Background: In 1996, Mexico started to register cases of childhood cancer. Here, we describe the incidence of cancer in children, residing in ten Mexican jurisdictions, who were treated by the Instituto Mexicano del Seguro Social (IMSS).

Background: There are very few studies that report the incidence of acute leukemias in children in Latin America. This work assesses the incidence of acute leukemias, between 1996 and 2000, in children from 0-14 years old who were attended at the Mexican Social Security Institute in Mexico City and in children from 0-11 years old in El Salvador.

The objective of this population-based survey was to assess the peak age of incidence of B-cell precursor acute lymphoblastic leukemia (ALL) in children in Mexico City (MC). All patients were classified according to their immunophenotype, and only B-cell precursor and T-lineage were analyzed. Rates of incidence were calculated x10 children. Of the 364 children from MC who were included in this study, immunophenotyping had been performed for 81.6%. The frequency of B-cell precursor ALL was 76.1%, whereas T lineage ALL showed a frequency of 23.6%. Peak age for ALL was 2 to 3 years of age. B-cell precursor ALL was the major contributor to peak age; T lineage ALL showed a peak among 1 and 3 years of age. We conclude that the age peak for children with ALL in MC is within the ranges reported for developed countries and that B-cell precursor ALL is the main contributor to these peak.

BackgroundNeuroblastoma (NB) is the principal tumor of the sympathetic nervous system in children under one year of age. The incidence in developed countries is greater than that in developing countries. The aim of this article is to present the epidemiological and some clinical characteristics of Mexican children with NB.MethodsA population-based, prolective study, with data obtained from the Childhood Cancer Registry of the Instituto Mexicano de Seguro Social. Statistical analysis: The simple frequencies of the variables of the study and the annual average incidence (per 1,000,000 children/years) by age and sex were obtained. The trend was evaluated by calculating the annual percentage of change. The curves of Kaplan-Meyer were employed for the survival rate and the log-rank test was used to compare the curves.ResultsOf a total of 2,758 children with cancer registered during the period from 1996–2005, 72 (2.6%) were identified as having Group IV, defined according to the International Classification of Childhood Cancer. The incidence for NB was 3.8 per 1,000,000 children/year; NB was highest in the group of children under one year of age, followed by the group of children between the ages 1–4 years (18.5 and 5.4 per 1,000,000 children/years, respectively). The male/female ratio was 1.1 and there was no trend toward an increase. The time of diagnosis was 26 days (median), but varied according to the stage at diagnosis. Stages III and IV were presented in 88% of the cases. There was no association between the stage, the age at time of diagnosis, or the histological pattern. The overall five-year survival rate was 64%; the patients with stage I, II, III, or IVs did not die; and the five-year survival rate of cases in Stage IV was 40%.ConclusionIt is possible that the low incidence of neuroblastoma in Mexican children is due to the difficulty in diagnosing the cases with the best prognosis, some of which could have had spontaneous regression. There was no trend to an increase; the majority of the cases were diagnosed in the advanced stages; and the overall five-years survival rate was similar to that for developed countries.