Allogeneic Stem Cell Transplantation as Treatment for Relapsed and High-Risk Peripheral T-Cell Lymphoma.

Background: Autologous stem cell transplant (ASCT) is the standard treatment for relapsed aggressive diffuse large B-cell lymphoma. Studies are conflicting as to whether ASCT has comparable salvage rates in peripheral T-cell lymphoma (PTCL). Emerging evidence suggests that a graft-versus-lymphoma effect may exist in PTCL. Thus, allogeneic stem cell transplant (allo-SCT) may be a favoured approach for relapsed PTCL patients.

Methods: The British Columbia Leukaemia/BMT database was reviewed to identify all PTCL patients who have undergone allo-SCT for relapsed/refractory or high risk PTCL. Twenty patients (13M, 7F) with PTCL received an allo-SCT between November 1990 and May 2007. Median age at transplant was 46.5 years (range 16–64 years). Lymphoma subtypes were PTCL-unspecified (n=7), anaplastic large cell (n=4), hepato-splenic γδ (n=4), angio-immunoblastic (n=3), enteropathy-type (n=1) and nasal-type natural killer (n=1). Seventy percent of the patients presented at diagnosis with two or three risk factors from the age-adjusted International Prognostic Index. The disease status at the time of transplant was: First complete remission (n=4; all 4 had hepatosplenic γδ PTCL); second or greater complete remission (n=6); first partial remission (n=1); first chemosensitive relapse (n=4); untested relapse (n=3); induction failure (n=2). Sixteen patients had matched sibling donors and 4 had unrelated donors (2 patients had mismatched donors). Sixteen patients received radiation-based conditioning regimens. Two patients received reduced-intensity conditioning regimens.

Results: At the time of analysis, 5 patients have died. Three patients died within fifty days of transplant with treatment-related complications (2 acute graft-versus-host disease (GVHD), 1 pulmonary hemorrhage), 1 died of chronic GVHD and 1 died of high-grade sarcoma. Non-relapse mortality was 19% at 2 years. Median follow-up of surviving patients was 21 months (range, 1 to 163 months). Of the remaining 15 patients alive at the time of analysis, 3 had relapsed lymphoma and 12 remain in remission. Seven patients (35%) had grade 2 acute GVHD or greater. Thirteen patients (65%) had chronic GVHD (3 limited, 10 extensive). Univariate analysis was performed to determine the influence of gender, age, previous number of lines of therapy, acute GVHD and chronic GVHD. None of these factors were found to be of prognostic significance. Estimated 2-year event-free and overall survival at was 49% [95% CI: 28–83%] and 77% [95% CI: 59–100%], respectively. Risk of relapse at 2 years was 40% (95% CI: 3–63%).

Conclusions: Allo SCT is a feasible option with encouraging results for patients with relapsed PTCL and select individuals with high-risk histologic subtypes.