Retinoblastoma in Low- and Middle-Income Countries

Abstract

In this issue of Pediatric Hematology and Oncology, there are three reports addressing the management of Retinoblastoma in Lowand Middle-Income Countries (LMIC) [1–3]. Retinoblastoma is the most common malignant intraocular tumor affecting children. There are reports suggesting that the incidence of Retinoblastoma is higher in LMIC compared to HIC and that the disease is more advanced locally and systemically in a higher percentage of patients in LMIC. Time to Diagnosis (TTD) from initial symptoms is often reported as one of the most important determinants of advanced disease at diagnosis and therefore the outcome. Some of the contributing factors that increase the TTD especially in LMIC are lack of immediate access to medical care, parental education, and socioeconomic factors. However, as the report by Campolina et al. [1] shows, it is difficult to assess the length of TTD and the outcome of patients especially in LMIC where a prolonged TTD is likely to have an adverse effect on outcome. The data are retrospective and the focus and emphasis are more on the treatment and outcome than with the causes and effects of prolonged TTD. Unless a carefully planned prospective study is carried out with carefully constructed questions to identify the time of the first symptom/sign coupled with diligent data collection, the true determinants of TTD and its effect on disease stage and outcome will still be elusive. A more important outcome of such a study will be efforts to shorten the TTD and thereby improve the outcome of the affected children. These efforts are discussed briefly by the authors with Honduras as an example. Another cofounding factor that is often discussed but never studied is the biology of the tumors that do show locoregional and systemic spread. Whether biology trumps TTD and therefore the latter does not really affect the prognosis is another question worth answering. Given the paucity of gene alterations other than in the RB locus it seems unlikely for now that biology will play a major role in determining the outcome. In the current era efforts to salvage the unilateral or bilateral eyes with advanced disease with local delivery techniques like intra-arterial chemotherapy and intravitreal chemotherapy are increasingly gaining acceptance. Systemic chemotherapy which was shown to be effective in group A–C eyes was less so with group D and E eyes. However, intra-arterial chemotherapy requires not only expertise in interventional radiology in children but also in pediatric anesthesia as this is not a risk-free procedure. Therefore, it is of interest to note that Buaboonnam et al. [2] report in this issue the use of intensive chemotherapy for group D and E disease with reasonable success.