Preventing Childhood Cancer
Childhood cancer is one of the major causes of death and serious illness in children in the developed world, and an emerging problem of significant magnitude in low and middle-income countries. Professor Terry Dwyer leads the pioneering International Childhood Cancer Cohort Consortium (I4C), which aims to obtain prospective evidence on the causes of childhood cancer.
Unlocking the causes
Childhood cancer has attracted a great deal of attention from medical researchers around the world, resulting in some very important successes – most notably in relation to how to treat children who develop cancer. However, much less attention has been paid to how the disease might be prevented, partly because childhood cancer is very complex.
For example, there are many different types of cancer that affect children and they are usually different from cancers in adults. A child’s risk of developing cancer depends on many factors, including age and genetics. Environmental exposures experienced by both the mother and baby may also influence risk.
The scarcity of evidence relating to the importance of early-life exposures has hindered efforts to advance our knowledge about how interventions in early life might reduce the risk of childhood cancer. For these reasons, The George Institute for Global Health at the University of Oxford is focusing its research on the causes of childhood cancers in order to tackle the puzzle of prevention.
A global research study
The George Institute, Oxford is leading a pioneering study, the International Childhood Cancer Cohort Consortium (I4C), to obtain the first prospective evidence for childhood cancer. This evidence will take the form of data collected in pregnancy and from the baby well before any cancer occurs, which is the key to understanding whether factors such as infectious agents or environmental chemicals contribute importantly to the risk of cancer in children.
Due to the rarity of many forms of childhood cancer, obtaining prospective evidence requires data from a very large number of mothers and children. Our aim is that the study will eventually involve up to one million mothers and babies, in cohorts from 10 different countries, with the children being followed from conception until the age of 15, making the I4C study unique in scope and scale.
Countries with participating cohorts in the I4C study: Australia, Brazil, China, Denmark, France, Israel, Japan, Norway, UK, USA
This is a vast undertaking, but excellent progress is being made, with data and bio-specimens from more than 400,000 mothers and babies being pooled by the cohorts and analysed. There are a number of important domains of risk we are studying, including: infections; birth size; environmental chemicals; radiation; factors relating to the age of both parents; and genetics.
We have already found that the incidence of childhood cancer rises with increasing birthweight; along a continuum, a one-kilogram birthweight increase correlates to a 26% increase in the risk of all childhood cancers. This finding gives us important clues about where to look next.
A long-term undertaking
As a long-term study, the enrolment of up to one million mothers and babies is likely to take 10 years. The next step for The George Institute, Oxford is to expand the number of participants from 400,000 to 700,000 between 2017 and 2022, potentially using existing cohorts in China, France, Brazil, Japan and Korea. During the following five years, we will expand from 700,000 participants to one million.
If we were to obtain reliable data on whether or not infections or environmental chemicals might contribute to the risk of childhood cancer, it would be a ground-breaking step. Some of the risk factors we discover might be preventable, and the insights generated could support major public health efforts to reduce childhood cancer in future.