A NEW STUDY in The Lancet Oncology journal estimates that there are almost 400,000 new cases of childhood cancer annually, while current records count only around 200,000. 

The new model makes predictions for 200 countries and estimates that undiagnosed cases could account for more than half of the total in Africa, South Central Asia and the Pacific Islands.

In North America and Europe, only 3% of cases remain undiagnosed. If no improvements are made, the study authors estimate that nearly three million further cases will be missed between 2015 and 2030. 

“Our model suggests that nearly one in two children with cancer are never diagnosed and may die untreated,” says study author Zachary Ward from the Harvard TH Chan School of Public Health, USA.

“Accurate estimates of childhood cancer incidence are critical for policy makers to help them set healthcare priorities and to plan for effective diagnosis and treatment of all children with cancer. While under-diagnosis has been acknowledged as a problem, this model provides specific estimates that have been lacking.”

Previous estimates for the total incidence of global childhood cancer have been based on data from cancer registries, which identify cases in defined populations. But 60% of countries worldwide do not have this sort of registry and those that do only cover a small fraction of the overall population.

The Lancet study says that many patients are not diagnosed and are therefore not recorded. This can occur due to lack of access to primary care, with patients dying undiagnosed at home, or due to misdiagnosis.

The new model developed for this study, the Global Childhood Cancer model, incorporates data from cancer registries in countries where they exist, combining it with data from the World Health Organisation’s Global Health Observatory, demographic health surveys and household surveys developed by Unicef.

In most regions of the world, the number of new childhood cancer cases is declining or stable. However, the authors estimate that 92% of all new cases occur in low and middle-income countries, a higher proportion than previously thought. 

The most common childhood cancer in most regions of the world in 2015 was found to be acute lymphoblastic leukaemia, with the exception of sub-Saharan Africa.

There were around 75,000 new cases globally, including nearly 700 in North Europe, over 1,500 in West Africa, over 3,500 in East Africa and nearly 30,000 in South Central Asia.

In East and West Africa, Burkitt’s lymphoma was more common, with over 4,000 cases in East Africa and over 10,000 in West Africa. For example, there were around 1,000 cases in the Democratic Republic of the Congo and Ethiopia, while only around 20 in the UK.