Acute megakaryoblastic leukemia: experience of GIMEMA trials.

The objective of the study was to evaluate the incidence, characteristics, treatment and outcome of acute megakaryoblastic leukemia (AMeL) in patients enrolled in GIMEMA trials. Between 1982 and 1999, 3603 new consecutive cases of AML aged over 15 years were admitted to GIMEMA trials. Of them, 24 were AMeL. The incidence of AMeL among AML patients enrolled in GIMEMA trials was 0.6% (24/3603). Diagnosis was based on morphological criteria. Out of 11 cytogenetic studies performed two presented chromosome 3 abnormalities. Twelve patients (50%) reached a CR, five (21%) died in induction and seven (27%) were unresponsive. The median duration of CR was 35 weeks (range 10-441). Seven patients underwent transplantation procedures (1 BMT, 4 aBMT, 2 aPBSCT). Four patients died in CR due to chemotherapy-related complications. Comparing the CR rate between AMeL and the other cases of AML enrolled in GIMEMA trials, no differences were observed. These results were mirrored for different age groups. The median survival was 40 weeks. At present, after a follow-up of a minimum of 2 years, only two patients are alive in CR, all the others having died. A 5-year Kaplan-Meier curve shows a disease-free survival of 17% and an actuarial overall survival of 10%. AMeL is a rare form of AML. The CR duration and the overall survival in this group of patients are very poor, even if similar to those observed in other AML. Furthermore, a high number of deaths in CR were observed. On the basis of these data, a specific therapeutic approach, possibly with innovative treatments, should be evaluated.