To the Editor We read the article by Yousef et al titled “Intra-arterial Chemotherapy for Retinoblastoma: A Systematic Review.”1 From our perspective from an intra-arterial chemotherapy (ophthalmic artery chemosurgery [OAC]) program in Argentina, we believe that some issues limit the validity of their conclusions regarding the risk of metastatic relapse.
First, the population analyzed is heterogeneous, coming from centers with diverse expertise, patient number, and sociocultural discrepancies that influence outcome. In our opinion, OAC is used in some settings as a way of saving the patient’s life when, for cultural reasons, their families would not accept enucleation.2 In such cases, after failing conservative therapy, extraocular relapse would inevitably occur and these children would die despite any treatment. In other settings, like those in most Western countries, OAC is used for eye salvage. If this treatment fails, we anticipate that patients undergo enucleation without delay and, regardless of the therapy used, metastatic relapse is not typical. In the article by Yousef and colleagues, results from groups treating 3 patients per year with a metastatic rate of 25% are analyzed together with leading centers treating more than 300 patients with a relapse rate of 3.5%.1 The former was performed in a setting where the authors reported that refusal for enucleation was present3 and 3 of their 6 patients treated with OAC after failing other treatments had metastases. Hence, the different uses of OAC throughout the world with different realities imply the inclusion of patients with diverse risk of metastatic disease, which makes calculations of the risk of metastatic disease extracted from the combination of these studies questionable.