A major study by UCL and Fondazione IRCCS Istituto Nazionale dei Tumori in Milan (INT) researchers has for the first time shown in detail how far children’s cancer has spread at diagnosis in a way that can be compared between countries.
While poorer survival following late-stage diagnosis is well recognised, the study is the first to show that differences in tumour stage at diagnosis may explain why childhood cancer survival varies between some European regions and tumour types.
Published in JAMA Network Open, the researchers analysed high-quality data from the cases of 9,883 children from 73 population-based cancer registries across 27 countries, mainly European, diagnosed with six different cancers – neuroblastoma, Wilms tumour, medulloblastoma, osteosarcoma, Ewing sarcoma and rhabdomyosarcoma – between 2014 and 2017.
They found that across all six cancers, survival at three years was strongly linked to tumour stage at diagnosis, with survival decreasing as stage increased.
Using Central Europe – made up of Austria, Belgium, France, Germany, Switzerland and the Netherlands – as the benchmark and looking at the data by region, they found significant variation in overall three-year survival rate between some regions in the cases of four of those cancers.
In the case of neuroblastoma – tumour of adrenal gland and some other sites – they found that children had lower survival rates in the UK and Ireland compared with Central Europe, a difference that could be explained by the relatively later stage at which that cancer was diagnosed in the UK and Ireland.
In the case of Ewing sarcoma (bone tumour), by contrast, in Eastern Europe and in the UK and Ireland, the lower survival rate compared with Central Europe wasn’t accounted for by later diagnosis. In fact, the difference was only seen for patients whose tumour had spread. The researchers suggested that other factors such as where the tumour had spread to and any differences in treatment approaches for children whose cancer has spread need to be investigated.
Until now the lack of reliable data on tumour stage at diagnosis has meant it was impossible to use registry data to shed light on the difference in child cancer survival rates by country.
The UCL and INT researchers’ International Benchmarking of Childhood Cancer Survival by Stage (BENCHISTA) project has improved the way national cancer registries collect childhood cancer data so it can be compared reliably.
Through an agreement which took 18 months to broker, the countries involved in the study – 23 European countries including the UK but also Brazil, Canada, Australia and Japan – improved their data collection techniques to ensure at least 90% of the child cancer cases in their countries had tumour stage recorded (a level deemed acceptable for accurate international data analysis) and in a consistent way (using what is known as the Toronto Childhood Cancer Stage Guidelines, which were developed in the 2010s).
The result is that for the first time researchers are in a position to better understand why childhood cancer survival rates differ from region to region with a view to guiding efforts to improve those rates.
Their findings highlight the need to examine other factors, such as differences in treatment approaches, access to specialised care, and health system differences.
This will be a focus of the next phase of the BENCHISTA project, which will also report five-year survival, the standard epidemiology cancer outcome measure.
