***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Objective We conducted a prospect i ve , r and omized , open-label , multicenter study to compare busulfan plus fludarabine ( BuFlu ) with busulfan plus cyclophosphamide ( BuCy ) as the conditioning regimen in allogeneic hematopoietic stem cell transplantation ( allo-HSCT ) for acute myeloid leukemia ( AML ) in first complete remission ( CR1 ) . Methods Totally 108 AML-CR1 patients undergoing allo-HSCT were r and omized into BuCy ( busulfan 1.6 mg/kg , q12 hours , -7 ~ -4d ; cyclophosphamide 60 mg/kg.d , -3 ~ -2d ) or BuFlu ( busulfan 1.6 mg/kg , q12 hours , -5 ~ -2d ; fludarabine 30 mg/m2.d , -6 ~ -2d ) group . Hematopoietic engraftment , regimen-related toxicity ( RRT ) , graft-versus-host disease ( GVHD ) , transplant related mortality ( TRM ) , and overall survival were compared between the two groups . Results All patients achieved hematopoietic reconstitution except for two patients who died of RRT during conditioning . All patients obtained complete donor chimerism by day + 30 post-transplantation . The incidence of total and III-IV RRT were 94.4 % and 81.5 % ( P = 0.038 ) , and 16.7 % and 0.0 % ( P = 0.002 ) , respectively , in BuCy and BuFlu group . With a median follow up of 609 ( range , 3–2130 ) days after transplantation , the 5-year cumulative incidence of TRM were 18.8 ± 6.9 % and 9.9 ± 6.3 % ( P = 0.104 ) ; the 5-year cumulative incidence of leukemia relapse were 16.5 ± 5.8 % and 16.2 ± 5.3 % ( P = 0.943 ) ; the 5-year disease-free survival and overall survival were 67.4 ± 7.6 % and 75.3 ± 7.2 % ( P = 0.315 ) , and 72.3 ± 7.5 % and 81.9 ± 7.0 % ( P = 0.177 ) , respectively in BuCy and BuFlu group . Conclusion Compared with BuCy , BuFlu as a myeloablative condition regimen was associated with lower toxicities and comparable anti-leukemic activity in AML-CR1 patients undergoing allo-HSCT We previously reported that the Charlson Comorbidity Index ( CCI ) was useful for predicting outcomes in patients undergoing allogeneic hematopoietic cell transplantation ( HCT ) . However , the sample size of patients with scores of 1 or more , captured by the CCI , did not exceed 35 % . Further , some comorbidities were rarely found among patients who underwent HCT . Therefore , the current study was design ed to ( 1 ) better define previously identified comorbidities using pretransplant laboratory data , ( 2 ) investigate additional HCT-related comorbidities , and ( 3 ) establish comorbidity scores that were suited for HCT . Data were collected from 1055 patients , and then r and omly divided into training and validation sets . Weights were assigned to individual comorbidities according to their prognostic significance in Cox proportional hazard models . The new index was then vali date d. The new index proved to be more sensitive than the CCI since it captured 62 % of patients with scores more than 0 compared with 12 % , respectively . Further , the new index showed better survival prediction than the CCI ( likelihood ratio of 23.7 versus 7.1 and c statistics of 0.661 versus 0.561 , respectively , P < .001 ) . In conclusion , the new simple index provided valid and reliable scoring of pretransplant comorbidities that predicted nonrelapse mortality and survival . This index will be useful for clinical trials and patient counseling before HCT In this multicenter retrospective study , the outcomes of 836 patients with myelodysplastic syndrome ( MDS ) who underwent transplantation with a human leukocyte antigen (HLA)-identical sibling donor were analyzed according to 2 types of conditioning : reduced-intensity conditioning ( RIC ) in 215 patients , and st and ard myeloablative ( or high-dose ) conditioning ( SMC ) in 621 patients . In multivariate analysis , the 3-year relapse rate was significantly increased after RIC ( hazard ratio [ HR ] , 1.64 ; 95 % confidence interval [ 95 % CI ] , 1.2 - 2.2 ; P = .001 ) , but the 3-year nonrelapse mortality ( NRM ) rate was decreased in the RIC group ( HR , 0.61 ; 95 % CI , 0.41 - 0.91 ; P = .015 ) . The 3-year probabilities of progression-free and overall survivals were similar in both groups ( 39 % after SMC vs 33 % in RIC ; multivariate P = .9 ; and 45 % vs 41 % , respectively ; P = .8 ) . In conclusion , the lower 3-year NRM after  RIC  is encouraging , since these patients were older ( age > 50 years in 73 % RIC vs 28 % in SMC , P < .001 ) and had more adverse pretransplantation variables . However , based on the higher risk of relapse , patients with no contraindications for SMC should not receive RIC outside of prospect i ve r and omized trials , which are needed to establish the position of RIC-based transplantation in the treatment of patients with MDS Although reduced-intensity conditioning ( RIC ) and non-myeloablative (NMA)-conditioning regimens have been used for over a decade , their relative efficacy vs myeloablative ( MA ) approaches to allogeneic hematopoietic cell transplantation in patients with AML and myelodysplasia ( MDS ) is unknown . We compared disease status , donor , graft and recipient characteristics with outcomes of 3731 MA with 1448 RIC/NMA procedures performed at 217 centers between 1997 and 2004 . The 5-year univariate probabilities and multivariate relative risk outcomes of relapse , TRM , disease-free survival ( DFS ) and OS are reported . Adjusted OS at 5 years was 34 , 33 and 26 % for MA , RIC and NMA transplants , respectively . NMA conditioning result ed in inferior DFS and OS , but there was no difference in DFS and OS between RIC and MA regimens . Late TRM negates early decreases in toxicity with RIC and NMA regimens . Our data suggest that higher regimen intensity may contribute to optimal survival in patients with AML/MDS , suggesting roles for both regimen intensity and graft vs leukemia in these diseases . Prospect i ve studies comparing regimens are needed to confirm this finding and determine the optimal approach to patients who are eligible for either MA or RIC/NMA conditioning In this multicenter retrospective study , the long-term outcomes of 878 adults with AML and refractory anemia with excess blasts ( RAEB ) with BM blasts < 10 % who underwent transplantation with an HLA-identical sibling donor between 1998 and 2004 were analyzed according to four regimens of conditioning intensity : reduced-intensity conditioning ( RIC ) ( either intermediate RIC ( IntermRIC ) or non-myeloablative ( NMA ) RIC ) , and myeloablative conditioning ( MC ) in 718 patients ( either conventional MC or hyperintense MC . In multivariate cox analysis , patients undergoing NMA transplantation had lower non-relapse mortality risk in the first 100 days after transplantation ( P<0.01 ) , but a higher risk beyond day + 100 ( P=0.02 ) , as well as higher relapse incidence in the first 12 months ( P<0.01 ) , but the risk was similar in all groups beyond 12 months . The probabilities of PFS and OS up to 7 years were significantly lower only in the NMA subgroup ( P⩽0.01 for both ) . The 7-year OS was 53 % , 29 % , 56 % and 51 % , respectively . Our data suggest that prospect i ve studies comparing RIC regimens ( especially IntermRIC ) with MC are appropriate in patients with AML and RAEB who are in a non-advanced disease status The objectives of this study were to develop transplantation regimens for patients with advanced myelodysplastic syndrome ( MDS ) that would be associated with low transplantation-related mortality and improved relapse-free survival .  Sixty patients with advanced MDS or acute myeloid leukemia evolving from MDS ( sAML ) , 12 to 62 years old ( median , 40 years ) , were conditioned with busulfan ( 7 mg/kg ) and TBI ( 6 x 200 cGy ) ( BU/TBI ) and received transplants from related ( n = 20 ) or unrelated donors ( n = 40 ) . By French-American-British ( FAB ) criteria , 21 patients had refractory anemia with excess blasts ( RAEB ) , 16 had RAEB in transformation ( RAEB-T ) , 15 had sAML , and 8 had chronic myelomonocytic leukemia ( CMML ) . By International Prognostic Scoring System ( IPSS ) criteria , 1 patient had low , 10 had intermediate-1 , 13 had intermediate-2 , and 31 had high-risk MDS ( 5 patients had proliferative CMML ) . All evaluable patients achieved sustained engraftment . The cumulative incidence ( CI ) of acute GVHD grade s II to IV was 83 % with unrelated donors and 85 % with related donors . The CI of relapse was 25 % at 3 years . The incidence of nonrelapse mortality ( NRM ) at 100 days was 38 % . The Kaplan-Meier estimate of survival was 26 % at 3 years . Major causes of death were relapse , organ failure , GVHD , and infection . In multivariate analysis , improved relapse-free survival was associated with good cytogenetic risk ( P = .002 ) and shorter disease duration ( P = .004 ) . NRM was increased with longer disease duration ( P = .0002 ) , positive cytomegalovirus serology ( P = .02 ) , and male sex ( P = .02 ) . Relapse was associated with poor cytogenetic risk ( P = .0004 ) . Thus , BU/TBI conditioning as used in this trial was associated with relapse rates comparable to those observed with a previously used more intensive regimen combining BU/TBI with cyclophosphamide . However , despite the omission of cyclophosphamide , transplantation-related morbidity and mortality were considerable , particularly with transplants from unrelated donors . Future trials should explore the efficacy and tolerability of reduced-intensity conditioning regimens The optimum intensity of conditioning therapy in patients aged 40–60 years with AML and myelodysplastic syndrome ( MDS ) undergoing allogeneic haematopoietic cell transplantation ( alloHCT )  remains uncertain . We compared outcomes of reduced intensity conditioning ( RIC ) and conventional intensity conditioning ( CIC ) in 101consecutive patients ( CIC , 62 ; RIC , 39 ) with AML and MDS aged 40–60 years undergoing alloHCT from 2002 to 2008 at our centre . The median age , unrelated transplants and co-morbidity index were higher in the RIC group . Median OS and EFS were 31.0 months ( 95 % confidence interval ( CI ) : 12.8–59.3 ) and 20.7 months ( 95 % CI : 11.0–30.4 ) , respectively , with no significant difference between the two cohorts . The 3-year treatment-related mortality ( TRM ) and relapse were 28 % ( 95 % CI : 21–39 ) and 25 % ( 95 % CI : 17–36 ) , respectively , with no significant difference between the two cohorts . No difference in OS , EFS , TRM or relapse was observed between the two cohorts in the multivariate model . Only disease risk was significantly associated with OS ( Hazard ratio ( HR ) : 1.85 , CI : 1.01–3.45 ) , EFS ( HR : 1.73 , 95 % CI : 1.00–3.10 ) and cumulative relapse ( HR : 3.24 , 95 % CI : 1.08–10.12 ) . Disease biology rather than intensity of conditioning regimen seems to determine outcomes of alloHCT in patients aged 40–60 years with AML/MDS The LAM2001 phase 3 trial , involving 832 patients with acute myeloid leukemia ( AML ; median : 46 years ) proposed HLA-identical sibling allograft HSCT for all patients with an identified donor . The trial compared reduced-intensity conditioning ( RIC ) for patients older than 50 years of age ( N = 47 ) and myeloablative conditioning for younger patients ( N = 117 ) .  BM HSCT was performed in the younger patients , while the older ones received a consolidation course , followed by peripheral blood allo-HSCT using RIC . The incidence of grade II-IV acute GVHD , was 51.9 % ( 95 % confidence interval [ 
    Output:
    
Significant heterogeneity was not found among the studies for any of the endpoints except for grade II-IV aGVHD .
RIC alloHSCT may be an effective treatment strategy for AML/MDS patients who are not suitable c and i date s for MAC alloHSCT .