Almost half of the world’s childhood cancer cases go undiagnosed and untreated, according to a new study published this week in the journal The Lancet. Using a model to estimate undiagnosed cases in different parts of the world in 2015, the researchers found that in addition to the 200,000 cases on record annually, nearly another 200,000 went undetected, according to Science Daily.
While in North America and Europe, undiagnosed cases totaled just 3 percent of estimated cases, they made up 49 percent in south Asia and 57 percent in West Africa. They also likely make up more than half of cancer cases in the Pacific islands, as well as Africa as a whole.
The researchers say 92 percent of new childhood cancer cases occurred in low or middle-income countries, with West Africa seeing a particularly high rate of new cases. Acute lymphoblastic leukemia was found to be the most common type of childhood cancer.
Without improvements in these areas, the study warns that almost three million cases will go undiagnosed between 2015 and 2030.
“Our model suggests that nearly one in two children with cancer are never diagnosed and may die untreated,” said Zachary Ward, first author of the study and Harvard University researcher.
Past estimates of childhood cancer have relied on cancer registries. But 60 percent of the world’s countries do not have registries, and many of the registries that do exist only include a small portion of the population. And of course, undiagnosed cases, stemming from lack of primary care or misdiagnosis, are never recorded as cancer.
The study estimates undiagnosed childhood cancer in 200 countries and territories.
“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,” said Ward.
The study used a model that combines data from the registries with data from World Health Organization’s Global Health Observatory and UNICEF surveys. Adjustments were made for known weaknesses in the healthcare systems of certain countries.
The authors say that barriers to healthcare access and referrals lead to the widespread failure to diagnose cancer cases in some regions. Current healthcare models often rely on treatment in a small number of specialized hospitals, and the authors call for more widely available healthcare networks.
According to Ward:
“As the hidden incidence of childhood cancer starts to come to the fore, stronger health systems are needed for timely diagnosis, referral and treatment.”