Myeloablative vs nonmyeloablative allogeneic transplantation for patients with myelodysplastic syndrome or acute myelogenous leukemia with multilineage dysplasia: a retrospective analysis.

Transplant outcome was analyzed in 150 patients with myelodysplastic syndrome (MDS) or acute myelogenous leukemia transformed from MDS (tAML) conditioned with nonmyeloablative or myeloablative regimens. A total of 38 patients received nonmyeloablative regimens of 2 Gy total body irradiation alone (n=2) or with fludarabine (n=36), 90mg/m2. A total of 112 patients received a myeloablative regimen of busulfan, 16mg/ kg (targeted to 800-900 ng/ml), and cyclophosphamide 120 mg/ kg. Nonmyeloablative patients were older (median age 62 vs 52 years, P<0.001), more frequently had progressed to tAML (53 vs 31%, P=0.06), had higher risk disease by the International Prognostic Scoring System (53 vs 30%, P=0.004), had higher transplant specific comorbidity indices (68 vs 42%, P=0.01) and more frequently had durable complete responses to induction chemotherapy (58 vs 14%). Three-year overall survival (27%/48% (P=0.56)), progression-free survival (28%/4 44%, (P=0.60)), and nonrelapse mortality (41%/34%, (P=0.94)) did not differ significantly between nonmyeloblative/myeloablative conditioning. Overall (HR=0.9, P=0.84) and progression-free survivals (HR=1, P=0.93) were similar for patients with chemotherapy-induced remissions irrespective of conditioning intensity. Graft vs leukemia effects may be more important than conditioning intensity in preventing progression in patients in chemotherapy-induced remissions at the time of transplantation. Randomized prospective studies are needed to further address the optimal choice of transplant conditioning intensity in myeloid neoplasms.