Hyperdiploidy with 58-66 chromosomes in childhood B-acute lymphoblastic leukemia is highly curable: 58951 CLG-EORTC results
Mené sur 936 patients pédiatriques atteints d'une leucémie lymphoblastique aiguë à cellules B et présentant une hyperdiploïdie supérieure à 50 chromosomes (durée de suivi : 6 ans), cet essai montre que la présence d'une hyperdiploïdie à 58-66 chromosomes est un facteur pronostique favorable
The aim of our study was to analyze the factors contributing to heterogeneity of prognosis in patients with hyperdiploidy>50 chromosomes (HD>50), a group of B-cell precursor acute lymphoblastic leukemia with favorable outcome. The 541 HD>50 patients registered prospectively in the 58951 CLG-EORTC trial, identified by karyotype (446 patients) and by DNA index (DI) (490 patients), had a 6-year EFS of 89.0% (SE=1.5%) and a 6-year overall survival (OS) of 95.9% (SE=0.9%). The strongest prognostic factor was the modal number of chromosomes (MNC): the 6-year EFS of 51-53, 54-57 and 58-66 MNC groups were 80%, 89% and 99% respectively (P<0.0001). Ploidy assessed by DNA index (DI) was also a favorable factor, the higher the DI the better the outcome: the 6-year EFS of the three subgroups of DI <1.16/≥1.16-<1.24/≥1.24 were 83%, 90% and 95% respectively (P=0.009). All usual combinations of trisomies (chromosomes 4,10,17,18) were significant favorable factors but had lower EFS when MNC was lower than 58. In multivariate analysis, MNC remained the strongest factor. Consequently, the best indicator for excellent outcome was ploidy assessed by karyotype because patients with 58-66 chromosomes stood every chance of being cured (OS of 100% at 6-year follow-up) with less intensive therapy. NCT00003728, Registered: http://www.eortc.org/, http://clinicaltrials.gov/show/NCT00003728
Blood , résumé, 2013