Implementation of a population-based cancer registry network in Mexico 2017-2020.

The growing cancer burden particularly among less developed countries requires local data to plan and evaluate cancer control measures. This article describes the development of a population-based cancer registry network (PBCRN) in Mexico that took place between 2017 and 2020 and present related data. The PBCRN, led by the National Cancer Institute (Incan), included nine registries representing 11.3% of the Mexican population. Definitions, coding, and operative processes were based on international standards. All cities were visited to set up local structure; personnel were hired by Incan and trained in basic cancer registration in Merida. A specific software was developed. Regular virtual meetings took place for data verification and quality control. Data collection included institutions of the public and private health system. Personnel included 34 registrars, nine local leaders, and 12 staff members at the Incan. A total of 13 517 cases were recorded between 2017-2020, 64% percent of them were among females. Breast cancer was the more frequent malignancy (23.3%), followed by digestive organs with (18.4%) and female genital cancers (13.5%). Childhood (0-14 years) and adolescents cancer represented 4.4% of the total new cancer cases. The network was suspended in 2020. The present effort lacked sustainability and data were only partial. However, the experience provides valuable insights to be considered for the renewed cancer registration efforts that are currently ongoing in Mexico.

Health Risk Assessment in Children Occupationally and Para-Occupationally Exposed to Benzene Using a Reverse-Translation PBPK Model.

Benzene is a known human carcinogen and one of the ten chemicals of major public health concern identified by the World Health Organization. Our objective was to evaluate benzene's carcinogenic and non-carcinogenic health risks (current and projected) in highly exposed children in Yucatan, Mexico. Benzene exposure was estimated through a reverse-translation, four-compartment, physiologically based pharmacokinetic model (PBPK) based on previously performed urine trans, trans-muconic acid (benzene metabolite) determinations. Using a risk assessment methodology, the carcinogenic and non-carcinogenic risks of benzene were estimated for 6-12-year-old children from a family of shoemakers. The children's hazard quotients for decreased lymphocyte count were 27 and 53 for 4 and 8 h/day exposure, respectively, and 37 for the projected 8 h/day exposure in adults. The risks of developing leukemia were 2-6 cases in 1000 children exposed 4 h/day; 4-10 cases in 1000 children exposed 8 h/day, and 2-9 cases in 1000 adults with an 8 h/day lifetime exposure. Children in Yucatan working in shoe-manufacturing workshops, or living next to them, are exposed to benzene concentrations above the reference concentration and have unacceptably high risks of presenting with non-carcinogenic and carcinogenic hematologic symptoms, now and in the future. Interventions to prevent further exposure and mitigate health risks are necessary.

Childhood acute lymphoblastic leukemia survival and spatial analysis of socio-environmental risks in Mexico.

Background: Acute lymphoblastic leukemia (ALL) etiology remains largely unknown; incidence patterns by age, sex, and geographical distribution suggest a potential environmental role. Aim: To identify ALL clusters from four contrasting urban areas of Mexico and to characterize the sources of environmental carcinogens. Methods: Hospital-based ALL cases (n = 443) diagnosed in children <19 years old from the Metropolitan Zones of Merida and San Luis Potosi, the State of Mexico, and Tijuana were analyzed (2015-2020). ALL cases were coded according to the International Classification of Diseases for Oncology. ALL clusters were identified by Kernel Density, and excess risk was estimated. Data of particulate matter ≤2.5 µm (PM2.5) concentrations measured by community-monitoring stations were analyzed. Geocoded datasets of benzene, polycyclic aromatic hydrocarbons, and PM2.5 sources were analyzed to characterize patterns of exposure in ALL clusters. Results: The survival rate for ALL ranged from 61.5% to 78.6%. Seven ALL clusters with excess risk (RR 1.4-2.3, p < 0.05) were identified. The carcinogen sources included artisanal brick kilns, gas stations, cement works, carpentry, paint, and chemical manufacturing establishments. PM2.5 levels ranged from 15 µg/m3 to 37 µg/m3 among study areas. Conclusion: ALL clusters were identified at the community level; the excess risk could be explained by small-scale carcinogen sources. The levels of PM2.5 in outdoor air ranged from 3 to 6 times above the World Health Organization (WHO) air quality guidelines. Healthcare providers must raise awareness of the increased risk of ALL in children living near sources of environmental carcinogens; cancer control and prevention strategies must be steered from a multi-sectoral and multi-action perspective to protect children's health.