Pediatric Acute Megakaryoblastic Leukemia without Down Syndrome: A Retrospective Study by the International Berlin-Frankfurt-Munster Study Group (I-BFMSG)
Bibliographic record
Abstract
Abstract Acute megakaryoblastic leukemia (AMKL) comprises up to 10% of childhood acute myeloid leukemia (AML) cases. However, no large-scale studies have comprehensively evaluated the clinical characteristics and outcomes of patients with AMKL. We performed a large-scale international retrospective study of pediatric patients (diagnosed at age ≤18 years) with de novoAMKL without Down syndrome treated from 1989 to 2009. The study included 490 patients with AMKL, which comprises 7.9% of the pediatric AML patients treated by 19 members of the I-BFMSG. At diagnosis, the median age of patients was 1.5 years (range, 0.0–16.5 years), median white blood cell count was 12.0×109/L (range, 0.6–188.0×109/L), 23 (4.7%) patients showed central nervous system involvement, and both sexes were equally represented. Complete remission (CR) was achieved in 417 (85.1%) patients, and 5-year event-free (EFS) and overall survival (OS) rates were 43.7%±2.7% and 49.0%±2.7%, respectively. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) was performed in 206 (42.0%) patients. The 5-year disease-free survival and OS rates for patients who received allo-HSCT in first CR (n=112, 56.3%±5.2%, and 57.7%±5.2%, respectively) and for those who did not receive transplantation in first CR (n=298, 50.2%±3.6% and 55.2%±3.5%) were not significantly different (P=0.12 and P=0.57). Complete cytogenetic data were available for 372 (75.9%) patients: diploid (n=49, 13.2%), hypodiploid (n=18, 4.8%), pseudodiploid (n=119, 32.0%), 47–50 chromosomes (n=142, 38.2%), and >50 chromosomes (n=44, 11.8%). Chromosome gain occurred in 195 (52.4%) patients: +21 was the most common (n=106, 28.5%), followed by +19 (n=93, 25.0%), and +8 (n=77, 20.7%). Losses occurred in 65 cases (17.5%), in the decreasing order of –7 (n=13, 3.5%), –9 (n=9, 2.4%), –13, and –15 (n=7 each, 1.9%). Structural chromosomal aberrations were observed in 278 (74.7%) patients, most commonly t(1;22) (n=51, 13.7%) and 11q23 rearrangements (n=38, 10.2%) with t(9;11) in 21 patients. Other abnormalities included 7p (n=43, 11.6%) and 13q (n=31, 8.3%; 16 with deletions) breakpoints. Patients with t(1;22) were significantly younger at diagnosis (P<0.001; median 0.6 years, range 0.0–6.3 years) and more often female (P=0.05; 64.7%) while those with –7 were significantly older (P=0.006; median 4.2 years, range 0.4–15.0 years) than those with other cytogenetic subgroups. Multiple regression analysis for EFS and OS with clinical and cytogenetic features showed that treatment period (1989–1999 vs. 2000–2009), normal cytogenetics, –7, t(9;11), 13q-, and –15 were associated with significantly worse outcomes than those for other subgroups, whereas abnormalities in 7p were associated with better outcomes (Table). Patients with –13 and 9p abnormalities other than t(9;11) had a poorer EFS and OS, respectively. Patients with +21 or t(1;22) did not show a significant difference in survival rates. This international study on the largest cohort of AMKL patients analyzed to date shows heterogeneity in cytogenetic findings and identifies some subgroups with a particularly dismal outcome. The advent of newer methods to evaluate genetic lesions can help identify therapeutic targets for improving the outcome in this subgroup of patients. Disclosures No relevant conflicts of interest to declare.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".