• Earlier use of high-dose cytarabine during induction II therapy improves EFS for ML-DS patients.• MRD assessment by flow cytometry after induction I is a new prognostic variable for ML-DS.Patients with myeloid leukemia of Down syndrome (ML-DS) have favorable event-free survival (EFS), but experience significant treatment-related morbidity and mortality. ML-DS blast cells ex vivo have increased sensitivity to cytarabine (araC) and daunorubicin, suggesting that optimizing drug dosing may improve outcomes while reducing toxicity. The Children's Oncology Group (COG) AAML0431 trial consisted of 4 cycles of induction and 2 cycles of intensification therapy based on the treatment schema of the previous COG A2971 trial with several modifications. High-dose araC (HD-araC) was used in the second induction cycle instead of the intensification cycle, and 1 of 4 daunorubicincontaining induction cycles was eliminated. For 204 eligible patients, 5-year EFS was 89.9% and overall survival (OS) was 93.0%. The 5-year OS for 17 patients with refractory/ relapsed leukemia was 34.3%. We determined the clinical significance of minimal residual disease (MRD) levels as measured by flow cytometry on day 28 of induction I. MRD measurements, available for 146 of the 204 patients, were highly predictive of treatment outcome; 5-year disease-free survival for MRD-negative patients (n 5 125) was 92.7% vs 76.2% for MRD-positive patients (n 5 21) (log-rank P 5 .011). Our results indicated that earlier use of HD-araC led to better EFS and OS in AAML0431 than in past COG studies. A 25% reduction in the cumulative daunorubicin dose did not impact outcome. MRD, identified as a new prognostic factor for ML-DS patients, can be used for risk stratification in future clinical trials. This trial was registered at www.clinicaltrials.gov as #NCT00369317. (Blood. 2017;129(25):3304-3313)
As with most genetic cancer predisposition syndromes, inherited susceptibility to myelodysplastic syndrome (MDS) and acute leukemia (AL) is likely to be more common than previously appreciated. As next-generation sequencing technologies become integrated into clinical practice, we anticipate that the number of cases of familial MDS/AL identified will increase. Although the existence of syndromes predisposing to MDS/AL has been known for some time, clinical guidelines for the screening and management of suspected or confirmed cases do not exist. Based on our collective experience caring for families with these syndromes, we propose recommendations for genetic counseling, testing, and clinical management. We welcome discussion about these proposals and hope that they will catalyze an ongoing dialog leading to optimal medical and psychosocial care for these patients.
BACKGROUND
Children who are treated for myeloid leukemia associated with Down syndrome (DS) experience superior survival compared with children who have myeloid leukemia without DS. To maintain excellent outcomes while avoiding toxicity, the Children’s Oncology Group (COG) conducted the phase 3 trial COG A2971, the first trial solely designed to provide uniform treatment of myeloid leukemia in North American children with DS. A2971 eliminated 2 induction drugs and 3 months of maintenance therapy from the standard-timing regimen of dexamethasone, cytarabine, 6-thioguanine, etoposide, and rubidomycin/daunomycin (DCTER) used in the previous study (Children’s Cancer Group [CCG] 2891).
METHODS
COG A2971 was a multi-institutional, nonrandomized, clinical trial that enrolled 132 patients who had DS with either acute myeloid leukemia (n = 91) or myelodysplastic syndrome (n = 41).
RESULTS
The median follow-up was 4.8 years (range, 0.8–8.6 years), the median age at diagnosis was 1.7 years (range, 0.3–13.6 years), and the median white blood cell count was 6200/μL (range, 900–164,900/μL). The remission rate (92.7% ± 6%) was similar to that reported in the CCG 2891 study (91.3% ± 5%; P = .679). The 5-year event free survival (EFS) rate was 79% ± 7% (vs 77% ± 7% in CCG 2891; P = .589), the disease-free survival (DFS) rate was 89% ± 6% (vs 85% ± 6% in CCG 2891; P = .337), and the overall survival rate was 84% ± 6% (vs 79% ± 7% in CCG 2891; P = .302). Induction day-14 bone marrow response trended toward a more favorable outcome (EFS: P = .12). Age >4 years was an adverse risk factor (5-year EFS rate: 33% ± 38% for children aged >4 years [median, 8.5 years; n = 6] vs 81% ± 7% for children ages 0–4 years [median, 1.7 years; n = 126]; P = .001).
CONCLUSIONS
The COG A2971 trial reduced the chemotherapy dose and maintained survival to that achieved by the CCG 2891 trial in children who had myeloid leukemia associated with DS.
Prevalent as an acquired abnormality in cancer, the role of TP53 as a germline mutation continues to evolve. The clinical impact of a germline TP53 mutation is often dramatic and affects the full life course, with a propensity to develop rare tumors in childhood and multiple common cancers of unexpectedly early onset in adulthood. We review the clinical relevance of germline mutations in the TP53 tumor suppressor gene in current healthcare practices, including the optimal ways to identify patients with Li-Fraumeni syndrome (LFS), to recognize the core-cancers associated with LFS and to develop strategies for early detection of LFS-associated tumors. Several TP53-targeted approaches to improve outcomes in LFS patients are also reviewed. A case report was used to highlight special TP53 testing dilemmas and unique challenges associated with genetic testing decisions in our current age of rapidly advancing genomic technologies.
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