Reduced-intensity transplantation in the treatment of haematological malignancies: current status and future-prospects.

The concept of reduced intensity conditioning (RIC) in allogeneic transplantation had challenged our conventional wisdom about the necessity of high-dose chemo-radiotherapy in order to achieve donor engraftment. The feasibility of RIC in elderly and infirm patients who would not otherwise be considered suitable for a conventional allogeneic transplantation caused a surge of interest in RIC procedures in the late 90s and early part of this decade which was however, not tempered by the balanced need for clinical trials. Although the initial expectations of reduction in graft-versus-host-disease (GVHD) were belied by the high incidences of GVHD, the importance of GVHD, particularly chronic, in controlling haematological malignancies with poor prognosis was often well exemplified. In addition, the conventional outcome measures in allogeneic transplantation such as 100- day mortality became irrelevant in the era of RIC due to reduction in early regimen-related toxicities. This did not always translate to improved overall survival due to late attritions from relapse, GVHD or late infectious complications. The enthusiasm for performing RIC in malignant diseases seems to have reached a plateau, but its true potential probably remains unexplored. In light of our current understanding of RIC, this article will highlight the future of this procedure in haematological malignancies.