Unrelated donor umbilical cord blood transplant versus unrelated hematopoietic stem cell transplant in patients with acute leukemia: A meta-analysis and systematic review.

Acute leukemia is a global disease with a poor prognosis for many patients. While an increasing number of patients with acute leukemia are being treated with unrelated hematopoietic stem cell transplants (HSCT) or umbilical cord blood transplants (UCBT), recent comparative reports of these 2 procedures are lacking. Therefore, we conducted a meta-analysis of the safety and efficacy of unrelated HSCT and unrelated single-unit UCBT for the treatment of pediatric and adult patients with acute lymphoblastic leukemia (ALL) or acute myeloid leukemia (AML). The primary outcomes were the rates of relapse, overall survival (OS), progression-free survival (PFS), and days to neutrophil and platelet recovery. Pooled effects (odds ratios [OR] or difference in means) were determined with either random- or fixed-effects models. Our meta-analysis included 9 studies that enrolled 6762 patients (UCBT: n=2026; HSCT: n=4736). The risk of relapse for patients undergoing UCBT was similar to that of patients who received an HSCT (OR=1.030; 95%CI, 0.767 to 1.383, P=0.847). We also found no difference between HSCT and UCBT for OS (pooled OR=1.417; 95%CI, 0.936 to 2.146; P=0.100) or PFS (OR=1.165; 95%CI, 0.996 to 1.362; P=0.056). However, neutrophil and platelet recovery periods were both shorter after HSCT than after UCBT (neutrophil recovery: difference in means=-3.420, 95% CI: -5.491 to -1.349, P=0.001; platelet recovery: difference in means -20.350, 95% CI: -33.656 to -7.044, P=0.003). Collectively, our data provide strong evidence to support increased use of cord blood transplants for both adults and children with acute leukemia.