Reduced-intensity conditioning regimen using low-dose total body irradiation before allogeneic transplant for hematologic malignancies: Experience from the European Group for Blood and Marrow Transplantation.
OBJECTIVE
The high rate of toxicity is the limitation of myeloblastive regimens before allogeneic transplantation. A reduced intensity regimen can allow engraftment of stem cells and subsequent transfer of immune cells for the induction of a graft-vs.-tumor reaction.


METHODS
The data from 130 patients (80 males and 50 females) treated between 1998 and 2003 for various hematologic malignancies were analyzed. The median patient age was 50 years (range, 3-72 years). Allogeneic transplantation using peripheral blood or bone marrow, or both, was performed in 104 (82%), 22 (17%), and 4 (3%) patients, respectively, from HLA identical sibling donors (n = 93, 72%), matched unrelated donors (n = 23, 18%), mismatched related donors (4%), or mismatched unrelated donors (6%). Total body irradiation (TBI) at a dose of 2 Gy delivered in one fraction was given to 101 patients (78%), and a total dose of 4-6 Gy was given in 29 (22%) patients. The median dose rate was 14.3 cGy/min (range, 6-16.4).


RESULTS
After a median follow-up period of 20 months (range, 1-62 months), engraftment was obtained in 122 patients (94%). Acute graft-vs.-host disease of Grade 2 or worse was observed in 37% of patients. Multivariate analysis showed three favorable independent factors for event-free survival: HLA identical sibling donor (p < 0.0001; relative risk [RR], 0.15), complete remission (p < 0.0001; RR, 3.08), and female donor to male patient (p = 0.006; RR 2.43). For relapse, the two favorable prognostic factors were complete remission (p < 0.0001, RR 0.11) and HLA identical sibling donor (p = 0.0007; RR 3.59).


CONCLUSIONS
In this multicenter study, we confirmed high rates of engraftment and chimerism after the reduced intensity regimen. Our results are comparable to those previously reported. Radiation parameters seem to have no impact on outcome. However, the lack of a statistically significant difference in terms of dose rate may have been due, in part, to the small population size in the subgroup analysis.
Belkacémi
Yazid
Y
Department of Radiation Oncology, Oscar Lambret Center and University of Lille II, Lille, France. y-belkacemi@o-lambret.fr
Labopin
Myriam
M
Hennequin
Christophe
C
Hoffstetter
Sylvette
S
Mungai
Raffaello
R
Wygoda
Marc
M
Lundell
Marie
M
Finke
Jurgen
J
Aktinson
Chris
C
Lorchel
Frédéric
F
Durdux
Catherine
C
Basara
Nadezda
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D005260:Female; D019337:Hematologic Neoplasms / Q000628:therapy*; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011879:Radiotherapy Dosage; D019172:Transplantation Conditioning / Q000379:methods*; D014184:Transplantation, Homologous; D016896:Treatment Outcome; D014916:Whole-Body Irradiation / Q000379:methods*