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Analysis of treatment failure in patients with minimally differentiated acute myeloid leukemia (AML-M0)
R Stasi1, G Del Poeta, A Venditti
1Division of Hematology, University of Rome Tor Vergata, S. Eugenio Hospital, Italy.
Abstract:
Reports of treatment of patients with minimally differentiated acute myeloid leukemia (AML-M0) are limited, heterogeneous, and controversial. We verified the prognosis of this subtype by analyzing the results of 189 consecutive patients with de novo AML. Fifteen cases fitting the criteria of AML-M0 were identified. No clinical features distinguished them from other patients with AML. The median age was 61 years (range 27 to 70), with a leukocyte count ranging from 0.6 to 185 x 10(9)/L. In all cases the leukemic cells expressed CD34 and reacted with at least one of the antibodies to early myeloid antigens, ie, CD13, CD33, or myeloperoxidase. Immunophenotypic analysis also showed positivity for CD7 in seven samples and the multidrug-resistance P-glycoprotein (P-170) in six. Cytogenetic analysis was abnormal in 12 of the 13 patients in whom an adequate number of mitoses could be evaluated. No single abnormality prevailed, the most common findings being trisomy 8 (three cases) and aberrations of chromosome 7 (two cases). Antileukemic treatment differed according to age, but for remission induction, all patients received a combination of cytosine arabinoside and an anthracycline or mitoxantrone. The prognosis of patients with AML-M0 was remarkably poor as compared with the other French-American-British subtypes. Whereas the overall rate of complete remission (CR) was 58% with a median survival of 63 weeks, only 6 of the 15 patients with AML-M0 achieved a CR, and the median survival of this group was 16 weeks (range 3 to 39). The major determinant of treatment failure was unresponsiveness to chemotherapy, as only one patient died of infection during the hypoplastic phase. The CR duration of responders was short, ranging from 3 to 22 weeks, and no second remissions were observed. We conclude that conventional combination chemotherapy yields disappointing results in AML-M0. The reason for this may be the convergence of various unfavorable prognostic factors, such as (1) the high incidence of cytogenetic abnormalities; (2) the lack of differentiation features and the expression of immaturity markers such as CD34 and CD7; and (3) the frequent expression of P-170. Nonconventional therapeutic approaches should be developed to alter the prognosis of this form of leukemia.
Insights
Minimally differentiated acute myeloid leukemia (AML-M0) shows a poor prognosis with conventional chemotherapy. New therapeutic strategies are needed due to low complete remission rates and short survival in AML-M0 patients.
Area of Science:
- Hematology
- Oncology
- Leukemia Research
Background:
- Minimally differentiated acute myeloid leukemia (AML-M0) treatment outcomes are poorly understood.
- Limited data exists on the prognosis and characteristics of AML-M0.
Purpose of the Study:
- To analyze the clinical features, immunophenotype, cytogenetics, and treatment outcomes of AML-M0 patients.
- To compare the prognosis of AML-M0 with other French-American-British (FAB) subtypes of AML.
Main Methods:
- Retrospective analysis of 189 de novo AML patients.
- Identification of 15 AML-M0 cases based on French-American-British (FAB) criteria.
- Evaluation of immunophenotypic markers (CD34, CD13, CD33, MPO, CD7, P-170) and cytogenetic abnormalities.
- Assessment of treatment response, complete remission (CR) rates, and survival.
Main Results:
- AML-M0 patients had a median age of 61, with no distinct clinical features from other AML subtypes.
- All AML-M0 cases expressed CD34 and myeloid antigens; 7/15 showed CD7 positivity, and 6/15 expressed P-170.
- Cytogenetic abnormalities were frequent (12/13 evaluable cases), with trisomy 8 and chromosome 7 aberrations being common.
- Only 6/15 AML-M0 patients achieved CR, with a median survival of 16 weeks, significantly poorer than other FAB subtypes (58% CR, 63 weeks median survival).
- Treatment failure was primarily due to chemotherapy unresponsiveness, with short CR duration and no second remissions in responders.
Conclusions:
- Conventional combination chemotherapy yields poor results for AML-M0.
- Unfavorable prognostic factors include high incidence of cytogenetic abnormalities, lack of differentiation, and expression of immaturity markers (CD34, CD7) and P-170.
- Development of non-conventional therapeutic approaches is crucial to improve AML-M0 prognosis.