Impact of Genetic Ancestry on T-cell Acute Lymphoblastic Leukemia Outcomes.

The influence of genetic ancestry on biology, survival outcomes, and risk stratification in T-cell Acute Lymphoblastic Leukemia (T-ALL) has not been explored. Genetic ancestry was genomically-derived from DNA-based single nucleotide polymorphisms in children and young adults with T-ALL treated on Children's Oncology Group trial AALL0434. We determined associations of genetic ancestry, leukemia genomics and survival outcomes; co-primary outcomes were genomic subtype, pathway alteration, overall survival (OS), and event-free survival (EFS). Among 1309 patients, T-ALL molecular subtypes varied significantly by genetic ancestry, including increased frequency of genomically defined ETP-like, MLLT10, and BCL11B-activated subtypes in patients of African ancestry. In multivariable Cox models adjusting for high-risk subtype and pathways, patients of Admixed American ancestry had superior 5-year EFS/OS compared with European; EFS/OS for patients of African and European ancestry were similar. The prognostic value of five commonly altered T-ALL genes varied by ancestry - including NOTCH1 , which was associated with superior OS for patients of European and Admixed American ancestry but non-prognostic among patients of African ancestry. Furthermore, a published five-gene risk classifier accurately risk stratified patients of European ancestry, but misclassified patients of African ancestry. We developed a penalized Cox model which successfully risk stratified patients across ancestries. Overall, 80% of patients had a genomic alteration in at least one gene with differential prognostic impact by genetic ancestry. T-ALL genomics and prognostic associations of genomic alterations vary by genetic ancestry. These data demonstrate the importance of incorporating genetic ancestry into analyses of tumor biology for risk classification algorithms.

Supplemental Nutrition Assistance Program participation gaps within a pediatric leukemia clinical trial cohort.

Poverty-exposed children with cancer are more likely to experience adverse outcomes. Supplemental Nutrition Assistance Program (SNAP) benefits improve food insecurity and child health outcomes, and could be used to mitigate disparities. We conducted a secondary analysis of parent-reported data collected in a frontline pediatric leukemia trial (NCT03020030) to assess SNAP eligibility (proxied by other means-tested program participation) and participation. At diagnosis, 105/287 families (37%) were SNAP-eligible, of whom 53 (50%) were SNAP participants. At 6 months, 104/257 families (41%) were SNAP-eligible, and 59 (57%) were SNAP participants. Interventions to increase benefits participation during childhood cancer treatment represent an immediate opportunity to reduce disparities.

Healthcare utilization disparities among children with high-risk neuroblastoma treated on Children's Oncology Group clinical trials.

INTRODUCTION: Disparities in relapse and survival from high-risk neuroblastoma (HRNBL) persist among children from historically marginalized groups even in highly standardized clinical trial settings. Research in other cancers has identified differential treatment toxicity as one potential underlying mechanism. Whether racial and ethnic disparities in treatment-associated toxicity exist in HRNBL is poorly understood. METHODS: This is a retrospective study utilizing a previously assembled merged cohort of children with HRNBL on Children's Oncology Group (COG) post-consolidation immunotherapy trials ANBL0032 and ANBL0931 at Pediatric Health Information System (PHIS) centers from 2005 to 2014. Race and ethnicity were categorized to reflect historically marginalized populations as Hispanic, non-Hispanic Black (NHB), non-Hispanic other (NHO), and non-Hispanic White (NHW). Associations between race-ethnicity and intensive care unit (ICU)-level care utilization as a proxy for treatment-associated toxicity were examined with log binomial regression and summarized as risk ratio (RR) and corresponding 95% confidence interval (CI). RESULTS: The analytic cohort included 370 children. Overall, 88 (23.8%) patients required ICU-level care for a median of 3.0 days (interquartile range [IQR]: 1.0-6.5 days). Hispanic children had nearly three times the risk of ICU-level care (RR 3.1, 95% CI: 2.1-4.5; fully adjusted RR [aRR] 2.5, 95% CI: 1.6-3.7) compared to NHW children and the highest percentage of children requiring cardiovascular-driven ICU-level care. CONCLUSION: Children of Hispanic ethnicity with HRNBL receiving clinical trial-delivered therapy were more likely to experience ICU-level care compared to NHW children. These data suggest that further investigation of treatment-related toxicity as a modifiable mechanism underlying outcome disparities is warranted.

Household material hardship and distress among parents of children with advanced cancer: A report from the PediQUEST Response trial.

BACKGROUND: The prevalence and characteristics of household material hardship (HMH) in families of children with advanced cancer and its association with parent distress are unknown and herein described. METHODS: Parents of children aged ≥2 years with advanced cancer at five cancer centers completed baseline surveys as part of the PediQUEST Response trial. HMH (housing, energy, and food) was operationalized as binary (≥1 HMH domains), ordinal (zero, one, or two or more HMH domains), and housing based (none, nonhousing [food and/or energy], only housing, or housing + other). Associations between HMH and parent distress measured by the State-Trait Anxiety Inventory-State and the 10-item Center for Epidemiologic Studies Depression Scale were estimated via linear models adjusting for confounders. RESULTS: Among 150 parents, 41% reported ≥1 HMH (housing, 28% [only housing, 8%; housing + other, 20%]; energy, 19%; food, 27%). HMH was more prevalent among Hispanic, other non-White race, Spanish-speaking, and single parents and those with lower education (associate degree or less) or who were uninsured/Medicaid-only insured. Parents endorsing HMH reported higher anxiety (mean difference [MD], 9.2 [95% CI, 3.7-14.7]) and depression (MD, 4.1 [95% CI, 1.7-6.5]) scores compared to those without HMH. Distress increased with the number of hardships, particularly housing insecurity. Specifically, parents experiencing housing hardship, alone or combined, reported higher distress (housing only: anxiety: MD, 10.2 [95% CI, 1.8-18.5]; depression: MD, 4.9 [95% CI, 1.3-8.6]; housing + other HMH: anxiety: MD, 12.0 [95% CI, 5.2-18.9]; depression: MD, 4.8 [95% CI, 1.8-7.8]). CONCLUSIONS: HMH is highly prevalent in pediatric advanced cancer, especially among historically marginalized families. Future research should investigate whether interventions targeting HMH, particularly housing stabilization efforts, can mitigate parent distress. PLAIN LANGUAGE SUMMARY: In our cohort of parents of children with advanced cancer, household material hardship (HMH) was highly prevalent and significantly associated with higher parent distress. Housing hardship was the primary driver of this association. Families of children with advanced cancer may benefit from systematic HMH screening as well as targeted HMH interventions, especially stabilizing housing.

Roadmap for the next generation of Children's Oncology Group rhabdomyosarcoma trials.

Clinical trials conducted by the Intergroup Rhabdomyosarcoma (RMS) Study Group and the Children's Oncology Group have been pivotal to establishing current standards for diagnosis and therapy for RMS. Recent advancements in understanding the biology and clinical behavior of RMS have led to more nuanced approaches to diagnosis, risk stratification, and treatment. The complexities introduced by these advancements, coupled with the rarity of RMS, pose challenges to conducting large-scale phase 3 clinical trials to evaluate new treatment strategies for RMS. Given these challenges, systematic planning of future clinical trials in RMS is paramount to address pertinent questions regarding the therapeutic efficacy of drugs, biomarkers of response, treatment-related toxicity, and patient quality of life. Herein, the authors outline the proposed strategic approach of the Children's Oncology Group Soft Tissue Sarcoma Committee to the next generation of RMS clinical trials, focusing on five themes: improved novel agent identification and preclinical to clinical translation, more efficient trial development and implementation, expanded opportunities for knowledge generation during trials, therapeutic toxicity reduction and quality of life, and patient engagement.

Poverty, race, ethnicity, and survival in pediatric nonmetastatic osteosarcoma: a Children's Oncology Group report.

BACKGROUND: Children living in poverty and those of marginalized race or ethnicity experience inferior disease outcomes across many cancers. Whether survival disparities exist in osteosarcoma is poorly defined. We investigated the association between race, ethnicity, and proxied poverty exposures and event-free and overall survival for children with nonmetastatic osteosarcoma receiving care on a cooperative group trial. METHODS: We conducted a retrospective cohort study of US patients with nonmetastatic, osteosarcoma aged 5-21 years enrolled on the Children's Oncology Group trial AOST0331. Race and ethnicity were categorized to reflect historically marginalized populations, as Hispanic, non-Hispanic Black, non-Hispanic Other, and non-Hispanic White. Poverty was proxied at the household and neighborhood levels. Overall survival and event-free survival functions of time from trial enrollment were estimated using the Kaplan-Meier method. Hypotheses of associations between risks for event-free survival, death, and postrelapse death with race and ethnicity were assessed using log-rank tests. RESULTS: Among 758 patients, 25.6% were household-poverty and 28.5% neighborhood-poverty exposed. Of the patients, 21% of children identified as Hispanic, 15.4% non-Hispanic Black, 5.3% non-Hispanic Other, and 54.0% non-Hispanic White. Neither household or neighborhood poverty nor race and ethnicity were statistically significantly associated with risks for event-free survival or death. Postrelapse risk for death differed statistically significantly across race and ethnicity with non-Hispanic Black patients at greatest risk (4-year postrelapse survival 35.7% Hispanic vs 13.0% non-Hispanic Black vs 43.8% non-Hispanic Other vs 38.9% non-Hispanic White; P = .0046). CONCLUSIONS: Neither proxied poverty exposures or race and ethnicity were associated with event-free survival or overall survival, suggesting equitable outcomes following frontline osteosarcoma trial-delivered therapy. Non-Hispanic Black children experienced statistically significant inferior postrelapse survival. Investigation of mechanisms underlying postrelapse disparities are paramount.

Enrollment on upfront high-risk neuroblastoma trials by race, ethnicity, and poverty status: A report from the Children's Oncology Group.

It is not clear whether trial access disparities exist in the Children's Oncology Group (COG). Here, we leverage a cohort of children with high-risk neuroblastoma (HR-NBL) enrolled on the COG ANBL00B1 neuroblastoma biology study to examine subsequent enrollment to upfront COG therapeutic trials by race, ethnicity, and proxied poverty status. Among 1917 children with HR-NBL enrolled on ANBL00B1, 696 (36.3%) subsequently enrolled on an upfront therapeutic trial with no difference by race, ethnicity, or proxied poverty status. In neuroblastoma, trial access disparities are not comparable to adult oncology, and efforts to advance equity should prioritize other mechanisms of survival disparities.

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.

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.

Social Determinants of Health and Cancer Care: An ASCO Policy Statement.

ASCO's new policy statement on SDOH supports practices that sustain and advance cancer health equity.

Prescription for Cash? Cash Support to Low-Income Families in Maternal and Pediatric Health Care Settings.

Policy Points Pregnancy and childhood are periods of heightened economic vulnerability, but current policies for addressing health-related social needs, including screening and referral programs, may be insufficient because of persistent gaps, incomplete follow-up, administrative burden, and limited take-up. To bridge gaps in the social safety net, direct provision of cash transfers to low-income families experiencing health challenges during pregnancy, infancy, and early childhood could provide families with the flexibility and support to enable caregiving, increase access to health care, and improve health outcomes.

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.

Gaps in Parental Understanding of Sleep Disturbances During Maintenance Therapy for Pediatric Acute Lymphoblastic Leukemia.

Background: Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood, with survival rates approaching 90%. Sleep disturbance is common among ALL patients, often developing during the initial stages of chemotherapy treatment. While there have been significant efforts to understand and intervene in this issue during survivorship, there is far less research on children who are actively receiving treatment. In the current study, we sought to better understand the parent's experience in the sleep domain during maintenance therapy, including their perceptions of how their child's medical team had managed sleep disturbances, and recommendations for how to improve sleep management. Method: Fifteen parents of pediatric ALL patients (aged 4-12 years) completed semistructured interviews. Interview content was analyzed using a multistage thematic analysis. Results: Parents consistently expressed feeling unprepared to manage the sleep disruptions that arose during treatment, often reporting that they did not recall being told this would be a side effect. They were enthusiastic about learning how to improve their child's sleep, though they did not want pharmacotherapeutic interventions or additional medical/psychosocial appointments to address this. Conclusion: Despite consistent provider communication on sleep, parents report limited knowledge of the issue. This provides an obvious intervention target to improve treatment-related sleep disturbances. Clear messaging may help direct parents' attention and expectations regarding their child's treatment and potential for disturbed sleep, possibly in the form of a behavioral intervention that empowers parents with information about how to support their child's sleep health while they are undergoing treatment for ALL.

Disparities in parental distress in a multicenter clinical trial for pediatric acute lymphoblastic leukemia.

BACKGROUND: Parent psychological distress during childhood cancer treatment has short- and long-term implications for parent, child, and family well-being. Identifying targetable predictors of parental distress is essential to inform interventions. We investigated the association between household material hardship (HMH), a modifiable poverty-exposure defined as housing, food, or utility insecurity, and severe psychological distress among parents of children aged 1-17 years with acute lymphoblastic leukemia (ALL) enrolled on the multicenter Dana-Farber ALL Consortium Trial 16-001. METHODS: This was a secondary analysis of parent-reported data. Parents completed an HMH survey within 32 days of clinical trial enrollment (T0) and again at 6 months into therapy (T1). The primary exposure was HMH at T0 and primary outcome was severe parental distress at T0 and T1, defined as a score greater than or equal to 13 on the Kessler-6 Psychological Distress Scale. Multivariable models were adjusted for ALL risk group and single parent status. RESULTS: Among 375 evaluable parents, one-third (32%; n = 120/375) reported HMH at T0. In multivariable analyses, T0 HMH was associated with over twice the odds of severe psychological distress at T0 and T1 HMH was associated with over 5 times the odds of severe distress at T1. CONCLUSIONS: Despite uniform clinical trial treatment of their children at well-resourced pediatric centers, HMH-exposed parents-compared with unexposed parents-experienced statistically significantly increased odds of severe psychological distress at the time of their child's leukemia diagnosis, which worsened 6 months into therapy. These data identify a high-risk parental population who may benefit from early psychosocial and HMH-targeted interventions to mitigate disparities in well-being.

"It's a lot of things": Household material hardship among Black and Hispanic parents of children with cancer.

Household material hardship (HMH)-housing, food, transportation, or utility insecurity-is an adverse social determinant of health that is modifiable in the clinical setting. This mixed-methods, single-center study explored the experiences of HMH among Black and Hispanic pediatric oncology parents utilizing a single timepoint survey (N = 60) and semi-structured interviews (N = 20 purposively sampled subcohort). Forty-four (73%) parents reported HMH. Qualitatively, participants expressed stress, anxiety, and embarrassment due to unmet basic resource needs, and childcare emerged as an additional important domain of HMH. Participants recommend a standardized approach to HMH screening and resource allocation, offering insight into targets for future intervention.

Association of unmet basic resource needs with frailty and quality of life among older adults with cancer-Results from the CARE registry.

BACKGROUND: Basic resource needs related to transportation, housing, food, and medications are important social determinants of health and modifiable indicators of poverty, but their role in modifying the risk of frailty and health-related quality of life (HRQoL) remains unknown. The goal of our study was to examine the prevalence of unmet basic needs and their association with frailty and HRQoL in a cohort of older adults with cancer. METHODS: The CARE registry prospectively enrolls older adults (≥60 years) with cancer. Assessments of transportation, housing, and material hardship were added to the CARE tool in 8/2020. The 44-item CARE Frailty Index was used to define frailty, and subdomains of physical and mental HRQoL were assessed using the PROMIS® 10-global. Multivariable analysis examined the association between unmet needs with frailty and HRQoL subdomains, adjusting for covariates. RESULTS: The cohort included 494 participants. Median age of 69 years, 63.6% were male and 20.2% were Non-Hispanic (NH) Black. Unmet basic needs were reported in 17.8% (transportation 11.5%, housing 2.8%, and material hardship 7.5%). Those with unmet needs were more often NH Black (33.0% vs. 17.8%, p = 0.006) and less educated (

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

BACKGROUND: Previous studies have identified racial and ethnic disparities in childhood acute lymphocytic leukaemia survival. We aimed to establish whether disparities persist in contemporaneous cohorts and, if present, are attributable to differences in leukaemia biology or insurance status. METHODS: Patients with newly diagnosed acute lymphocytic leukaemia in inpatient and outpatient centres in the USA, Canada, Australia, and New Zealand, aged 0-30 years, who had race or ethnicity data available, enrolled on eight completed Children's Oncology Group trials (NCT00103285, NCT00075725, NCT00408005, NCT01190930, NCT02883049, NCT02112916, NCT02828358, and NCT00557193) were included in this secondary analysis. Race and ethnicity were categorised as non-Hispanic White, Hispanic, non-Hispanic Black, non-Hispanic Asian, and non-Hispanic other. Event-free survival and overall survival were compared across race and ethnicity groups. The relative contribution of clinical and biological disease prognosticators and insurance status was examined through multivariable regression models, both among the entire cohort and among those with B-cell lineage versus T-cell lineage disease. FINDINGS: Between Jan 1, 2004, and Dec 31, 2019, 24 979 eligible children, adolescents, and young adults with acute lymphocytic leukaemia were enrolled, of which 21 152 had race or ethnicity data available. 11 849 (56·0%) were male and 9303 (44·0%) were female. Non-Hispanic White patients comprised the largest racial or ethnic group (13 872 [65·6%]), followed by Hispanic patients (4354 [20·6%]), non-Hispanic Black patients (1517 [7·2%]), non-Hispanic Asian (n=1071 [5·1%]), and non-Hispanic other (n=338 [1·6%]). 5-year event-free survival was 87·4% (95% CI 86·7-88·0%) among non-Hispanic White patients compared with 82·8% (81·4-84·1%; hazard ratio [HR] 1·37, 95% CI 1·26-1·49; p<0·0001) among Hispanic patients and 81·8% (79·3-84·0; HR 1·45, 1·28-1·65; p<0·0001) among non-Hispanic Black patients. Non-hispanic Asian patients had a 5-year event-free survival of 88·1% (95% CI 85·5-90·3%) and non-Hispanic other patients had a survival of 82·8% (76·4-87·6%). Inferior event-free survival among Hispanic patients was substantially attenuated by disease prognosticators and insurance status (HR decreased from 1·37 [1·26-1·49; p<0·0001] to 1·11 [1·00-1·22; p=0·045]). The increased risk among non-Hispanic Black patients was minimally attenuated (HR 1·45 [1·28-1·65; p<0·0001] to 1·32 [1·14-1·52; p<0·0001]). 5-year overall survival was 93·6% (91·5-95·1%) in non-Hispanic Asian patients, 93·3% (92·8-93·7%) in non-Hispanic White patients, 89·9% (88·7-90·9%) in Hispanic, 89·7% (87·6-91·4%) in non-Hispanic Black patients, 88·9% (83·2-92·7%) in non-Hispanic other patients. Disparities in overall survival were wider than event-free survival (eg, among non-Hispanic other patients, the HR for event-free survival was 1·43 [1·10-1·85] compared with 1·74 [1·27-2·40] for overall survival). Disparities were restricted to patients with B-cell acute lymphocytic leukaemia, no differences in event-free survival or overall survival were seen in the T-cell acute lymphocytic leukaemia group. INTERPRETATION: Substantial disparities in outcome for B-cell acute lymphocytic leukaemia persist by race and ethnicity, but are not observed in T-cell acute lymphocytic leukaemia. Future studies of relapsed patients, access to and quality of care, and other potential aspects of structural racism are warranted to inform interventions aimed at dismantling racial and ethnic disparities. FUNDING: National Cancer Institute and St Baldrick's Foundation.

Secondary Neoplasms After Hematopoietic Cell Transplant for Sickle Cell Disease.

PURPOSE: To report the incidence and risk factors for secondary neoplasm after transplantation for sickle cell disease. METHODS: Included are 1,096 transplants for sickle cell disease between 1991 and 2016. There were 22 secondary neoplasms. Types included leukemia/myelodysplastic syndrome (MDS; n = 15) and solid tumor (n = 7). Fine-Gray regression models examined for risk factors for leukemia/MDS and any secondary neoplasm. RESULTS: The 10-year incidence of leukemia/MDS was 1.7% (95% CI, 0.90 to 2.9) and of any secondary neoplasm was 2.4% (95% CI, 1.4 to 3.8). After adjusting for other risk factors, risks for leukemia/MDS (hazard ratio, 22.69; 95% CI, 4.34 to 118.66; P = .0002) or any secondary neoplasm (hazard ratio, 7.78; 95% CI, 2.20 to 27.53; P = .0015) were higher with low-intensity (nonmyeloablative) regimens compared with more intense regimens. All low-intensity regimens included total-body irradiation (TBI 300 or 400 cGy with alemtuzumab, TBI 300 or 400 cGy with cyclophosphamide, TBI 200, 300, or 400 cGy with cyclophosphamide and fludarabine, or TBI 200 cGy with fludarabine). None of the patients receiving myeloablative and only 23% of those receiving reduced-intensity regimens received TBI. CONCLUSION: Low-intensity regimens rely on tolerance induction and establishment of mixed-donor chimerism. Persistence of host cells exposed to low-dose radiation triggering myeloid malignancy is one plausible etiology. Pre-existing myeloid mutations and prior inflammation may also contribute but could not be studied using our data source. Choosing conditioning regimens likely to result in full-donor chimerism may in part mitigate the higher risk for leukemia/MDS.