Actualités du Registre Suisse du Cancer de l’Enfant

19.03.2018 13:05

Spatial clustering of childhood cancers in Switzerland: A nationwide study

Research questions:

We investigated whether children who develop childhood cancers tend to live closer to each other than expected by chance (spatial clustering) and whether there are specific areas in Switzerland with a particularly high risk (spatial cluster). We investigated both the place of residence at birth and at diagnosis.

Why is this important?

The causes of childhood cancers are largely unknown. However, studies indicate that environmental factors such as exposure to background radiation, infectious agents as Epstein-Barr virus, might play a role. Because exposure to such factors depends on where children live, childhood cancer risks might vary from place to place. Conversely, the presence of spatial clustering or clusters could thus provide new clues about possible environmental risk factors.

What did we do?

We included children aged less than 16 years who developed cancer in Switzerland during 1985-2015.  In particular, we examined children with lymphoma, Hodgkin lymphoma, non-Hodgkin lymphoma, central nervous system tumours, astrocytoma, intracranial and intraspinal embryonal tumours, other central nervous system tumours, neuroblastoma, nephroblastoma, malignant bone tumours and soft tissue sarcomas. For almost all children we had geocoded place of birth and diagnosis. We carefully corrected for the fact that we carried out numerous tests, which can increase the risk of false discoveries if left uncorrected.

What did we find?

We included 6,057 children who developed childhood cancer. After accounting for the fact that we had performed numerous tests, we found no statistical evidence of spatial clustering. However, the results of individual tests did indicate spatial clustering, the evidence being strongest for Hodgkin lymphomas and intracranial and intraspinal embryonal tumours. The test for spatial clusters also suggested a cluster of intracranial and intraspinal embryonal tumours in the French-speaking part of Switzerland.

What does this mean?

Overall, this study provides little support for spatial clustering or spatial clusters of childhood cancers. Individual tests, however, were indicative of spatial clustering for specific diagnostic groups consistent with previous studies. Our study thus suggests that different cancer subgroups might have different environmental risk factors, highlighting the need to investigate different diagnostic subgroups separately in future studies.

Additional information:

Garyfallos Konstantinoudis, Email : garyfallos.konstantinoudis@ispm.unibe.ch

Konstantinoudis et al. Cancer Causes and Control 2018. DOI: 10.1007/s10552-018-1011-6


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