HIGH-RISK OF THERAPY-RELATED LEUKEMIA AFTER BEAM CHEMOTHERAPY AND AUTOLOGOUS STEM-CELL TRANSPLANTATION FOR PREVIOUSLY TREATED LYMPHOMAS IS MAINLY RELATED TO PRIMARY CHEMOTHERAPY AND NOT TO THE BEAM-TRANSPLANTATION PROCEDURE

A cohort of 76 patients with previous chemotherapy for Hodgkin's disea se and non-Hodgkin lymphomas received high-dose carmustine, etoposide, cytosine-arabinoside and melphalan (BEAM) followed by autologous stem cell transplantation (ASCT) and was followed for relapse and developm ent of leukemic complications. Six patients, four with Hodgkin's disea se and two with non-Hodgkin lymphomas, developed leukemic complication s, myelodysplasia (MDS) in four cases and overt acute myeloid leukemia (AML) in two. All six showed an abnormal karyotype, in four of them h ighly characteristic of therapy-related MDS (t-MDS) and therapy-relate d AML (t-AML). The cumulative risk of t-MDS and t-AML increased from 1 6 months after start of the primary chemotherapy for lymphoma and reac hed 17.3% (s.e. 8.5%) after 74 months. If calculated from start of BEA M and ASCT, the cumulative risk increased as early as 4 months and rea ched 24.3% (s.e. 12.9%) after 43 months. For the whole course of the d isease, the relative risk (RR) of AML was 357 (95% CI: 43-1290), as tw o overt leukemias were observed vs 0.0056 expected cases of de novo AM L. In the present cohort the risk of t-MDS and t-AML although high, di d not differ from our previous experience in patients treated conventi onally for Hodgkin's disease and non-Hodgkin lymphomas, and did not di ffer for patients receiving stem cells isolated from the bone marrow a s compared to patients receiving stem cells isolated from peripheral b lood. Antecedent chemotherapy seems to be the critical factor for the development of t-MDS and t-AML rather than the BEAM and ASCT regimen, which however may accelerate the evolution of the disease.