Unrelated cord blood transplantation versus haploidentical transplantation in adult and pediatric patients with hematological malignancies-A meta-analysis and systematic review.

Several clinical trials have compared the safety and efficacy of umbilical cord blood transplantation (UCBT) with haploidentical transplantation (HIT) in patients with hematological malignancies. To obtain more reliable evidence, we performed a systematic review and meta-analysis. Seven studies were included and there was a combined total of 102 children and 1311 adults undergoing UCBT, along with 94 children and 915 adults undergoing HIT. Pooled comparisons of studies of UCBT and HIT in children found that the incidence of chronic graft-versus-host disease (GVHD) and disease-free survival (DFS) at 2 years (RR 0.34, 95% CI (0.03, 4.53), P=0.41; HR 0.51, 95% CI (0.23, 1.09), P=0.08) were not statistically different. For adults, although the incidence of grade II-IV acute GVHD differ (RR 1.17, 95% CI (1.02, 1.34), P=0.02), but it indicates a very small difference between the groups as the RR is barely above 1. On the other hand, although the incidence of grade III-IV acute GVHD did not differ (RR 1.51, 95% CI (0.78, 2.92), P=0.22), but there is a tendency of higher risk for the UCBT. And the incidence of chronic GVHD did not differ (RR 1.05, 95% CI (0.82, 1.34), P=0.71). There was no difference in relapse, non-relapse mortality (NRM) and DFS at 2 years (HR 0.92, 95% CI (0.74, 1.13), P=0.42; HR 0.87, 95% CI (0.49, 1.52) P=0.62 and HR 0.74 95% CI (0.39, 1.43), P=0.37). In conclusion, UCBT and HIT could be considered as equally effective option for adult patients without HLA-matched donors.