Developing countries bear more than four-fifths of the global burden of childhood cancer - the equivalent of 7 million years of healthy life lost - because of a lack of early detection and limited treatment, a study has found.
The study, published on Monday in The Lancet Oncology, showed that children with cancer in low- and lower-middle-income countries have much lower survival rates, with less than 40 per cent still alive five years after diagnosis. In wealthy countries, around 80 per cent of children survive five years after their cancer is identified.
To calculate the burden of disease, researchers estimated the number of years of healthy life that children and adolescents with cancer have lost due to illness, disability and premature death - known as disability-adjusted life years (DALYs).
Lisa Force, a co-author and clinical fellow at the St Jude Children's Research Hospital in Memphis, United States, said: "By assessing the global burden of childhood cancer through the lens of disability-adjusted life-years, we can more comprehensively understand the devastating impact of cancer on children globally."
Researchers found that developing countries faced a disproportionately high child cancer burden, relative to the incidence of disease, with low- and middle-income countries accounting for 82 per cent of the global total. This was attributed to poor diagnosis and access to healthcare, while younger populations were also cited as a factor.
In 2017, countries with a low or lower-middle socio-demographic index accounted for 38 per cent of children newly diagnosed with cancer - 159,600 cases. However, they represented 60 per cent of DALYs.
The study, which combined information on childhood cancers from 195 countries, estimated that about 7 million years of healthy life was lost in these poorer countries.
Globally, childhood cancers killed 142,300 children in 2017, and caused a loss of more than 11.5 million DALYs. This compares to around 37 million DALYs lost every year to malaria and 7.6 million lost due to tuberculosis.
Among the 50 most populous countries, India, China, Nigeria, Pakistan and Indonesia carried a particularly high childhood cancer burden. Sub-Saharan Africa was identified as the region with the highest burden across different cancer types, ranking highest for six out of the ten cancer types studied.
Alexandra Martiniuk, an associate professor at the medicine faculty of Australia's University of Sydney, says developing countries face a multitude of barriers when it comes to child cancer care, including inadequate staff training and the high cost of diagnostic tools.
"There are also barriers within the population regarding seeking care for particular symptoms, [as well as] a lack of financial means to seek healthcare," she told SciDev.Net.
Tharcisse Mpunga, director of Butaro Hospital in Rwanda, believes delayed diagnosis is a big problem. "Delays happen both in the community and in the health system," he said. "This includes lack of follow-up and abandonment of treatment, especially due to financial constraints, as well as high rate of relapse and deaths related to drugs' toxicity."
Issues such as these were reflected in the study, which found that 26 per cent of all globally reported childhood cancers were "uncategorised". This is because, at present, information on most childhood cancers is collected using a system developed to report on adult cancer. The authors said that this lack of information makes it more difficult to develop appropriate health and policy interventions. This is despite the fact that, according to the study, childhood cancers represented a larger cause of DALYs than any adult cancer.
Neha Faruqui, a doctoral student at the University of Sydney, has researched access to childhood cancer treatments in New Delhi, India. She told SciDev.Net that many governments in low- to middle-income countries face difficult choices when it comes to paying for tools to diagnose and treat rare diseases such as childhood cancer versus more common diseases.
"So many regional hospitals will not get funding," she said, citing resulting problems such as bed shortages, poor dietary advice and inconsistent drug supply.
Children in rural settings are more likely to struggle with accessing treatment, said Faruqui, adding: "Since treatment is concentrated in selected urban cities, the geographical barriers contribute to the overall difficulties experienced."