Role of Front-Line High Dose Therapy with Stem Cell Transplant in Peripheral T-Cell Lymphomas. A Single Center Experience.
Authors: Gritti Giuseppe , Rossi Andrea , Barbui Anna Maria , Grassi Anna , Algarotti Alessandra , Micò Caterina , Delaini Federica , Rambaldi Alessandro 
Published: October 2019

Abstract
Abstract 2733

Introduction:
The best treatment of peripheral T-cell lymphomas (PTCLs) currently remains a matter of debate. Some retrospective study and few phase II trials have shown that first line high dose therapy (HDT) with autologous stem cell transplant (SCT) may apparently offer better results. However, no comparative trials are currently available.

Material and Methods:
We retrospectively evaluated the outcome of previously untreated patients with PTCL, excluding mycosis fungoides and Sézary syndrome, referred to our Center between 1996 and 2012. An in-house histologic revision was performed to confirm the diagnosis according to the latest WHO criteria. From this analysis we excluded patients with diagnosis of ALK positive anaplastic large cell lymphoma (ALCL). We stratify patients according to treatment. Conventional therapy (CT) consisted of CHOP, CHOEP or MACOP(-B). From early 90s at our Center was adopted the strategy to consolidate response to initial treatment with either autologous or allogeneic SCT, whenever possible, in patients aged <65 years. These patients were assigned to HDT group.

Results:
The specific diagnosis of the 124 patients evaluated was PTCL-not otherwise specified (n=70), angioimmunoblastic T-cell lymphoma (n=21), ALCL ALK negative (n=19), other subtypes (n=14). At diagnosis, 43 patients were planned to receive HDT plus SCT but only 26 (60%) eventually received it (22 autologous, 4 allogeneic) while the remaining experienced early death (8 patients), progression (8 patients) or mobilization failure (1 patient). The median age of this first cohort was 47.9 years (range 23–63), that also showed an advanced Ann-Arbor stage (III-IV) or an int-high/high IPI in 77% and 58% of the cases, respectively. The rate of complete remission (CR) was 57% with 21% of patients dying during treatment (5 patients not evaluable for response, 3 responders and 1 with progressive disease). Eighty-one patients were treated according to a CT strategy. The median age of this latter group was 66.7 years (25–85), an advanced stage (III-IV) or an int-high/high IPI was present in 73% and 61%, respectively. The CR rate was 57% with 19% of the patient dying during treatment (11 patients not evaluable for response, 2 responders and 1 with progressive disease). With a median follow up of 1.63 years (0–25) and 82 deaths, by intention to treat analysis the 5-years overall survival (OS) was 43% and 32% for HDT and CT (p=.90, figure 1), respectively, while the 5-years OS of those patients eventually receiving SCT was 64%. Irrespectively from the adopted treatment strategy, patients who achieved a CR showed a similar 5-years OS and disease free survival that were 57% and 52% in the CT group and 80% and 64% in the HDT cohort (p=.43 and p=.44), respectively. Of the 54 patients with relapsed or refractory disease, 9 underwent salvage SCT (4 autologous, 5 allogeneic) with 3 patients achieving a sustained remission.

Conclusions:
The overall clinical outcome of most PTCL patients remains unsatisfactory, with a large fraction of patients not responding to front-line treatment. The advantage of a post-remission consolidation with SCT has to be confirmed by appropriate ad hoc designed clinical studies. On the contrary, allogeneic SCT, despite remaining a potentially curative treatment option for these patients, unfortunately has a limited applicability due to the frequent advanced age and comorbidities as well as to the difficulty in finding a donor.

Disclosures:
No relevant conflicts of interest to declare.