Long-term outcomes after reduced-intensity conditioning allogeneic stem cell transplantation for low-grade lymphoma: a survey by the French Society of Bone Marrow Graft Transplantation and Cellular Therapy (SFGM-TC).

High-dose chemotherapy with allogeneic stem cell transplantation (SCT) has proven to be a successful treatment for low-grade lymphoma (LGL), but is associated with considerable transplant-related mortality (TRM). In an effort to reduce toxic mortality while maintaining the graft-versus-leukemia effect, allogeneic SCT has been combined with a reduced-intensity conditioning (RIC) regimen. The aim of this study was to determine the outcome of patients with LGL treated with RIC allogeneic SCT. This retrospective multicenter study included 73 patients with relapsed or refractory LGL allografted after a RIC regimen between 1998 and 2005 whose data were recorded in a French registry. Patients received a median of three lines of therapy prior to RIC allogeneic SCT. The most widely used conditioning regimens were fludarabine + busulfan + antithymocyte globulin (n=43) and fludarabine + total body irradiation (n=21). Prior to allografting, patients were in complete response (CR; n=21), partial response (PR; n=33) or had chemoresistant disease (n=19). The median follow-up was 37 months (range, 16 to 77 months). In patients in CR, PR and chemoresistant disease, the 3-year overall survival rates were 66%, 64% and 32%, respectively, while the 3-year event-free survival rates were 66%, 52% and 32%, respectively. The 3-year cumulative incidences of TRM were 32%, 28% and 63%, respectively. The incidence of relapse was 9.6%. Although associated with significant TRM, RIC allogeneic SCT in advanced chemosensitive disease leads to long-term survival.