Intravenous and intra-arterial chemotherapy for retinoblastoma: what have we learned?

To review the recent literature on two methods of chemotherapy for retinoblastoma using intravenous versus intra-arterial route.

In 1996, the era of intravenous chemotherapy (chemoreduction) for retinoblastoma was introduced with major centers providing published information on impressive tumor control, without the need for external beam radiotherapy or enucleation. Later reports heralded continued impressive long-term control, minimal systemic toxicities, likely prevention of pinealoblastoma (trilateral retinoblastoma), and reduction in numbers of germline mutation second cancers. There is no reported ophthalmic toxicity and no evidence of reduction in fertility with chemoreduction. In 2011, the era of intra-arterial chemotherapy was announced with several studies and three conflicting editorials in the literature. This technique requires a catheterization through the arterial tree from the femoral artery into the ophthalmic artery. Outstanding tumor control is achieved with only three cycles, but more-than-expected ocular ischemic events have been noted. Further improvements in this technique could minimize complications.

Both intravenous and intra-arterial chemotherapy are powerful methods for retinoblastoma control. In addition to tumor control, intravenous chemotherapy protects from systemic metastasis and pinealoblastoma, minimizes long-term second cancers, and has few systemic and no ocular toxicities. Intra-arterial chemotherapy provides excellent tumor control for slightly more advanced eyes with retinoblastoma and, in addition, can be used to treat eyes that fail other methods. However, local ocular toxicities can be vision-threatening and long-term systemic toxicities are not yet understood.