Different Outcome for Angioimmunoblastic T-Cell Lymphoma (AIL) and Peripheral T-Cell Lymphoma Unspecified (PTCL-U) Following Upfront Autologous Stem Cell Transplantation.

Introduction: Peripheral T-cell lymphomas (PTCL) are rare diseases and optimal treatment strategies still remain to be defined. With the exception of the ALK-positive anaplastic large cell lymphoma (ALCL) that shows a favourable outcome following conventional chemotherapy, PTCL are known for their poorer prognosis compared to aggressive B-cell lymphomas. However, the impact of the different PTCL-subtypes on treatment outcome has not been clearly demonstrated in prospective studies. PTCL unspecified (PTCL-U) and angioimmunoblastic T-cell lymphoma (AIL) represent the most common subtypes of PTCL in Western countries, accounting for approximately 70% of PTCL. We therefore analysed the data of our study on myeloablative radiochemotherapy followed by autologous stem cell transplantation (ASCT) in primary diagnosed PTCL with regard to the main histologic subtypes.

Material and Methods: From 06/00 to 06/06 92 patients with confirmed diagnosis of PTCL entered the study. Primary cutaneous PTCL and ALK+ ALCL were excluded from the trial. Main subtypes were PTCL-U (n= 37) and AIL (n= 28) accounting for 65 of the 92 patients (71%). 0f these patients 53 (PTCL, n= 31; AIL, n= 22) were evaluable for the analysis (82%).

Results: Median age was 50 years in the PTCL-U and 47.5 years in the AIL group, respectively. The International Prognostic Index (IPI) did not differ in both groups. In the PTCL-U and the AIL group a low/intermediate-low risk was found in 35% and 36%, respectively and a high/intermediate-high risk in 65% and 64%, respectively. There were slightly more patients in stage IV in the AIL group compared to the PTCL-U group (64% versus 53%). In addition, more patients in the AIL group complained of B-symptoms and had bone marrow involvement compared to the PTCL-U group (86% versus 66% and 48% versus 39%, respectively). However, in an intent-to treat analysis only 58% in the PTCL-U group compared to 82% in the AIL group underwent ASCT mainly due to a higher rate of patients with progressive disease in the PTCL-U group. The median overall survival (OS) was 11 months in the PTCL-NOS and 20 months in the AIL group. Regarding only patients undergoing ASCT, the median OS was 13.5 months in the PTCL-U and 25.5 months in the AIL group.

Conclusion: Our analysis suggests that patients with AIL, although showing a slightly more unfavourable risk profile at diagnosis, benefit more from upfront autotransplantation than patients with PTCL-U in our study.