Stem Cell Transplantation for Chronic Lymphocytic Leukaemia: Is this the Way Forward in the New Millennium?; Malignancy; Current Clinical Practice

The failure of conventional chemotherapy to eradicate chronic lymphocytic leukaemia cells and induce cure has led many clinicians to investigate the use of high dose chemotherapy and haemopoietic stem cell rescue in this disease. The selection of patients remains a major problem because this is a disease of elderly patients with a median overall survival of 7 years and will only therefore be applicable to a minority of patients. However transplantation is the most likely therapeutic option at this time to lead to cure in this condition. The best type of transplant is not known and not all patients will be able to mobilise adequate numbers of stem cells or have a suitable donor identified. Autologous transplantation relies on the ability of high doses of chemotherapy to eradicate disease whilst allogeneic transplantation attempts to harvest the graft versus leukaemia effect that has been identified in chronic granulocytic leukaemia. However, the high treatment related mortality and morbidity of allogeneic transplants has led to interest in the use of non-myeloablative allografts which hope to maximise the immunological effects of transplantation to achieve durable remissions. To date there have been no randomised clinical trials to compare the efficacy of combination chemotherapy, autologous or allogeneic transplants and this is unlikely to happen in the near future. Other issues that need to be addressed include the timing of transplantation, the source of stem cells, the optimal conditioning regimen and the role of immunomodulation post transplantation. This review attempts to answer some of these questions.