About childhood cancer
 The global burden of childhood cancer
In Britain and much of the developed world, childhood cancer incidence rates have increased over recent decades. Whilst some of the increase is clearly due to improvements in diagnosis and registration, there is believed to be a genuine increase in underlying risk.
It is estimated that more than 175,000 children develop cancer every year globally and that around 96,000 of these children do not survive.
Cancer is emerging as a major cause of childhood death in developing nations where fewer children are now dying from preventable infectious diseases.
Geographic variations in childhood cancer
There is considerable variation in the incidence of different types of childhood cancer between different regions of the world and between ethnic groups in the same country.
In some instances, a higher than average incidence of cancer can be easily explained: the high incidence of Kaposi sarcoma in Central and East Africa, for example, is related to the AIDS epidemic; the high incidence of thyroid carcinoma in Belarus was a result of the Chernobyl nuclear disaster.
However, explanations for other differences in incidence are less clear,
- Why is the incidence of acute lymphoblastic leukaemia (ALL) lower in developing countries?
- Why are children in developing countries at higher risk of retinoblastoma and Hodgkin disease?
- Why do Black children in the US, but not the UK, have a lower incidence of ALL than White children?
- Why is there a lower incidence of rhabdomyosarcoma among children in South & East Asia and also among Asian children in the UK (compared with White children)?
Overall, Britain has a lower childhood cancer rate than most western industrialised countries. Australia and the US have some of the highest rates. The reasons for these differences are not clear.
Time trends
In Britain, recorded childhood cancer incidence rates increased by 38 per cent between 1966 and 2000 - an increase of almost 1 per cent per year. Improvements in diagnosis and registration can explain some of this increase but there is believed to be a real underlying increase in risk.
Supportive of this is the fact that there are differences between diagnostic groups.
CNS tumours, and in particular astrocytomas, show one of the larger increases of all tumour types. The astrocytoma subgroup includes a substantial proportion of low-grade tumours which, in earlier decades, could have remained undiagnosed for many years, and often beyond the child's 15th birthday. The introduction and refinement of diagnostic imaging techniques, particularly computerized tomography (CT) in the 1970s and magnetic resonance imaging (MRI) in the 1980s enabled earlier detection of these tumours, thereby increasing the number of reported childhood cases.
In contrast, the increase in rates of childhood leukaemia seems more likely to be real. Childhood ALL and acute myeloid leukaemia (AML) are acute diseases that are rapidly fatal without treatment. Diagnostic methods for these diseases have been well established for many years. The time trend for the two diseases is different - the recorded incidence rate of childhood ALL increased on average by 0.7 per cent per year between 1971 and 2000 whereas the rate of childhood AML remained stable. It therefore seems likely that there has been a real increase in the risk of childhood ALL.
Similar time trends have been reported in countries across Europe as well as in the United States.
Progress
In the developed world, most children diagnosed with cancer have a reasonably positive outlook. In the UK, the five-year survival rate among children diagnosed 2001 to 2005 was 78 per cent, and 73 per cent are expected to survive to 10 years.
Survival rates in the developing world fall far short of this.
As well as finding new ways to treat those forms of cancer which still have a poor prognosis, a major challenge facing us today is how to make treatments safer and minimise the risk of treatment-related harm. Childhood cancer survivors are at risk of a range of late effects, including a risk of second cancers.
There are more than 30,000 five-year survivors of childhood cancer alive in the UK today.
During Childhood Cancer 2012 we will consider the geographic variations and time trends in childhood cancer incidence - and what insight these patterns give to the aetiology of different cancers. We will also look at the progress that has been made in our understanding and treatment of childhood cancer.
Read more: Conference programme | Submitted abstracts | Registration
References
- American Cancer Society. Global Cancer Facts & Figures 2nd Edition. Atlanta: American Cancer Society; 2011.
- C A Stiller & G J Draper. The epidemiology of cancer in children in Cancer in Children, Clinical Management. P A Voute, A Barrett, M C G Steverns, H N Caron (eds). Oxford University Press, 2005.
- Charles Stiller. Childhood Cancer in Britain: Incidence, survival, mortality. Oxford University Press, 2007.
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