NEW YORK (Reuters Health) – Patients with follicular non-Hodgkin lymphoma that has transformed into aggressive-histology lymphoma do better when treated with high-dose chemotherapy followed by autologous stem-cell transplantation (autoSCT) rather than allogeneic stem-cell transplantation (alloSCT), according to a Canadian study.

“The benefit of alloSCT seems to be offset by higher TRM (transplantation-related mortality),” the investigators report in the Journal of Clinical Oncology online February 11.

Dr. Diego Villa, with the British Columbia Cancer Agency in Vancouver, and colleagues explain that most patients with transformed follicular lymphoma receive conventional systemic chemotherapy, but selected patients receive high-dose chemotherapy followed by autologous or allogeneic hematopoietic stem-cell transplantation. It’s not known if one treatment is better than another.

Furthermore, the addition of rituximab to chemotherapy for B-cell lymphomas has improved outcomes, but its benefit in patients with transformation is unclear, particularly in those undergoing stem-cell transplantation.

To look into these questions, the team collected data on outcomes of 172 patients with follicular lymphoma and subsequent biopsy-proven aggressive-histology transformation treated at 14 institutions in Canada between 1992 and 2010.

“All patients received at least one cycle of an anthracycline- or platinum-containing regimen with rituximab for transformation according to local protocols and policies,” the authors note. Within the cohort, 22 patients received alloSCT, 97 were treated with autoSCT, and 53 received rituximab-containing chemotherapy only.

Five-year progression-free survival rates after transformation in the three groups were similar at 46%, 55% and 40%, according to the report. However, corresponding 5-year overall survival rates were 46%, 65%, and 61%.

On multivariate analysis, the primary endpoint of overall survival (OS) was improved for patients treated with autoSCT (hazard ratio 0.13; p

Transplantation-related mortality at 5 years was 23% in the alloSCT group compared to just 5% in those treated with autoSCT, Dr. Villa and colleagues note.

They acknowledge that the study has several limitations, but nonetheless conclude, “Our data suggest that eligible patients with transformed follicular lymphoma may benefit from autoSCT because it improves OS compared with rituximab-containing chemotherapy. However, the superiority of autoSCT is modest. Patients with significant comorbidities related to organ dysfunction or age may be best served by treatment with rituximab-containing chemotherapy.”

They add, “AlloSCT may be considered in certain circumstances, particularly if an autologous stem-cell graft cannot be collected or if better strategies emerge to minimize TRM. However, relapse and TRM remain significant problems in patients with transformation who undergo SCT, even in the rituximab era.”

SOURCE: Autologous and Allogeneic Stem-Cell Transplantation for Transformed Follicular Lymphoma: A Report of the Canadian Blood and Marrow Transplant Group
J Clin Oncol 2013;30.