Low incidence of secondary myelodysplasia and acute myeloid leukemia after high-dose chemotherapy as adjuvant therapy for breast cancer patients: a study by the Solid Tumors Working Party of the European Group for Blood and Marrow Transplantation.

BACKGROUND To determine the incidence of secondary myelodysplasia (sMDS) or acute myeloid leukemia (AML) in node-positive breast cancer patients who received high-dose chemotherapy (HDCT) followed by autologous stem-cell support as adjuvant therapy. PATIENTS AND METHODS The incidence of sMDS/AML was retrospectively assessed in 364 node-positive breast cancer patients who received HDCT followed by autologous stem-cell support as adjuvant therapy between November 1989 and December 1997 and were reported to the European Group for Blood and Marrow Transplantation registry. RESULTS The median age of the patients was 45 years (range 22-62 years). Two hundred and ninety-one patients received peripheral blood stem cells and 55 patients received autologous bone marrow as stem-cell support. The most frequently used conditioning regimen was the STAMP-V regimen (32%), followed by melphalan-thiotepa (22%) and melphalan-mitoxantrone-cyclophosphamide (21%). The 5-year probability of overall survival is 71% (95% CI 65% to 77%). After a median follow-up of 48 months (range 1-108 months) only one case of AML was observed, resulting in a crude incidence of 0.27%. This case of AML was observed 18 months after HDCT consisting of three cycles of epirubicin and cyclophosphamide with a cumulative dose of epirubicin 960 mg and cyclophosphamide 19 g. The French-American-British type of AML was M4, and the cytogenetic analysis showed a translocation t(9;11)(p22;q23). After complete remission following high-dose cytarabine and idarubicin the patient relapsed and died. CONCLUSIONS In contrast to patients with malignant lymphoma there seems to be no increased risk of sMDS/AML after HDCT in breast cancer. Continued monitoring is required to confirm this low incidence after a longer follow-up period.