Worldwide, it is estimated that more than 400,000 children and young people (aged 0 to 24 years) are diagnosed with cancer every year.
In the UK, there are around 4,000 new cases every year, contributing to a total of around 35,000 in Europe.
Cancer remains one of the leading killers of children and young people
Prior to the late 1960s cancer in children was largely incurable.
Today, thanks to advances in research and treatment, more than 80 per cent of young patients are disease-free five years from diagnosis. Most of these can be considered cured.
However, in a significant minority of children, their cancer proves resistant to treatment, or treatment proves too toxic. Cancer is the leading medical cause of death beyond infancy in children and young people in developed countries, responsible for some 6,000 deaths every year in Europe.
The recently published SIOPE Strategic Plan for 2015 to 2020 sets out three main groups of childhood cancers:
those with a good prognosis (with a higher than 85 per cent chance of survival after five years) under current standard multi-disciplinary treatments (acute lymphoblastic leukaemia, lymphomas, retinoblastoma, renal tumours);
those with a poor prognosis (~50% or less five year survival) such as acute myeloid leukaemia, several CNS tumours, neuroblastoma, bone and soft tissue sarcomas. Among these diseases, some have a very poor prognosis such as diffuse intrinsic pontine glioma, high-risk neuroblastoma and metastatic sarcomas;
the extremely rare tumours, for which there is insufficient information on their real incidence and survival.
Survival has plateaued in the last five years or more for these first two groups of patients. What remains is a group of high-risk, difficult to treat cancers that require innovative new treatments with new mechanisms of action.
Survivors are at risk of a range of long-term and late effects
As survival rates have increased through recent decades, large numbers of children and young people are surviving cancer and living into adulthood. It is estimated that there are 300,000 survivors of childhood cancer in Europe.
It is apparent that these survivors are at risk of a wide range of long-term and late-effects. Two thirds of survivors have late side effects of treatment, half of whom experience severe effects that impact on their daily life.
In recent years, innovations in molecular profiling have enabled the application of precision medicine in some groups of patients, with improved risk stratification leading to the reduction of treatment intensity in order to decrease the risk of long-term sequelae.
We still know little about why children get cancer, or how to prevent it
In spite of much effort, our understanding of the causes of childhood cancer remains limited.
A number of factors have been shown to influence childhood cancer risk, with varying degrees of certainty. Exposure to ionising radiation in utero is one factor that has been accepted as having a strong enough association with cancer risk to warrant the adoption of preventive strategies.
But despite growing evidence of the role of certain environmental factors – including air pollution and pesticides - few other putative causes have been accepted as sufficiently important to merit the implementation of such preventive strategies.
Research is complicated by the relative rarity of childhood cancers, combined with the fact that most are likely multi-causal and multi-factorial. Many cases may simply be attributable to a random, catastrophic mutation that evades the body’s usual surveillance.
References The SIOPE Strategic Plan: A European Cancer Plan for Children and Adolescents: www.siope.eu