Racial and ethnic disparities in childhood and young adult acute lymphocytic leukaemia: secondary analyses of eight Children's Oncology Group cohort trials

Acute lymphoblastic leukaemia

Acute lymphoblastic leukaemia (ALL) is a haematological malignancy characterized by the uncontrolled proliferation of immature lymphoid cells. Over past decades, significant progress has been made in understanding the biology of ALL, resulting in remarkable improvements in its diagnosis, treatment and monitoring. Since the advent of chemotherapy, ALL has been the platform to test for innovative approaches applicable to cancer in general. For example, the advent of omics medicine has led to a deeper understanding of the molecular and genetic features that underpin ALL. Innovations in genomic profiling techniques have identified specific genetic alterations and mutations that drive ALL, inspiring new therapies. Targeted agents, such as tyrosine kinase inhibitors and immunotherapies, have shown promising results in subgroups of patients while minimizing adverse effects. Furthermore, the development of chimeric antigen receptor T cell therapy represents a breakthrough in ALL treatment, resulting in remarkable responses and potential long-term remissions. Advances are not limited to treatment modalities alone. Measurable residual disease monitoring and ex vivo drug response profiling screening have provided earlier detection of disease relapse and identification of exceptional responders, enabling clinicians to adjust treatment strategies for individual patients. Decades of supportive and prophylactic care have improved the management of treatment-related complications, enhancing the quality of life for patients with ALL.

Prevalence and Treatment Outcomes of Childhood Acute Lymphoblastic Leukemia in Kosovo

Advances in research, including novel biomarker identification and patient stratification, have significantly improved the therapy for childhood acute lymphoblastic leukemia (ALL), though access to improved healthcare services varies across geographical regions. In an effort to evaluate the advances in therapeutic approaches, we performed a retrospective analysis of childhood ALL in Kosovo. Our retrospective analysis included 225 cases diagnosed between 2008 and 2023, representing 52% of 429 diagnosed childhood cancers. The average annual incidence was 14, with a median age diagnosis of seven years, and a male predominance (59.54%). Patients were categorized into risk groups, with the majority (43%) in the standard-risk category. We identified five different treatment protocols for this study period. Over 61% of patients achieved remission after the first chemotherapy cycle and we observed a 20% mortality rate. Survival analysis showed that 55% and 40% of patients achieved 2-year and 5-year event-free survival (EFS), respectively, with significant differences across risk groups. Treatment advancements significantly correlated with improved survival rates, achieving a 5-year overall survival (OS) of 88% in the currently used standardized AIEOP-BFM-2009 protocol. Our study emphasizes the need for continued research and customized care strategies to enhance clinical outcomes.

Effect of American genomic ancestry on severe toxicities in children with acute lymphoblastic leukemia in the Amazon region

BACKGROUND

Acute Lymphoblastic Leukemia (ALL) is a neoplasm of the hematopoietic system characterized by a clonal expansion of abnormal lymphocyte precursor cells. ALL is the most common form of cancer in children, but despite advances in treatment, it can still be fatal. Ethnic differences influence survival rates, and genomic ancestry plays an important role, especially in mixed-race populations such as Latin America. This study aims to analyze the influence of genomic ancestry on toxicity in children with ALL in the Amazon region.

METHODS

The study included 171 patients (protocol number 119,649/2012-Ethics Committee) with ALL treated at a pediatric treatment center in Belém do Pará, in the Brazilian Amazon. The patients were submitted to the BFM protocol of induction therapy for ALL. Toxicity was assessed based on laboratory tests and adverse events, classified according to the CTC-NCI guide. Genomic ancestry was determined using autosomal informative markers.

RESULTS

The majority of children (94.74%) developed some type of toxicity during treatment, 87.04% of which were severe. Infectious toxicity was the most common, present in 84.8% of cases, 77.24% of which were severe. Amerindian ancestry showed an association with the risk of severe general toxicity and severe infectious toxicity, with a contribution of 35.0% demonstrating a significant increase in risk. In addition, post-induction refractoriness and relapse were also associated with an increased risk of death.

CONCLUSION

This study highlights the influence of Amerindian genomic ancestry on response to therapy and toxicity in children with ALL in the Amazon region. Understanding these associations can contribute to personalizing treatment and improving clinical outcomes.

Providing Groceries and Transportation to Poverty-Exposed Pediatric Oncology Families: The PediCARE Pilot Randomized Clinical Trial

This randomized clinical trial evaluates the Pediatric Cancer Resource Equity (PediCARE) intervention, which provided groceries and transportation, vs usual care, for poverty-exposed pediatric oncology families.

A noncoding regulatory variant in IKZF1 increases acute lymphoblastic leukemia risk in Hispanic/Latino children

Hispanic/Latino children have the highest risk of acute lymphoblastic leukemia (ALL) in the US compared to other racial/ethnic groups, yet the basis of this remains incompletely understood. Through genetic fine-mapping analyses, we identified a new independent childhood ALL risk signal near IKZF1 in self-reported Hispanic/Latino individuals, but not in non-Hispanic White individuals, with an effect size of ∼1.44 (95% confidence interval = 1.33-1.55) and a risk allele frequency of ∼18% in Hispanic/Latino populations and <0.5% in European populations. This risk allele was positively associated with Indigenous American ancestry, showed evidence of selection in human history, and was associated with reduced IKZF1 expression. We identified a putative causal variant in a downstream enhancer that is most active in pro-B cells and interacts with the IKZF1 promoter. This variant disrupts IKZF1 autoregulation at this enhancer and results in reduced enhancer activity in B cell progenitors. Our study reveals a genetic basis for the increased ALL risk in Hispanic/Latino children.

Household income and health-related quality of life in children receiving treatment for acute myeloid leukemia: Potential impact of selection bias in health equity research

OBJECTIVE

Examine the influence of household income on health-related quality of life (HRQOL) among children with newly diagnosed acute myeloid leukemia (AML).

DESIGN

Secondary analysis of data prospectively collected from pediatric patients receiving treatment for AML at 14 hospitals across the United States.

EXPOSURE

Household income was self-reported on a demographic survey. The examined mediators included the acuity of presentation and treatment toxicity.

OUTCOME

Caregiver proxy reported assessment of patient HRQOL from the Peds QL 4.0 survey.

RESULT

Children with AML (n = 131) and caregivers were prospectively enrolled to complete PedsQL assessments. HRQOL scores were better for patients in the lowest versus highest income category (mean ± SD: 76.0 ± 14 household income <$25,000 vs. 59.9 ± 17 income ≥$75,000; adjusted mean difference: 11.2, 95% CI: 2.2-20.2). Seven percent of enrolled patients presented with high acuity (ICU-level care in the first 72 h), and 16% had high toxicity (any ICU-level care); there were no identifiable differences by income, refuting mediating roles in the association between income and HRQOL. Enrolled patients were less likely to be Black/African American (9.9% vs. 22.2%), more likely to be privately insured (50.4% vs. 40.7%), and more likely to have been treated on a clinical trial (26.7% vs. 18.5%) compared to eligible unenrolled patients not enrolled. Evaluations of potential selection bias on the association between income and HRQOL suggested differences in HRQOL may be smaller than observed or even in the opposing direction.

CONCLUSIONS

While primary analyses suggested lower household income was associated with superior HRQOL, differential participation may have biased these results. Future studies should partner with patients/families to identify strategies for equitable participation in clinical research.

Non-homologous End-joining Genotype, mRNA Expression, and DNA Repair Capacity in Childhood Acute Lymphocytic Leukemia

BACKGROUND/AIM

The capacity for non-homologous end-joining (NHEJ) repair plays a pivotal role in maintaining genome stability and in carcinogenesis. However, there is little literature on the involvement of NHEJ-related genes in childhood acute lymphocytic leukemia (ALL). Our study aimed to elucidate the impact of polymorphisms of X-ray repair cross-complementing group 4 (XRCC4) (rs6869366, rs2075685, rs2075686, rs28360071, rs3734091, rs28360317, rs1805377), XRCC5 (rs828907, rs11685387, rs9288518), XRCC6 (rs5751129, rs2267437, rs132770, rs132774), XRCC7 rs7003908, and DNA ligase IV (LIG4) rs1805388, on the odds of childhood ALL.

MATERIALS AND METHODS

Genotypes NHEJ-related genes of 266 cases and 266 controls were determined, and the genotype-phenotype correlation was investigated by examining mRNA transcript expression and the capacity for overall and precise NHEJ repair.

RESULTS

The variant genotypes of XRCC4 rs3734091, rs28360071, XRCC5 rs828907, and XRCC6 rs5751129 were significantly associated with increased odds of childhood ALL. Further analysis based on susceptibility genotypes showed no significant differences in mRNA transcript expression levels among childhood ALL cases with various putative high-risk genotypes, except XRCC6 rs5751129. Moreover, the overall NHEJ repair capacity was similar among carriers of different XRCC4, XRCC5, and XRCC6 genotypes. However, it is worth noting that individuals carrying the variant C allele at XRCC6 rs5751129 exhibited lower precise NHEJ repair capacity compared to those with the wild-type T allele.

CONCLUSION

Our study identified significant associations between XRCC4 rs3734091, rs28360071, XRCC5 rs828907, and XRCC6 rs5751129 genotypes and childhood ALL. Notably, lower transcriptional expression and reduced precise NHEJ repair capacity were observed in patients carrying the C allele of XRCC6 rs5751129. Further investigations are required to gain deeper insights into childhood ALL development.

Recent advances in the treatment of childhood cancers

PURPOSE OF REVIEW

Although cancer remains the leading nonaccidental cause of mortality in children, substantial advances in care have led to 5-year overall survival exceeding 85%. However, improvements in outcomes have not been uniform across malignancies or strata of social determinants of health. The current review highlights recent areas of advancement and anticipated directions for future progress.

RECENT FINDINGS

Incorporation of rational targeted agents into upfront treatment regimens has led to incremental improvements in event-free survival for many children, sometimes with potential reductions in late effects. For rare or challenging-to-treat cancers, the increasing feasibility of molecular profiling has provided specific treatment options to patients with some of the greatest needs. Simultaneously, increased focus is being given to patient-reported outcomes and social determinants of health, the importance ofwhich are becoming readily recognized in providing equitable, quality care. Finally, as survival from malignant diseases improves, breakthroughs in the prevention and management of adverse late effects will promote long-term quality of life.

SUMMARY

Multi-institutional collaboration and risk-adapted approaches have been crucial to recent advancements in the care of children with cancer and inform potential directions for future investigation.

The genetic risk of acute lymphoblastic leukemia and its implications for children of Latin American origin

Acute lymphoblastic leukemia (ALL) is the most common cancer in children, and disproportionately affects children of Hispanic/Latino ethnicity in the United States, who have the highest incidence of disease compared with other racial/ethnic groups. Incidence of childhood ALL is similarly high in several Latin American countries, notably in Mexico, and of concern is the rising incidence of childhood ALL in some Hispanic/Latino populations that may further widen this disparity. Prior studies have implicated common germline genetic variants in the increased risk of ALL among Hispanic/Latino children. In this review, we describe the known disparities in ALL incidence as well as patient outcomes that disproportionately affect Hispanic/Latino children across the Americas, and we focus on the role of genetic variation as well as Indigenous American ancestry in the etiology of these disparities. Finally, we discuss future avenues of research to further our understanding of the causes of the disparities in ALL incidence and outcomes in children of Latin American origin, which will be required for future precision prevention efforts.

Impact of Social Disparities on 5-Year Survival Rates in Pediatric Hematologic Malignancies

BACKGROUND

Socioeconomic disparities exist in pediatric patients with hematologic malignancies, leading to suboptimal survival rates. Social determinants of health impact health outcomes, and in children, they may not only lead to worse survival outcomes but carry over into late effects in adult life. The social deprivation index (SDI) is a composite score using geographic county data to measure social determinants of health. Using the SDI, the purpose of the present study is to stratify survival outcomes in pediatric patients with hematologic malignancies based on area deprivation.

METHODS

A retrospective cohort study was performed using the national Surveillance, Epidemiology, and End Results oncology registry in the USA from 1975 to 2016 based on county-level data. Pediatric patients (≤18 y old) with a diagnosis of leukemia or lymphoma based on the International Classification for Oncology, third edition (ICD-O-3) were used for inclusion criteria. Patients were grouped by cancer subtype for leukemia into acute lymphoblastic leukemia (ALL) and acute myeloid leukemia while for lymphoma into non-Hodgkin's lymphoma and Hodgkin's lymphoma. SDI scores were calculated for each patient and divided into quartiles, with Q1 being the lowest area of deprivation and Q4 being the highest, respectively.

RESULTS

A total of 38,318 leukemia and lymphoma patients were included. Quartile data demonstrated stratification in survival based on area deprivation for ALL, with no survival differences in the other cancer subtypes. Patients with ALL from the most deprived area had a roughly 3% difference in both overall and cancer-specific morality at 5 years compared with the least deprived area.

CONCLUSION

Disparities in pediatric patients with ALL represent a significant area for quality improvement. Social programs may have value in improving survival outcomes and could rely on metrics such as SDI.

Leveraging health care technology to improve health outcomes and reduce outcome disparities in AYA leukemia

Significant improvements have occurred for adolescent and young adult (AYA) B-cell acute lymphoblastic leukemia (B-ALL) patients following the widespread adoption of "pediatric-inspired" treatment regimens for AYA patients cared for in adult oncology settings. However, for AYA patients, aged 15 to 39, an outcomes gap remains in B-ALL, necessitating the incorporation of novel therapies into up-front treatment regimens. As a result, clinical trial enrollment remains the current standard of care for AYA B-ALL across disease subtypes when available and accessible. Currently, several up-front trials are looking to incorporate the use of inotuzumab, blinatumomab, and chimeric antigen receptor T-cell therapy into existing chemotherapy backbones for AYA patients, as well as tyrosine kinase inhibitors for both Philadelphia-positive (Ph+) and Ph-like B-ALL. In addition to ongoing attempts to improve up-front treatments by incorporating immunotherapy and targeted approaches, the increased use of next generation sequencing for measurable residual disease evaluation has led to superior risk-stratification and a decreased need to pursue consolidative hematopoietic stem cell transplantation during the first complete remission for many patients.

Innovations in Cancer Treatment of Children

Pediatric cancer outcomes have significantly improved, and yet this success is not spread equally across cancer types or patients. Disparities data in pediatric oncology highlight needed improvements in access to care, including clinical trials and advanced testing for all patients. For cancers such as brain tumors and sarcomas, continued advancement in understanding the biology of tumor heterogeneity is an essential step toward finding new therapeutic combinations to improve outcomes. Pediatric cancer survivors need access to emerging technologies aimed at reducing or better managing toxicities from therapy. With advances in treatment and survival, pediatric oncology patients continue to need longitudinal, multidisciplinary subspecialty care. Refining the communication between pediatric oncologists, primary pediatricians, survivorship clinics, and adult primary care is key in ensuring the best lifelong care of pediatric cancer survivors. In this State-of-The-Art review, we discuss 5 major domains in pediatric oncology: reducing toxicity, cancer biology, novel therapies, detection and monitoring, and access to care, to highlight recent advances and areas for continued improvement.

Retrospective analysis of outcomes for pediatric acute lymphoblastic leukemia in South American centers

Introduction

Acute lymphoblastic Leukemia (ALL) is the most common pediatric malignancy. While the survival rate for childhood ALL exceeds 90% in high-income countries, the estimated survival in low-and middle-income countries ranges from 22-79%, depending on the region and local resources.

Methods

This study retrospectively reviewed demographic, biological, and clinical parameters of children under 18 years of age with newly diagnosed ALL presenting between 2013-2017 across five pediatric centers in 4 countries in South America. Survival analyses were estimated using the Kaplan-Meier method.

Results

Across the five centers, 752 patients were analyzed (Bolivia [N=9], Ecuador [N=221], Paraguay [N=197], Peru [N=325]) and 92.1% (n=690) patients were diagnosed with B-cell and 7.5% (n= 56) with T-cell ALL. The median age was 5.5 years old (IQR 7.29). At diagnosis, 47.8% of patients were categorized as standard and 51.9% as high risk per their institutional regimen. Advanced diagnostics availability varied between modalities. MRD was evaluated in 69.1% of patients; molecular testing was available for ETV6-RUNX, BCR-ABL1, TCF3-PBX1, and KMT2A-rearranged ALL in 75-81% of patients; however, karyotyping and evaluation for iAMP21 were only performed in 42-61% of patients. Central nervous system (CNS) involvement was evaluated at diagnosis in 57.3% (n=429) patients; of these, 93.7% (n=402) were CNS 1, 1.6% (n=7) were CNS 2, 0.7% (n=11) were CNS3, 1.9% (n=8) had cranial nerve palsy, and 2.1% (n=9) results unavailable. Chemotherapy delays >2 weeks were reported in 56.0% (n=421) patients during treatment. Delays were attributed to infection in 63.2% (n=265), drug-related toxicities in 47.3% (n=198), and resource constraints, including lack of bed availability in 23.2% (n=97) of patients. The 3-year Abandonment-sensitive EFS and OS were 61.0±1.9% and 67.2±1.8%, respectively. The 3-year EFS and OS were 71.0±1.8% and 79.6±1.7%, respectively.

Discussion

This work reveals opportunities to improve survival, including addressing severe infections, treatment interruptions, and modifications due to drug shortages. In 2018, healthcare professionals across South America established the Pediatric Oncology Latin America (POLA) group in collaboration with St. Jude Children's Research Hospital. POLA collaborators developed an evidence-based, consensus-derived, adapted treatment guideline, informed by preliminary results of this evaluation, to serve as the new standard of care for pediatric ALL in participating institutions.

Drivers of Differential Time to Diagnosis in Pediatric ALL Tied to Race and Ethnicity

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, with diagnosis preceded by symptoms that may include fever, weight loss, fatigue, bleeding, and bruising. Timely diagnosis and treatment of ALL may lead to improved outcomes and reduced morbidity from associated complications, including tumor lysis syndrome, hyperviscosity, and stroke. We performed a retrospective cohort analysis of 274 pediatric pre-B cell ALL and acute lymphoblastic lymphoma patients within Montefiore Health System to determine whether there were factors associated with time from symptom onset to diagnosis. The median time to diagnosis for all patients was 11.5 days (interquartile range: 7.8, 14.3). Those with Medicaid insurance (n=189) were diagnosed sooner than those with private/self-pay insurance (n=85) (median of 10 vs. 16 days; P =0.05). English and other language speakers experienced fewer median days from symptom onset to diagnosis date compared with Spanish speakers (11 vs. 7 vs. 14; P =0.05). Insurance status may impact the time to diagnosis to a greater degree in non-Hispanic patients, while the English language and female sex may represent a greater advantage to Hispanic patients. Insurance status and language preference may impact the time to diagnosis of pediatric ALL. There is a further need to confirm our findings and to study possible causes driving these disparities.

Involvement of Diverse Populations in Transfusion Medicine Research

Communities of color and diverse communities (eg, race, socioeconomic status, language, sexual orientation etc.) have not been recruited and enrolled equitably to participate in research studies in transfusion medicine. The exclusion of diverse communities in transfusion research can lead to health disparities lack of access to approved therapeutics and unequal allocation of interventions, resulting in missed opportunities to optimize health for individuals and communities. Involvement of diverse populations in research goes beyond inclusion as research subjects. Strategies should include specific studies on health conditions of importance to diverse communities with stable funding sources and specific funding announcements to develop projects led by diverse researchers, mentorship of diverse researchers, and openness to various ways of communicating research plans. Qualitative approaches and interdisciplinary collaboration should be supported to enhance inclusivity.

Children's Oncology Group's 2023 blueprint for research: Diversity and health disparities

The Children's Oncology Group (COG) Diversity and Health Disparities Committee's (DHDC's) mission is to guarantee the highest standard of care for children and adolescents and young adults (AYA) with cancer regardless of ethnic, racial, gender, or socioeconomic background. We strive to identify and address issues of disparity within the existing scientific structure of COG and to support research across COG to improve survival by ensuring equitable access to COG-sponsored clinical trials. We are committed to advance COG-led research identifying mechanistic drivers of disparities and, concurrently, evaluating interventions to alleviate disparities in the COG trial setting. As trials identify the most promising therapies, diverse representation is critical to ensure that findings are relevant to everyone. Factors impacting clinical trial participation among vulnerable populations are complex, consisting of barriers at societal, systems, and individual levels. Recent efforts by investigators within DHDC demonstrated that trial-embedded collection of family-reported sociodemographic data and social determinants of health (SDoH) is feasible and acceptable in the context of COG. Diversity in the pediatric oncology workforce is essential and one potential approach to improving representation on clinical trials. To support and retain diverse oncology providers and researchers, a Minority Young Investigator Award (MYIA) was created to facilitate opportunities for graduating trainees and YIs with an interest in childhood cancer disparities research within COG. Although there are challenges to achieve the DHDC's priorities, only through collaboration and support for this work we will be able to elucidate mechanisms underlying inferior survival outcomes for historically marginalized children and AYA, and more importantly, implement interventional investigation to improve outcomes.

Partnering With Patients and Caregivers in Cancer Care: Lessons From Experiences With Transgender, Hispanic, and Pediatric Populations

A cancer diagnosis thrusts patients and caregivers into a foreign world of health care with systems, protocols, and norms that can leave little room for individual needs and circumstances. Quality and efficacious oncology care requires clinicians to partner with patients and caregivers to understand and incorporate their needs, values, and priorities into information sharing, decision making, and care provision. This partnership is necessary for effective patient- and family-centered care and access to individualized and equitable information, treatment, and research participation. Partnering with patients and families also requires oncology clinicians to see that our personal values, preconceived ideas, and established systems exclude certain populations and potentially lead to poorer care for all patients. Furthermore, inequitable access to participation in research and clinical trials can contribute to an unequal burden of cancer morbidity and mortality. Leveraging the expertise of the authorship team with transgender, Hispanic, and pediatric populations, this chapter provides insights and suggestions for oncology care that are applicable across patient populations to mitigate stigma and discrimination and improve the quality of care for all patients.