Efficacy of Immediate Allogeneic Hematopoietic Stem Cell Transplantation Versus Bridging Therapy Followed by Transplantation in Higher-Risk Myelodysplastic Syndrome Patients

Inclusion Criteria: 1. Age ≥18 years 2. High relapse risk MDS, defined by: * IPSS-R score ≥3.5. * IPSS-M stratification as intermediate-high, high, or very high risk. 3. Eligible for allogeneic HSCT (including matched or mismatched related/unrelated donor transplantations). 4. Karnofsky Performance Status (KPS) ≥60. 5. Signed informed consent. Exclusion Criteria: 1. Severe organ dysfunction: * Left ventricular ejection fraction \<50%. * Oxygen supplementation requirement. * Serum bilirubin \>1.5x upper limit of normal (unless due to Gilbert syndrome) or AST/ALT \>5x upper limit of normal. * Estimated glomerular filtration rate (eGFR) \<50 mL/min. 2. History of prior allogeneic HSCT. 3. Any condition deemed unsuitable by the investigator.