Space‐time clustering of childhood cancer around the residence at birth

Abstract

Previously, we identified space-time clustering in certain childhood cancers around diagnosis residence. These findings provided support for the involvement of environmental agents in etiological processes occurring close to diagnosis. We have reanalyzed the same British population-based dataset. The aim of the study was to determine whether there was space-time clustering around the residence at birth in relation to time of birth and separately from time of diagnosis. A total of 29,553 cases, diagnosed during the period 1969-1993, were examined by a second-order procedure based on K-functions. Locations were birth addresses, but separately, both dates of birth and diagnosis were analyzed. There was statistically significant space-time clustering for Hodgkin lymphoma (HL) and central nervous system (CNS) tumors (p 5 0.047 and 0.01, respectively, based on birth date) and for total leukemia at ages 1-4 years only, Non-Hodgkin lymphoma (NHL) and Wilms tumor (p 5 0.01, 0.02 and 0.006, respectively, based on diagnosis date). These results, interpreted together with other epidemiological evidence, suggest an etiological role for environmental factors focused around birth address for certain childhood cancers. For HL and CNS tumors, findings suggest that etiological exposures occurred at similar ages or in utero. Key words: etiology; cancer; children; infections; space-time clustering Space-time clustering is said to occur when an excess of cases is seen within small geographical areas over limited temporal periods, and this pattern cannot be attributed to general excesses in those areas or at those periods. We have previously reported statistically significant space-time clustering for certain childhood cancers diagnosed in Great Britain during the period 1969-1993. The analyses were based on place of diagnosis and time of diagnosis. Space-time clustering was evident for acute lymphoblastic leukemia (ALL), soft tissue sarcomas and osteosarcomas. These findings supported the involvement of environmental factors (especially infections) in etiological processes acting around residence at diagnosis.

Spatial clustering of childhood leukaemia with the integration of the Paediatric Environmental History

“…However, in the past decade, only a few studies that analyse the addresses during pregnancy, birth and diagnosis have emerged, showing more conclusive results with pregnancy and birth addresses. These studies support that development of childhood cancers initiates in utero or beginning of infancy, catalysed by a common exposure within a shared geographic area (Kreis et al, 2016; McNally et al, 2009b). Additionally, much progress has been made in the study of the geographical differences in areas with smaller populations, allowing the observation of major differences in low overall prevalence diseases like childhood AL (Ortega-Garcia et al, 2016).…”

Analysis of spatial-temporal clusters of childhood cancer incidence in the province of Córdoba, Argentina (2004-2013)

“…Although they cannot be directly compared, those studies found, as in our study, clusters within the large groups of total tumors, leukemias, tumors of the central nervous system, and lymphomas. 7,[24][25][26][27][28][29][30][31] However, those studies failed to establish a conclusive relationship between results and a socioenvironmental factor, even though the presence of clusters is probably an evidence of the fact that environmental factors are related to the presence and development of cancer. [32][33][34] Apart from ionizing radiation and some congenital genetic syndromes, there is little evidence -and lots of suspicion-regarding other factors that may influence the clustering of childhood cancer.…”

Análisis de conglomerados espacio-temporales de incidencia del cáncer pediátrico en la provincia de Córdoba, Argentina (2004-2013)

“…Si bien no pueden ser comparados de manera directa, estas investigaciones encuentran conglomerados, al igual que nosotros, dentro de los grandes grupos de tumores totales, leucemias, tumores del sistema nervioso central y linfomas. 7,[24][25][26][27][28][29][30][31] Sin embargo, estas investigaciones no pudieron, de manera concluyente, relacionar sus resultados con algún factor socioambiental, a pesar de que la presencia de los conglomerados probablemente sea evidencia de que los factores ambientales están relacionados con la presencia y desarrollo de la enfermedad. [32][33][34] Más allá de la radiación ionizante y algunos síndromes genéticos congénitos, existe poca evidencia, y muchas sospechas, de otros factores que tengan una influencia en el agrupamiento del cáncer pediátrico en conglomerados.…”