Preconditioning With a Combination of Thiotepa, Cyclophosphamide, and Busulfan for Allogeneic Hematopoietic Stem Cell Transplantation in the Treatment of NK/T-Cell Lymphoma

Inclusion Criteria: 1\. Age range: 18-70 years old, gender not restricted. 2. Patients diagnosed with NK/T cell lymphoma through histopathology or flow cytometry, 1) with stage III/IV patients receiving first-line or salvage treatment and achieving remission, 2) stage II patients with relapsed/refractory disease after salvage treatment achieving remission, 3) patients with NK cell lymphoma/leukemia receiving first-line or salvage treatment and achieving remission, 4) patients with relapsed/refractory disease. 3. Patients must have a suitable hematopoietic stem cell donor. 1) The related donor must have at least 5/10 HLA-A, -B, -C, -DQB1, and -DRB1 matching. 2) The unrelated donor must have at least 8/10 HLA-A, -B, -C, -DQB1, and -DRB1 matching. 4. HCT-specific comorbidity index score (HCT-CI) \<= 2. 5. ECOG: 0-2 points. 6. Liver and kidney functions, as well as heart and lung functions, must meet the following requirements: 1) Serum creatinine \<= 1.5 × ULN; 2) Cardiac function: Ejection fraction \>= 50%; 3) Basal oxygen saturation \> 92%; 4) Total bilirubin \<= 1.5 × ULN; ALT and AST \<= 2.0 × ULN; 5) Pulmonary function: DLCO (hemoglobin corrected) \>= 40% and FEV1 \>= 50%. 7. Patients must be capable of understanding and willing to participate in this study, and sign the informed consent form. Exclusion Criteria: 1\. Patients allergic to stietap, cyclophosphamide or busulfan or its components. 2. Any unstable systemic diseases: including but not limited to unstable angin…