Haploidentical donor versus double-unit cord blood transplantation in hematologic malignancies: comparative survival and graft-versus-host disease outcomes from a decade of real-world experience

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative option for patients with hematologic malignancies, but the limited availability of HLA-matched sibling donors necessitates alternative graft sources. Haploidentical donors (HIDs) and double-unit umbilical cord blood (DUCB) are two widely used alternatives, yet direct comparisons of their clinical outcomes remain limited. METHODS: We conducted a retrospective single-center study of 97 patients with hematologic malignancies who underwent HSCT between August 2014 and May 2024. Patients received either HID transplantation (n = 57) or DUCB transplantation (n = 40). Hematopoietic recovery, graft-versus-host disease (GVHD), and long-term survival outcomes were assessed using cumulative incidence and Kaplan-Meier analyses, with multivariate Cox regression applied to identify prognostic factors. RESULTS: HID recipients achieved significantly faster neutrophil (median: 14.00 vs. 22.50 days) and platelet recovery (median: 15.00 vs. 44.50 days) than DUCB recipients (both P < 0.001). The incidence of grade II-IV acute GVHD (16.80% vs. 47.70%, P < 0.001) and chronic GVHD (10.30% vs. 28.60%, P = 0.033) was lower in the HID group, although severe grade III-IV aGVHD rates were comparable (13.00% vs. 23.90%, P = 0.160). Five-year overall survival (56.70% HID vs. 48.90% DUCB, P = 0.573), relapse-free survival (76.60% vs. 89.70%, P = 0.210), GVHD-free relapse-free survival (48.00% vs. 46.30%, P = 0.410), and non-relapse mortality (NRM) (35.40% vs. 47.00%, P = 0.188) did not differ significantly between groups. CONCLUSION: Both HID and DUCB transplantation are viable alternatives in the absence of an HLA-matched sibling donor. However, HID transplantation offers faster hematopoietic recovery and a reduced GVHD burden, which may provide practical clinical advantages when donor availability permits.