Childhood leukemia incidence in Brazil according to different geographical regions.
BACKGROUND
Resource-rich countries tend to have a higher incidence of childhood acute lymphoblastic leukemia (ALL), whereas lower rates are seen in more deprived countries. This study describes the incidence of childhood acute leukemia in Brazil, an upper middle-income country, based on data from 16 population-based cancer registries (PBCRs).


METHODS
Data were examined from 16 PBCRs in Brazilian cities located in five geographical regions during the period from 1997 to 2004. Incidence rates were analyzed according to gender, age, and type of leukemia. The Wilcoxon test was performed to evaluate for gender-age based difference between by leukemia type.


RESULTS
The median age-adjusted incidence rate (AAIR) of leukemia in children aged 0-14 years old was 53.3 per million. A different AAIR was found regarding ALL and myeloproliferative disorders (MPD) that ranged from 24.8 to 76.84 per 1,000,000 children. Manaus, although located in a poor area of Brazil, exhibited the highest AAIR (56.6 per million) of ALL. Goiania had the highest AAIR (24.5 per million) of MPD. The median age-specific incidence rate (ASIR) for the 16 Brazilian PBCRs demonstrated a marked peak in incidence of ALL at age 3 years old, in both genders.


CONCLUSIONS
This population-based study of childhood leukemia demonstrates that substantial regional differences exist regarding the incidence of acute leukemia in Brazil, which warrants further ecological study.
Coordenação de Prevenção e Vigilância, Instituto Nacional do Câncer, Rua dos Inválidos, Rio de Janeiro, Brazil.
Rejane
R
de Souza Reis
Beatriz
B
de Camargo
Marceli
M
de Oliveira Santos
Juliana Moreira
JM
de Oliveira
Fernanda
F
Azevedo Silva
Maria S
MS
Pombo-de-Oliveira
D000293:Adolescent; D000367:Age Factors; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003625:Data Collection; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000453:epidemiology* / Q000209:etiology; D012042:Registries; D012737:Sex Factors; D012959:Socioeconomic Factors; D019371:Topography, Medical / Q000706:statistics & numerical data*