Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

Abstract

BackgroundWorldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City.MethodsIncluded in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level).ResultsAlthough a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive correlation between the average number of persons per household and the incidence of the pre-B immunophenotype (Pearson's r, 0.789; P = 0.02).ConclusionsThe frequency of ALL in Mexico City is among the highest in the world, similar to those found for Hispanics in the United States and in Costa Rica.

Geographical Distribution and Cluster Detection of Childhood Leukemia in the Metropolitan Area of Guadalajara, Mexico

“…The commonest type of childhood leukemia is acute lymphoblastic leukemia (ALL), which occurs in approximately 80% of leukemia cases, followed by acute myeloid leukemia (AML) and chronic myeloid leukemia, and a few other categories 2 . A worldwide cancer survey in 2012 estimated a higher incidence in developing countries than in developed ones: in Canada, the USA, and the UK, the incidence rates are 5.8, 4.6, and 4.0 per 100,000 inhabitants per year, respectively 3 .…”

Morbidity and mortality rates for childhood cancer in Argentina. 2006-2008

“…19,20 In relation to the incidence by tumor type, the incidence rate of leukemia is similar to that observed in Uruguay (44.0 per million) and in some developed countries, such as the USA (46.9 per million) and Spain (45.1 per million), 5 and lower than other Latin American countries, e.g., Mexico 21 (58 per million) and Costa Rica 22 (63 per million).…”

From HSC to B-Lymphoid Cells in Normal and Malignant Hematopoiesis

“…At present, ALL is the most frequent malignancy in children worldwide and a serious problem of public health, constituting 25% of all childhood cancers and 75%-85% of the cases of childhood leukemias (Perez-Saldivar et al, 2011). Near to 80% of ALL cases have precursor B-cell immunophenotype, while approximately 15% show T-cell immunophenotype.…”

“…Near to 80% of ALL cases have precursor B-cell immunophenotype, while approximately 15% show T-cell immunophenotype. Even when a relatively high efficiency of therapeutic agents has been demonstrated (Pieters & Carroll, 2010), there has been a slight but gradual increase in the incidence of ALL in the past 25 years, and appears to be highest in Hispanic population, which also show superior rates of high risk patients (Fajardo-Gutiérrez et al, 2007;Abdullaev et al, 2000;Perez-Saldivar et al, 2011;Mejía-Aranguré et al, 2011). Factors such as drug resistance, minimal residual disease, cell lineage switch, and the rise of mixed lineages often put the success of treatment at risk and change the prognosis of the illness.…”