Incidence of childhood cancer in Latin America and the Caribbean: coverage, patterns, and time trends

Objective

To provide a comprehensive overview of geographical patterns (2001-2010) and time trends (1993-2012) of cancer incidence in children aged 0-19 years in Latin America and the Caribbean (LAC) and interpret the findings in the context of global patterns.

Methods

Geographical variations in 2001-2010 and incidence trends over 1993-2012 in the population of LAC younger than 20 years were described using the database of the third volume of the International Incidence of Childhood Cancer study containing comparable data. Age-specific incidence per million person-years (ASR) was calculated for population subgroups and age-standardized (WSR) using the world standard population.

Results

Overall, 36 744 unique cases were included in this study. In 2001-2010 the overall WSR in age 0-14 years was 132.6. The most frequent were leukemia (WSR 48.7), central nervous system neoplasms (WSR 23.0), and lymphoma (WSR 16.6). The overall ASR in age group 15-19 years was 152.3 with lymphoma ranking first (ASR 30.2). Incidence was higher in males than in females, and higher in South America than in Central America and the Caribbean. Compared with global data LAC incidence was lower overall, except for leukemia and lymphoma at age 0-14 years and the other and unspecified tumors at any age. Overall incidence at age 0-19 years increased by 1.0% per year (95% CI [0.6, 1.3]) over 1993-2012. The included registries covered 16% of population aged 0-14 years and 10% of population aged 15-19 years.

Conclusions

The observed patterns provide a baseline to assess the status and evolution of childhood cancer occurrence in the region. Extended and sustained support of cancer registration is required to improve representativeness and timeliness of data for childhood cancer control in LAC.

A new method of estimating prevalence of childhood cancer survivors (POCCS): example of the 20-year prevalence in The Netherlands

BACKGROUND

Estimating the number of childhood cancer survivors is crucial for cancer control, including clinical guidelines. To compare estimates across countries despite data sharing restrictions, we propose a new method of computing limited-duration prevalence of childhood cancer survivors (POCCS) using aggregated data.

METHODS

We developed a Markov model that simulates, for each calendar year and birth cohort in a population, the proportion of individuals in the following health states: healthy, newly diagnosed with cancer, surviving with cancer, and deceased. Transitions between health states were informed using annual sex- and age-specific incidence rates, conditional 1-year net survival probabilities from the Netherlands Cancer Registry (1989-2011), and annual mortality probability by sex and age group for The Netherlands from the Human Mortality Database. Applying a Markov model, we computed 20-year prevalence of childhood cancer survivors. The resulting POCCS estimates, stratified by sex, were compared with SEER*Stat estimates derived from individual cancer records from the same registry.

RESULTS

In 2011, POCCS predicted 654 males [95% confidence interval (95% CI): 637-672] and 539 females (95% CI: 523-555) per million persons living in The Netherlands after childhood cancer diagnosed within the previous 20 years. Using SEER*Stat, the 20-year prevalence was 665 males (95% CI: 647-683) and 544 females (95% CI: 529-560) per million persons on 1 July 2011.

CONCLUSIONS

Using the POCCS model and aggregated cancer data, our estimates of childhood cancer survivors limited-duration prevalence were consistent with those computed by a standard method requiring individual cancer records. The POCCS method provides relevant information for planning follow-up and care for childhood cancer survivors.

Challenges on participation in a cooperative group of childhood renal tumors in Brasil

OBJECTIVE

Children with renal tumors included in clinical trials have significantly better outcomes. In Brasil, the enrollment of patients in clinical trials remains challenging. Here we aimed to describe participation accrual in the Brazilian Wilms Tumor Study Group (BWTSG) and to identify barriers to trial registration of children with renal tumors.

METHODS

We determined the numbers of renal tumor diagnoses in 105 hospital-based cancer registries from 2001-2009. We then compared these totals with the numbers of renal tumor cases registered in the BWTSG from the same hospitals during the same time period. We also invited members of the Brazilian Pediatric Oncology Society to complete a 5-point Likert-type scale questionnaire regarding their opinions of the importance of participation in cooperative group trials.

RESULTS

The accrual rate of patient participation per hospital varied from 25% to 76%, and was highest in the South region. The accrual rate of hospital participation also varied according to the region (20-31%) and was highest in the Southeast region. For the questionnaire regarding the importance of participation in cooperative groups, the responses showed an agreement of >75% on 10 of the 13 statements.

CONCLUSION

Our results demonstrated low accrual of participation in a cooperative group trial in Brasil. We identified variations in registration rates according to geographic region and hospital, which may help targeted efforts to increase registration rates. The survey responses demonstrated that colleagues understand the importance of trial participation.

Musculoskeletal complaints, absenteeism and associated factors among cytotechnologists: cross-sectional study

Background

Cytotechnologists are laboratory professionals who analyze cytology slides under optical microscopes. Static postures, speed and repetitive movements are associated with occurrence of musculoskeletal complaints.

Objective

To establish the main musculoskeletal complaints among cytotechnologists at the National Cancer Institute, Brazil, test associations between absenteeism due to musculoskeletal complaints and individual and occupational variables, and characterize absenteeism related to diseases of the musculoskeletal system in 2016 and 2017.

Method

Cross-sectional study in which we administered the Nordic Musculoskeletal Questionnaire and tested associations between exposure variables and absenteeism. We also analyzed morbidity records kept at the Occupational Health Division (OHD) to establish the main disorders related to absenteeism. Associations were investigated by means of Fisher's test using SPSS version 20.0. The significance level was set to p<0.05.

Results

34.4% of the sample required sick leave due to musculoskeletal complaints. The most affected body site was the neck (18%). As per the OHD records, sickness absenteeism was mainly due to diseases of the musculoskeletal system and connective tissue (25%). We found statistically significant association of absenteeism with length in the job and body mass index.

Conclusion

Diseases of the musculoskeletal system and connective tissue were the main reason for missing work days. Absenteeism was associated with length in the job and high body mass index.

Delays in the health care system for children, adolescents, and young adults with bone tumors in Brazil

OBJECTIVE

To identify delays in the health care system experienced by children and adolescents and young adults (AYA; aged 0-29 years) with osteosarcoma and Ewing sarcoma using information from the Brazilian hospital-based cancer registries.

METHODS

Patient data were extracted from 161 Brazilian hospital-based cancer registries between 2007 and 2011. Hospital, diagnosis, and treatment delays were analyzed in patients without a previous histopathological diagnosis. Referral, hospital, and health care delays were calculated for patients with a previous histopathological diagnosis. The time interval was measured in days.

RESULTS

There was no difference between genders in overall delays. All delays increased at older ages. Patients without a previous histopathological diagnosis had the longest hospital delay when compared to patients with a previous histopathological diagnosis before first contact with the cancer center. Patients with Ewing sarcoma had longer referral and health care delays than those with osteosarcoma who had a previous histopathological diagnosis before first contact with the cancer center. The North and Northeast regions had the longest diagnosis delay, while the Northeast and Southeast regions had the longest treatment delay.

CONCLUSION

Health care delay among patients with a previous diagnosis was longer, and was probably associated with the time taken for to referral to cancer centers. Patients without a previous histopathological diagnosis had longer hospital delays, which could be associated with possible difficulties regarding demand and high-cost procedures. Despite limitations, this study helps provide initial knowledge about the healthcare pathway delays for patients with bone cancer inside several Brazilian hospitals.

Who cares for adolescents and young adults with cancer in Brazil?

OBJECTIVE

Approximately 6% of all cancers arise in adolescents and young adults. Currently, the ward type best placed to treat this patient group remains controversial. The aim of this study was to evaluate exactly where adolescents and young adults with cancer are treated in Brazil.

METHODS

Data were extracted from 271 Brazilian hospital-based cancer registries (2007-2011), including all five national regions (North, Northeast, Midwest, South, and Southeast). Variables included gender, age, ethnicity, National Code of Health Establishment, hospital unit state, and region. Tumors were classified according to the World Health Organization classification for adolescents and young adults with cancer. Odds ratios with 95% confidence intervals were computed by unconditional logistic regression.

RESULTS

Most patients were managed on medical oncology wards, followed by pediatric oncology and then by non-specialist wards. Of patients aged 15-19 years, 49% were managed on pediatric wards; most of the older patients (96%; aged 20-24) were managed on adult wards. Patients were more likely to be seen in medical oncology wards as their age increased (OR=2.03 [1.98-2.09]), or if they were based in the South (OR=1.50 [1.29-1.73]). Conversely, bone tumors were less likely to be treated (decreased OR) on medical oncology wards, regardless of age, gender, and region.

CONCLUSION

An elevated risk of treatment on medical oncology wards was observed for older patients and those treated in the South. Bone tumors were generally treated in pediatric oncology wards, while skin cancers were treated in medical oncology wards, regardless of age, gender, and region.

Association between long interspersed nuclear element-1 methylation levels and relapse in Wilms tumors

Background

Wilms tumor (WT) is a curable pediatric renal malignancy, but there is a need for new molecular biomarkers to improve relapse risk-directed therapy. Somatic alterations occur at relatively low frequencies whereas epigenetic changes at 11p15 are the most common aberration. We analyzed long interspersed element-1 (LINE-1) methylation levels in the blastemal component of WT and normal kidney samples to explore their prognostic significance.

Results

WT samples presented a hypomethylated pattern at all five CpG sites compared to matched normal kidney samples; therefore, the averaged methylation levels of the five CpG sites were used for further analyses. WT presented a hypomethylation profile (median 65.0%, 47.4–73.2%) compared to normal kidney samples (median 71.8%, 51.5–77.5%; p < 0.0001). No significant associations were found between LINE-1 methylation levels and clinical–pathological characteristics. We observed that LINE-1 methylation levels were lower in tumor samples from patients with relapse (median methylation 60.5%) compared to patients without relapse (median methylation 66.5%; p = 0.0005), and a receiving operating characteristic curve analysis was applied to verify the ability of LINE-1 methylation levels to discriminate WT samples from these patients. Using a cut-off value of 62.71% for LINE-1 methylation levels, the area under the curve was 0.808, with a sensitivity of 76.5% and a specificity of 83.3%. Having identified differences in LINE-1 methylation between WT samples from patients with and without relapse in this cohort, we evaluated other prognostic factors using a logistic regression model. This analysis showed that in risk stratification, LINE-1 methylation level was an independent variable for relapse risk: the lower the methylation levels, the higher the risk of relapse. The logistic regression model indicated a relapse risk increase of 30% per decreased unit of methylation (odds ratio 1.30; 95% confidence interval 1.07–1.57).

Conclusion

Our results reinforce previous data showing a global hypomethylation profile in WT. LINE-1 methylation levels can be suggested as a marker of relapse after chemotherapy treatment in addition to risk classification, helping to guide new treatment approaches.

Electronic supplementary material

The online version of this article (10.1186/s13148-017-0431-6) contains supplementary material, which is available to authorized users.

Mother and child characteristics at birth and early age leukemia: a case-cohort population-based study

OBJECTIVE

The population-based cancer registries (PBCR) and the Information System on Live Births in Brazil (Sistema de Informações sobre Nascidos Vivos [SINASC]) have information that enables the test for risk factors associated with leukemia at an early age. The aim of this study was to identify maternal and birth characteristics associated with early-age acute leukemia (EAL) in Brazil.

METHODS

A case-cohort study was performed using secondary dataset information of PBCR and SINASC. The risk association variables were grouped into (i) characteristics of the child at birth and (ii) characteristics of maternal exposure during pregnancy. The case-control ratio was 1:4. Linkage was performed using R software; odds ratio (OR) and 95% confidence interval (CI) were calculated by logistic regression models.

RESULTS

EAL was associated with maternal occupational exposure to chemicals (agricultural, chemical, and petrochemical industry; adjOR: 2.18, 95% CI: 1.16-4.10) and with birth defects (adjOR: 3.62, 95% CI: 1.19-11.00).

CONCLUSIONS

The results of this study, with the identification of EAL risk factors in population-based case-cohort study, strengthen the knowledge and improve databases, contributing to investigations on risk factors associated with childhood leukemia worldwide.

Incidence Trends of Cervical Cancer in Adolescents and Young Adults: Brazilian Population Based Data

PURPOSE

High incidence rates for cervical cancer in adolescents and young adults (AYAs: 15-29 years) make this the most common carcinoma in Brazil. Our aim was to analyze the incidence trends for cervical cancer (CC) and in situ neoplasia (IsN) among this age group.

METHODS

Incidence data were extracted from 21 Brazilian population-based cancer registries (PBCRs). Tumors with behavior code/3 (malignant) were classified as CC. Tumors with behavior code/2 were classified as IsN. Age-adjusted and age-specific incidence rates were calculated for individuals aged 15-19 years, 20-24 years, and 25-29 years. Incidence trends were evaluated by joinpoint regression analyses.

RESULTS

The median incidence rate of CC for AYA in Brazil was 3.63 per 100,000, with the highest rate observed in Recife (27.50 per 100,000). Significant increase in incidence for CC was identified in two PBCRs, with decreased rates for three PBCRs. The median incidence rate of IsN was 16.78 per 100,000 and was highest in Roraima (93.37 per 100,000). Increased incidence rates for IsN were identified in six PBCRs, with significant decreases in two PBCRs.

CONCLUSION

The incidence rate for CC among AYA in Brazil is high and warrants intervention in terms of both prevention and control.

Birth weight and risk of childhood solid tumors in Brazil: a record linkage between population-based data sets

OBJECTIVE

To analyze the relationship between the development of childhood solid tumors and 1) birth weight and 2) fetal growth, using two Brazilian population-based data sets.

METHODS

A case-cohort study was performed using two population-based data sets, and linkage between the Live Birth Information System (Sistema de Informação sobre Nascidos Vivos, SINASC) and 14 population-based cancer registries (PBCRs) was established. Four controls per case were chosen randomly from the SINASC data set. Tumors were classified as central nervous system (CNS), non-CNS embryonal, and other tumors ("miscellaneous"). Adjustments were made for potential confounders (maternal age, mode of delivery, maternal education, birth order, gestational age, sex, and geographic region). Odds ratios (ORs) with 95% confidence intervals (CIs) were computed using unconditional logistic regression analysis.

RESULTS

In a trend analysis, for every 500 g of additional birth weight, the crude OR was 1.12 (CI: 1.00-1.24) and the adjusted OR was 1.02 (CI: 0.90-1.16) for all tumors. For every 1 000 g of additional birth weight, the crude OR was 1.25 (CI: 1.00-1.55) and the adjusted OR was 1.04 (CI: 0.82-1.34) for all tumors. Among children diagnosed after reaching the age of 3 years, in the miscellaneous tumor category, the OR was significantly increased for every additional 500 g and 1 000 g of birth weight.

CONCLUSIONS

The study data suggested that increased birth weight was associated with childhood solid tumor development, especially among children more than 3 years old with "miscellaneous" tumors.

Maternal and Birth Characteristics and Childhood Embryonal Solid Tumors: A Population-Based Report from Brazil

BACKGROUND

Several maternal and birth characteristics have been reported to be associated with an increased risk of many childhood cancers. Our goal was to evaluate the risk of childhood embryonal solid tumors in relation to pre- and perinatal characteristics.

METHODS

A case-cohort study was performed using two population-based datasets, which were linked through R software. Tumors were classified as central nervous system (CNS) or non-CNS-embryonal (retinoblastoma, neuroblastoma, renal tumors, germ cell tumors, hepatoblastoma and soft tissue sarcoma). Children aged <6 years were selected. Adjustments were made for potential confounders. Odds ratios (OR) with 95% confidence intervals (CI) were computed by unconditional logistic regression analysis using SPSS.

RESULTS

Males, high maternal education level, and birth anomalies were independent risk factors. Among children diagnosed older than 24 months of age, cesarean section (CS) was a significant risk factor. Five-minute Apgar ≤8 was an independent risk factor for renal tumors. A decreasing risk with increasing birth order was observed for all tumor types except for retinoblastoma. Among children with neuroblastoma, the risk decreased with increasing birth order (OR = 0.82 (95% CI 0.67-1.01)). Children delivered by CS had a marginally significantly increased OR for all tumors except retinoblastoma. High maternal education level showed a significant increase in the odds for all tumors together, CNS tumors, and neuroblastoma.

CONCLUSION

This evidence suggests that male gender, high maternal education level, and birth anomalies are risk factors for childhood tumors irrespective of the age at diagnosis. Cesarean section, birth order, and 5-minute Apgar score were risk factors for some tumor subtypes.