Allogeneic bone marrow transplantation for secondary leukemia or myelodysplasia

Marrow transplantation results in disease-free survival for less than one-third of patients treated for secondary leukemia. The objective of this report is to review results following allogeneic marrow transplantation for treatment of secondary leukemia or myelodysplasia at a single tertiary referral center to determine the patient characteristics which lead to better survival and lower relapse.

The medical records of 99 patients with secondary leukemia or myelodysplasia transplanted consecutively at the Fred Hutchinson Cancer Research Center between 1971 and 1997 were reviewed. Prior to development of secondary leukemia or myelodysplasia, the patients' original diagnoses were hematopoietic malignancies, solid tumors, aplastic anemia, or miscellaneous individual disorders previously treated by chemotherapy alone, radiation alone, chemoradiotherapy, or immunosuppressive therapy. At the time of transplantation, at each stage of myelodysplasia the numbers of patients were 52 with acute myelogenous leukemia (AML), 15 with refractory anemia with excess blasts in transition (RAEB-T), 18 with refractory anemia with excess blasts (RAEB), 11 with refractory anemia (RA), 1 with refractory anemia with ringed sideroblasts (RARS), and 2 with hypoplastic unclassifiable hematologic disorders. Sixty-five patients received marrow from an HLA identical or partially identical family member, and 34 received marrow from an HLA identical unrelated donor after conditioning with chemotherapy and total body irradiation or chemotherapy alone.

The Kaplan-Meier probability of survival after transplantation for all patients was 13%, and by stage of disease was 33% for RA/RARS, 20% for RAEB, and 8% for RAEB-T/AML. The probability of relapse for all patients was 47%, was 34% for RAEB, and 58% for RAEB-T/AML. None of the patients with RA/RARS has relapsed. The overall probability of non-relapse mortality was 78%, divided equally among infection or organ failure-related causes of death.

The main impediments to long-term survival after transplantation for secondary leukemia or myelodysplasia are relapse and mortality from infections or organ failure. The survival is better when transplantation is done during the early stages of myelodysplasia because it is then associated with a lower relapse rate. These data suggest that patients at risk of secondary myelodysplasia should be followed prospectively to detect the early stages of myelodysplasia, and be considered for transplantation at that time.