Single-Centre Experience with Stem-Cell Transplantation in Patients with Transformed Lymphoma: A Potential Curative Option

Context: Outcomes of patients with transformed lymphoma have historically been poor, prompting many centres to include stem-cell transplant (SCT) as part of the treatment strategy. However, several studies in the rituximab era suggest that survival may be more favourable than previously recognized, questioning the need for such intensive therapies. Objective: We analyzed the efficacy of SCT in transformed lymphomas at a single reference Transplant Unit. Design: We collected data from 51 patients; the indication was a diagnosis of diffuse large B-cell lymphoma (DLBCL) transformed from an indolent lymphoma, from 1995 to 2018. Of them, 36 received an auto-SCT and 15 an allo-SCT. Results: Median age was 60 (range, 40-69) and 52 (range, 35-65) years for patients receiving auto-SCT and allo-SCT, respectively. Patients in the allo-SCT group had been more intensively pretreated, as 13 (87%) patients received \u003e3 lines of treatment before SCT and 13 (87%) underwent a previous auto-SCT, whereas patients in the auto-SCT group were pretreated with a median of 2 (range, 1 to 4) lines of treatment. Regarding disease status at transplant, most patients (78% and 73% in the auto and allo-SCT groups, respectively) were transplanted in complete remission (CR). All auto-SCT patients received BEAM as conditioning regimen, whereas patients in the allo-SCT group received several fludarabine-based combinations. Transplant-related mortality (TRM) was 3.2% and 27% in the auto and allo-SCT groups, respectively. With a median follow-up of 61 and 50 months,4-year overall survival (OS) and progression-free-survival (PFS) were 87% and 76%, for the auto-SCT patients, and 52% and 56%, respectively, for the allo-SCT patients. In the auto-SCT group, 12 (33%) patients experienced disease progression and 7 (19.5%) died (5 [13.9%] from lymphoma), whereas in the allo-SCT group, only 2 (13%) patients had disease progression but 4 (27%) died due to transplant-related causes. Conclusions: SCT is a potentially curative option for patients with transformed lymphoma, since more than a half of patients are long-term survivors. Progression is the major cause of failure in auto-SCT whereas allo-SCT patients died because of toxicity. Efforts need to be made to identify patients who do not benefit from auto-SCT to avoid toxicity.