Intensive treatment of patients age 60 years and older with de novo acute myeloid leukemia - Analysis of prognostic factors

BACKGROUND. This study aimed to defined pre-treatment parameters with prognostic significance in elderly patients with de novo acute myeloid leukemia (AMI) who were treated with aggressive regimens. METHODS. We analyzed, retrospectively, the clinical and laboratory features of 159 consecutive patients age > 60 years with AML. Ninety-two patients presenting as de novo AML were considered suitable for aggressive chemotherapy according to inclusion criteria not different from those commonly used for younger adults. They belonged to all of the French-American-British classification types except M3, and their median age was 67 years (range: 60-79). Antileukemic treatment consisted of 1 of 3 sequential protocols adopted at the S. Eugenio University Hospital of Rome between 1987 and 1993. The three therapeutic groups were similar in number and presenting characteristics. In addition to arabinosylcytosine, induction schedules included mitoxantrone (Groups I and II) or daunorubicin (Group III), and etoposide (Group I and III). Once in complete remission (CR), patients were consolidated with two other course of chemotherapy using reduced dosages of the same drug given during induction. RESULTS. Induction treatment achieved a 52.2% CR rate, with median remission duration and event free survival (EFS) of 35 and 27 weeks, respectively. Because no significant differences between the results of the three therapeutic groups were observed, all cases wee pooled to evaluate the prognostic factors. In univariate analysis, the only presenting characteristic significantly associated with failure of induction treatment was age > 67 years (P = 0.007). Factors associated with an increased likelihood of shorter remission duration were CD7 expression on leukemic cells (P = 0.007) and an abnormal karyotype (P = 0.010); those predicting shorter EFS were a chromosomal status other than normal (P = 0.002) and detection of CD14 antigen (P = 0.008). Logistic regression results identified age and CD14 expression as the variables with independent prognostic impact on CR achievement. In a stepwise proportional hazards general linear model, CD7 and karyotypic retained their predictive value regarding remission duration, whereas the karyotypic pattern at diagnosis and CD14 antigen expression were the most important determinants of EFS, with age showing a borderline statistical value. A simple 'risk factor score' was developed that would allow for stratification of patients into prognostic groups. CONCLUSIONS. Cytogenetic analysis and immunophenotyping might help to select elderly patients with AML who have little benefit from current therapeutic strategies and with whom new approaches might be experimented.