Hematopoietic stem cell transplantation in the treatment of peripheral T-cell lymphomas.

Peripheral T-cell lymphomas (PTCL) are a rare group of heterogeneous lymphoproliferative disorders with their origin in the post-thymic T cells. Most PTCL have a relatively poor outcome, with a 5-year overall survival of less than 30%. Anaplastic large cell lymphoma (ALCL) has a better prognosis compared with other subtypes of PTCL. As with aggressive B-cell non-Hodgkin's lymphoma, high-dose chemotherapy followed by autologous stem cell transplantation should be offered to patients with PTCL in their first relapse. Patients with poor-risk features (alk-negative ALCL, histologic subtypes other than ALCL, and high International Prognostic Index score at presentation) may be candidates for autologous stem cell transplantation as first-line therapy. Initial results of allogeneic stem cell transplantation, both with standard and nonmyeloablative conditioning, look promising. Randomized, multi-institutional clinical trials are needed to optimally define the role of stem cell transplantation in PTCL.