Nonchromosomal birth defects and risk of childhood acute leukemia: An assessment in 15 000 leukemia cases and 46 000 controls from the Childhood Cancer and Leukemia International Consortium.

Although recent studies have demonstrated associations between nonchromosomal birth defects and several pediatric cancers, less is known about their role on childhood leukemia susceptibility. Using data from the Childhood Cancer and Leukemia International Consortium, we evaluated associations between nonchromosomal birth defects and childhood leukemia. Pooling consortium data from 18 questionnaire-based and three registry-based case-control studies across 13 countries, we used multivariable logistic regression models to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the association between a spectrum of birth defects and leukemia. Our analyses included acute lymphoblastic leukemia (ALL, n = 13 115) and acute myeloid leukemia (AML, n = 2120) cases, along with 46 172 controls. We used the false discovery rate to account for multiple comparisons. In the questionnaire-based studies, the prevalence of birth defects was 5% among cases vs 4% in controls, whereas, in the registry-based studies, the prevalence was 11% among cases vs 7% in controls. In pooled adjusted analyses, there were several notable associations, including (1) digestive system defects and ALL (OR = 2.70, 95% CI: 1.46-4.98); (2) congenital anomalies of the heart and circulatory system and AML (OR = 2.86, 95% CI: 1.81-4.52) and (3) nervous system defects and AML (OR = 4.23, 95% CI: 1.50-11.89). Effect sizes were generally larger in registry-based studies. Overall, our results could point to novel genetic and environmental factors associated with birth defects that could also increase leukemia susceptibility. Additionally, differences between questionnaire- and registry-based studies point to the importance of complementary sources of birth defect phenotype data when exploring these associations.

Associations between birth defects with neural crest cell origins and pediatric embryonal tumors.

BACKGROUND: There are few assessments evaluating associations between birth defects with neural crest cell developmental origins (BDNCOs) and embryonal tumors, which are characterized by undifferentiated cells having a molecular profile similar to neural crest cells. The effect of BDNCOs on embryonal tumors was estimated to explore potential shared etiologic pathways and genetic origins. METHODS: With the use of a multistate, registry-linkage cohort study, BDNCO-embryonal tumor associations were evaluated by generating hazard ratios (HRs) and 95% confidence intervals (CIs) with Cox regression models. BDNCOs consisted of ear, face, and neck defects, Hirschsprung disease, and a selection of congenital heart defects. Embryonal tumors included neuroblastoma, nephroblastoma, and hepatoblastoma. Potential HR modification (HRM) was investigated by infant sex, maternal race/ethnicity, maternal age, and maternal education. RESULTS: The risk of embryonal tumors among those with BDNCOs was 0.09% (co-occurring n = 105) compared to 0.03% (95% CI, 0.03%-0.04%) among those without a birth defect. Children with BDNCOs were 4.2 times (95% CI, 3.5-5.1 times) as likely to be diagnosed with an embryonal tumor compared to children born without a birth defect. BDNCOs were strongly associated with hepatoblastoma (HR, 16.1; 95% CI, 11.3-22.9), and the HRs for neuroblastoma (3.1; 95% CI, 2.3-4.2) and nephroblastoma (2.9; 95% CI, 1.9-4.4) were elevated. There was no notable HRM by the aforementioned factors. CONCLUSIONS: Children with BDNCOs are more likely to develop embryonal tumors compared to children without a birth defect. Disruptions of shared developmental pathways may contribute to both phenotypes, which could inform future genomic assessments and cancer surveillance strategies of these conditions.

A population-based assessment of metastatic hepatoblastoma in Texas reveals ethnic disparities.

Background: Hepatoblastoma (HB) is the most common primary liver cancer in children with emerging evidence that incidence is increasing globally. While overall survival for low risk hepatoblastoma is >90%, children with metastatic disease have worse survival. As identifying factors associated with high-risk disease is critical for improving outcomes for these children, a need for a further understanding of the epidemiology of hepatoblastoma is warranted. Therefore, we conducted a population-based epidemiologic study of hepatoblastoma in Texas, a large state characterized by ethnic and geographic diversity. Methods: Information on children diagnosed with hepatoblastoma at 0-19 years of age for the period of 1995-2018 was obtained from the Texas Cancer Registry (TCR). Demographic and clinical variables including sex, race/ethnicity, age at diagnosis, urban-rural status, and residence along the Texas-Mexico border were evaluated. Multivariable Poisson regression was used to calculate adjusted incidence rate ratios (aIRRs) and 95% confidence intervals (CIs) for each variable of interest. Joinpoint regression analysis was used to determine the trend in incidence of hepatoblastoma, overall and by ethnicity. Results: Overall, 309 children diagnosed with hepatoblastoma in Texas for the period of 1995-2018. Joinpoint regression analysis showed no joinpoints in the overall or the ethnic-specific analyses. Over this period, the incidence increased at 4.59% annually; with the annual percent change higher among Latinos (5.12%) compared to non-Latinos (3.15%). Among these children, 57 (18%) had metastatic disease at diagnosis. Factors associated with hepatoblastoma included male sex (aIRR = 1.5, 95% CI: 1.2-1.8, p = 0.002); infancy (aIRR = 7.6, 95% CI: 6.0-9.7, p < 0.001); and Latino ethnicity (aIRR = 1.3, 95% CI: 1.0-1.7, p = 0.04). Additionally, children living in rural areas were less likely to develop hepatoblastoma (aIRR = 0.6, 95% CI: 0.4-1.0, p = 0.03). While residence on the Texas-Mexico border association with hepatoblastoma approached statistical significance (p = 0.06) in unadjusted models, this finding did not remain significant after adjusting for Latino ethnicity. The two factors associated with being diagnosed with metastatic hepatoblastoma included Latino ethnicity (aIRR = 2.1, 95% CI: 1.1-3.8, p = 0.02) and male sex (aIRR = 2.4, 95% CI: 1.3-4.3, p = 0.003). Conclusions: In this large population-based study of hepatoblastoma, we found several factors associated with hepatoblastoma and metastatic disease. The reasons for a higher burden of hepatoblastoma among Latino children is unclear but could be due to differences in geographic genetic ancestry, environmental exposures, or other unmeasured factors. Additionally, it is notable that Latino children were also more likely to be diagnosed with metastatic hepatoblastoma compared to non-Latino white children. To our knowledge, this has not been previously reported and warrants further study to delineate the causes of this disparity and identify interventions to improve outcomes.

Ethnic disparities in childhood leukemia survival by border residence: A Texas population-based analysis.

BACKGROUND: The US-Mexico border is a medically underserved region where survival disparities have been observed in adults diagnosed and treated for various malignancies. Studies examining survival disparities among children living in this region and diagnosed with cancer are lacking. The objective of this study was to evaluate the impact of border residence on survival among children with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), and living near the Texas-Mexico border at the time of their diagnosis. The authors hypothesized that this group experiences inferior survival compared with patients with childhood leukemia living in nonborder areas. METHODS: The authors conducted a retrospective survival analysis leveraging data from the Texas Cancer Registry. The study included patients aged birth to 19 years who were diagnosed with ALL or AML between 1995 and 2017. Cox proportional hazards models were used to evaluate the factors associated with the risk of death. Overall survival estimates were calculated using Kaplan-Meier methods. RESULTS: During the study period, there were 6002 children diagnosed with ALL and 1279 diagnosed with AML. Inferior 5-year overall survival was observed among children with ALL living along the border region compared with those living in nonborder areas (77.5% vs. 85.8%). In adjusted models, children with ALL living along the border experienced a 30% increased hazard of death versus children living in nonborder areas. In contrast, for children with AML, survival estimates did not vary by border versus nonborder residence. CONCLUSIONS: Living along the border was associated with inferior survival among children with ALL, but not among children with AML. Additional studies are urgently needed to identify the factors driving these disparities to effectively design multilevel interventions and influence state and national cancer control programs.

Medical radiation exposure and risk of sporadic retinoblastoma.

BACKGROUND: While there is evidence that parental exposure to medical radiation is associated with increased risk of sporadic bilateral retinoblastoma in offspring, this association has not been confirmed. Additionally, the relationship between paternal and maternal exposures and sporadic unilateral retinoblastoma has not been fully investigated. PROCEDURE: Data were obtained from two large multicenter case-control studies of retinoblastoma. For the paternal analyses, 268 bilateral cases, 155 unilateral cases, and 358 controls were included. For the maternal analyses, 298 bilateral cases, 184 unilateral cases, and 404 controls were included. Logistical regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) to evaluate the associations between parental exposures to medical radiation and sporadic retinoblastoma, while adjusting for potential confounders. RESULTS: Paternal exposure to medical radiation was not significantly associated with sporadic bilateral retinoblastoma in offspring. However, increasing paternal exposure to gonadal radiation was associated with increased risk of unilateral retinoblastoma (P-trend = .03). Maternal history of upper and lower gastrointestinal (GI) series was associated with bilateral retinoblastoma (OR = 1.9, 95% CI: 1.1-3.2 and OR = 6.9, 95% CI: 2.9-16.4, respectively). However, there was no association between maternal exposure to medical radiation and unilateral retinoblastoma in offspring. CONCLUSION: Our investigation adds to the evidence that medical radiation exposure in fathers as well as mothers prior to pregnancy may increase the risk of germline alterations leading to the development of retinoblastoma in their offspring. However, our findings could point to a more complex etiological framework for this important pediatric malignancy.

Cancer diagnostic profile in children with structural birth defects: An assessment in 15,000 childhood cancer cases.

BACKGROUND: Birth defects are established risk factors for childhood cancer. Nonetheless, cancer epidemiology in children with birth defects is not well characterized. METHODS: Using data from population-based registries in 4 US states, this study compared children with cancer but no birth defects (n = 13,111) with children with cancer and 1 or more nonsyndromic birth defects (n = 1616). The objective was to evaluate cancer diagnostic characteristics, including tumor type, age at diagnosis, and stage at diagnosis. RESULTS: Compared with the general population of children with cancer, children with birth defects were diagnosed with more embryonal tumors (26.6% vs 18.7%; q < 0.001), including neuroblastoma (12.5% vs 8.2%; q < 0.001) and hepatoblastoma (5.0% vs 1.3%; q < 0.001), but fewer hematologic malignancies, including acute lymphoblastic leukemia (12.4% vs 24.4%; q < 0.001). In age-stratified analyses, differences in tumor type were evident among children younger than 1 year and children 1 to 4 years old, but they were attenuated among children 5 years of age or older. The age at diagnosis was younger in children with birth defects for most cancers, including leukemia, lymphoma, astrocytoma, medulloblastoma, ependymoma, embryonal tumors, and germ cell tumors (all q < 0.05). CONCLUSIONS: The results indicate possible etiologic heterogeneity in children with birth defects, have implications for future surveillance efforts, and raise the possibility of differential cancer ascertainment in children with birth defects. LAY SUMMARY: Scientific studies suggest that children with birth defects are at increased risk for cancer. However, these studies have not been able to determine whether important tumor characteristics, such as the type of tumor diagnosed, the age at which the tumor is diagnosed, and the degree to which the tumor has spread at the time of diagnosis, are different for children with birth defects and children without birth defects. This study attempts to answer these important questions. By doing so, it may help scientists and physicians to understand the causes of cancer in children with birth defects and diagnose cancer at earlier stages when it is more treatable.

Perinatal and familial risk factors for soft tissue sarcomas in childhood through young adulthood: A population-based assessment in 4 million live births.

Perinatal factors have been associated with soft tissue sarcomas (STS) in case-control studies. However, (i) the contributions of factors including fetal growth remain unknown, ( ii) these factors have not been examined in cohort studies and (iii) few assessments have evaluated risk in specific STS subtypes. We sought to identify the role of perinatal and familial factors on the risk of STS in a large population-based birth cohort. We identified 4,023,436 individuals in the Swedish Birth Registry born during 1973-2012. Subjects were linked to the Swedish Cancer Registry, where incident STS cases were identified. We evaluated perinatal and familial factors obtained from Statistics Sweden, including fetal growth, gestational age, and presence of a congenital malformation. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs) for associations between perinatal factors and STS overall, as well as by common subtypes. There were 673 individuals diagnosed with STS in 77.5 million person-years of follow-up. Having a congenital malformation was associated with STS (IRR = 1.70, 95% CI: 1.23-2.35). This association was stronger (IRR = 2.90, 95% CI: 1.25-6.71) in recent years (2000-2012). Low fetal growth was also associated with STS during the same time period (IRR = 1.86, 95% CI: 1.05-3.29). Being born preterm was associated with rhabdomyosarcoma (IRR = 1.74, 95% CI: 1.08-2.79). In our cohort study, those with congenital malformations and other adverse birth outcomes were more likely to develop a STS compared to their unaffected contemporaries. These associations may point to disrupted developmental pathways and genetic factors influencing the risk of STS.

Incidence and predictors of treatment-related conjugated hyperbilirubinemia during early treatment phases for children with acute lymphoblastic leukemia.

Conjugated hyperbilirubinemia (CHB) and liver transaminase elevation are known complications of acute lymphoblastic leukemia (ALL) therapy, but host risk factors are poorly understood. Among 373 children diagnosed with ALL between 2011 and 2016, clinically significant CHB and transaminase elevation were observed in 15 (4.0%) and 12 (3.2%) children, respectively, during induction and consolidation. Body mass index ≥95th percentile (odds ratio 9.20, 95% confidence interval 2.56-32.96) was the only host factor independently associated with CHB, and no host factors were associated with transaminase elevation. Obese patients warrant closer monitoring of hepatic function to facilitate early intervention prior to the development of severe, adverse hepatic events.

Weight trends in a multiethnic cohort of pediatric acute lymphoblastic leukemia survivors: A longitudinal analysis.

BACKGROUND: As survival rates for childhood acute lymphoblastic leukemia (ALL) continue to improve, there is growing concern over the chronic health conditions that survivors face. Given that survivors of childhood ALL are at increased risk of cardiovascular complications and obesity, we sought to characterize BMI trends from diagnosis through early survivorship in a multi-ethnic, contemporary cohort of childhood ALL patients and determine if early weight change was predictive of long-term weight status. METHODS: The study population consisted of ALL patients aged 2-15 years at diagnosis who were treated with chemotherapy alone at Texas Children's Hospital. Each patient had BMI z-scores collected at diagnosis, 30-days post-diagnosis, and annually for five years. Linear regression models were estimated to evaluate the association between: 1) BMI z-score change in the first 30 days and BMI z-scores at five-years post-diagnosis; and 2) BMI z-score change in the first year post-diagnosis and BMI z-scores at five-years post-diagnosis. RESULTS: This retrospective cohort study included longitudinal data from 121 eligible patients. The mean BMI z-scores for the population increased significantly (p-value<0.001) from baseline (mean = 0.25) to 30 days post-diagnosis (mean = 1.17) before plateauing after one year post-diagnosis (mean = 0.99). Baseline BMI z-scores were statistically significant predictors to five year BMI z-scores (p <0.001). Independent of baseline BMI z-score and other clinical factors, the BMI z-score at one year post-diagnosis was significantly associated with BMI z-score at five-years post-diagnosis (ß = 0.63, p <0.001), while BMI z-score at 30 days post-diagnosis was not (ß = 0.10, p = 0.23). CONCLUSION: Our results suggest that weight gain within the first year after diagnosis is more strongly associated with long-term BMI than early weight gain (within 30 days). If confirmed, this information may help identify a window of time during therapy when ALL patients would benefit most from weight management directed interventions.

Association Between Birth Defects and Cancer Risk Among Children and Adolescents in a Population-Based Assessment of 10 Million Live Births.

IMPORTANCE: Birth defects affect approximately 1 in 33 children. Some birth defects are known to be strongly associated with childhood cancer (eg, trisomy 21 and acute leukemia). However, comprehensive evaluations of childhood cancer risk in those with birth defects have been limited in previous studies by insufficient sample sizes. OBJECTIVES: To identify specific birth defect-childhood cancer (BD-CC) associations and characterize cancer risk in children by increasing number of nonchromosomal birth defects. DESIGN, SETTING, AND PARTICIPANTS: This multistate, population-based registry linkage study pooled statewide data on births, birth defects, and cancer from Texas, Arkansas, Michigan, and North Carolina on 10 181 074 children born from January 1, 1992, to December 31, 2013. Children were followed up to 18 years of age for a diagnosis of cancer. Data were retrieved between September 26, 2016, and September 21, 2017, and data analysis was performed from September 2, 2017, to March 21, 2019. EXPOSURES: Birth defects diagnoses (chromosomal anomalies and nonchromosomal birth defects) recorded by statewide, population-based birth defects registries. MAIN OUTCOMES AND MEASURES: Cancer diagnosis before age 18 years, as recorded in state cancer registries. Cox regression models were used to generate hazard ratios (HRs) and 95% CIs to evaluate BD-CC associations and the association between number of nonchromosomal defects and cancer risk. RESULTS: Compared with children without any birth defects, children with chromosomal anomalies were 11.6 (95% CI, 10.4-12.9) times more likely to be diagnosed with cancer, whereas children with nonchromosomal birth defects were 2.5 (95% CI, 2.4-2.6) times more likely to be diagnosed with cancer before 18 years of age. An increasing number of nonchromosomal birth defects was associated with a corresponding increase in the risk of cancer. Children with 4 or more major birth defects were 5.9 (95% CI, 5.3-6.4) times more likely to be diagnosed with cancer compared with those without a birth defect. In the analysis of 72 specific BD-CC patterns, 40 HRs were statistically significant (adjusted P < .05) after accounting for multiple comparisons. Cancers most frequently associated with nonchromosomal defects were hepatoblastoma and neuroblastoma. CONCLUSIONS AND RELEVANCE: Several significant and novel associations were observed between specific birth defects and cancers. Among children with nonchromosomal birth defects, the number of major birth defects diagnosed was significantly and directly associated with cancer risk. These findings could inform clinical treatment for children with birth defects and may elucidate mechanisms that lead to these complex outcomes.

Intermittent or uneven daily administration of low-dose hydroxyurea is effective in treating children with sickle cell anemia in Angola.

BACKGROUND: Although hydroxyurea is proven effective in treatment of sickle cell anemia (SCA) and is widely prescribed in high-income countries, due to questions about feasibility of treating large numbers of patients in resource-limited health systems, its use is limited in sub-Saharan Africa (SSA), where most children with SCA live. We assessed hematological response and toxicity of hydroxyurea treatment for SCA in Angola. METHODS: Retrospective study of children with SCA (not selected for clinical severity) treated on a fixed dose of hydroxyurea for at least 6 months. Because only the 500 mg capsule was available, dose was averaged weekly. We evaluated toxicity events and magnitude of hydroxyurea-induced changes in blood counts and compared patients who received a uniform daily dose to those prescribed intermittent or uneven daily doses. RESULTS: Only 13% of 303 patients received a uniform dose of hydroxyurea daily. Dose ranged from 16.5 to 22.8 mg/kg/day. Hydroxyurea increased HGB and mean cell volume values by 0.5 g/dL (P < 0.0001) and 8 fL (P < 0.0001), while ANC, PLT, and ARC decreased 1.1 × 109 /L (P < 0.0001), 34 × 109 /L (P = < 0.0001), and 19 × 109 /L (P = 0.0008), respectively. There were no differences in magnitude of hydroxyurea-induced changes between patients prescribed intermittent or uneven doses and uniform daily doses, or between those treated in the lower and higher dose quartiles. Hematological toxicity events were mild and reversible. CONCLUSION: Intermittent or uneven daily dosing of hydroxyurea is as effective as fixed daily doses in treating SCA. This strategy may enable treatment of additional children with SCA in SSA.