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.