Allogeneic transplantation in T-cell lymphomas.

Except for ALK-positive anaplastic large cell lymphoma (ALCL) and patients with limited disease, mature T- and natural killer (NK) cell lymphomas are disorders with a poor prognosis. Patients with relapsed or refractory ALK-negative ALCL, angioimmunoblastic T-cell lymphoma (AITL), or peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) after allogeneic transplantation of hematopoietic stem cells (alloSCT) achieve long-term survival in 35%-50% of cases. Survival in patients with less frequent subtypes (NK/T-cell lymphoma, cutaneous T-cell lymphomas, acute T-cell leukemia/lymphoma, or hepatosplenic T-cell lymphoma) also seems promising. These results are significantly better than those of any other treatment modality, including the new drugs. Therefore, alloSCT should be considered in patients with relapsed/ refractory T-cell lymphoma. Because of low patient numbers and lack of comparative studies, the optimum conditioning regimen prior to transplantation as well as other details of the transplant procedure remain unknown and await further study. Studies investigating the role of alloSCT as part of first-line therapy in poor-risk T-cell lymphomas are ongoing. At present, data are not sufficient to recommend alloSCT outside of clinical trials.