Comparative Single-Institute Analysis of Cord Blood Transplantation from Unrelated Donors with Unrelated Bone Marrow or Related Peripheral Blood Stem-Cell Transplants in Elderly Patients with Hematologic Diseases after Reduced Intensity-Conditioning Regimen.

Although cord blood (CB) transplantation with reduced-intensity (RI) conditioning (RICBT) has been widely applied to those who lack available related or unrelated donors and are not eligible for conventional conditioning, indication of RICBT to elderly patients relative to other stem-cell sources is still controversial due to higher early mortality post-transplant and undefined long-term outcome. Since there has been not much data available regarding this issue, we retrospectively reviewed patients aged 55 and older who underwent RI allogeneic stem-cell transplantation at our institute from Nov. 2000 to Dec. 2006 consecutively. The study includes 121 recipients of CB (n=42), unrelated bone marrow (UBM, n=41), and related mobilized peripheral blood (RPB, n=38) for AML / MDS (n=66), ALL (n=11), CML (n=4), ML (n=31), MF (n=3), and AA (n=6). The median age for CB, UBM, and RPB recipients were 61 (range 56–69), 60 (55–70), and 60 (55–66), respectively. CB recipients had more serologically HLA-mismatched grafts (98% vs. 24% vs. 5%, P < .05), were conditioned more frequently with melphalan (90% vs. 34% vs. 32%, P < .05) and with total body irradiation (88% vs. 71% vs. 16%, P < .05), used more tacrolimus (100% vs. 71% vs. 18%, P < .05) and less methotrexate (0% vs. 76% vs. 74%, P < .05) for GVHD prophylaxis, had shorter duration of donor search (median 41 days (14–151) vs. 166 (93–345) vs. 130 (41–311), P < .05), and were transplanted more recently (2005–2006: 71% vs. 56% vs. 37%, P < .05). CB recipients tended to have high-risk disease status (76%) relative to UBM (59%) and RPB (66%) recipients, although not statistically significant. Other characteristics such as sex, diagnosis, and body weight were balanced among three groups. Median follow-up time of survivors was 554 days (25–1132), 667 days (315–1794), and 703 days (57–2214) for CB, UBM, and RPB recipients, respectively. CB recipients tended to show slower neutrophil recovery (median 19 days (12–36) vs. 16 (10–27) vs. 13 days (10–21)), and lower rate of myeloid engraftment (86% vs. 90% vs. 100%), although not statistically significant. The incidence of grades II–IV acute GVHD among evaluable CB recipients (61%) was lower than that of UBM (83%, P < .05) and comparable to that of RPB recipients (50%). The incidences of chronic GVHD for evaluable CB, UBM, and RPB recipients were 45%, 71%, and 71%, respectively (N.S.). The disease-free survival and overall survival (OS) at 2 years post-transplant were 23+/–7% and 33+/–8% for CB, 42+/–8% and 47+/–8% for UBM, and 35+/–9% and 40+/–9% for RPB recipients, respectively (N.S.). Within those who had standard risk diseases, 2-year OS were 67+/–15.7%, 48+/–13%, and 59+/–14% for CB (n=10), UBM (n=17), and RPB (n=13) recipients, respectively (N.S.). These data suggest that CB could be a viable stem-cell source for elderly patients as UBM or RPB, not just expanding opportunity of transplant. A larger-sized, randomized study is needed to further define the position of CB for this population of patients.