Comparison of total body irradiation versus non-total body irradiation containing regimens for de novo acute myeloid leukemia in children

Umbilical Cord Blood Reduced Relapse but Increased Nonrelapse Mortality Compared to Matched Unrelated Donor Transplantation in Pediatric Acute Myeloid Leukemia With Active Disease: A CIBMTR 2008 to 2017 Analysis of Donor Source and Residual Disease

Umbilical cord blood (UCB) and matched unrelated donors (MUD) are common alternative donor options in children with high-risk acute myeloid leukemia (AML). Emerging evidence suggests an augmented graft-versus-leukemia (GVL) effect of UCB, but uncertainties persist due to the heterogeneity of the hematopoietic cell transplantation (HCT) characteristics in the previous studies. We reviewed 1148 patients aged ≤18 years with AML, who underwent the first HCT between 2008 to 2017, using a publicly available dataset from the Center for International Blood and Marrow Transplantation Research (CIBMTR) registry data. Multivariable analyses evaluated predictors of DFS and other clinical outcomes, factoring in graft source, conditioning regimen, patient age, cytogenetic risk, and HCT year (significance at P < .01). Residual disease status was assessed both as a covariate and as a stratifying factor. Additionally, the differential effects of conditioning regimens were analyzed specifically within the UCB cohort. UCB was used most frequently (33.8%) followed by MUD (29.1%), both of which had comparable DFS and overall survival. In patients with minimal residual disease or not in remission prior to HCT, human-leukocyte antigen (HLA) ≤5/8 matched UCB was associated with lower relapse rates than MUD (hazard risk [HR]: 0.25 and 0.29, P = .005 and .006, respectively) but with increased nonrelapse mortality (HR: 32.8 and 7.5, P = .001 and .012, respectively). Conditioning regimens varies by graft type; total body irradiation (TBI)-based regimens, primarily combined with cyclophosphamide and fludarabine, were more common in the UCB cohort (45% in UCB versus 19% in the other grafts, P < .001). Within the 388 patients received UCB, multivariable analysis demonstrated comparable DFS and OS across variable busulfan- and TBI-based regimens, with no trend of superiority for either approach. In conclusion, highly HLA-mismatched UCB reduced relapse in pediatric AML with higher disease burden but increased nonrelapse mortality, resulting in similar DFS to MUD. Improved supportive care and toxicity mitigation may improve the outcomes of UCB transplant. Overall, UCB should be considered a viable alternative graft source with equally favorable outcomes to MUD. Further research is warranted to refine conditioning regimen, including TBI- and busulfan-based strategies, mitigate toxicity, and improve supportive care to optimize UCB HCT outcomes.

The Role of Radiotherapy in Hematologic Malignancies in Children, Adolescents, and Young Adults

Hematologic cancers in pediatric, adolescent, and young adult populations include a diverse spectrum of malignancies. The cornerstone of treatment is multiagent chemotherapy. While radiation therapy (RT) is highly effective and played a pivotal role historically, its use has evolved. In classic HL, advancements in systemic therapy have allowed for reduced RT volumes and doses and careful patient selection. Similarly, NLPHL management has shifted toward observation after complete resection, or limited chemotherapy after incomplete resection with RT used only for partially responding disease sites. In primary mediastinal B-cell lymphoma, the role of RT is an area of active study, and treatment with chemotherapy alone has shown promise in adults. Frontline treatment of diffuse large B-cell lymphoma and Burkitt lymphoma relies on chemotherapy; evidence do not support a role for consolidative RT. In leukemia, the use of prophylactic cranial and testicular RT is declining in the setting of modern chemotherapy regimens. RT may play an important role in the salvage of relapsed/refractory lymphomas and leukemias. In addition, palliative RT is often integral to symptom relief and function preservation. Future research aims to refine risk stratification, personalize treatment approaches, and incorporate novel therapies to maintain or improve oncologic outcomes while mitigating late effects.

Long-Term Outcomes of Reduced-Toxicity Conditioning Using 8-Gray Total Body Irradiation, Fludarabine, and Cyclophosphamide in Children, Adolescents, and Young Adults With Hematological Malignancies

Recent studies have indicated that total body irradiation (TBI)-based reduced-toxicity conditioning (RTC) may be a potential treatment modality, especially in adults with leukemia. However, its efficacy and safety in children with hematological malignancies remain unclear. To investigate the long-term outcomes and safety of allogeneic hematopoietic stem cell transplantation (allo-HSCT) using an 8-Gray (Gy) TBI/fludarabine (FLU)/cyclophosphamide (CY) RTC in children with hematological malignancies. We included 66 consecutive patients with leukemia, lymphoma, or myelodysplastic syndrome in this retrospective cohort study. Participants were < 25 years old and received an 8-Gy TBI/FLU/CY RTC regimen followed by the first allo-HSCT at Shinshu University Hospital between March 2004 and March 2021. The 5-year overall and relapse-free survival probabilities were 88.2% and 76.5%, respectively, in the lymphoid malignancy group. The myeloid malignancy group had probabilities of 72.4% and 58.6%, respectively. The 5-year cumulative incidences of relapse and non-relapse mortality were 20.6% and 2.9%, respectively, in the lymphoid malignancy group. These incidences were 37.9% and 3.4%, respectively, in the myeloid malignancy group. All patients had engraftment without early relapse and none developed grade 5 regimen-related toxicity within 28 days after allo-HSCT. Nonetheless, two patients had congenital abnormalities caused by chromosomal aberrations and died without relapse. 8-Gy TBI/FLU/CY RTC was safe in children with hematological malignancies, regardless of the donor source. However, safety concerns were noted in cases of chromosomal aberration-induced congenital abnormalities. Additionally, patients in the lymphoid and myeloid malignancy groups had favorable prognoses.

Haploidentical versus Cord Blood Transplantation in Pediatric AML. A Retrospective Outcome Analysis on Behalf of the Pediatric Subcommittee of GETH (Grupo Español de Trasplante Hematopoyético)

Haploidentical stem cell transplantation (Haplo-SCT) and cord blood transplantation (CBT) are both effective alternative treatments in patients suffering from acute myeloid leukemia (AML) and lacking a matched HLA donor. In the last years, many centers have abandoned CBT procedures mostly due to concern about poorer immune recovery compared with Haplo-SCT. We conducted a retrospective multicenter study comparing the outcomes using both alternative approaches in AML. A total of 122 transplants (86 Haplo-SCTs and 36 CBTs) from 12 Spanish centers were collected from 2007 to 2021. Median age at hematopoietic stem cell transplantation (HSCT) was 7 years (0.4-20). Thirty-nine patients (31.9%) showed positive minimal residual disease (MRD) at HSCT and a previous HSCT was performed in 37 patients (30.3%). The median infused cellularity was 14.4 × 106/kg CD34+ cells (6.0-22.07) for Haplo-SCT and 4.74 × 105/kg CD34+ cells (0.8-9.4) for CBT. Median time to neutrophil engraftment was 14 days (7-44) for Haplo-SCT and 17 days (8-29) for CBT (P = .03). The median time to platelet engraftment was 14 days (6-70) for Haplo-SCT and 43 days (10-151) for CBT (P < .001). Graft rejection was observed in 13 Haplo-SCTs (15%) and in 6 CBTs (16%). The cumulative incidence of acute graft versus host disease (GvHD) grades II-IV was 54% and 51% for Haplo-SCT and CBT, respectively (P = .50). The cumulative incidence of severe acute GvHD (grades III-IV) was 22% for Haplo-SCT and 25% for CBT (P = .90). There was a tendency to a higher risk of chronic GvHD in the Haplo-SCT group being the cumulative incidence of 30% for Haplo-SCT and 12% for CBT (P = .09). The cumulative incidence of relapse was 28% and 20% for Haplo-SCT and CBT, respectively (P = .60). We did not observe statistically significant differences in outcome measures between Haplo-SCT and CBT procedures: 5-year overall survival (OS) was 64% versus 57% (P = .50), 5-year disease-free survival (DFS) 58% versus 57% (P = .80), GvHD-free and relapse-free survival (GFRFS) 41% versus 54% (P = .30), and cumulative incidence of transplant-related mortality (TRM) 14% versus 15% (P = .80), respectively. In the multivariate analysis, MRD positivity and a disease status >CR1 at the time of HSCT were significantly associated with poorer outcomes (P < .05). In conclusion, our study supports that both haploidentical and cord blood transplantation show comparable outcomes in pediatric AML patients. We obtained comparable survival rates, although CBT showed a trend to lower rates of chronic GvHD and higher GFRFS, demonstrating that it should still be considered a valuable option, particularly for pediatric patients.

Unsupervised Clustering Analysis of Regimen and HLA Characteristics in Pediatric Umbilical Cord Blood Transplantation

HLA matching is a critical factor in allogeneic unrelated hematopoietic cell transplantation (HCT) because of its impact on post-transplantation survival and quality of life. Umbilical cord blood transplantation (UCBT) offers unique advantages, but determining the optimal approach to graft selection and immunosuppression remains challenging. Unsupervised clustering, a machine learning technique, has potential for analyzing transplantation outcomes, but its application in investigating leukemia outcomes has been limited. This study aimed to identify optimal combinations of HLA/ killer immunoglobulin receptor (KIR) donor-patient pairing, conditioning, and immunosuppressive regimens in pediatric patients with acute lymphoblastic leukemia (ALL) or acute myeloblastic leukemia (AML) undergoing UCBT. Outcome data for single, unmanipulated UCBT in pediatric AML (n = 708) and ALL (n = 1034) patients from the Eurocord/EBMT registry were analyzed using unsupervised clustering. Resulting clusters were used to inform post hoc competing risks and Kaplan-Meier analyses. In AML, single HLA-C mismatches with other loci fully matched (7/8) were associated with poorer relapse-free survival (RFS) (P = .039), but a second mismatch at any other locus counteracted this effect. In ALL, total body irradiation (TBI) effectively prevented relapse mortality (P = .007). KIR/HLA-C match status affected RFS in AML (P = .039) but not in ALL (P = .8). Administration of antithymocyte globulin (ATG) substantially increased relapse, with no relapses occurring in the 85 patients who did not receive ATG. Our unsupervised clustering analyses generate several key statistical and mechanistic hypotheses regarding the relationships between HLA matching, conditioning regimens, immunosuppressive therapies, and transplantation outcomes in pediatric AML and ALL patients. HLA-C and KIR combinations significantly impact RFS in pediatric AML but not in ALL. ATG use in fully matched pediatric patients is associated with late-stage relapse. TBI regimens appear to be beneficial in ALL, with efficacy largely independent of histocompatibility variables. These findings reflect the distinct genetic and biological profiles of AML and ALL.

Effects of Total Body Irradiation on Hematopoietic Cell Transplantation Outcomes in Pediatric Acute Myeloid Leukemia with Prior Central Nervous System Involvement

The implications of previous central nervous system (CNS) involvement in children with acute myeloid leukemia (AML) undergoing hematopoietic cell transplantation (HCT) remain inadequately understood. Patients with CNS disease require more upfront CNS-directed intrathecal therapy, but little is known about whether transplant conditioning regimens should be intensified or if previous CNS involvement impacts post-HCT outcomes. While total body irradiation (TBI) remains standard for pediatric acute lymphoblastic leukemia myeloablative conditioning, it has been largely replaced with chemotherapy-only myeloablation in pediatric AML, primarily due to toxicity and late effects associated with TBI. In the setting of previous CNS involvement, it has been suggested that TBI-based myeloablation may have advantages due to superior CNS tissue penetration and thus decreased rates of AML relapse post-HCT. We analyzed a publicly available dataset derived from the Center for International Blood and Marrow Transplantation Research (CIBMTR) registry to characterize the impact of TBI in HCT preparative regimens in pediatric AML patients with a history of CNS involvement. The study dataset was obtained from the CIBMTR data repository. The study cohort included patients aged ≤21 years who underwent initial allogeneic HCT with myeloablative conditioning for de novo AML in the first or second complete remission (CR) between 2008 and 2016, who provided consent for research. Patients with mismatched related donor transplants and noncalcineurin inhibitor graft-versus-host disease (GVHD) prophylaxis were excluded. The dataset was further modified by excluding patients with missing disease site data or those with non-CNS extramedullary disease. Patients were categorized as CNS-positive or -negative AML (AML-CNS(+) and AML-CNS(-), respectively) based on the disease status at diagnosis. The Cox regression model and Fine-Grey methods were employed to delineate the effects of TBI and CNS disease on key HCT outcomes. The study cohort comprised 550 pediatric AML patients, of which 25% (n = 136) were AML-CNS(+). CNS involvement was more prevalent in patients aged 0 to 3 years, patients who were in the second CR, and those with a mismatched unrelated donor or umbilical cord blood. AML-CNS(+) patients demonstrated a lower relapse rate (hazard ratio: 0.50, 95% confidence interval: 0.33 to 0.76) compared to AML-CNS(-) patients, with comparable disease-free survival (DFS) and overall survival (OS) (P = .10 and 0.20, respectively) in the two cohorts. The entire TBI-treated cohort showed an association with increased risks of grade 2 to 4 acute GVHD, bloodstream infections, and endocrine dysfunction. TBI use within the AML-CNS(+) cohort was associated with a lower relapse rate but increased risks of nonrelapse mortality and a trend of higher grade 3 to 4 acute GVHD. In this population-based analysis of pediatric patients with de novo AML undergoing HCT, TBI-based conditioning regimens did not confer an advantage in DFS or OS compared to non-TBI regimens, irrespective of CNS disease status. However, TBI use was associated with increased risks of short- and long-term comorbidities. These findings underscore the need for careful consideration of TBI in pediatric AML.

Navigating Treatment Options and Communication in Relapsed Pediatric AML

Despite improved outcomes in newly diagnosed pediatric AML, relapsed disease remains a therapeutic challenge. Factors contributing to slow progress in improving outcomes include inherent challenges in pediatric clinical trial accrual and the scarcity of novel targeted/immunotherapy agents available for pediatric development. This paradigm is changing, however, as international collaboration grows in parallel with the development of promising targeted agents. In this review, we discuss the therapeutic landscape of relapsed pediatric AML, including conventional chemotherapy, targeted therapies, and the challenges of drug approvals in this patient population. We highlight current efforts to improve communication among academia, industry, and regulatory authorities and discuss the importance of international collaboration to improve access to new therapies. Among the therapeutic options, we highlight the approach to second hematopoietic stem cell transplant (HSCT) and discuss which patients are most likely to benefit from this potentially curative intervention. Importantly, we acknowledge the challenges in providing these high-risk interventions to our patients and their families and the importance of shared communication and decision making when considering early-phase clinical trials and second HSCT.

Increased donor inhibitory KIR are associated with reduced GVHD and improved survival following HLA-matched unrelated donor HCT in paediatric acute leukaemia

Killer immunoglobulin-like receptor (KIR) and KIR-ligand (KIRL) interactions play an important role in natural killer cell-mediated effects after haematopoietic stem cell transplantation (HCT). Previous work has shown that accounting for known KIR-KIRL interactions may identify donors with optimal NK cell-mediated alloreactivity in the adult transplant setting. Paediatric acute leukaemia patients were retrospectively analysed, and KIR-KIRL combinations and maximal inhibitory KIR ligand (IM-KIR) scores were determined. Clinical outcomes were examined using a series of graphs depicting clinical events and endpoints. The graph methodology demonstrated that prognostic variables significant in the occurrence of specific clinical endpoints remained significant for relevant downstream events. KIR-KIRL combinations were significantly predictive for reduced grade 3-4 aGVHD likelihood, in patients transplanted with increased inhibitory KIR gene content and IM-KIR = 5 scores. Improvements were also observed in associated outcomes for both ALL and AML patients, including relapse-free survival, GRFS and overall survival. This study demonstrates that NK cell KIR HLA interactions may be relevant to the paediatric acute leukaemia transplant setting. Reduction in aGVHD suggests KIR effects may extend beyond NK cells. Moving forward clinical trials utilizing donors with a higher iKIR should be considered for URD HCT in paediatric recipients with acute leukaemia to optimize clinical outcomes.

Maintain Efficacy and Spare Toxicity: Traditional and New Radiation-Based Conditioning Regimens in Hematopoietic Stem Cell Transplantation

Novelty in total body irradiation (TBI) as part of pre-transplant conditioning regimens lacked until recently, despite the developments in the field of allogeneic stem cell transplants. Long-term toxicities have been one of the major concerns associated with TBI in this setting, although the impact of TBI is not so easy to discriminate from that of chemotherapy, especially in the adult population. More recently, lower-intensity TBI and different approaches to irradiation (namely, total marrow irradiation, TMI, and total marrow and lymphoid irradiation, TMLI) were implemented to keep the benefits of irradiation and limit potential harm. TMI/TMLI is an alternative to TBI that delivers more selective irradiation, with healthy tissues being better spared and the control of the radiation dose delivery. In this review, we discussed the potential radiation-associated long-term toxicities and their management, summarized the evidence regarding the current indications of traditional TBI, and focused on the technological advances in radiotherapy that have resulted in the development of TMLI. Finally, considering the most recent published trials, we postulate how the role of radiotherapy in the setting of allografting might change in the future.

Metabolic/endocrine disorders in survivors of childhood-onset and cranial radiotherapy- treated ALL/NHL: a meta-analysis

BACKGROUND

Cranial radiotherapy (CRT) is recommended to high-risk pediatric patients with acute lymphoblastic leukemia or aggressive non-Hodgkin's lymphoma (ALL/NHL). However, effects of CRT treatment on the development of metabolic/endocrine disorders remain unclear. This meta-analysis aimed to identify metabolic and endocrine disturbances in survivors of childhood-onset and CRT-treated ALL/NHL.

METHODS

Different online databases were searched using restricted search fields. Follow-up data and outcome measurements, including the prevalence of growth hormone (GH) deficiency, hypothyroidism, vitamin D deficiency, overweight/obesity, and hypogonadism were recorded. The height data was indicated by height-standard deviation score (height-SDS). Statistical estimates such as odds ratio (OR) and weighted standard mean difference (SMD) were compared between additional CRT treatment group and non-CRT treatment group. Study-to-study heterogeneity was calculated by calculating I-squared statistic, and fixed/random effect was applied to synthesize and analyze extracted data.

RESULTS

Fifteen studies were included (4269 patients in total). Adult height SDS was lower in CRT-treated patients (pooled SMD = -0.581, 95% CI: -0.649--0.512), and CRT-treated patients were likely to develop short stature (pooled OR = 2.289, 95% CI:1.674-3.130). Regardless of the study year, which potentially reflects the state-of-the-art CRT technique, the prevalence of short stature and GH deficiency was time-independent. Additionally, previous CRT can increase the risk of precocious puberty (pooled OR = 2.937, 95% CI: 1.281-6.736), hypothyroidism (pooled OR = 2.057, 95% CI:1.510-2.801), and hypogonadism (pooled OR = 3.098, 95% CI:2.521-3.807). However, the risk of being overweight/obese was similar between the patients with and without CRT (pooled OR = 1.278, 95% CI: 0.675-2.421).

CONCLUSION

Childhood-onset and CRT-treated ALL/NHL survivors are likely to have shorter height, precocious puberty, hypothyroidism, and hypogonadism.

Myeloid sarcoma: more and less than a distinct entity

Myeloid sarcoma (MS) is a distinct entity among myeloid neoplasms defined as a tumour mass of myeloid blasts occurring at an anatomical site other than the bone marrow, in most cases concomitant with acute myeloid leukaemia (AML), rarely without bone marrow involvement. MS may also represent the blast phase of chronic myeloproliferative neoplasms (MPN) and myelodysplastic syndromes (MDS). However, the clinical and molecular heterogeneity of AML, as highlighted by the 2022 World Health Organization (WHO) and International Consensus (ICC) classifications, indirectly define MS more as a set of heterogeneous and proteiform diseases, rather than a homogeneous single entity. Diagnosis is challenging and relies mainly on histopathology, immunohistochemistry, and imaging. Molecular and cytogenetic analysis of MS tissue, particularly in isolated cases, should be performed to refine the diagnosis, and thus assign prognosis guiding treatment decisions. If feasible, systemic therapies used in AML remission induction should be employed, even in isolated MS. Role and type of consolidation therapy are not univocally acknowledged, and systemic therapies, radiotherapy, or allogeneic hematopoietic stem cell transplantation (allo-HSCT) should be considered. In the present review, we discuss recent information on MS, focusing on diagnosis, molecular findings, and treatments also considering targetable mutations by recently approved AML drugs.

Outcomes after allogeneic haematopoietic stem cell transplantation in young adults in Germany

Young adults (YA) represent a minority among recipients of allogeneic haematopoietic stem cell transplantation (HSCT). In order to describe the outcome of YA following HSCT in Germany, 9299 patients who were registered with the German Registry for Stem Cell Transplantation were included in this retrospective analysis of the years 1998-2019. The impact of the variables, such as patient age and sex, sex differences, stem cell source, donor type, conditioning, year of HSCT, the diagnosis, and the achieved remission status were tested in univariable and multivariable analysis for overall, event-free and relapse-free survival as well as for the cumulative incidences of non-relapse and therapy-related mortality. Altogether, the outcome of YA after HSCT improved over time and was determined by the underlying disease, the age at disease onset, stem cell source, and donor type. Patients were most likely to die from relapse, and survival of HSCT recipients after 10 years was reduced by more than half in comparison to the general population of YA. Deeper understanding of modifiable risk factors may be gained by studies comparing the outcome of YA post-HSCT with that of children, adolescents and elderly patients. A deliberate and strong patient selection may further improve mortality rates.

Total Body Irradiation in Haematopoietic Stem Cell Transplantation for Paediatric Acute Lymphoblastic Leukaemia: Review of the Literature and Future Directions

Total body irradiation (TBI) has been a pivotal component of the conditioning regimen for allogeneic myeloablative haematopoietic stem cell transplantation (HSCT) in very-high-risk acute lymphoblastic leukaemia (ALL) for decades, especially in children and young adults. The myeloablative conditioning regimen has two aims: (1) to eradicate leukaemic cells, and (2) to prevent rejection of the graft through suppression of the recipient's immune system. Radiotherapy has the advantage of achieving an adequate dose effect in sanctuary sites and in areas with poor blood supply. However, radiotherapy is subject to radiobiological trade-offs between ALL cell destruction, immune and haematopoietic stem cell survival, and various adverse effects in normal tissue. To diminish toxicity, a shift from single-fraction to fractionated TBI has taken place. However, HSCT and TBI are still associated with multiple late sequelae, leaving room for improvement. This review discusses the past developments of TBI and considerations for dose, fractionation and dose-rate, as well as issues regarding TBI setup performance, limitations and possibilities for improvement. TBI is typically delivered using conventional irradiation techniques and centres have locally developed heterogeneous treatment methods and ways to achieve reduced doses in several organs. There are, however, limitations in options to shield organs at risk without compromising the anti-leukaemic and immunosuppressive effects of conventional TBI. Technological improvements in radiotherapy planning and delivery with highly conformal TBI or total marrow irradiation (TMI), and total marrow and lymphoid irradiation (TMLI) have opened the way to investigate the potential reduction of radiotherapy-related toxicities without jeopardising efficacy. The demonstration of the superiority of TBI compared with chemotherapy-only conditioning regimens for event-free and overall survival in the randomised For Omitting Radiation Under Majority age (FORUM) trial in children with high-risk ALL makes exploration of the optimal use of TBI delivery mandatory. Standardisation and comprehensive reporting of conventional TBI techniques as well as cooperation between radiotherapy centres may help to increase the ratio between treatment outcomes and toxicity, and future studies must determine potential added benefit of innovative conformal techniques to ultimately improve quality of life for paediatric ALL patients receiving TBI-conditioned HSCT.

The Role of Allogeneic Hematopoietic Stem Cell Transplantation in Pediatric Leukemia

Allogeneic hematopoietic stem cell transplantation (HSCT) offers potentially curative treatment for many children with high-risk or relapsed acute leukemia (AL), thanks to the combination of intense preparative radio/chemotherapy and the graft-versus-leukemia (GvL) effect. Over the years, progress in high-resolution donor typing, choice of conditioning regimen, graft-versus-host disease (GvHD) prophylaxis and supportive care measures have continuously improved overall transplant outcome, and recent successes using alternative donors have extended the potential application of allotransplantation to most patients. In addition, the importance of minimal residual disease (MRD) before and after transplantation is being increasingly clarified and MRD-directed interventions may be employed to further ameliorate leukemia-free survival after allogeneic HSCT. These advances have occurred in parallel with continuous refinements in chemotherapy protocols and the development of targeted therapies, which may redefine the indications for HSCT in the coming years. This review discusses the role of HSCT in childhood AL by analysing transplant indications in both acute lymphoblastic and acute myeloid leukemia, together with current and most promising strategies to further improve transplant outcome, including optimization of conditioning regimen and MRD-directed interventions.

Late outcomes in survivors of childhood acute myeloid leukemia: a report from the St. Jude Lifetime Cohort Study

Cumulative burden of chronic health conditions and neurocognitive and physical function were examined among survivors of childhood acute myeloid leukemia (AML) treated with hematopoietic cell transplant (HCT; n = 66) or conventional therapy (CT; n = 67). Survivors and controls underwent a comprehensive clinical assessment, and health conditions were graded using a modified version of the Common Terminology Criteria for Adverse Events. By age 40 years, HCT and CT survivors had an average 17.4 (95% confidence interval [CI] 14.6-20.1) and 9.3 (7.7-11.1) grade 1-4 conditions versus 3.8 (3.3-4.2) in community controls. Compared to controls, HCT survivors had a higher prevalence of hypertriglyceridemia (45.5% vs. 18.3%), hypercholesterolemia (47.0% vs. 30.9%), hypothyroidism (27.3% vs. 4.0%), and primary hypogonadism (p < 0.001). CT survivors had a higher prevalence of cardiomyopathy (11.9% vs. 2.7%) and hypertension (53.7% vs. 44.3%). Neurocognitive impairment was elevated across all domains compared to controls but did not differ by treatment modality. Compared to controls, a higher proportion of HCT survivors had impairments in strength and endurance; whereas flexibility and mobility impairments were noted among CT survivors. Despite successful advances in childhood AML therapy, many therapeutic exposures remain unchanged. These findings support ongoing investigations of novel therapies and strategies to ameliorate the risk of late morbidities.

Treatment of acute myeloid leukemia in children: A practical perspective

Pediatric acute myeloid leukemia (AML) is a heterogeneous disease that requires a multifaceted treatment approach. Although outcomes for low-risk AML have improved significantly over recent decades, high-risk AML continues to be associated with an adverse prognosis. Recent advances in molecular diagnostics, risk stratification, and supportive care have contributed to improvements in outcomes in pediatric AML. Targeted approaches, for example, the use of tyrosine kinase inhibitors to treat FLT3-ITD AML, offer promise and are currently undergoing clinical investigation in pediatric patients. New approaches to hematopoietic stem cell transplantation, including the use of haploidentical donors, are significantly expanding donor options for patients with high-risk AML. This review provides an overview of recent advances in the treatment of pediatric AML that are likely to have clinical impact and reshape the standard of care.

A validated pediatric disease risk index for allogeneic hematopoietic cell transplantation

A disease risk index (DRI) that was developed for adults with hematologic malignancy who were undergoing hematopoietic cell transplantation is also being used to stratify children and adolescents by disease risk. Therefore, to develop and validate a DRI that can be used to stratify those with AML and ALL by their disease risk, we analyzed 2569 patients aged <18 years with acute myeloid (AML; n = 1224) or lymphoblastic (ALL; n = 1345) leukemia who underwent hematopoietic cell transplantation. Training and validation subsets for each disease were generated randomly with 1:1 assignment to the subsets, and separate prognostic models were derived for each disease. For AML, 4 risk groups were identified based on age, cytogenetic risk, and disease status, including minimal residual disease status at transplantation. The 5-year leukemia-free survival for low (0 points), intermediate (2, 3, 5), high (7, 8), and very high (>8) risk groups was 78%, 53%, 40%, and 25%, respectively (P < .0001). For ALL, 3 risk groups were identified based on age and disease status, including minimal residual disease status at transplantation. The 5-year leukemia-free survival for low (0 points), intermediate (2-4), and high (≥5) risk groups was 68%, 51%, and 33%, respectively (P < .0001). We confirmed that the risk groups could be applied to overall survival, with 5-year survival ranging from 80% to 33% and 73% to 42% for AML and ALL, respectively (P < .0001). This validated pediatric DRI, which includes age and residual disease status, can be used to facilitate prognostication and stratification of children with AML and ALL for allogeneic transplantation.