Use of a decision analysis model to assess the cost-effectiveness of 18F-FDG PET in the management of metachronous liver metastases of colorectal cancer Lejeune C, Bismuth M J, Conroy T, Zanni C, Bey P, Bedenne L, Faivre J, Arveux P, Guillemin F Record Status This is a critical abstract of an economic evaluation that meets the criteria for inclusion on NHS EED. Each abstract contains a brief summary of the methods, the results and conclusions followed by a detailed critical assessment on the reliability of the study and the conclusions drawn. Health technology The study examined two strategies for the diagnosis of liver recurrences in patients with colorectal cancer (CRC). Computed tomography (CT) of the thorax, abdomen and pelvis was compared with initial CT of the thorax, abdomen and pelvis followed by fluorodeoxyglucose positron emission tomography (FDG-PET or simply PET). Type of intervention Diagnosis. Economic study type Cost-effectiveness analysis. Study population The study population comprised a hypothetical cohort of 68-year-old patients who had previously undergone resection for CRC, with suspected metachronous liver metastases. Metachronous metastases were defined as lesions diagnosed during follow-up after the resection of the primary tumour by abdominal ultrasonography. Setting The setting was outpatient (ambulatory patients). The economic study was carried out in France. Dates to which data relate The effectiveness data were derived from studies published between 1986 and 2003. No dates for resource use were explicitly reported. The price year was 2004. Source of effectiveness data The clinical and epidemiological data used in the decision model were: the probability of metachronous liver metastases if abnormal abdominal ultrasound; the sensitivity and specificity of CT, PET, magnetic resonance imaging (MRI) and liver biopsy; the proportion of resectable metastases; the frequency of use of diagnostic procedures; the morbidity and mortality rates associated with curative surgery; the life expectancy with absence of recurrence, curative surgery, chemotherapy and symptomatic treatment. Page: 1 / 5
Modelling The structure of the decision tree was represented graphically, with pathways were extensively illustrated and described. Both strategies under examination started with the use of the diagnostic tool, and then considered the use of liver biopsy, surgery or palliative treatment. Clearly, the accuracy of the diagnostic procedure determined the subsequent clinical pattern of care. The decision tree was populated with data derived from published literature and then validated by a committee of multidisciplinary experts composed of surgeons, oncologists and gastroenterologists. The time horizon of the analysis was the patient's lifetime. Sources searched to identify primary studies Details of the primary studies used to derive much of the clinical data were generally not reported. The frequency of use of diagnostic procedures and the sensitivity of second liver biopsy were mainly based on expert opinion. Life expectancy came from the Burgundy Digestive Cancer Registry database over the period 1976 to 1995. Methods used to judge relevance and validity, and for extracting data No systematic search for primary studies was reported. It is therefore possible that the primary sources might have been identified selectively. No details of the methods used to combine the primary estimates were given. However, much of the data obtained from published studies were validated by a committee of multidisciplinary experts. Measure of benefits used in the economic analysis The summary benefit measure used was the expected average life expectancy. This was estimated using a modelling approach. Life-years (LYs) were discounted at an annual rate of 5%. Other model outputs were also estimated. Such outputs were the number of true diagnoses of recurrence, the number of unseen recurrences, and the numbers of wellsuited treatments (curative resection, palliative treatment) and not well-suited treatments (unnecessary exploratory surgery, palliative treatment) amongst patients with suspected liver metastases. However, these outcomes were not combined with the costs. Direct costs The analysis of the costs was performed from the viewpoint of the national health insurance. It included the costs of diagnostic procedures (PET, CT, biopsy, and MRI) and treatment procedures. The unit costs and the quantities of resources used were presented separately for most items. The costs of the diagnostic procedures were obtained from "Nomenclature Generale des Actes Professionnels", a fixed-costs scale of medical procedures based on practitioners' fees, fixed costs for the medical procedures themselves, and fixed costs for operating the equipment. The cost of hospital stay required for liver biopsy and the costs of treatment procedures were based on the national reimbursement rate for the medical department of the Dijon University Hospital. The length of hospitalisation was estimated on the basis of diagnosis-related groups. Other resource quantities were based on authors' opinions. Discounting was not relevant as the costs were incurred during less than one year. The price year was 2004. Statistical analysis of costs The costs and quantities were treated deterministically. Indirect Costs Productivity costs were not considered. Currency Euros (EUR) and US dollars ($). Sensitivity analysis Page: 2 / 5
A univariate sensitivity analysis was carried out to assess the robustness of the cost-effectiveness ratios to variations in the clinical and economic inputs. Alternative ranges of clinical data were based on published estimates. The sources of the alternative cost data were not reported. Threshold values were also determined in order to assess the cut-off points beyond which the ranking of the strategies could change. Estimated benefits used in the economic analysis The expected LYs were 1.88 with both CT and CT+PET. When other clinical outputs were considered, the analysis confirmed that the two strategies were similar. The only difference between CT and CT+PET was in therapeutic management. Compared with CT+PET, CT alone was associated with a relative risk reduction of 9.5% in correctly assessing patients with non-resectable disease. The relative risk that patients would undergo inappropriate surgery was estimated to be reduced by 88.4% with CT+PET compared with CT alone (the percentage of inappropriate surgeries was 6.9% with CT and 0.8% with CT+PET). Cost results The estimated costs per patient were EUR 17,064 ($20,526) with CT+PET and EUR 19,735 ($23,739) with CT. Synthesis of costs and benefits An incremental analysis was performed to compare the two strategies. However, a cost-effectiveness ratio was not calculated as CT was as effective as CT+PET but was also more expensive. Therefore, CT+PET was the dominant strategy. The sensitivity analysis showed that CT+PET remained the dominant strategy under most of the alternative scenarios considered in the sensitivity analysis. Only when the cost of PET was set at an unrealistically high value (EUR 8,992 versus EUR 1,034 in the base-case) did CT become the preferred option. Authors' conclusions The use of computed tomography (CT) followed by positron emission tomography (PET) in the diagnosis and staging of liver metastases after curative resection of colorectal cancer (CRC) was as effective as CT alone in terms of expected survival, but was less expensive from the perspective of the French health insurance system. Savings were mainly due to a reduction in inappropriate surgeries. CRD COMMENTARY - Selection of comparators The rationale for the choice of the comparators was clear. The selection of CT alone and CT+PET reflected French guidelines for the management of patients after curative resection of CRC. Details on the two techniques were given. The authors stated that percutaneous radiofrequency was not considered to be a relevant comparator since it was a new protocol that still needed to be assessed. You should decide whether they are valid comparators in your own setting. Validity of estimate of measure of effectiveness The sources of the clinical data were given. However, no systematic search for data was reported. Some of the sources used were national statistics, which are generally valid. Expert opinion was also used to validate some of the published estimates. However, limited information on the other primary sources was given, which means that an objective assessment of the validity of the clinical inputs is not possible. Validity of estimate of measure of benefit The estimation of health benefits (LYs) was modelled using a decision analytic model. Discounting was performed, as Page: 3 / 5
recommended by international guidelines. The impact of the interventions on quality of life was not investigated. Validity of estimate of costs The cost analysis was consistent with the perspective adopted in the analysis. Extensive information on the unit costs and quantities of resources used was given, which enhances the possibility of replicating the analysis in other settings. Statistical analyses of the costs were not performed, but the sensitivity analysis addressed the impact of variations in the cost estimates. The sources of the costs were reported for all items. The price year was reported, which will facilitate reflation exercises in other time periods. Discounting was not relevant and was not performed. Other issues The authors reported the results from two published economic evaluations of CT+PET, which reported results similar to those achieved in the current study. The issue of the generalisability of the study results to other settings was implicitly addressed in the sensitivity analysis, in which alternative scenarios were considered. Specifically, the cost estimates were varied extensively. The study referred to a hypothetical cohort of patients at risk of developing liver recurrences after curative resection of CRC, and this was reflected in the authors' conclusions. The authors provided a comprehensive report of the results of the analysis. Implications of the study The study results suggest that CT+PET is a cost-effective diagnostic approach in comparison with CT alone. The authors pointed out the need for clinical trials that better evaluate the cost-effectiveness of adding PET to the diagnostic work-up of liver recurrence after CRC resection. Source of funding Supported by the Ministry of Health, the Urban Community of Nancy, and the Region of Lorraine. Bibliographic details Lejeune C, Bismuth M J, Conroy T, Zanni C, Bey P, Bedenne L, Faivre J, Arveux P, Guillemin F. Use of a decision analysis model to assess the cost-effectiveness of 18F-FDG PET in the management of metachronous liver metastases of colorectal cancer. Journal of Nuclear Medicine 2005; 46(12): 2020-2028 PubMedID 16330566 Other publications of related interest Because readers are likely to encounter and assess individual publications, NHS EED abstracts reflect the original publication as it is written, as a stand-alone paper. Where NHS EED abstractors are able to identify positively that a publication is significantly linked to or informed by other publications, these will be referenced in the text of the abstract and their bibliographic details recorded here for information. Park KC, Schwimmer J, Shepherd JE, et al. Decision analysis for the cost-effective management of recurrent colorectal cancer. Ann Surg. 2001;233:310-9. Gambhir SS, Valk P, Sheperd J, et al. Cost-effective analysis modeling of the role of FDG PET in the management of patients with recurrent colorectal cancer. J Nucl Med 1997;38 Suppl:90P. Ruhlmann J, Schomburg A, Bender H. Fluorodeoxyglucose whole-body positron emission tomography in colorectal patients studied in routine daily practice. Dis Colon Rectum 1997;40:1195-204. Nordlinger B, Guiguet M, Vaillant JC, et al. Surgical resection of colorectal carcinoma metastases to the liver: a prognostic scoring system to improve case selection, based on 1568 patients-french Surgical Association. Cancer Page: 4 / 5
Powered by TCPDF (www.tcpdf.org) 1996;77:1254-62. Indexing Status Subject indexing assigned by NLM MeSH Colorectal Neoplasms /pathology /radionuclide imaging; Cost-Benefit Analysis /methods; Decision Support Techniques; Fluorodeoxyglucose F18; Humans; Liver Neoplasms /pathology /radionuclide imaging; Neoplasm Metastasis; Neoplasm Staging /methods; Neoplasms /epidemiology; Positron-Emission Tomography /economics /methods; Sensitivity and Specificity; Time Factors; Tomography, X-Ray Computed; Treatment Outcome AccessionNumber 22007000878 Date bibliographic record published 30/09/2007 Date abstract record published 30/09/2007 Page: 5 / 5