title: Socioeconomic status and the incidence of non-central nervous system childhood embryonic tumours in Brazil.
abstract: BACKGROUND
  Childhood cancer differs from most common adult cancers, suggesting a distinct aetiology for some types of childhood cancer. Our objective in this study was to test the difference in incidence rates of 4 non-CNS embryonic tumours and their correlation with socioeconomic status (SES) in Brazil.
  
  
  METHODS
  Data was obtained from 13 Brazilian population-based cancer registries (PBCRs) of neuroblastoma (NB), Wilms'tumour (WT), retinoblastoma (RB), and hepatoblastoma (HB). Incidence rates by tumour type, age, and gender were calculated per one million children. Correlations between social exclusion index (SEI) as an indicator of socioeconomic status (SES) and incidence rates was investigated using the Spearman's test.
  
  
  RESULTS
  WT, RB, and HB presented with the highest age-adjusted incidence rates (AAIRs) in 1 to 4 year old of both genders, whereas NB presented the highest AAIR in ≤11 month-olds. However, differences in the incidence rates among PBCRs were observed. Higher incidence rates were found for WT and RB, whereas lower incidence rates were observed for NB. Higher SEI was correlated with higher incidences of NB (0.731; p = 0.0117), whereas no SEI correlation was observed between incidence rates for WT, RB, and HB. In two Brazilian cities, the incidence rates of NB and RB were directly correlated with SEI; NB had the highest incidence rates (14.2, 95% CI, 8.6-19.7), and RB the lowest (3.5, 95% CI, 0.7-6.3) in Curitiba (SEI, 0.730). In Natal (SEI, 0.595), we observed just the opposite; the highest incidence rate was for RB and the lowest was for NB (4.6, 95% CI, 0.1-9.1).
  
  
  CONCLUSIONS
  Regional variations of SES and the incidence of embryonal tumours were observed, particularly incidence rates for NB and RB. Further studies are necessary to investigate risk factors for embryonic tumours in Brazil.
authors.affiliation: Pediatric Hematology and Oncology Program, Research Center, Instituto Nacional de Câncer, Rio de Janeiro, Brazil. bdecamar@terra.com.br
authors.forename: Beatriz
authors.initials: B
authors.lastname: de Camargo
authors.forename: Juliana Moreira
authors.initials: JM
authors.lastname: de Oliveira Ferreira
authors.forename: Rejane
authors.initials: R
authors.lastname: de Souza Reis
authors.forename: Sima
authors.initials: S
authors.lastname: Ferman
authors.forename: Marceli
authors.initials: M
authors.lastname: de Oliveira Santos
authors.forename: Maria S
authors.initials: MS
authors.lastname: Pombo-de-Oliveira
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018197:Hepatoblastoma / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009447:Neuroblastoma / Q000453:epidemiology*; D012042:Registries; D012175:Retinoblastoma / Q000453:epidemiology*; D012923:Social Class; D009396:Wilms Tumor / Q000453:epidemiology*