Background Information:

Retinoblastoma is the commonest primary ocular malignancy of childhood originating from primitive retinoblasts with tendency towards cone differentiation, Retinoblasts arise from the inner neuroepithelial layers of the embryonic optic cup [1]. Retinoblastoma (Rb) is a rare disease with a low incidence; however, it is responsible for about 6% of all cancers in children below 5y of age. It is one of the most common childhood ocular malignancies in the first 3-5y of life [2].

The clinical signs of Rb vary depending on the stage of the disease at diagnosis, The most common and noticeable sign is leukocoria (or white pupillary reflex) also known as cat’s eye reflex, which can be detected when the tumor is large, Strabismus may be seen in small tumors [3]. Other non-specific signs and symptoms include decreased visual acuity, red-eye, exophthalmos, and glaucoma [4]. In bilateral Rb, the eyes are asymmetrically involved and the signs and symptoms are more severe in one eye, many children are diagnosed before the age of 5y but the age of onset depends on the Rb type (heritable vs non-heritable) [5].

Globally, the incidence of Rb not only varies between different countries but there are also different reports in the same country, for example, an incidence of 12.9 in 1 000 000 children aged 0-4y was reported in the USA that has not changed in many years [6], but the incidence is higher in non-Hispanic black and Hispanic white populations. There is a similar pattern in European countries so that the highest incidence was seen in Western Europe like Belgium and the lowest was reported in Austria [7].

In Tanzania, Retinoblastoma is the most common malignancy in children, with a prevalence of 29.1% among other childhood tumors. A study found that the incidence of retinoblastoma was 1.5 cases per million children per year, with the median age at diagnosis of 24 months and 70% of the children presented with advanced disease, However, the estimated disease-free survival for children with intraocular retinoblastoma in Tanzania is only 24% at 30 months [8].