New Delhi: India along with China, Nigeria, Pakistan, Indonesia, and the USA face the largest burden of childhood cancer among countries with the highest population of children, the first Global Burden of Disease Study (GBD) to assess childhood and adolescent cancer burden in 195 countries in 2017, published in The Lancet Oncology journal on Monday said.
While the number of new cancer cases in children and adolescents (aged 0-19 years) is relatively low at around 416,500 globally in 2017, treatment-related ill-health and disability and fatal cancer are estimated to cause around 11.5 million years of healthy life lost globally every year, the study said.
While four of the five countries with the highest childhood cancer burden were in Asia and Oceania (India, China, Pakistan, and Indonesia), the USA had the sixth largest burden in 2017, and sub-Saharan Africa had the biggest DALY burden for more childhood cancer types than any other region, according to the study.
The study puts the annual toll of childhood cancer at over 11.5 million years of healthy life lost in 2017. This compares with around 37 million years of healthy life lost globally due to malaria, and 7.6 million from tuberculosis. In 2017, childhood cancer was among the top four biggest contributors to the burden of general diseases of childhood in middle and high-middle SDI countries, ranking higher than malaria and HIV/AIDS.
Children with cancer who live in high-income countries tend to have good survival, with around 80% surviving 5 years after diagnosis. But these improvements have not translated to most low- and middle-income countries (LMICs), where survival is approximately 35-40%, but some estimates suggest it could be as 20%. Around 90% of children at risk of developing cancer live in LMICs, the study highlighted.
Children in the poorest countries face a disproportionately high cancer burden--contributing over 82% of the global childhood cancer burden--equivalent to almost 9.5 million years of healthy life lost in 2017. Most (97%) of this global burden is related to premature death, with around 3% due to impaired quality of life, the study pointed out.
The study estimates the number of years of healthy life that children and adolescents with cancer have lost due to illness, disability, and premature death--a measurement known as disability-adjusted life years (DALYs). One DALY is equivalent to one year of healthy life lost. However, disability in childhood cancer survivors was limited to the first 10 years after cancer diagnosis, rather than across the whole life course, so the global burden of DALYs associated with childhood cancer is probably underestimated, researchers 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," said Lisa Force from St Jude Children's Research Hospital in the USA, who led the research in collaboration with the Institute for Health Metrics and Evaluation.
The findings of the study found that that high and high-middle SDI countries accounted for about 35% (147,300) of new cases of childhood cancer in 2017, but only 18% of DALYs (around 2 million years of healthy life lost), whereas low-middle and low SDI countries with 38% of global incidence (159,600 new cases) accounted for 60% of DALYs (almost 7 million years of healthy life lost).
This study was funded by the Bill & Melinda Gates Foundation, American Lebanese Syrian Associated Charities (ALSAC), and St. Baldrick's Foundation. It was conducted by researchers from St Jude Children's Research Hospital, Memphis, TN, USA and University of Washington, Seattle, WA, USA.