Blog：Distribution of cases

Researchers looked at around 5,000 cases of all childhood cancers that had occurred in the north west from 1954 and 2001.
They found cases of Hodgkin’s Disease, a cancer of the lymphatic system, and a kind of brain tumour called astrocytoma occurred in the same areas and time periods much more frequently than would have been expected.
Clusters were defined as covering children born within a year of each other and living within 5 km of each other when they were born.
The same kind of clustering was seen with Acute Lymphoblastic Leukaemia (ALL) and astrocytomas and with ALL and Non-Hodgkin’s Lymphoma.
The figures were adjusted to take account of the differences between built-up and rural areas.
Although most of the clusters were small, typically around three or four cases, the researchers from the Cancer Research UK Paediatric and Familial Cancer Research Group at the Royal Manchester Children’s Hospital said the frequency of the clusters was unusual.
The team had previously found separate clusters of childhood brain cancers and ALL.