Frequency and Impact of Allogeneic Hematopoetic Stem Cell Transplant and Preparative Regimen in Patients with High and Intermediate Risk AML at a Small Center

Background: Allogeneic hematopoietic cell transplantation (HCT) likely prolongs survival in high and intermediate risk adults with acute myeloid leukemia (AML). Prior studies, however, suggest that only about 15-20% of AML patients especially older than 50 with abnormal cytogenetics receive HCT. In this report, we evaluated the impact of transplant and preparative regimen on high- or intermediate-risk AML patients treated in our center.

Methods: We retrospectively reviewed all patients who were diagnosed with AML (non promyelocytic) in our center between 2002 and 2012. Primary objective was to study the impact of HCT and preparative regimen in high and intermediate risk AML patients. Demographics and disease-related variables were collected. OS was defined as the time from diagnosis to the time of death or last follow up.

Results: Between 2002 and 2012, 123 patients with high or intermediate risk AML patients were treated at our center. Median age at diagnosis was 60 (range 19-89). 82 patients had high-risk features while 41 had intermediate risk features. Median OS for all patients was 368 days.

Of these 124 patients, fifty-one patients (41%) received allogeneic HSCT at a median of 4.6 months from diagnosis. Median age of patients who received HCT was 53 while median age of patients who did not get HCT was 68. Of the 51 patients who received HCT, 13 patients with median age of 61 received a reduced toxicity/ Intensity conditioning regimen (RIC) while 37 patients with median age of 49 received a fully myelo-ablative regimen (MA). One got transplant elsewhere with unknown regimen.  Median percentage of blasts in bone marrow at time of HCT was 3 and 3.5% for the RIC and MA regimens, respectively. Number of patients who had 10% or more blasts in the bone marrow at transplant was 9 of the 37 patients (24%) who received MA regimen and 3 of the 13 patients (23%) who received RIC regimen.

Median OS for patients who received HCT was 551 days while it was 200 days for patients who did not receive HCT (p=0.0013) Fig1. The median OS for patients who got RIC was 1095 days but less at 434 days for MA patients but not statistically significant (p=0.64) Fig2. The cumulative incidence of relapse was not different between the two groups.

Conclusion: In this small cohort of consecutive patients from a single center, the results suggest that HCT can be performed in patients with high and Intermediate-risk AML patients including older patients using RIC. RIC in older patients and MA in younger patients did not differ in term of OS. However this is limited by the small number of patients and a larger prospective evaluation is needed taking into consideration better models encompassing performance status and co-morbidities.

Figure1

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