Acute Erythroleukemia: An Analysis of 108 Patients Treated with Cytarabine-Containing Regimens at the M.D. Anderson Cancer Center.

Acute erythrocytic leukemia (AML-M6) is an uncommon subtype of acute myeloid leukemia (AML). It usually presents as a proliferation of dysplastic erythroid elements mixed with blasts of myeloid origin, although there are some rare cases of pure erythroid proliferation (DiGuglielmo’s disease). It has previously been associated with a poor prognosis. Here, we report the experience at the M.D. Anderson Cancer Center. From January, 1980 to May, 2006 there were 2992 patients with newly diagnosed AML (excluding APL), and 108 (4%) had the diagnosis of AML-M6. Diagnosis was based on morphological features according to the FAB classification, PAS-positivity by cytochemistry and immunophenotypical positivity for glycophorin A when available. Seventy (65%) were males; median age was 60 years (range 17 – 85). Antecedent hematological disorder (AHD) and/or MDS was present in 54 patients (50%) compared to 40% in other AML patients (p=0.056), and 27 (25%) patients had previously received treatment for other malignancies. The median white blood cell count at diagnosis was 2.5x10⁹/L (0.3–45.1), hemoglobin 7.8 g/dL (2.5–12.6) and platelet count 40x10⁹/L (3–22). Information about bone marrow dysplasia was available in 80 patients. Significant morphological dysplasia of erythroid lineage was found in 66 (83%), of myeloid lineage in 38 (48%) and of megakaryocytic lineage in 36 (45%) cases. Cytogenetic analysis was available in 106 (98%) cases, and was abnormal in 77 (71%) patients. The most common abnormalities were: Monosomy 5/Monosomy 7 in 50 (46.3%) and Trisomy 8 in 9 (8.3%). Poor risk cytogenetics were found in 46% of patients with AML-M6, comparing to 19% of the control group (other AML patients excluding APL) (p<0.001). All patients received induction chemotherapy containing cytarabine. Complete remission rates were 63% for AML-M6 patients, comparing to 58% for the control group (p = 0.285). Seventeen patients (15.7%) were refractory and 23 (21.3%) had induction death. Median disease free survival of AML-M6 patients was 31 weeks, compared to 49 weeks for the control group (p = 0.03). Median overall survival of AML-M6 patients was 33 weeks, compared to 42 weeks for the control group (p = 0.190). A total of 24 patients underwent allogeneic stem cell transplantation. Their median survival after transplantation was 32 weeks. We conclude that acute erythrocytic leukemia is a rare subtype of AML. It is commonly associated with a previous diagnosis of MDS and often presents with dysplastic features at diagnosis. It is frequently associated with poor-risk cytogenetics and a poor outcome.