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 myelo-dysplastic 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 2Gy total body irradiation alone (n = 2) or with fludarabine (n = 36), 90mg/m(2). A total of 112 patients received a myeloablative regimen of busulfan, 16 mg/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%/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.