High-dose chemotherapy (HDT) followed by autologous bone marrow transplantation (ABMT) has proved to provide significant advantage regarding event-free and overall survival in patients with chemosensitive relapses of aggressive non-Hodgkin's lymphoma (NHL) after conventional therapy. These results encouraged many investigators to use HDT as part of first-line therapy but the results are contradictory. There is no consensus regarding management of relapsed or refractory DLBCL. In follicular lymphomas, autologous stem cell transplantation (SCT) is considered the treatment of choice for young patients with relapsed disease. Autologous SCT has also been evaluated in prospective trials as first-line treatment for high risk patients at diagnosis, but the results are not yet conclusive. In mantle cell lymphoma, autologous stem cell transplantation has been employed as part of first-line therapy. Allo-SCT for patients with lymphoma was first performed in the mid-1980s. The high transplant-related mortality, seen after myeloablative conditioning, discouraged broader interest in this approach and made further research difficult. The generally lower relapse rates after allo-SCT, the association of GvHD with reduced relapse rates, the increase of relapse rates after ex vivo or in vivo T-cell depletion, and the frequent responses to DLIs all support the existence of a graft-vs.-lymphoma effect. However, further data analysis supports the view that not all lymphomas are equal. While slowly proliferating diseases such as follicular lymphoma seem particularly sensitive targets for allogeneic T-cells, results of allo-SCT with aggressive B-cell lymphomas have been less convincing. Patients with these latter diseases obviously need vigorous debulking of their tumor prior to conditioning. Reduced-intensity conditioning fueled a renaissance of allo-SCT as treatment of lymphoma because the lower expected TRM was highly attractive for a patient population where the transplant-related death rate after myeloablative conditioning had, in many instances, exceeded 50%.
Non-Hodgkin lymphomas; stem cell transplantation; aggressive lymphomas; indolent lymphomas
