Area-based differentials in childhood cancer incidence in Australia, 1996-2006

Background: International studies examining theassociation between the incidence of childhood cancer and characteristics ofthe area in which the patient lives have generally reported inconsistentpatterns. Area-based differentials in childhood cancer throughout Australiahave not been previously published at a national level.

Procedure: Population-based information from theAustralian Paediatric Cancer Registry was used to identify all children aged 0-to 14-years old diagnosed with invasive cancer or intracranial and intraspinaltumors of benign or uncertain behavior between 1996 and 2006. Age-standardizedincidence rates per million children per year and the corresponding incidencerate ratios were calculated, categorized by remoteness of residence and anarea-based index of socioeconomic disadvantage. Results were also stratified bythe most common types of childhood cancer.

Results: There was a significant, decreasing gradient in the incidence ofchildhood cancer as remoteness of residence increased. Children living inremote or very remote areas were 21% less likely to be diagnosed with cancercompared to children in major cities, mainly due to differences in theincidence of leukemias and lymphomas. This differential was no longersignificant when only non-Indigenous children were considered. No clearrelationship was found between incidence and socioeconomic status (SES) incontrast to similar earlier studies.

Conclusions: The findings by remoteness of residence areconsistent with the lower incidence rates of cancer that are typicallyassociated with Indigenous Australians. There is also a suggestion that theetiological factors associated with childhood leukemia and SES may have alteredover time.