Acceptable Outcomes for Patients Receiving Allogeneic Hematopoietic Stem Cell Transplantation (AlloSCT) for Relapsed Aggressive Non-Hodgkin’s Lymphoma (NHL).

Background: AlloSCT for the treatment of aggressive histology NHL is appealing on the grounds of providing both a tumour free graft and a graft versus lymphoma mechanism for disease clearance. Currently only modest experience has been acquired concerning this treatment modality because of the fear of increased treatment related mortality (TRM).

Methods: Retrospective review of 47 consecutive patients with aggressive histology NHL who proceeded to AlloSCT between 1987–2003 in Vancouver. Patients with Burkitt’s lymphoma and lymphoblastic lymphoma were excluded.

Characteristics: WHO classification histology: 24, diffuse large B cell (including 5 T cell Rich B cell and 3 primary mediastinal); 16, transformed indolent to diffuse large B cell; 7, peripheral T cell unspecified. Gender M:F 27:20. Median age at AlloSCT 40 years (range 19–55 years). Disease status at AlloSCT: 33 (71%) chemosensitive relapse; 12 (25%) primary resistant /resistant relapse; 2 (4%) first complete remission. 39 (83%) had advanced stage disease at SCT. Stem cell source: 33 (71%) HLA-identical sibling bone marrow; 3 (6%) HLA-identical sibling peripheral blood; 8 (17%) unrelated donor bone marrow; 3 (6%) unrelated donor peripheral blood. Cyclophosphamide /TBI conditioning was used in 81% of patients.

Results: 22 patients remain alive post AlloSCT with a median follow-up of 40 months (3–135 months). The 5 year overall survival and event free survival (EFS) for the 47 patients was 47% (95% CI 32% – 63%) and 43% (95% CI 27% – 59%) respectively. The 5 year EFS for the individual disease groups was diffuse large B Cell 37%; transformed indolent B Cell 12%; peripheral T cell - unspecified 86%. Chemosensitivity at SCT was associated with a 5 year EFS of 41% (95% CI 23% – 60%) as compared to 37% (95% CI 8% – 67%) for those with chemorefractory disease (p = 0.61). The cumulative incidence of TRM at 3 months and relapse at 3 years were 17% (95% CI 8% – 29%) and 32% (95% CI 18% – 47%) respectively for the entire 47 patients. Cumulative incidence of relapse at 3 years was 54% for patients with chemoresistant disease versus 25% for those with chemosensitive disease (p=0.049). The incidence of acute and chronic graft versus host disease (GVHD) was 57% and 51% respectively.

Conclusion: AlloSCT for aggressive NHL results in an acceptable TRM and favourable long term EFS and OS for patients with advanced stage disease having relapsed after primary treatment. Patient with chemoresistant disease can have a durable remission post AlloSCT although they are at increased risk of relapse.