Asian countries face largest burden of childhood cancer globally
Asian countries face the largest burden of childhood cancer in terms of disability-adjusted life-years (DALYs), according to a recent analysis of the Global Burden of Diseases, Injuries and Risk Factors Study (GBD) 2017.
This first report of the global and regional estimates of childhood (age, 0–19 years) cancer burden based on DALYs covered 195 countries. The results highlight a substantial DALY burden of childhood cancers, particularly in resource-limited countries, despite a relatively low absolute number of incident cases and deaths in 2017. [Lancet Oncol 2019, doi: 10.1016/S1470-2045(19)30339-0]
In 2017, 11.5 million DALYs were lost globally due to childhood cancer. A disproportionately high burden – 82.2 percent (equivalent to almost 9.5 million DALYs) – was in low, low-middle and middle Socio-demographic Index (SDI) countries that are concentrated in Asia, Africa, and Central and South America.
Furthermore, low and low-middle SDI countries accounted for 38 percent of the global incidence (159,600 new cases) but a disproportionate 60 percent of the global burden (almost 7 million DALYs) of childhood cancers. In comparison, high and high-middle SDI countries accounted for about 35 percent of the global incidence (147,300 new cases) but only 18 percent of the global burden (about 2 million DALYs) of childhood cancers.
Among the world regions analyzed, South Asia faced the largest absolute burden of childhood cancers (almost 3 million DALYs), followed by Southeast Asia, East Asia and Oceania combined (about 2.5 million DALYs).
Among 50 countries with the largest population of children, India had the highest burden of childhood cancers, followed by China, Pakistan, Nigeria and Indonesia.
A majority (97.3 percent) of the global DALY burden of childhood cancers was from years of life lost (YLLs), while 2.7 percent of the burden was due to years lived with disability (YLDs).
The study also showed that the 0–4 year age group contributed to most (37 percent, or 4.3 million DALYs) of the global burden of childhood cancers.
In terms of disease-specific contribution, leukaemias accounted for the highest proportion (34.2 percent) of childhood cancer burden globally, followed by brain and nervous system cancers (18.1 percent). The highest absolute burden of leukaemias was in South Asia (954,000 DALYs).
According to the investigators, the geographical distribution pattern of childhood cancer burden is “noticeably different” from that seen in adult cancers, where only 50.3 percent of the global absolute DALY burden was in low, low-middle and middle SDI countries.
Risk-reduction strategies and screening interventions for addressing the cancer burden in adults are not as relevant to childhood cancers, they added, because childhood cancers tend to progress rapidly, are not amenable to screening programmes, and are fatal without swift diagnosis and treatment. “This highlights the crucial role of early diagnosis and treatment in reducing the global burden of childhood cancers,” they noted.
The study also revealed an unexpected association between childhood cancer incidence and SDI, with age-standardized incidence rates being higher in high SDI countries than in low, low-middle and middle SDI countries. According to the investigators, the cause of this trend is unknown and probably multifactorial, including limited access to health care and limited diagnostic capacity, which may contribute to underdiagnosis of childhood cancers in resource-limited settings.