Outcome of allogeneic stem cell transplantation in myelodysplastic syndrome patients: prognostic implication of monosomal karyotype

Objective Monosomal karyotype (MK) is defined as the presence of two or more autosomal monosomies or a single monosomy associated with a structural abnormality. It was first described as a high-risk cytogenetic abnormality for acute myeloid leukemia and more recently in myelodysplastic syndromes (MDS). However, allotransplant outcome in MDS with MK has not been described. Patients and Methods We retrospectively reviewed data of 79 patients with MDS who underwent allotransplant at the University of Iowa from 1990 to 2009. We recorded patients' cytogenetic data, clinical characteristics and evaluated outcome following allogeneic stem cell transplant stratified by cytogenetic classification. Results Of 79 patients, 37 (47%) had unfavorable karyotypes (23 complex karyotype, 25 abnormal chromosome 7). Twenty-four patients (30%) had MK. Twenty-four patients (30%) relapsed and 59 (74.7%) died during study period. Patients with MK had higher 2-yr relapse incidence (RI) (51% vs. 29%; P = 0.01), lower 2-yr event-free survival (EFS) (8% vs. 40%; P = 0.02), and lower 2-yr overall survival (OS)(6% vs. 41%; P = 0.02) than patients without MK. We further analyzed the effect of MK in each unfavorable karyotype composite. Although the outcome was not statistically different, unfavorable karyotypes with patients with MK showed a trend toward higher 2-yr RI [hazard ratio (HR), 1.7; P = 0.34], lower 2-yr EFS (HR, 1.5; P = 0.29), and lower 2-yr OS (HR, 1.5; P = 0.28) compared to unfavorable karyotypes without MK. Conclusion Cytogenetic abnormalities remain an important prognostic factor for allotransplant outcome of MDS. Our results suggested poor allotransplant outcomes with high RI and low OS in MDS with MK.