Myelodysplastic syndrome after acute promyelocytic leukemia: the European APL group experience.

With improved treatment of acute promyelocytic leukemia (APL) by all trans retinoic acid (ATRA) combined to anthracycline-aracytin chemotherapy (CT), a larger number of those patients may be at risk of late complications. Recently, the Rome group reported five cases of myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML, non-APL) occurring during the course of 77 APL patients (6.5%) in complete remission (CR). From 1991 to 1998, we treated 677 newly diagnosed cases of APL, and 617 of them achieved CR with ATRA combined to CT (n=579) or CT alone (n=38); 246 of them received subsequent maintenance CT with 6 mercaptopurine and methotrexate. With a median follow-up of 51 months, 6 patients (0.97%) developed MDS, 13-74 months after the diagnosis of APL. In all six cases, t(15;17) and PML-RARalpha rearrangement were absent at the time of MDS diagnosis, and karyotype mainly showed complex cytogenetic abnormalities involving chromosomes 5 and/or 7, typical of MDS observed after treatment with alkylating agents, although none of the six patients had received such agents for the treatment of APL. Our findings suggest that MDS can indeed be a long-term complication in APL, although probably at lower incidence than that previously reported.