Background: It is estimated that two-thirds of acute leukemia patients who require stem cell transplantation do not have a matched sibling donor. In these cases, a Stem Cell matched unrelated donor (mud-SCT) is recommended. However, in development countries the lack of transplantation lists and difficult the access to mud-SCT and delays the transplantation, increasing the risk of complications. Nowadays a potentially effective alternative for mud-SCT is the Stem Cell haploidentical transplant (haplo-SCT) which has mayor probability to recruit a compatible donor.
Objective: To compare the benefits and damages between mud-SCT and haplo-SCT in acute leukemia patients.
Methods: We performed a systematic review of randomized clinical trials and controlled cohorts published in scientific journals that compared the benefits and damages between haplo-SCT and mud-SCT in acute leukemia patients (either lymphoblastic or myeloid). This search was performed in two steps: 1) search at three search engines (Pubmed, Scopus and CENTRAL), and 2) search the list of references from the studies included at step 1. Two reviewers realized and independent selection of the studies and data extraction. The certainty of evidence for each outcome was assessed using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. Protocol is available at 10.6084/m9.figshare.12089457.
Results: No randomized clinical trials were found. We included eight cohort studies (n= 6595 patients with acute leukemia). One of these studies used propensity scores to match haplo-SCT and mud-SCT groups, and reported two mud-SCT groups: MUD 9/10 and MUD 10/10 (Piamontese, 2017). When the meta-analysis was performed, we found a statistically significant difference that favored to MUD-SCT at the global survival (HR 0.89, 95% CI 0.8-0.99) and disease-free survival (HR: 0.85, 95% CI 0.75-0.96). The sensitivity analysis excluding the MUD 10/10 result from the Piamontese study did not found significant statistic differences. However, the results of this study suggest that MUD 10/10 had better results than MUD 9/10. Also, we found a statistically significant difference that favored haplo-SCT at the mortality without relapses outcome (HR 0.77, 95% CI 0.65-0.92), and no significant statistic differences in the relapse outcome (HR 0.97, 95% CI 0.85-1.10).
Conclusion: Haplo-SCT seems to be similar to MUD-SCT 9/10, even if the results based on the Piamontese study suggest that MUD 10/10 had better results.