Background
Optimal chemotherapy for treating mixed‐phenotype acute leukemia (MPAL) and the role of hematopoietic stem cell transplantation (HSCT) remain uncertain. Major limitations in interpreting ...available data are MPAL's rarity and the use of definitions other than the currently widely accepted criteria: the World Health Organization 2016 (WHO2016) classification.
Methods
To assess the relative efficacy of chemotherapy types for treating pediatric MPAL, the Children's Oncology Group (COG) Acute Leukemia of Ambiguous Lineage Task Force assembled a retrospective cohort of centrally reviewed WHO2016 MPAL cases selected from banking studies for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Patients were not treated in COG trials; treatment and outcome data were captured separately. The findings were then integrated with the available, mixed literature to develop a prospective trial in pediatric MPAL.
Results
The central review confirmed that 54 of 70 cases fulfilled WHO2016 criteria for MPAL. ALL induction regimens achieved remission in 72% of the cases (28 of 39), whereas AML regimens achieved remission in 69% (9 of 13). The 5‐year event‐free survival (EFS) and overall survival (OS) rates for the entire cohort were 72% ± 8% and 77% ± 7%, respectively. EFS and OS were 75% ± 13% and 84% ± 11%, respectively, for those receiving ALL chemotherapy alone without HSCT (n = 21).
Conclusions
The results of the COG MPAL cohort and a literature review suggest that ALL chemotherapy without HSCT may be the preferred initial therapy. A prospective trial within the COG is proposed to investigate this approach; AML chemotherapy and/or HSCT will be reserved for those with treatment failure as assessed by minimal residual disease. Embedded biology studies will provide further insight into MPAL genomics.
Acute lymphoblastic leukemia–directed chemotherapy without hematopoietic stem cell transplantation may be sufficient therapy for most children with World Health Organization 2016 classification–defined mixed‐phenotype acute leukemia. A proposed prospective trial will investigate this approach and explore mixed‐phenotype acute leukemia genomics and correlative biology.
A detailed understanding of the genome-wide variability of single-nucleotide germline mutation rates is essential to studying human genome evolution. Here, we use ~36 million singleton variants from ...3560 whole-genome sequences to infer fine-scale patterns of mutation rate heterogeneity. Mutability is jointly affected by adjacent nucleotide context and diverse genomic features of the surrounding region, including histone modifications, replication timing, and recombination rate, sometimes suggesting specific mutagenic mechanisms. Remarkably, GC content, DNase hypersensitivity, CpG islands, and H3K36 trimethylation are associated with both increased and decreased mutation rates depending on nucleotide context. We validate these estimated effects in an independent dataset of ~46,000 de novo mutations, and confirm our estimates are more accurate than previously published results based on ancestrally older variants without considering genomic features. Our results thus provide the most refined portrait to date of the factors contributing to genome-wide variability of the human germline mutation rate.
Improved survival has led to interest in functional health status (FHS) as patients with dextro-transposition of the great arteries (d-TGA) transition to adulthood. Our primary objectives were (1) ...evaluation of The Medical Outcomes Study Short Form-36 Health Survey (SF-36) results; (2) comparison with results of patients who completed the Child Health Questionnaire-Child Form 87 (CHQ-CF87) previously, or the PedsQL Generic Core Scales (PedsQL) survey subsequently; and (3) determination of factors associated with SF-36 domains.
Survivors from the d-TGA Congenital Heart Surgeons' Society cohort (1985-1989) completed the SF-36 (2010) as a measure of FHS (n = 210; age 21-26 years). Patient characteristics, medical history, psychosocial factors, and previous adolescent CHQ-CF87 FHS assessment (2000) were explored for association with SF-36 domains, along with comparison with recent PedsQL data (2017).
Patients scored themselves the same/higher than published normative data in 10 of 10 SF-36 summary scores/domains and similar in 5 of 6 PedsQL summary scores/domains. Factors commonly associated with lower summary scores/domains of the SF-36 were presence of cardiac symptoms, heart condition impacting physical activity/overall health/quality of life, unemployment, and lack of postsecondary education. Less commonly associated factors were lower birth weight, greater total medication number, female sex, shorter procedure-free interval, poor health knowledge, lower family income, younger age at SF-36, living with parents, and being married. These factors accounted for 17% to 47% of the variation in FHS summary scores/domains. FHS was minimally related to d-TGA morphology and repair type.
Patients with d-TGA surviving into adulthood, regardless of morphology or repair type, can primarily expect normal FHS. Addressing the challenges of patients with d-TGA entering adulthood requires consideration of psychosocial factors and clinical management.
Longitudinal functional health status of patients with repaired d-TGA during a 17-year period. Display omitted
Neuroblastoma, the most common extracranial solid tumor that occurs in early childhood, can be identified in the preclinical stages by the detection of catecholamines in the urine. However, it is ...unknown whether routine screening for neuroblastoma reduces mortality due to this disease.
Through their parents, we offered screening for neuroblastoma at three weeks and six months of age to all 476,654 children born in the province of Quebec, Canada, during a five-year period (May 1, 1989, through April 30, 1994). The participation rate was 92 percent. The rate of death due to neuroblastoma was determined and compared with the rates in several unscreened control populations born during the same period.
Among children younger than eight years of age in the Quebec cohort, there were 22 deaths due to neuroblastoma; the cumulative (+/-SE) mortality rate due to neuroblastoma was 4.78+/-1.14 per 100,000 children over a period of nine years. The standardized incidence ratios for death due to neuroblastoma for the Quebec cohort were 1.11 (95 percent confidence interval, 0.64 to 1.92) as compared with a control group in Ontario, Canada; 0.90 (95 percent confidence interval, 0.48 to 1.70) as compared with a control group in Minnesota; 1.40 (95 percent confidence interval, 0.81 to 2.41) as compared with a control group in Florida; and 0.96 (95 percent confidence interval, 0.56 to 1.66) as compared with a control group in the Greater Delaware Valley. The standardized mortality ratio for the Quebec cohort as compared with the rest of Canada was 1.39 (95 percent confidence interval, 0.85 to 2.30); the odds ratio for the comparison with a cohort born in Quebec before the screening program began was 0.98 (95 percent confidence interval, 0.54 to 1.77).
Screening infants for neuroblastoma does not appear to reduce mortality due to this disease.
Five-year survival following childhood acute myeloid leukemia (AML) has increased following improvements in treatment and supportive care. Long-term health outcomes are unknown. To address this, ...cumulative incidence of late mortality and grades 3 to 5 chronic health condition (CHC) were estimated among 5-year AML survivors diagnosed between 1970 and 1999. Survivors were compared by treatment group (hematopoietic cell transplantation HCT, chemotherapy with cranial radiation chemo + CRT, chemotherapy only chemo-only), and diagnosis decade. Self-reported health status was compared across treatments, diagnosis decade, and with siblings. Among 856 survivors (median diagnosis age, 7.1 years; median age at last follow-up, 29.4 years), 20-year late mortality cumulative incidence was highest after HCT (13.9%; 95% confidence interval CI, 10.0%-17.8%; chemo + CRT, 7.6%; 95% CI, 2.2%-13.1%; chemo-only, 5.1%; 95% CI, 2.8%-7.4%). Cumulative incidence of mortality for HCT survivors diagnosed in the 1990s (8.5%; 95% CI, 4.1%-12.8%) was lower vs those diagnosed in the 1970s (38.9%; 95% CI, 16.4%-61.4%). Most survivors did not experience any grade 3 to 5 CHC after 20 years (HCT, 45.8%; chemo + CRT, 23.7%; chemo-only, 27.0%). Furthermore, a temporal reduction in CHC cumulative incidence was seen after HCT (1970s, 76.1%; 1990s, 38.3%; P = .02), mirroring reduced use of total body irradiation. Self-reported health status was good to excellent for 88.2% of survivors; however, this was lower than that for siblings (94.8%; P < .0001). Although HCT is associated with greater long-term morbidity and mortality than chemotherapy-based treatment, gaps have narrowed, and all treatment groups report favorable health status.
Background
The prognostic impact of central nervous system (CNS) involvement in children with acute myeloid leukemia (AML) has varied in past trials, and controversy exists over the degree of ...involvement requiring intensified CNS therapy. Two recent Children's Oncology Group protocols, AAML03P1 and AAML0531, directed additional intrathecal (IT) therapy to patients with CNS2 (≤5 white blood cell WBC with blasts) or CNS3 (>5 WBC with blasts or CNS symptoms) disease at diagnosis.
Methods
We examined disease characteristics and outcomes of the 1,344 patients on these protocols, 949 with CNS1 (no blasts), 217 with CNS2, and 178 with CNS3, with the latter two receiving additional IT therapy.
Results
Young age (P = 0.003), hyperleukocytosis (P < 0.001), and the presence of inversion 16 (P < 0.001) were the only factors more prevalent in patients with CNS2 or CNS3 disease. Complete remission at the end of induction (EOI) 2 was achieved less often in patients with CNS involvement (P < 0.001). From diagnosis, event‐free survival (EFS) for patients with CNS involvement was significantly worse (P < 0.001), whereas overall survival (OS) was not (P = 0.16). From the EOI1, there was a higher relapse rate (RR) and worse disease‐free survival (DFS), but less impact on OS (CNS1:DFS 58.9%, RR 34.1%, OS 69.3%; CNS2:DFS 53.2%, RR 40.9%, OS 74.7%; CNS3:DFS 45.2%, RR 48.8%, OS 60.8%; P = 0.006, P < 0.001, P = 0.045, respectively). Multivariable analysis showed that independently CNS2 and CNS3 status adversely affected RR and DFS. Traumatic diagnostic lumbar puncture was not associated with worse outcome.
Conclusions
CNS leukemia confers greater relapse risk despite more aggressive locally directed therapy. Novel approaches need to be investigated in this group of patients.
The rarity of mixed phenotype acute leukemia (MPAL) has precluded adequate data to incorporate minimal residual disease (MRD) monitoring into therapy. Fluidity in MPAL classification systems further ...complicates understanding its biology and outcomes; this includes uncertainty surrounding the impact of shifting diagnostic requirements even between iterations of the World Health Organization (WHO) classification. Our primary objective was to address these knowledge gaps. To do so, we analyzed clinicopathologic features, therapy, MRD, and survival in a centrally-reviewed, multicenter cohort of MPAL uniformly diagnosed by the WHO classification and treated with acute lymphoblastic leukemia (ALL) regimens. ALL induction therapy achieved an EOI MRD negative (<0.01%) remission in most patients (70%). EOI MRD positivity was predictive of 5-year EFS (HR = 6.00, p < 0.001) and OS (HR = 9.57, p = 0.003). Patients who cleared MRD by EOC had worse survival compared with those EOI MRD negative. In contrast to adults with MPAL, ALL therapy without transplantation was adequate to treat most pediatric patients. Earlier MRD clearance was associated with better treatment success and survival. Prospective trials are now necessary to validate and refine MRD thresholds within the pediatric MPAL population and to identify salvage strategies for those with poor predicted survival.
The Flt3 gene encodes a tyrosine kinase receptor that regulates proliferation and differentiation of hematopoietic stem cells. An internal tandem duplication of the Flt3 gene (Flt3/ITD) has been ...reported in acute myelogenous leukemia (AML) and may be associated with poor prognosis. We analyzed diagnostic bone marrow specimens from 91 pediatric patients with AML treated on Children's Cancer Group (CCG)-2891 for the presence of the Flt3/ITD and correlated its presence with clinical outcome. Fifteen of 91 samples (16.5%) were positive for the Flt3/ITD. Flt3/ITD-positive patients had a median diagnostic white count of 73 800 compared with 28 400 for the Flt3/ITD-negative patients (P = .05). The size of the duplication ranged from 21 to 174 base pairs (bp). Nucleotide sequencing of the abnormal polymerase chain reaction products demonstrated that all duplications involved exon 11 of theFlt3 gene and also preserved the reading frame. Lineage restriction analysis revealed that Flt3/ITD was not present in the lymphocytes, suggesting a lack of stem cell involvement for this mutation. None of the Flt3/ITD-positive patients had unfavorable cytogenetic markers, and there was no predominance of a particular FAB class. The remission induction rate was 40% in Flt3/ITD-positive patients compared with 74% in Flt3/ITD-negative ones (P = .005). The Kaplan-Meier estimates of event-free survival at 8 years for patients with and without Flt3/ITD were 7% and 44%, respectively (P = .002). Multivariate analysis demonstrated that presence of the Flt3/ITD was the single most significant, independent prognostic factor for poor outcome (P = .009) in pediatric AML.
PDF
