Systemic chemotherapy as a new conservative treatment for intraocular retinoblastoma

Retinoblastoma is the most common malignant intraocular tumor in childhood. With advances in the methods for early detection of this disease, the survival rate is over 90% in developed countries. The management of intraocular retinoblastoma has gradually changed over the past few decades. Every effort has been made to save life, with the preservation of the eye and sight, if possible. External beam radiotherapy has been a standard treatment for medium and large, or visually threatening, intraocular retinoblastoma, but it markedly increases the risk of cosmetic deformities and secondary cancer in children with germline RB mutations. For the past decade, primary systemic chemotherapy called "chemoreduction" has been employed to avoid radiotherapy and enucleation. This article gives an overview of the results of current trials of primary chemoreduction for intraocular retinoblastoma, and discusses its role and its limitations in conservative treatment. The article also discusses future directions to expand the indications for this treatment. Many children with advanced intraocular retinoblastoma could be spared external beam radiotherapy and enucleation, mostly as a result of chemoreduction and focal methods. Chemoreduction combined with focal treatments will continue to play an important role in the conservative management of children with intraocular retinoblastoma, possibly even in children with advanced disease, with the combined use of multidrug-resistance modulators.