Secondary AML that has evolved from MDS shows different clinical features and outcomes compared to de novo AML. Prognostic implications of immunophenotypes have been studied in de novo AML, whereas those have not well been defined in secondary AML from MDS.
This retrospective study involved analysis of data from 65 adult patients, 37 males and 28 females, who were diagnosed with AML arising from MDS at a single institute. Data for baseline clinico-pathological features, treatments, and outcomes were collected from medical records of each patient. Immunophenotyping was performed for the markers including TdT, CD34, CD13, CD33, CD117, CD14, CD56, HLA-DR, CD3, CD7, CD10, and CD19 using flow cytometry.
At the time of MDS diagnosis, the WHO subtype was RA/RARS in 5, RCMD in 10, RAEB-1 in 17, RAEB-2 in 29, and unknown in 4. For the treatment of MDS, hypomethylating agents were given to 17 patients and 2 patients underwent allogeneic hematopoietic cell transplantation (HCT). Median duration of MDS prior to diagnosis of AML was 4.9 months (range, 0.3–91.1). At the time of AML evolution, median age was 50.7 years (range, 18–80), and cytogenetic risk group was good-risk in 1, intermediate-risk in 45, and poor-risk in 18. Proportion of positivity of each immunophenotype marker was as follows: TdT (5%), CD34 (65%), CD13 (98%), CD33 (97%), CD117 (90%), CD14 (22%), CD56 (10%), HLA-DR (93%), CD3 (2%), CD7 (35%), CD10 (8%), and CD19 (2%). After the evolution to AML, 52 patients received induction chemotherapy consisted of cytarabine plus idarubicin or daunorubicin and 8 patients underwent allogeneic HCT as initial treatment of AML. Complete remission (CR) was induced in 27 patients after treatment. At a median follow-up time of 29.2 months (range, 2.6–116.2) among surviving patients, 49 patients died, 13 relapsed, and 53 died or relapsed. Median overall survival (OS), relapse-free survival (RFS), and event-free survival (EFS) were 7.6, 26.1, and 5.4 months, respectively. Of immunophenotype markers, CD14 positivity only showed prognostic implications at the univariate analyses: lower CR rate after induction chemotherapy (P=0.034) and shorter survivals (OS, P<0.001; RFS, P=0.078, and EFS, P<0.001). Differences in OS and EFS remained significant after adjustment for other variables (OS, HR, 4.49, 95% CI, 2.16–9.87, P<0.001; EFS, HR, 4.06, 95% CI, 2.03–8.13, P<0.001). Other prognostic variables included age of 60 years or older (shorter OS [P=0.003] and EFS [P=0.020]), WBC over 60,000/mcl (shorter OS [P<0.001] and EFS [P=0.001]), and poor cytogenetic risk group (shorter OS [P=0.005]).
Surface expression of CD14 on leukemic blasts was an independent prognostic factor for survivals in the patients with AML arising from MDS.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.