title: Space-time clustering patterns in childhood solid tumours other than central nervous system tumours.
abstract: The aetiology of most childhood solid tumours (other than central nervous system [CNS] tumours) is unclear. To investigate whether certain environmental exposures may be involved, we have analysed for space-time clustering using population-based data from North West England for the period 1954-98. Knox tests for space-time interactions between cases were applied with fixed thresholds of close in space, <5 km, and close in time, <1 year apart. Addresses at birth and at diagnosis were used. Tests were repeated replacing geographical distance with distance to the Nth nearest neighbour. N was chosen such that the mean distance was 5 km. Data were also examined by a second order procedure based on K-functions. There was significant evidence of space-time clustering for Wilms' tumours (p = 0.03 and 0.04, using the geographical distance and nearest neighbour versions of the Knox test; and p = 0.07 and 0.03, using the geographical distance and nearest neighbour versions of the K-function method), and soft tissue sarcomas (p = 0.01, using both the geographical distance and nearest neighbour versions of the Knox test; and p = 0.001 and 0.002, using the geographical distance and nearest neighbour versions of the K-function method) based on time and location at birth, but not time and location at diagnosis. There was little or no evidence of space-time clustering amongst other diagnostic groups. These are the first results to demonstrate space-time clustering for childhood Wilms' tumours and soft tissue sarcomas. The results are consistent with environmental exposure hypotheses, relating to locations pre-natally or peri-natally.
authors.affiliation: Cancer Research UK Paediatric and Familial Cancer Research Group, Central Manchester and Manchester Children's University Hospitals NHS Trust, Manchester, United Kingdom. richard.mcnally@man.ac.uk
authors.forename: Richard J Q
authors.initials: RJ
authors.lastname: McNally
authors.forename: Anna M
authors.initials: AM
authors.lastname: Kelsey
authors.forename: Osborn B
authors.initials: OB
authors.lastname: Eden
authors.forename: Freda E
authors.initials: FE
authors.lastname: Alexander
authors.forename: Donal P
authors.initials: DP
authors.lastname: Cairns
authors.forename: Jillian M
authors.initials: JM
authors.lastname: Birch
mesh_terms: D000293:Adolescent; D016543:Central Nervous System Neoplasms; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004739:England / Q000453:epidemiology; D005260:Female; D005843:Geography; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009369:Neoplasms / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D013029:Space-Time Clustering