Clinical effectiveness and cost-effectiveness of stem cell transplantation in the management of acute leukaemia: a systematic review.

BACKGROUND

Acute leukaemia is a group of rapidly progressing cancers of bone marrow and blood classified as either acute myeloid leukaemia (AML) or acute lymphoblastic leukaemia (ALL). Haemopoietic stem cell transplantation (SCT) has developed as an adjunct to or replacement for conventional chemotherapy with the aim of improving survival and quality of life.

OBJECTIVES

A systematic overview of the best available evidence on the clinical effectiveness and cost-effectiveness of SCT in the treatment of acute leukaemia.

DATA SOURCES

Clinical effectiveness: electronic databases, including MEDLINE, EMBASE and the Cochrane Library, were searched from inception to December 2008 to identify published systematic reviews and meta-analyses. Cochrane CENTRAL, MEDLINE, EMBASE and Science Citation Index (SCI) were searched from 1997 to March 2009 to identify primary studies. Cost-effectiveness: MEDLINE, EMBASE, Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database (NHS EED) were searched from inception to January 2009.

STUDY SELECTION

Potentially relevant papers were retrieved and independently checked against predefined criteria by two reviewers (one in the case of the cost-effectiveness review).

STUDY APPRAISAL

Included reviews and meta-analyses were critically appraised and data extracted and narratively presented. Included randomised controlled trials (RCTs) and donor versus no donor (DvND) studies were mapped to the evidence covered in existing systematic reviews and meta-analyses according to a framework of 12 decision problems (DPs): DP1 related to SCT in adults with AML in first complete remission (CR1); DP2 to adults with AML in second or subsequent remission or with refractory disease (CR2+); DP3 to children with AML in CR1; DP4 to children with AML in CR2+; DP5 to adults with ALL in CR1; DP6 to adults with ALL in CR2+; DP7 to children with ALL in CR1; DP8 to children with ALL in CR2+; DP9 to comparison of different sources of stem cells in transplantation; DP10 to different conditioning regimens; DP11 to the use of purging in autologous SCT; and DP12 to the use of T-cell depletion in allogeneic SCT.

RESULTS

Fifteen systematic reviews/meta-analyses met the inclusion criteria for the review of clinical effectiveness, thirteen of which were published from 2004 onwards. Taking into account the timing of their publications, most reviews appeared to have omitted an appreciable proportion of potentially available evidence. The best available evidence for effectiveness of allogeneic SCT using stem cells from matched sibling donors came from DvND studies: there was sufficient evidence to support the use of allogeneic SCT in DP1 (except in good-risk patients), DP3 (role of risk stratification unclear) and DP5 (role of risk stratification unclear). There was conflicting evidence in DP7 and a paucity of evidence from DvND studies for all decision problems concerning patient groups in CR2+. The best available evidence for effectiveness of autologous SCT came from RCTs: overall, evidence suggested that autologous SCT was either similar to or less effective than chemotherapy. There was a paucity of evidence from published reviews of RCTs for DPs 9-12. Nineteen studies met the inclusion criteria in the cost-effectiveness review, most reporting only cost information and only one incorporating an economic model. Although there is a wealth of information on costs and some information on cost-effectiveness of allogeneic SCT in adults with AML (DPs 1 and 2), there is very limited evidence on relative costs and cost-effectiveness for other DPs.

LIMITATIONS

Time and resources did not permit critical appraisal of the primary studies on which the reviews/meta-analyses reviewed were based; there were substantial differences in methodologies, and consequently quantitative synthesis of data was neither planned in the protocol nor carried out; some of the studies were quite old and might not reflect current practice; and a number of the studies might not be applicable to the UK.

CONCLUSIONS

Bearing in mind the limitations, existing evidence suggests that sibling donor allogeneic SCT may be more effective than chemotherapy in adult AML (except in good-risk patients) in CR1, childhood AML in CR1 and adult ALL in CR1, and that autologous SCT is equal to or less effective than chemotherapy. No firm conclusions could be drawn regarding the cost-effectiveness of SCT in the UK NHS owing to the limitations given above. Future research should include the impact of the treatments on patients' quality of life as well as information on health service use and costs associated with SCT from the perspective of the UK NHS.