The Total Body Irradiation Schedule Affects Acute Leukemia Relapse After Matched T Cell-Depleted Hematopoietic Stem Cell Transplantation.
We sought to determine whether the total body irradiation (TBI) schedule affected outcome in patients with acute leukemia in complete remission who received T cell-depleted allogeneic hematopoietic stem cell transplantation from HLA identical siblings.



The study recruited 55 patients (median age, 48 years; age range, 20-66 years; 30 men and 25 women; 34 with acute myeloid leukemia and 21 with acute lymphoid leukemia). Hyperfractionated TBI (HTBI) (1.2 Gy thrice daily for 4 days [for a total dose of 14.4 Gy] from day -12 to day -9) was administered to 29 patients. Single-dose TBI (STBI) (8 Gy, at a median dose rate of 10.7 cGy/min on day -9) was given to 26 patients.



All patients achieved primary, sustained engraftment with full donor-type chimerism. At 10 years, the overall cumulative incidence of transplant-related mortality was 11% (SE, ±0.1%). It was 7% (SE, ±0.2%) after HTBI and 15% (SE, ±0.5%) after STBI (P=.3). The overall cumulative incidence of relapse was 33% (SE, ±0.5). It was 13% (SE, ±0.5%) after HTBI and 46% (SE, ±1%) after STBI (P=.02). The overall probability of disease-free survival (DFS) was 59% (SE, ±7%). It was 67% (SE, ±0.84%) after HTBI and 37% (SE, ±1.4%) after STBI (P=.01). Multivariate analyses showed the TBI schedule was the only risk factor that significantly affected relapse and DFS (P=.01 and P=.03, respectively).



In patients with acute leukemia, HTBI is more efficacious than STBI in eradicating minimal residual disease after HLA-matched T cell-depleted hematopoietic stem cell transplantation, thus affecting DFS.
Radiation Oncology Section, Department of Surgery and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy. Electronic address: cynthia.aristei@unipg.it.
Cynthia
C
Aristei
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Alessandra
A
Carotti
Radiation Oncology Section, University of Perugia, Perugia, Italy.
Elisa
E
Palazzari
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Lucia
L
Amico
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Loredana
L
Ruggeri
Radiation Oncology Division, Perugia General Hospital, Perugia, Italy.
Elisabetta
E
Perrucci
Radiation Oncology Division, Perugia General Hospital, Perugia, Italy.
Lorenzo
L
Falcinelli
Radiation Oncology Section, University of Perugia, Perugia, Italy.
Valentina
V
Lancellotta
Radiation Oncology Section, Department of Surgery and Biomedical Sciences, University of Perugia and Perugia General Hospital, Perugia, Italy.
Isabella
I
Palumbo
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Franca
F
Falzetti
Hematology and Bone Marrow Transplant Unit, Department of Clinical and Experimental Medicine, Parma General Hospital and University, Parma, Italy.
Franco
F
Aversa
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Mara
M
Merluzzi
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Andrea
A
Velardi
Division of Hematology and Clinical Immunology and Bone Marrow Transplant Program, Department of Medicine, Perugia General Hospital and University, Perugia, Italy.
Massimo Fabrizio
MF
Martelli
D000328:Adult; D000368:Aged; D002423:Cause of Death; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D006086:Graft vs Host Disease / Q000517:prevention & control; D018380:Hematopoietic Stem Cell Transplantation / Q000401:mortality; D006648:Histocompatibility; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000276:immunology / Q000628:therapy*; D008212:Lymphocyte Depletion; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology / Q000628:therapy*; D012008:Recurrence; D012074:Remission Induction; D055502:Secondary Prevention / Q000379:methods*; D035781:Siblings; D013601:T-Lymphocytes; D013997:Time Factors; D019172:Transplantation Conditioning / Q000379:methods; D016896:Treatment Outcome; D014916:Whole-Body Irradiation / Q000379:methods*; D055815:Young Adult