Allogeneic Hematopoietic Stem Cell Transplantation Therapy

Most patients with an HLA-compatible donor, sibling or otherwise, will preferentially undergo transplantation therapy while still in chronic phase.43 This will occur either as initial treatment or in patients not responding to interferon or imatinib therapy. The results of transplantation therapy for patients in blast phase are poor, and many institutions are reluctant to perform this procedure unless the patient is able to achieve a second chronic phase with chemotherapy or imatinib prior to transplantation. The decision not to offer transplantation to patients with advanced-phase CML has been based on results from cooperative groups and/or large single institutions that have reported long-term survival for transplantation in blast phase of 0-14% and survival rates for accelerated-phase patients of 15-20%.4445 On the other hand, since no other therapies exist for these patients that are associated with long-term survival, many patients are transplanted in advanced phases of disease for want of better treatment.

To better identify patients likely to survive transplantation, despite entering the advanced phases of disease, several groups have employed prognostic scoring systems generated from multivariate analyses of transplantation outcomes in relatively large numbers of patients. One of these scoring systems, the Gratwohl Score, based on results of transplantation in patients reported by the European Blood and Marrow Transplantation Group, has been widely used.46 In this scoring system, a higher score (associated with a worse survival) is given based on several pre-transplantation variables predictive for poor outcome, including increasing patient age, advanced stage of disease, incompatibility of donor and recipient, prolonged time from diagnosis to transplant, and donor -recipient sex mismatch. Thus, a young patient (age, 20-40) with an HLA-identical sibling match, transplanted within 12 months of diagnosis may still be a suitable candidate for transplantation, even in the accelerated or blast phase of disease, whereas a patient above the age of 40 in blast phase undergoing a matched unrelated transplantation would have a small chance for long-term survival. Although improvement continues in the supportive care and treatment of graft-versus host disease for patients undergoing allogeneic hematopoietic stem cell transplantation, transplantation of CML in the advanced stages should be avoided with every effort being made to identify those patients unlikely to be long-term survivors with nontransplan-

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