This trial is a prospective, single-arm, single-center clinical study. A total of 44 elderly (aged 60 to 69 years) patients with hematological malignancies who need to receive a single-unit unrelated umbilical cord blood transplantation (UCBT) are planned to be enrolled. After screening and enrollment, patients are scheduled to receive the following drug treatment regimen: Thiotepa 5 mg/kg every 12 hours on day -8; Granulocyte Colony-Stimulating Factor(G-CSF) 5 ug/kg/day from day -8 to -5; Cytarabine 1.5 g/m2 from day -7 to -5; Fludarabine 30 mg/m2/day from day -7 to -4; Busulfan 0.8 mg/kg every 6 hours from day -4 to -2. Umbilical cord blood hematopoietic stem cells are reinfused on day 0. Routine monitoring of blood routine is conducted, and platelets and red blood cells are transfused when necessary.

Inclusion Criteria:

• Aged between 60 and 69 years old (inclusive), gender not restricted.

• Patients with hematological malignancies who plan to receive a single unrelated umbilical cord blood transplantation treatment

• The liver and kidney functions, as well as the heart and lung functions, must meet the following requirements:

  1. Serum creatinine ≤ 1.5 × ULN
  2. Cardiac function: Ejection fraction > 50%
  3. Baseline oxygen saturation > 92%
  4. Total bilirubin ≤ 1.5 × ULN; ALT and AST ≤ 2.5 × ULN
  5. Pulmonary function: DLCO (hemoglobin-corrected) > 65% and FEV1 > 65%

• ECOG PS≤2

• HCT-CI≤2

• Expected survival period ≥ 6 months

• By signing the informed consent form, one voluntarily participates in this study and is willing and able to cooperate with the data collection in this research.

Exclusion Criteria:

• For those who are allergic to the drugs and their related metabolites
• Any unstable systemic diseases: including but not limited to stable angina pectoris, cerebrovascular accident or transient cerebral ischemia (within 3 months before screening), myocardial infarction (within 3 months before screening), congestive heart failure (NYHA classification ≥ 3), severe arrhythmias requiring drug treatment, liver, kidney or metabolic diseases; patients with pulmonary hypertension; or diseases that, in the judgment of the investigator, pose a serious threat to the safety of the patient or affect the patient's ability to complete the study.
• Active and uncontrolled infection: Hemodynamic instability related to the infection, or new symptoms or signs of infection appear, or new infection lesions are found on imaging, or persistent fever without symptoms or signs that cannot rule out the presence of an infection.
• The patient is currently involved in a clinical intervention study
• The patient is unable to understand the nature of the study or has not given informed consent
• Other circumstances where the researcher deems the patient unsuitable for inclusion in this study