A new study covering almost 300,000 cancer cases among children diagnosed between 2001 and 2010 reported an increase of 13% in childhood cancers worldwide over the last 20 years.

"This study updates information on cancer incidence in children published almost 20 years ago and adds the first global overview of cancer incidence in young people aged 15-19 years," say the authors, headed by Eva Steliarova-Foucher, from the Division of Cancer Control and Population Sciences, at the National Cancer Institute in Bethesda, Maryland.

Coordinated by the International Agency for Research on Cancer (IARC), the findings revealed that 185 adolescents in every million are diagnosed with cancer, most commonly lymphomas, which are cancers of the white blood cells. Among children below 15 years of age, leukaemia was the most common cancer, constituting almost a third of childhood cancer cases.

The IARC added that "this study suggests that the incidence of childhood cancers may be influenced by doctors' changing awareness about childhood cancer or by effects of external factors, such as infection or some environmental pollutants."

“Cancer is a significant cause of death in children and adolescents, in spite of its relatively rare occurrence before the age of 20 years,” said IARC’s director, Christopher Wild. “This extensive new set of information on the pattern and incidence of cancer in young people is vital to raise awareness and to better understand and combat this neglected area of health early in life.”

Mortality rate on the decline but not evenly spread out

Data from a study led by Audrey Bonaventure of the Cancer Survival Group at the London School of Hygiene and Tropical Medicine report a stark contrast between Germany with a 92% five-year survival rate and a high mortality rate of 52% for Colombian children inflicted with the disease.

"The results suggest that good access to health care and appropriate treatment have a clear population effect on survival for children with leukaemia," the authors said, adding that there is room for improvement in the management of childhood leukaemia in many countries.

They call for more resources to improve treatment delivery in poorer countries, greater international collaboration and development of treatment guidelines.

Professor Philippe Autier of the University of Strathclyde Institute of Global Public Health at the International Prevention Research Institute in France noted the global increase has occurred in all regions of the world except sub-Saharan Africa.

”The improvements in cancer survival achieved by high-income countries reporting five-year net survival of 80% should not distract from the dire reality that about 80% of leukaemia cases in children occur in low-income and middle-income countries (LMICs).”

Rise in children’s cancers may be due to improvements in diagnosis

“When you see an increase like that - that fast - in a short period of time, most likely it is going to be driven by some exposure to environmental factors,” says Catherine Metayer, an adjunct professor at the University of California.

However, Anna Perman, Cancer Research UK’s senior science information manager points to better diagnosis. “We now have a better understanding of the symptoms of children’s cancers, which helps doctors to spot those who might have gone undiagnosed before. It’s unlikely environmental factors that children are exposed to either early in life or during development in the womb play a big role in this rise.”

She added that although some environmental and lifestyle factors that do play a role in cancer are on the rise, these usually take many years to influence cancer risk and would be unlikely to cause cancer at a young age.

Professor Autier said the slow but steady rise in the incidence of many childhood cancers is real, especially for acute leukaemia in some areas.

“There is still a lot we don't know about the causes of childhood cancer. Until we do, we should not try to compensate explanations that are not based on evidence,” he said, urging cancer registries to record the probable cause of death — or at least the health causes associated with death. MIMS

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