Retinal and choroidal cancers: Blood-retinal barriers considerations in ocular chemotherapy

Abstract Despite significant recent advances in the local treatment of ocular diseases, the use of systemic treatments is still required to cure and control refractory ocular cancers and metastatic relapse, particularly in retinoblastoma, and other intra-ocular cancers. To achieve effective anticancer drug activity, drug distribution from the blood into the tumor site remains a critical pharmacokinetic process. Release and penetration of many anticancer drugs into the retinal parenchyma are often sub-optimal due to specific anatomical and biochemical features of the retina, regulated through blood-retinal barriers molecular exchanges with the blood compartment. This chapter reviews clinical and therapeutic aspects of retinoblastoma and choroidal melanoma, the main retinal and choroidal cancers, as well as anatomy, histology and biochemical aspects of the blood-retinal barriers focusing on drug-metabolizing enzymes and drug transporters, with respect to ocular chemotherapy.