Acute erythroid leukemia with <20% bone marrow blasts is clinically and biologically similar to myelodysplastic syndrome with excess blasts.

In acute erythroleukemia, erythroid/myeloid subtype, blasts usually comprise 5-19% of total bone marrow cells, similar to the myelodysplastic syndrome subtype refractory anemia with excess blasts; recent studies have raised the question if acute erythroleukemia should be considered as a myelodysplastic syndrome subtype. We reviewed 77 de novo acute erythroleukemia and 279 de novo refractory anemia with excess blasts from three large medical centers. Compared to refractory anemia with excess blasts, acute erythroleukemia patients had higher total bone marrow blasts, lower platelets, hemoglobin, and absolute neutrophil counts, with more patients being assigned a very-poor-karyotype risk and very-high Revised International Prognostic Scoring System score. Induction chemotherapy was administered to 55% of acute erythroleukemia patients, but was not associated with longer overall survival compared to acute erythroleukemia patients treated with lower-intensity therapies or supportive care (P=0.44). In multivariable analysis of all patients, Revised International Prognostic Scoring System very high (P<0.0001) or high (P=0.005) risk, but not a diagnosis of acute erythroleukemia (P=0.30), were independent risk factors for shorter overall survival. Our data show that acute erythroleukemia patients have similar risk-adjusted outcome to refractory anemia with excess blasts patients and do not appear to gain survival advantage with acute myeloid leukemia-type induction chemotherapy. These data suggest that acute erythroleukemia, erythroid/myeloid subtype with <20% blasts may be more appropriately classified as refractory anemia with excess blasts rather than as an acute myeloid leukemia subtype.