Comparison of Outcomes of Unrelated Bone Marrow and Umbilical Cord Blood Transplants in Children with Hematologic Malignancies: Single Center Study in Korea.

In order to compare the outcomes of unrelated umbilical cord blood transplants (UCBT) or bone marrow transplants, 102 children with hematologic malignancies transplanted with unrelated umbilical cord blood (n=35, M:F=21:14, median age 4 years) or unrelated bone marrow transplants (UBMT) (n= 67, M:F=49:18, median age 9 years) were analyzed in a retrospective single center study (between Aug. 1997 and Dec. 2003 in the Catholic Hematopoietic Stem Cell Transplantation Center of Korea). HLA mismatches were defined by serology for class I and molecular typing for DRB1. The donor was HLA mismatched in 94% of UCBTs (33 of 35 UCBT) and in 0 % of UBMT. Non-adjusted estimates of 2-year event-free survival rates were 46 % and 57 %, respectively (P > 0.2). Engraftment failures of donor cells occurred in 17 % (6 out of 35) of UCBT and in 6 % (4 out of 67) of UBMT. Grade >= III acute GVHDs developed in 3 out of 29 (10 %) engrafted patients who underwent UCBT and in 17 out of 63 (27 %) engrafted patients who underwent UBMT. Early TRM at day 100 was 31 % (11 out of 35) for UCBT and 22 % (12 out of 67) for UBMTs. Within post-transplant month 3, CMV infections occurred in 37 % of UCBT and 54 % of UBMT, but most of them did not progress to CMV disease due to early ganciclovir treatment. Chronic GVHD developed in 2 out of 22 (9 %) patients who underwent UCBT and in 15 out of 49 (31 %) patients underwent UBMT.

In conclusion, the use of UCBT as a source of hematopoietic stem cells is a reasonable option for children with hematologic malignancies lacking an acceptable, matched unrelated marrow donor.