Background Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is a curative treatment for adult patients with acute lymphoblastic leukemia (ALL). Cyclophosphamide plus total body irradiation (TBI/Cy) or plus busulfan (Bu/Cy) is a widely used pre-transplant conditioning regimen for ALL. We retrospectively compared the overall survival (OS), disease-free survival (DFS), and other transplant outcomes of allo-HSCT in 119 adult patients with ALL who received an HLA-matched sibling allo-HSCT using TBI-based versus non-TBI-based conditioning regimens. Patients were divided into two groups by their conditioning regimen: TBI/Cy or Bu/Cy. Results Median OS was 11 months in the TBI/Cy group and 6.2 months in the Bu/Cy group. Median DFS was 11.1 months in the TBI group versus 6.8 months in the Bu group, without a statistically significant difference. A higher risk of relapse was observed with the Bu/Cy regimen (HR 2.709, CI 95% 1.106 to 6.638, p = 0.029). Patients who received a transplant in ≥ CR2 were associated with poor DFS. Conclusion Despite the high relapse rate in the non-TBI regimen (Bu/Cy), both regimens had no statistically significant differences in OS, DFS, and NRM. Additional prospective studies are indeed warranted to evaluate the long-term outcomes of radiation-free regimens, including oral and intravenous busulfan, and compare these regimens with TBI-based ones.

Background Autologous stem cell transplantation (ASCT) is a curative treatment for patients with hematological malignancies. Melphalan either alone or in combination with other chemotherapeutic agents is a widely used pre-transplant conditioning regimen with known gastrointestinal (GI) complications. We retrospectively evaluate the incidence and severity of GI toxicities, the possible risk factors, and their impact on transplant outcomes in 47 patients who received ASCT using melphalan-based conditioning. Results Median age was 50 years. Among our patients, 48.9% received melphalan at 200 mg/m2. Mucositis was developed in 93.6% of patients, nausea in 87.2% and grade 2 vomiting in 36.2% of patients. Grade 3 diarrhea was detected in 42.6%. Severe GI toxicities were associated with significantly delayed engraftment, longer hospital stay, and increased transfusion requirements but overall survival (OS) and transplant-related mortality (TRM) were not affected by the severity of GI symptoms. Conclusion Despite using prophylactic and supportive care, some patients developed severe GI complications following different doses of melphalan with a negative effect on some transplant outcomes. Melphalan dose or disease type was not identified as a risk factor for severe GI toxicity. Additional larger prospective studies with higher doses, different formulations, and better prophylactic measures are warranted to evaluate potential risk factors and their impact on GI toxicities.