Descriptive Epidemiology in Mexican children with cancer under an open national public health insurance program.

BACKGROUND: All the children registered at the National Council for the Prevention and Treatment of Childhood Cancer were analyzed. The rationale for this Federal Government Council is to financially support the treatment of all children registered into this system. All patients are within a network of 55 public certified hospitals nationwide. METHODS: In the current study, data from 2007 to 2012 are presented for all patients (0-18 years) with a pathological diagnosis of leukemia, lymphoma and solid tumors. The parameters analyzed were prevalence, incidence, mortality, and abandonment rate. RESULTS: A diagnosis of cancer was documented in 14,178 children. The incidence was of 156.9/million/year (2012). The median age was 4.9. The most common childhood cancer is leukemia, which occurs in 49.8% of patients (2007-2012); and has an incidence rate of 78.1/million/year (2012). The national mortality rate was 5.3/100,000 in 2012, however in the group between 15 to 18 years it reaches a level of 8.6. CONCLUSIONS: The study demonstrates that there is a high incidence of childhood cancer in Mexico. In particular, the results reveal an elevated incidence and prevalence of leukemia especially from 0 to 4 years. Only 4.7% of these patients abandoned treatment. The clinical outcome for all of the children studied improved since the establishment of this national program.

Analysis of Thiopurine S-Methyltransferase Deficient Alleles in Acute Lymphoblastic Leukemia Patients in Mexican Patients.

BACKGROUND AND AIMS: It has been demonstrated that heterozygote and homozygote thiopurine S-methyltransferase (TPMT) mutant allele carriers are at high risk to develop severe and potentially fatal hematopoietic toxicity after treatment with standard doses of 6-mercaptopurine (6-MP) and methotrexate (MX). Those drugs are the backbone of acute lymphoblastic leukemia (ALL) and several autoimmune disease treatments. We undertook this study to determine the frequency of the TPMT deficient alleles in children with ALL and non-ALL subjects from Mexico City and Yucatan, Mexico. METHODS: We included 849 unrelated subjects, of which 368 ALL children and 342 non-ALL subjects were from Mexico City, and 60 ALL cases and 79 non-ALL individuals were from Yucatan. Genotyping of the rs1800462, rs1800460 and rs1142345 SNPs was performed by 5'exonuclease technique using TaqMan probes (Life Technologies Foster City, CA). RESULTS: The mutant TPMT alleles were present in 4.8% (81/1698 chromosomes) and only 0.2% were homozygote TPMT*3A/TPMT*3A. We did not find statistically significant differences in the distribution of the mutant alleles between patients from Mexico City and Yucatan in either ALL cases or non-ALL. Nonetheless, the TPMT*3C frequency in ALL patients was higher than non-ALL subjects (p = 0.03). To note, the null homozygous TPMT*3A/TPMT*3A genotype was found in 2.5% of the non-ALL subjects. CONCLUSIONS: TPMT mutant alleles did not exhibit differential distribution between both evaluated populations; however, TPMT*3C is overrepresented in ALL cases in comparison with non-ALL group. Assessing the TPMT mutant alleles could benefit the ALL children and those undergoing 6-MP and MX treatment.

Brain tumors in children under 1 year of age: emphasis on the relationship of prognostic factors.

OBJECTS: Primary brain tumors in infants under 12 months of age have a different prognosis from older children. MATERIAL: A retrospective analysis was done in all patients less than 12 months old with primary brain tumors. RESULTS: Out of 1682 children with primary brain tumors, 61 (3.6%) were infants under 12 months old. The mean age at diagnosis was 181.6 days (SD 128) with a range of 1 to 364 days. There were 37 males (60.6%). The most common tumor was astrocytoma ( n=22) (36%). Supratentorial tumors were present in 63.9% but this was not related to survival ( p=0.1095). Complete surgical resection ( n=14) was favorable for survival ( p=0.039). Intracranial hypertension at diagnosis did not influence survival ( p=0.89). The overall survival rate was 32%, mean 42.08 (SD 7.38). A total of 24 patients are alive and without evidence of disease. CONCLUSION: Complete surgical resection was necessary for a favorable prognosis, and the long-term effects are a valid problem.