Comparative Outcomes of Reduced-Intensity and Myeloablative Conditioning in Unrelated Cord Blood Transplantation for Adult Standard-Risk Hematological Diseases

Unrelated cord blood transplantation (uCBT) using reduced-intensity conditioning (RIC) is increasingly used for older and medically unfit patients. Data on the efficiency of hematopoietic stem cell transplantation (HCT) after RIC in younger and standard-risk patients are limited relative to myeloablative conditioning (MAC).

To compare the outocomes of RIC to MAC in uCBT for adult patients with standard-risk hematological diseases, we retrospectively reviewed medical records of 57 standard risk hematological disease patients who underwent first uCBT at Toranomon Hospital from Jan. 2005 to December.2011. The definition of standard risk disease is severe aplastic anemia (SAA), myelodysplastic syndrome (MDS) in RA, RARS, and RCMD, acute myeloid or lymphoid leukemia (AML, ALL) in complete remission (CR) 1 or 2, chronic myeloid leukemia (CML) in chronic phase, malignant lymphoma (ML) and adult T-cell leukemia (ATL) in CR. RIC and MAC are defined according to previously reported criteria.

The median age of the studied patients was 55 years (range; 26–70). Twenty nine of patients received RIC and 28 MAC. Eleven patients of SAA, 7 MDS, 17 AML, 12 ALL, 5 CML, 2 ML, and 3 ATL were included in this study. Median follow-up days of survivors was 299 (11–2522). Cumulative incidence of neutrophil engraftment was 89.2% and the median days of engraftment is 20 days (11–51). Cumulative incidence of grade 2 to 4 acute graft versus host disease (aGVHD) was 42.9%. The 5-year disease-free and overall survival (DFS and OS) rates were 49.1% and 42.6%, respectively. The 5-years OS was comparable between MAC and RIC (RIC= 52.1% versus MAC= 44.2%; P=0.90). The 5-years OS of the elderly patients >54 years (n=27, 47%) were significantly lower than that in the younger patients (n=30, 53%) (35.1% versus 63.7%; P=0.042). The 5-years transplant-related mortality (TRM) was comparable between MAC and RIC (RIC= 35.0% versus MAC= 28.6%; P=0.56). The relapse rate was also comparable in two groups (RIC=11.9% versus MAC=33.6%; P=0.2)

This study showed that uCBT with RIC for standard risk disease patients with median age of 55 years old had the similar results as MAC regimens in the 5-years OS, DFS, TRM and relapse rate.

No relevant conflicts of interest to declare.