Evidence of spatial clustering of childhood acute lymphoblastic leukemia cases in Greater Mexico City: report from the Mexican Inter-Institutional Group for the identification of the causes of childhood leukemia

Background

A heterogeneous geographic distribution of childhood acute lymphoblastic leukemia (ALL) cases has been described, possibly, related to the presence of different environmental factors. The aim of the present study was to explore the geographical distribution of childhood ALL cases in Greater Mexico City (GMC).

Methods

A population-based case-control study was conducted. Children <18 years old, newly diagnosed with ALL and residents of GMC were included. Controls were patients without leukemia recruited from second-level public hospitals, frequency-matched by sex, age, and health institution with the cases. The residence address where the patients lived during the last year before diagnosis (cases) or the interview (controls) was used for geolocation. Kulldorff's spatial scan statistic was used to detect spatial clusters (SCs). Relative risks (RR), associated p-value and number of cases included for each cluster were obtained.

Results

A total of 1054 cases with ALL were analyzed. Of these, 408 (38.7%) were distributed across eight SCs detected. A relative risk of 1.61 (p<0.0001) was observed for the main cluster. Similar results were noted for the remaining seven ones. Additionally, a proximity between SCs, electrical installations and petrochemical facilities was observed.

Conclusions

The identification of SCs in certain regions of GMC suggest the possible role of environmental factors in the etiology of childhood ALL.

Persistently high incidence rates of childhood acute leukemias from 2010 to 2017 in Mexico City: A population study from the MIGICCL

Introduction

Over the years, the Hispanic population living in the United States has consistently shown high incidence rates of childhood acute leukemias (AL). Similarly, high AL incidence was previously observed in Mexico City (MC). Here, we estimated the AL incidence rates among children under 15 years of age in MC during the period 2010-2017.

Methods

The Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia conducted a study gathering clinical and epidemiological information regarding children newly diagnosed with AL at public health institutions of MC. Crude age incidence rates (cAIR) were obtained. Age-standardized incidence rates worldwide (ASIRw) and by municipalities (ASIRm) were calculated by the direct and indirect methods, respectively. These were reported per million population <15 years of age; stratified by age group, sex, AL subtypes, immunophenotype and gene rearrangements.

Results

A total of 903 AL cases were registered. The ASIRw was 63.3 (cases per million) for AL, 53.1 for acute lymphoblastic leukemia (ALL), and 9.4 for acute myeloblastic leukemia. The highest cAIR for AL was observed in the age group between 1 and 4 years (male: 102.34 and female: 82.73). By immunophenotype, the ASIRw was 47.3 for B-cell and 3.7 for T-cell. The incidence did not show any significant trends during the study period. The ASIRm for ALL were 68.6, 66.6 and 62.8 at Iztacalco, Venustiano Carranza and Benito Juárez, respectively, whereas, other municipalities exhibited null values mainly for AML.

Conclusion

The ASIRw for childhood AL in MC is among the highest reported worldwide. We observed spatial heterogeneity of rates by municipalities. The elevated AL incidence observed in Mexican children may be explained by a combination of genetic background and exposure to environmental risk factors.

Clinical characteristics and mortality predictors of patients with cancer hospitalized by COVID-19 in a pediatric third-level referral center

BACKGROUND

More than 135 million COVID-19 cases (coronavirus disease 2019) have been reported worldwide until today, with over 2.9 million deaths. Several studies have demonstrated that disease severity is lower in the pediatric population than in adults; however, differences are described in patients with chronic diseases, including oncological patients. Current world literature suggests patients with comorbidities, including cancer, have an increased risk of unfortunate outcomes. Therefore, our objective was to describe the clinical characteristics and epidemiological factors associated with mortality in a cohort of pediatric cancer patients hospitalized for COVID-19.

METHODS

This is a retrospective, descriptive study of the cases of patients with cancer hospitalized for COVID-19. A total of 40 pediatrics were included in the analysis. Data from pediatric patients with COVID-19 included clinical and epidemiological records, laboratory, imaging studies, COVID-19 diagnostic methods, and medical treatment.

RESULTS

Of the 40 pediatric patients admitted with cancer with a confirmed diagnosis of COVID-19, 42.5% were solid tumors, 40% leukemias, and 17.5% lymphomas. The clinical parameters associated with mortality were stage IV tumor (p = 0.029) and intubation (p < 0.001). The biochemical factors associated with lower survival were thrombocytopenia under 25,000 cells/mm³ (p < 0.001), D-dimer over 1 μg/ml (p = 0.003), clinical malnutrition (p = 0.023), and disseminated intravascular coagulation (p = 0.03).

CONCLUSION

Our findings showed that the fever was the most frequent symptom, and the clinical parameters associated with mortality were stage IV tumor, intubation, saturation percentage, RDW, platelets, creatinine, ALT, D-dimer, ferritin, and FiO2 percentage. The thrombocytopenia, D-dimer, nutritional status, and disseminated intravascular coagulation were significantly associated with lower survival.

Does the Human Development Index relate with acute lymphoblastic leukemia incidence?

BACKGROUND

The association between childhood cancer and socioeconomic status has been widely studied. However, none of the results are conclusive. This study aimed to analyze the association between the Human Development Index (HDI) and the acute lymphoblastic leukemia (ALL) incidence in children under the Popular Medical Insurance Care.

METHODS

We conducted an observational, descriptive, and population-based study covering 55% of the Mexican population (58 million).

RESULTS

The most impoverished states were located in the south east region of Mexico, while the north was more homogeneous, with HDIs varying between 0.73 and 0.79. Our findings emphasize that the metropolitan area of Mexico City and the State of Nuevo Leon have the highest levels of HDI. Regions were graded from I to IV according to their HDIs in ascending order. The HDIs varied from 0.667 to 0.830/100,000 children/year, with a national average of 0.746. The leukemia incidence for regions I, II, III, and IV was 6.12, 6.53, 4.96, and 9.95. An analysis of ALL incidence in Mexico showed significant differences for region IV in comparison with the other regions based on the HDI values (p = 0.0001).

CONCLUSIONS

Further in-depth studies, including the economic aspects of the different geographic regions and their ethnographic characteristics, would give a more comprehensive panorama.

Extremely Low-Frequency Magnetic Fields and the Risk of Childhood B-Lineage Acute Lymphoblastic Leukemia in a City With High Incidence of Leukemia and Elevated Exposure to ELF Magnetic Fields

It is important to study the relationship between extremely low-frequency magnetic fields (ELF-MFs) and childhood leukemia, particularly in locations with a high incidence of this neoplasm in children and an elevated exposure to ELF-MF, such as Mexico City. The aim was to investigate the association between ELF-MF exposure and the risk of B-lineage acute lymphoblastic leukemia (B-ALL). A case-control study was conducted in Mexico City during the period from 2010 to 2011. Residential 24-h ELF-MF measurements were obtained for 290 incident B-ALL patients and 407 controls, aged less than 16 years. Controls were frequency-matched by sex, age (±18 months), and health institution. The adjusted odds ratios (aOR) and 95% confidence intervals (CIs) were calculated. ELF-MF exposure at <0.2 μT was used to define the reference group. ELF-MF exposure at ≥0.3 μT was observed in 11.3% of the controls. Different ELF-MF intensity cutoff values were used to define the highest exposure category; the highest exposure category for each cutoff value was associated with an increased risk of B-ALL compared with the corresponding lower exposure categories. The aORs were as follows: ≥0.2 μT = 1.26 (95% CI: 0.84-1.89); ≥0.3 μT = 1.53 (95% CI: 0.95-2.48); ≥0.4 μT = 1.87 (95% CI: 1.04-3.35); ≥0.5 μT = 1.80 (95% CI 0.95-3.44); ≥0.6 μT = 2.32 (95% CI: 1.10-4.93). ELF-MF exposure as a continuous variable (per 0.2 μT intervals) was associated with B-ALL risk (aOR = 1.06; 95% CI: 1.01-1.12). In the present study, the proportion of children exposed to ≥0.3 μT is among the highest reported worldwide. Additionally, an ELF-MF exposure ≥0.4 μT may be associated with the risk of B-ALL. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

Maternal and paternal ages at conception of index child and risk of childhood acute leukaemia: A multicentre case-control study in Greater Mexico City

BACKGROUND

The parental age at conception has been reported to be a risk factor for childhood acute leukaemia (AL); however, the relationship is controversial. The aim of the present study was to investigate the association between parental age at conception and the risk of AL in Mexican children, a population with a high incidence of the disease and a high prevalence of pregnancies in adolescents and young adults.

METHODS

A multicentre case-control study was conducted. Incident AL cases younger than 17 years of age diagnosed between 2010 and 2015 were included. Controls were matched with cases according to age, sex, and health institution. Using logistic regression analysis, adjusted odds ratios (aOR) and 95 % confidence intervals (95 % CI) were calculated for each maternal stratum after adjusting for paternal age at conception of index child. The maternal age between 25 and 29.99 years was selected as the reference category.

RESULTS

In most strata where maternal and paternal ages were assessed, no association was found with the risk of developing acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML) in their offspring. An increased risk for AML was observed when the mother was between 20 and 24.99 years of age and the father aged 25-29.99 years (aOR, 1.94; 95 % CI, 1.03-3.67). In addition, there was a positive association for ALL when the mother´s age was between 20 and 24.99 years and the father was <20 years of age, however, a very wide confidence interval was noted (aOR, 12.26; 95 % CI, 1.41-106.83).

CONCLUSION

In the present study, maternal and paternal ages assessed in different strata showed little association with risk of developing ALL and AML in children. Positive associations between risk of both types of childhood AL were observed with younger paternal and maternal ages.

Feeding difficulties and eating disorders in pediatric patients with cancer

Background

Feeding difficulties and disorders are a common problem in the pediatric population, which involve a series of deficient behaviors about nutrition processes that can adversely affect psychomotor, psychosocial, and physical development of children. This study aimed to describe the frequency of feeding difficulties or disorders in pediatric patients with cancer.

Methods

A prospective study which included 125 children from 1-19 years treated at the Department of Oncology of the Instituto Nacional de Pediatría, Mexico City, was conducted. The diagnosis of eating disorders and feeding difficulties was determined during the first 48 h since admission, and the age of the patient influenced the type of disorder and feeding difficulties.

Results

Children older than 11 years presented more frequently an intense resistance of feeding because of discomfort pain (fear of feeding) than younger children (11.4 ± 4.7 vs. 7.4 ± 4.9, p ≤ 0.001). The most frequent alteration associated with malnutrition was loss of appetite (odds ratio [OR]: 8.8, confidence interval [CI] 95% 2.9-26.9, p<0.001), followed by fear of feeding (OR: 3.14, CI 95% 1.24-7.9, p=0.015), and the organic causes showed the highest risk for malnutrition (OR: 3.1, CI 95% 0.98-9.7, p=0.054).

Conclusions

Over 90% of the studied population demonstrated at least one eating disorder or feeding difficulty. The principal effect is inadequate nutritional intake due to limited appetite and fear of feeding, which can result in undernutrition. For this reason, the identification of alterations in nutrition processes should be part of the comprehensive assessment of cancer patients.

A greater birthweight increases the risk of acute leukemias in Mexican children-experience from the Mexican Interinstitutional Group for the Identification of the Causes of Childhood Leukemia (MIGICCL)

In Mexico, due to the high rates of diabetes, overweight, and obesity, there has also been noted an increased newborn weight, which may be contributing to the elevated incidence rate of childhood acute leukemia (AL). We conducted a case-control study in public hospitals of Mexico City aimed to know whether a greater weight at birth is associated with a higher risk of developing leukemia. We included incident cases with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) diagnosed between 2010 and 2015. Controls were frequency-matched to the cases by age, sex, and health institution. Logistic regression analysis was performed adjusting risks by child's sex, overcrowding index, birth order, and mother's age at the time of pregnancy. Adjusted odds ratios (aORs) and 95% confidence intervals were calculated. A total of 1455 cases and 1455 controls were included. An evident association between ALL and child's birthweight ≥2500 g was found (aOR 2.06; 95% CI: 1.59, 2.66) and also, in those with birthweight ≥3500 g (aOR 1.19; 95% CI: 1.00, 1.41). In AML patients with birthweight ≥2500 g and ≥3500 g, an aOR of 1.77 (95% CI: 1.07, 2.94) and 1.42 (95% CI: 1.03-1.95) was observed, respectively. No association was noticed with either type of AL and a birthweight ≥4000 g. To sum up, we found a moderate association between not having a low birthweight and an increased risk of acute leukemias. Birthweight ≥3500 g was also a risk factor for both types of leukemia. This suggests that a greater birthweight may increase the risk of acute leukemias in Mexican children.

Current outlook of childhood cancer epidemiology in a middle-income country under a public health insurance program

In Mexico, childhood cancer (0-18 years) is treated in a multidisciplinary way while providing care for more than half of the affected children through a public medical insurance. This insurance is given to all children who do not have any health care coverage in Mexico. This program is offered to the poorest of all Mexicans. All the children with this disease are submitted to pathology diagnosis and treatment according to national treatment protocols from 57 accredited medical institutions. From 2007 to 2015, a total of 24,039 children with cancer have been registered; the male gender predominates by 55%. The highest incidence was in the group aged between 0 and 4 years. Every year, there has been an increment in registration. In 2015, there were 3,433 new patients with an incidence of 150.1/million. In the same year, the incidence for all types of leukemia increased to 89.5/million. But for acute lymphoblastic leukemia, the incidence was found to be 79.8/million, which is extremely high. The mortality rate for all these patients in 2015 was 5.3/100,000. However, with regard to children aged between 15 and 18 years, the mortality rate was 8.5/100,000. Abandonment rate was 10%, and there were nine state institutions that had a mortality rate between 25% and 50% among their patients. Coincidentally, as per the Human Development Index, the parameters for education, health, and income were low for those nine institutions. The purpose of this work is to show the epidemiology and the burden we are facing due to this disease.

Tumor neuroectodérmico primitivo primario de páncreas en un paciente pediátrico. Reporte de caso y revisión de la literatura

<p>Los tumores neuroectodérmicos primitivos son tumores de células pequeñas y redondas derivadas del tejido blando, pertenecen a la familia del sarcoma de Ewing. El tumor neuroectodérmico primario del páncreas es muy poco frecuente, en la literatura sólo se han reportado 17 casos. Reportamos el caso de una paciente de 9 años de edad, con diagnóstico de tumor neuroectodérmico primario del páncreas a la que se le realizó una cirugía de Whipple e inició tratamiento de quimioterapia con ciclofosfamida, vincristina, doxorrubicina pegilada, etopósido e ifosfamida y radioterapia. Desde marzo de 2013 la paciente se encuentra en vigilancia, con un periodo de seguimiento de 23 meses. Actualmente, se encuentra en buenas condiciones generales y sin evidencia de actividad tumoral.</p>

Linfoma no Hodgkin primario de sistema nervioso central en un paciente pediátrico sin inmunodeficiencia relacionada

<p>El linfoma no Hodgkin primario de sistema nervioso central es una afección poco frecuente en la población pediátrica. No existen (o son pocas) las recomendaciones o estudios clínicos que sean útiles para definir la mejor opción terapéutica. El objetivo de este trabajo es describir el caso de una niña con linfoma primario de sistema nervioso central, sin ninguna inmunodeficiencia asociada, y realizar de una revisión cualitativa de la literatura especializada sobre esta enfermedad en niños.</p><p>Se ha postulado la posibilidad de cambios citogenéticos que pudieran explicar la heterogeneidad en el comportamiento de esta enfermedad pues se ha visto que es distinto al de otros linfomas en presentaciones habituales. La experiencia de tratamiento en niños con linfoma se basa en resultados de tratamientos obtenidos en pacientes adultos, con regímenes basados principalmente en antimetabolitos como metotrexato y citarabina. Aún es controvertida la utilidad de la radioterapia craneal, la cual sólo se recomienda en casos específicos.</p>

Allergy and acute leukaemia in children with Down syndrome: a population study. Report from the Mexican inter-institutional group for the identification of the causes of childhood leukaemia

Background:

Allergies have been described as protective factors against the development of childhood acute leukaemia (AL). Our objective was to investigate the associations between allergy history and the development of AL and acute lymphoblastic leukaemia (ALL) in children with Down syndrome (DS).

Methods:

A case–control study was performed in Mexico City. The cases (n=97) were diagnosed at nine public hospitals, and the controls (n=222) were recruited at institutions for children with DS. Odds ratios (OR) were calculated.

Results:

Asthma was positively associated with AL development (OR=4.18; 95% confidence interval (CI): 1.47–11.87), whereas skin allergies were negatively associated (OR=0.42; 95% CI: 0.20–0.91).

Conclusion:

Our findings suggest that allergies and AL in children with DS share biological and immune mechanisms. To our knowledge, this is the first study reporting associations between allergies and AL in children with DS.

Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology

Background

Worldwide, 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.

Methods

Included 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).

Results

Although 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).

Conclusions

The 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.

Is autologous bone marrow transplant (ABMT) and high-dose chemotherapy an approach that can rescue some children with advanced cancer disease?

The object was to determine the role ABMT in children with advanced cancer Those included had failed to respond to conventional treatment with 4 different ablative chemotherapy regimens. Bone marrow stem cells were identified with CD34. Cellular viability was determined after the bone marrow extraction and before the infusion. Fifteen patients were included, whose ages ranged from 1 to 13 years old with a median of 7. Six had acute leukemia, 6 with primitive neuroectodermic tumors, and 3 with other tumors. The median disease-free survival for the whole group was of 2 months, range of 1 to 29 months and SD of 10.1. A total of 6 children are alive (40%) and without evidence of tumor activity from 1 to 29 months. The disease-free survival rate for these group was of 19.1 months, with an SD of 7.9 months.

Childhood acute leukemia and intestinal parasitosis

Infectious complications are the leading cause of mortality in children with acute leukemia. Despite the fact that intestinal parasitosis is a rather frequent finding and a health problem in underdeveloped countries, in our experience the incidence of helminthic and protozoan infections among children with leukemia is uncommon. We analyzed 54 consecutive patients with leukemia in a period of 5 years, and only seven (12.9%) had intestinal parasites, four of whom died because of the infection or complication by the parasites. One hundred children without any malignancy were the control group, 26 (26%) of whom had intestinal parasitosis. When we compared the frequency of parasitosis in the control group with the children with leukemia and parasitosis, we found a statistical difference (p less than 0.05). We speculate that parasitic infections may reduce the risk of childhood leukemia.

[Meningeal sarcoma in childhood. Experiences with 17 cases]

A total of 17 patients with meningeal sarcoma were diagnosed and treated at the National Institute of Pediatrics in Mexico City in a period of 15 years. Among the diagnostic methodology used in this group we found that angiography is still the best to be used so far. On the other hand, the chemotherapy protocol employed did not improve the survival obtained with surgery and radiotherapy. Therefore we suggest that a new chemotherapy protocol has to be designed in order to obtain better results. Of particular interest, we found in this group of patients that the time elapsed between the first sign of disease to the moment of diagnosis varied from 2 months to 10 years without any prognostic significance.