The Confirmation of Safety for the Intensified Conditioning Regimens: A Retrospective Study of Allogeneic Hematopoietic Stem Cell Transplantation for Non-Remission Hematological Malignant Diseases

Background: The prognosis of allogeneic hematopoietic stem cell transplantation (HSCT) for non-remission hematological malignant diseases is usually unfavorable. The most uncontrollable factor is residual disease or relapse. To overcome this problem, intensified conditioning regimens- sequential and/or additional chemotherapy to the standard regimen- could be effective. However, increasing the intensity of conditioning might also lead to more complications. Materials and Methods: We retrospectively analyzed 81 patients with non-remission disease who received allogeneic HSCT in our institution between 2007 and 2011. Results: 55.6% in 36 myeloablative conditioning patients and 46.7% in 45 reduced-intensity conditioning patients received intensified conditioning. The 5-year probability of overall survival was 35.0% and 17.1% in the standard and intensified group, respectively (p=0.027). Relapse mortality was 30% in the standard regimen group and 36.6% in the intensified regimen group (p=0.54). Transplant-related mortality (TRM) at 30 and 100 days was 5%, 17.1% (p=0.086) and 27.5%, 34.2% (p=0.52) in the standard and intensified group, respectively. There was no difference in TRM between the 2 groups at 30 days and 100 days. Conclusion: The results of the study confirm the safety of the intensified conditioning regimen. Meanwhile, it could be considered as one of the few methods available to reduce the tumor burden before HSCT for refractory malignant diseases.