Autologous stem cell transplantation in acute myelocytic leukemia.

IN THE PAST 30 YEARS, the treatment of acute myelocytic leukemia (AML) has considerably evolved and improved. The general evolution in the therapeutic strategy has invariably been on the direction of more aggressive treatment being administered early, as soon as a first complete remission (CR1) has been achieved. The rationale has been to provide maximum antitumor effect with so-called consolidation (or intensification) at a stage of minimal residual disease in an effort to eradicate the very last leukemic cells in the patient’s body. However, it is important to remember that total leukemia eradication is not mandatory, because indirect evidence has shown that cure of the disease is achievable if reduction of the tumor burden can reach a level low enough to be controlled by the patient’s own immune system. Such a level can today be obtained, although still unpredictably, by modern conventional chemotherapy or high-dose myeloablative regimens with or without total body irradiation (TBI) followed by stem cell transplantation. Numerous retrospective data exist from single institutions and from international registries on the use of conventional chemotherapy alone or allogeneic or autologous blood or marrow stem cell transplantation (ABMT). Recently, results of randomized studies comparing chemotherapy alone to allogeneic and autologous stem cell transplantation have become available. In parallel, prognostic factors have been identified, among which age, response to induction therapy in reaching CR1, and cytogenetics have proved major. Nonetheless, the choice of the therapeutic strategy has reached no consensus. Other important questions regarding ABMT, such as the role of purging the autograft from residual tumor cells and the potential benefit of autologous peripheral blood (PB) over marrow stem cells, are still being investigated.