Conventional allograft and autograft in low grade lymphoma

Abstract

In low grade non-Hodgkin's lymphoma (NHL), while conventional chemotherapy does increase progression-free survival (PFS), overall survival (OS) has not been improved by the newer chemotherapies and advanced indolent NHL remains essentially incurable without allogeneic bone marrow transplant. High dose therapy (HDT) followed by autologous stem cell transplantation (ASCT) aims to eradicate residual tumour cells. Nevertheless, it is still unclear if despite extending PFS it prolongs OS. However, even if ASCT does so, it does not guarantee cure and the majority of patients will eventually relapse. There is accumulating evidence that by using a non-contaminated graft (obtained with stem cell purging), OS does improve. However, data from prospective randomised trials comparing purged versus unpurged autografts is awaited. Nevertheless, allogeneic stem cell transplantation (Allo SCT) appears to provide the best/highest chances for cure, providing a non-contaminated graft along with a graft versus lymphoma (GVL) effect. However, the procedure is age limited due to its high toxicity, (especially in patients over 50 years), limiting this procedure to younger patients whose life expectancy due to disease is short. Reduced intensity SCT may therefore be a reasonable approach in younger patients with advanced disease, allowing a GVL effect with less toxicity compared with conventional allograft. However, data is still limited and follow-up in the majority of studies is relatively short, highlighting the need for longer follow-up to establish the role of reduced intensity SCT in low grade lymphoma.