The EBMT Lymphoma Working Party-European Mantle Cell Lymphoma Network Consensus Project On The Role Of Autologous and Allogeneic Stem Cell Transplantation In Mantle Cell Lymphoma: Recommendations Applying The Delphi Procedure
Authors: Robinson Stephen Paul , Corradini Paolo , Dreger Peter , Caballero Dolores , Geisler Christian H , Ghielmini Michele , Le Gouill Steven , Kimby Eva , Rule Simon , Vitolo Umberto , Dreyling Martin , Hermine O. 
Published: October 2019

Abstract

Introduction
The role of both autologous (autoSCT) and allogeneic stem cell transplantation (alloSCT) in the management of patients with mantle cell lymphoma (MCL) remains to be clarified. In the absence of prospective comparative trials decision making for clinicians remains challenging. We have conducted a consensus project to provide guidance on how stem cell transplantation should be employed in MCL.

Methods
This was a collaborative project between the Lymphoma Working Party of the EBMT and the European Mantle Cell Lymphoma Network. The RAND modified Delphi consensus procedure was used. 12 clinicians, recognized for their expertise in MCL, from both transplant and non-transplant centres contributed. A literature search was performed and consensus statements were formulated. Panel members ranked each statement. The statements were reviewed and modified and then a second round of ranking was performed.

Results
Consensus agreement was reached on the following statements: 1. Patients should be considered for transplant strategies based on their biological age and comorbidities and not just chronological age. 2. An autoSCT should be considered as the standard first line consolidation therapy in all patients considered suitable for high dose therapy. 3. First line induction therapy prior to SCT should incorporate high dose cytarabine and Rituximab based regimens. 4. Patients achieving either complete remission or partial remission following induction therapy should be considered for autoSCT. 5. Patients failing to achieve a PR or CR following induction therapy should not proceed directly to an autoSCT. 6. Patients undergoing an allogeneic SCT should receive reduced intensity conditioning regimens.
There was consensus disagreeing with the following statement: Prognostic criteria are available that permit the identification of low risk patients in need of first line therapy who should be considered for non-transplant based treatment.
There was partial consensus agreeing with the following statements: 1. Patients relapsing after an autoSCT should be considered for an allogeneic stem cell transplant following reinduction therapy.2. Patients with evidence of MRD relapse post alloSCT should, in the absence of graft versus host disease, be considered for rapid withdrawal of immunesuppression and donor lymphocyte infusions.
There was a partial consensus disagreeing with the following statements: 1 Patients should receive Rituximab maintenance following first line autologous stem cell transplant. 2. There are sufficient prognostic criteria to identify patients who should undergo an allogeneic stem cell transplantation as first line consolidation. 3. In patients relapsing after non-transplant first line therapy there are sufficient prognostic criteria to determine whether autoSCT or alloSCT consolidation should be used.
Finally there was no consensus with respect to the following statements. 1. Disease response to induction therapy prior to autoSCT should be assessed by PET scan. 2. Minimal residual disease (MRD) negativity is mandatory prior to autoSCT. 3. A TBI based regimen should be considered as the standard for conditioning prior to autoSCT. 4. Patients undergoing an autoSCT should receive in-vivo purging with Rituximab at the time of high dose conditioning therapy. 5. Patients with relapsed disease following non-transplant first line therapy should be considered for an autologous stem cell transplant to consolidate second (or higher) response. 6. Patients with relapsed disease following non-transplant first line therapy should be considered for an allogeneic SCT to consolidate second (or higher) response. 7. Patients undergoing autoSCT should be monitored for MRD post transplant. 8. Patients with evidence of MRD relapse post autoSCT should receive preemptive Rituximab. 9. Patients undergoing alloSCT should be monitored for MRD post transplant.

Conclusions
Consensus was obtained with regard to the role of autologous SCT in first line consolidation. However, the application of appropriate clinical and molecular prognostic factors to guide therapeutic decisions and the role of allogeneic transplantation warrant further clinical investigation.

Disclosures:
No relevant conflicts of interest to declare.