapy protocols combined with use of focal laser consolidation, treatment paradigms have shifted from enucleation to external beam radiation therapy to chemotherapy as globe-salvaging therapies. Smaller, less complex tumors may be controlled by plaque radiotherapy or focal laser ablative therapy. However, larger and more complex tumors, such as those that have vitreous or subretinal seeding, require methods of chemoreduction combined with focal consolidation to yield better outcomes. Standard chemotherapy protocols utilize vincristine, etoposide, and carboplatin with or withoutcyclophosphamide. Finally, there has been a recent push in local treatments for retinoblastoma to minimize systemic toxicities. These modalities include intravitreal or subconjunctival injections and more recently, direct chemotherapy administration into the ophthalmic artery. As a result, enucleation is used less often, but remains an important treatment for the most aggressive, refractory cases. The advancement of retinoblastoma treatment looks promising; however, worldwide access to these treatments and the lack of long-term followup of new local treatment modalities constitute current and future challenges.