Challenging the Global Retinoblastoma Burden

Saturday July 7, 2018

Helen Dimaras Ph.D considers the effect of our expanding global population on the expected numbers of children who will develop eye cancer each year, and the provision of effective care to meet their needs.

Two young girls, one Caucasian, one African, recline together on a blue sofa, smiling.

On world population day, observed annually on July 11, we are urged to “focus attention on the urgency and importance of population issues.”

83 million babies are born every year. The earth’s population currently stands at 7.6 billion. By 2030, this is estimated to increase to 8.6 billion, and by 2100, 11.2 billion. Current projections indicate that 97% of this population increase will occur in low-and-middle income countries (LMICs).

What Does This Mean for Retinoblastoma?

Put simply, the total number of patients with retinoblastoma will increase. The best available evidence indicates that the incidence of retinoblastoma is constant worldwide: for every 16,000 children born, one will develop retinoblastoma. Currently, this translates to about 9,000 new retinoblastoma patients per year.

Most of these children already live in LMICs, which is not surprising since those populations are generally bigger and have higher birth rates. The projected population boom means that over the next several years, we can expect even more kids with retinoblastoma in LMICs.

How Many Children Survive Retinoblastoma Worldwide?

This is problematic, because survival rates for retinoblastoma are much lower in LMICs as compared to the rest of the world. In some regions, as few as 3 in 10 children with retinoblastoma will survive. Barriers to survival in LMICs include low awareness of presenting signs of retinoblastoma, combined with poor access to and availability of retinoblastoma care.

In contrast, in high-income countries (HICs), more than 95% of children with retinoblastoma will survive to lead happy, healthy lives. Clearly, we know how to cure retinoblastoma. We simply need methods to effectively and consistently apply that knowledge in low-resource settings.

How Do We Monitor Global Retinoblastoma Care?

A tool that tracks the availability of retinoblastoma treatment around the world is the One Retinoblastoma World map. Freely available online, the map was created to collect global data on ‘where’ (e.g. what hospitals), ‘how’ (e.g. with what resources and expertise) and ‘how many’ (e.g. patient numbers) children with retinoblastoma are treated.

The map currently documents information from 178 retinoblastoma treatment centers in 76 countries. They represent 111 centers in LMICs and 67 from HICs. An estimated 7,966 new patients are expected each year in LMICs, and 784 in HICs. The 111 LMIC centers on the map report treating 2,882 of the expected 7,966 patients in their region (36%), while the 67 high-income centers report treating 691 of the 784 of the expected patients in their region (88%).

One Retinoblastoma World Map, showing location of specialist treatment centres across the globe.

The One Retinoblastoma World Map documents available treatment at 178 retinoblastoma treatment centers in 76 countries.

What Could Account for the ‘Missing’ Patients?

One reason for the difference between expected new diagnoses and numbers of recorded children treated could be that medical records are incomplete or inaccurate in some centers. So the patient burden they report to the map is incorrect. This is a known challenge in many parts of the world, and efforts to improve accuracy of medical records are ongoing.

Another reason for the missing patients could be that the One Retinoblastoma World map itself is missing treatment centers. The map support team continues to work to identify and engage additional treatment centers so that they are added to the map.

Finally, it is possible that many patients with retinoblastoma do not ever present to a treatment center in order to be counted in the first place. Public awareness efforts are key here, so that parents recognize the signs of childhood eye cancer and understand the importance of getting their child to a treatment center early. Along with removing barriers, such as high costs of transportation or treatment, that may hinder a family’s access to care.

Of the centers on the map, documentation of key resources and expertise point out the areas where improvements can be made to delivery to care. A key difference between centers in LMIC and HIC centers is in the availability of important diagnostic equipment, such as fundus photography and eye ultrasound; these modalities are more commonly available in HIC centers. Focal therapy (laser and cryotherapy) are also more commonly available in HIC centers, limiting the possibility of eye and vision salvage for patients in LMICs.

How Can Capacity For Retinoblastoma Care Be Improved In Treatment Centers Around The World?

National strategies are working to identify strengths and challenges at the country-level. Working nationally, agreed upon guidelines can give centers the framework to follow to deliver care. The situational analysis provided by the map can indicate where key improvements in resources or staff can be made in treatment centers to most efficiently provide care to patients.

The National Strategy model has been followed in Canada and Kenya, and most recently Ethiopia has started their own strategy.

Of course, availability of retinoblastoma care is only one piece of the puzzle. Ensuring that available care is of good quality, adheres to evidence-based guidelines, and that available resources are maintained in working order, are paramount. A future role for the One Retinoblastoma World map could be to assist in maintaining an optimal standard of treatment, through regular audits and standardization practices.

Another important challenge will be to ensure that optimal care is accessible to families no matter the socioeconomic conditions they face.

Connecting all of these puzzle pieces will require the entire retinoblastoma community to work together globally, and leverage individual strengths for the benefit of all children, survivors and their families.

About the Author

Dr. Helen Dimaras holds a PhD in Molecular & Medical Genetics, and completed post-doctoral training in clinical trials and global health. Her work has contributed to the understanding of the molecular genetic development of the childhood eye cancer, retinoblastoma. She leads a research program that lies at intersection of global health, cancer genetics and clinical research, and focuses on determining how to deliver optimal retinoblastoma care worldwide and improve patient outcomes. She is Scientist and Director of Global Eye Health Research at The Hospital for Sick Children, and Assistant Professor at the University of Toronto.