Children in low income countries are at 16 per cent higher risk of dying of eye cancer retinoblastoma at any time within three years of diagnosis than those in high-income countries, claimed a new study published in The Lancet Global Health.
The research, led by the International Centre for Eye Health (ICEH) at the London School of Hygiene & Tropical Medicine (LSHTM), came across stark differences in survival for children with retinoblastoma between high-income and low-income countries. Retinoblastoma is the most common form of childhood eye cancer.
In the study, the researchers said that risk of death due to this eyes cancer in children in high-income countries dropped dramatically over the last few decades. They said that deaths are rare because of robust diagnosis and treatment pathways, including specialist retinoblastoma centres.
The study is claimed to be the largest and most geographically comprehensive one. They analysed 4,064 children with retinoblastoma from 149 countries (categorised as high, upper-middle, lower-middle and lowincome) globally. These are estimated to be 50% of all new cases worldwide in 2017. They then analysed the three-year survival rate for these children following their diagnosis. They found that over two-fifths (40 per cent) of children die within three years of diagnosis in low-income countries, compared with fewer than one in 100 (one per cent) in high-income countries.
Noting that the results were shocking, ICEH Director at LSHTM Professor Matthew Burton said that the reasons for the disparity in low and high income countries should be ascertained and policies enacted that close this survival gap. Meanwhile, lead author Dr Ido Didi Fabian said: ‘we have always known there was a difference in outcomes between higher and lower income countries, but the differences were seeing in this study, the largest of its kind, are very worrying for children affected by retinoblastoma. Better awareness of the early signs, improving access to timely diagnosis, and implementing existing guidelines aimed at children in low- and middle-income countries, are critical to improving retinoblastoma outcomes worldwide.” Fabian is the Principal Investigator of the Global Retinoblastoma Study Group at LSHTM.
The authors also said that there were certain limitations to the study, including that the cohort was a sample taken from a previous study (despite containing half of all cases worldwide for that year). The study also did not collect detailed data on treatment, for instance specific treatment protocols and complications. Future studies could include these sub-analyses.
Despite the study showing that the main treatments for retinoblastoma (the removal of an eye, or enucleation, and intravenous chemotherapy) being available in all countries, several factors may be responsible for the reduced survival rate. Previous studies suggest that low-income countries are less likely to have specialised treatment centres containing sophisticated equipment and techniques such as MRI machines and targeted chemotherapy. Limited awareness among the general public and health care workers, and issues accessing treatment due to travel distance and cost are all suggested to contribute to worse outcomes and increased risk of death.
Retinoblastoma is cancer of the retina. The retina is the light-sensitive lining at the back of the eye. During the early stages of a baby’s development, retinal eye cells grow very quickly and then stop growing. But in rare cases, one or more cells continue to grow and form a cancer called retinoblastoma. In about four out of ten (40 per cent) cases, retinoblastoma is caused by a faulty gene, which often affects both eyes (bilateral).
The faulty gene may be inherited from a parent, or a change to the gene (mutation) may occur at an early stage of the child’s development in the womb.
It’s not known what causes the remaining 6 out of 10 (60%) retinoblastoma cases. In these cases, there’s no faulty gene and only 1 eye is affected (unilateral).