Clonal Cytogenetic Evolution in Relapse of Myeloid Hematological Neoplasms After Allogeneic Stem Cell Transplantation

Background: Relapse is the leading cause of treatment failure in patients with myeloid hematologic malignancies undergoing allogeneic hematopoietic cell transplantation. Clonal genomic evolution may contribute to post-transplant relapse, yet its determinants and prognostic impact remain incompletely characterized. Methods: In this retrospective study, we analyzed 63 patients with myeloid neoplasms who underwent cytogenetic evaluation both at diagnosis and at relapse after allogeneic hematopoietic stem cell transplantation. Cytogenetic changes (CGE), including evolution, devolution, or combined patterns, were assessed and correlated with clinical characteristics, prior treatment exposure, and survival outcomes. Results: Cytogenetic changes were observed in 46.1% of patients. The presence of cytogenetic changes (CGE) was strongly associated with the presence and complexity of cytogenetic abnormalities at initial diagnosis, whereas prior chemotherapy exposure, conditioning intensity, and donor type showed no significant association. Patients with cytogenetic changes had a lower complete remission rate at day 30 after transplantation; however, relapse-free survival and post-relapse survival did not differ significantly between groups. Conclusions: These findings suggest a potential association between post-transplant cytogenetic changes and intrinsic genomic instability, although treatment-related effects cannot be excluded. Larger, disease-stratified studies integrating cytogenetic and molecular analyses are warranted to further clarify the biological and prognostic relevance of clonal evolution following transplantation.