Prognostic relevance of immunophenotyping in 379 patients with acute myeloid leukemia

We investigated the prognostic relevance of immunophenotype and other clinical pathological features in 379 adult patients with de novo (acute myeloid leukemia) AML diagnosed and treated at our institution during an 8-year period. Acute promyelocytic leukemia (APL) cases were excluded because they received different treatment. The overall complete remission (CR) rate post-induction therapy with Ara-C and daunorubicin (DNR) was 60% with a median disease free survival (DFS) of 72 weeks, and a median overall survival (OS) of 54 weeks. At diagnosis, CD34, deoxynucleotidyl transferase (TdT), CD7, CD56, HLADR and CD19 were expressed in 65, 19, 32, 15, 87 and 5%, respectively, of 379 evaluable cases. CD34 positive patients had a significantly lower CR rate (P=0.0003) than CD34 negative patients and there was a trend to a lower remission rate in HLADR positive patients (P=0.067). In multi-variate analysis, co-expression of CD34 and HLADR was an independent adverse factor for achieving CR (P=0.0364). CD56 expression was associated with a significantly shorter overall survival (P=0.0262), but did not affect remission rate or disease free survival. Neither TdT nor CD7 expression was associated with treatment outcome. Age (60 years or older) and cytogenetic features (classified by favorable, intermediate and unfavorable groups) were associated with a lower CR rate, shorter disease free survival and shorter OS. Patients with higher white cell counts (WBC) also had a significantly lower remission rate (P=0.0064) and OS (P=0.0127). We propose a prognostic score for achieving CR in AML patients based on age, WBC, cytogenetics and CD34/HLADR status as four independent factors. Defined by number of factors, this score system may help to stratify AML patients to alternative treatment for better outcome.