Clinical and biological characteristics of acute myeloid leukemia with 20-29% blasts: a retrospective single-center study.

It is controversial whether acute myeloid leukemia (AML) patients with 20-29% bone marrow (BM) blasts should be considered AML or myelodysplastic syndromes (MDS). We retrospectively studied 382 patients, including 108 AML with 20-29% BM blasts (AML20-29), 210 AML with ≥30% BM blasts (AML ≥ 30), and 64 MDS with 10-19% BM blasts (MDS-EB2). We found that AML20-29 were more similar to MDS-EB2 in terms of advanced age, less blood count, the increased presence of poor-risk cytogenetics. The frequency of mutated genes in AML20-29 had both the characters of AML and MDS. Median overall survival of AML20-29 and MDS-EB2 were similar and shorter than those of AML ≥ 30 (p = .045). Multivariate analysis showed inferior survival with increased age, low platelet count and FLT3 mutations. Our findings suggest that AML20-29 have clinical features more similar to MDS than AML.