Positron emission tomography with selected mediastinoscopy compared to routine mediastinoscopy offers cost and clinical outcome benefits for pre-operative staging of nonsmall cell lung cancer Yap K K, Yap K S, Byrne A J, Berlangieri S U, Poon A, Mitchell P, Knight S R, Clarke P C, Harris A, Tauro A, Rowe C C, Scott A M 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 Two diagnostic approaches for the preoperative staging of non-small-cell lung cancer (NSCLC) were examined. The approaches were routine 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) with selected mediastinoscopy versus routine mediastinoscopy without FDG-PET. Type of intervention Diagnosis. Economic study type Cost-effectiveness analysis. Study population The study population comprised a hypothetical cohort of patients requiring a diagnostic technique for the detection of resectable or unresectable NSCLC. Setting The setting was a hospital. The economic study was carried out in Australia. Dates to which data relate The effectiveness data were derived from studies published between 1996 and 2004. The resource use data were gathered from July 2000 to June 2001. The costs were expressed using 2000/01 prices. Source of effectiveness data The effectiveness evidence was derived from a synthesis of published studies. Modelling A decision tree model was constructed to assess the clinical outcomes and costs associated with routine FDG-PET plus selected mediastinoscopy, in comparison with routine mediastinoscopy alone, in a hypothetical cohort of 200 patients (100 in each diagnostic arm of the tree). A graphical representation of the decision tree was provided. In the mediastinoscopy arm, positive cases (N2 or greater disease) were excluded from surgery and assigned to medical management, with negative (N1 or less) cases proceeding directly to thoracotomy. In the FDG-PET arm, patients with a negative scan (i.e. no evidence of N2 or greater disease) proceeded directly to thoracotomy, while patients with an FDG-PET scan demonstrating distant metastases were excluded from further Page: 1 / 5
investigation and assigned to medical management. Patients with a positive scan suggesting non-resectable local disease were further assessed by mediastinoscopy to evaluate suitability for surgery, and those with a subsequent negative mediastinoscopy continued to an attempt at curative surgery. Outcomes assessed in the review The outcomes assessed were prevalence of disease, and the sensitivity and specificity of the diagnostic techniques. Study designs and other criteria for inclusion in the review A literature search was carried out to identify relevant data with which to populate the decision model. Details of the review were not provided. Local data, obtained from the Austin Hospital, Melbourne, Australia, were also used. One of the studies was a review of 14 studies (total sample of 5,687 patients). Sources searched to identify primary studies Criteria used to ensure the validity of primary studies Methods used to judge relevance and validity, and for extracting data Number of primary studies included Eight primary studies provided clinical data. Methods of combining primary studies A narrative approach appears to have been used to combine the primary estimates. Investigation of differences between primary studies Results of the review The prevalence of locally advanced non-operable disease was 20% and the prevalence of distant metastases was 6%. Thus, of the 100 patients included in each arm of the model, 20 had non-resectable locally advanced disease and 6 had distant metastatic disease, while 74 were potentially curable by thoracotomy. The sensitivity of mediastinoscopy was 81% and the specificity was 100%. The sensitivity of FDG-PET was 84% and the specificity was 89%. Measure of benefits used in the economic analysis The health outcomes were left disaggregated and no summary benefit measure was used. In effect, a cost-consequences analysis was performed. However, some model outputs, such as numbers of patients undergoing medical management, appropriate thoracotomies and futile thoracotomies, were reported. Page: 2 / 5
Direct costs The perspective adopted in the analysis was unclear. The cost categories included in the analysis were mediastinoscopy, thoracotomy and FDG-PET. Hospital stay was also considered. The unit costs were not presented separately from the quantities of resources used for all items, but details of the cost calculation were reported clearly. Resource use was estimated from a sample of patients undergoing mediastinoscopy and/or thoracotomy for the staging or treatment of proven histological NSCLC between July 2000 and June 2001 at the Austin Hospital, Heidelberg, Victoria, Australia. The costs of mediastinoscopy came from the hospital's accounting system, while the costs of FDG-PET were estimated from commercial prices, staffing, infrastructure and equipment costs (including service contacts). Equipment was depreciated over a 7-year timeframe. The calculation of FDG-PET costs took patient throughput into consideration. Discounting was not relevant as the costs were incurred over a short timeframe. The costs were evaluated using 2000/01 prices. Statistical analysis of costs The costs were treated deterministically. Indirect Costs The indirect costs were not considered. Currency Australian dollars (AUD). Sensitivity analysis One- and two-way sensitivity analyses were carried out to assess the robustness of the cost results to variations in the model inputs, including clinical and economic data. The ranges of values used were presumably derived from the literature and from the authors' cost calculations. Estimated benefits used in the economic analysis With routine mediastinoscopy, the numbers of patients undergoing medical management, appropriate thoracotomies and futile thoracotomies were 16, 74 and 10, respectively. The corresponding numbers with routine FDG-PET plus mediastinoscopy were 20 (medical management), 74 (appropriate thoracotomies) and 6 (futile thoracotomies). Cost results The mean costs used in the model were AUD 4,160 (range: 3,230 to 7,180; median 3,759) for mediastinoscopy, AUD 15,642 (range: 7,368 to 42,492; median 13,724) for thoracotomy and AUD 1,500 for FDG-PET. Given the number of appropriate and futile thoracotomies with the two approaches, the average cost per patient was AUD 17,269 with routine mediastinoscopy and AUD 15,141 with routine FDG-PET plus selected mediastinoscopy. The cost-saving per patient associated with routine FDG-PET plus selected mediastinoscopy was AUD 2,128. The sensitivity analysis showed that an increase in the cost of FDG-PET reduced the cost-savings, as expected. However, cost-savings were achieved even when the cost of mediastinoscopy was reduced to a reasonable figure. Another interesting result was that FDG-PET remained more efficient for a prevalence of locally advanced disease of up to 0.62. In general, the base-case cost results were robust to variations in the clinical and economic model inputs. Synthesis of costs and benefits A synthesis of the costs and benefits was not relevant since a cost-consequences approach was adopted. Page: 3 / 5
Authors' conclusions The routine use of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) plus selected mediastinoscopy for preoperative staging of non-small-cell lung cancer (NSCLC) patients led to a reduction in unnecessary thoracotomies at lower costs in comparison with routine mediastinoscopy performed on all patients. CRD COMMENTARY - Selection of comparators The authors justified their choice of the comparators used in the analysis, which were appropriate for the objective of the study. You should decide whether they are valid comparators in your own setting. Validity of estimate of measure of effectiveness The effectiveness evidence came from a synthesis of studies, which were presumably identified selectively. No details of the methods and conduct of a systematic review of the literature were provided. The authors provided limited information on the characteristics of the primary studies. For example, one was a review of 14 studies, but details of the designs of these studies were not provided. Some data were derived from a study performed at the authors' hospital, but few details were given. The impact of changes in clinical estimates on the results of the analysis was investigated in a sensitivity analysis. Validity of estimate of measure of benefit No summary benefit measure was used in the analysis because a cost-consequences analysis was conducted. Please refer to the comments in the 'Validity of estimate of measure of effectiveness' field (above). Validity of estimate of costs The authors did not state explicitly which perspective was adopted in the study. Only the hospital costs strictly related to the two diagnostic approaches were included in the analysis. The costs associated with patients requiring a longer hospital stay were included in the analysis as a potential complication of the procedures. The costs were calculated using a modelling approach. Resource consumption was based on data derived from a sample of patients managed at the authors' institution. The cost estimates were specific to the study setting but the impact of using alternative cost estimates was investigated in a sensitivity analysis. The unit costs were given for some items. The price year (namely the financial year) was reported, which will permit reflation exercises in other time periods. The authors noted that the costs of further investigations were not included because they were difficult to quantify. Other issues The authors stated that their results confirm those observed in other published studies, although the current study used real cost data extracted from a database at the authors' institution. The issue of the generalisability of the study results to other settings was not explicitly addressed, but alternative scenarios for both costs and accuracy data were considered in the sensitivity analysis. This might increase the external validity of the study. The analysis referred to patients requiring staging for NSCLC and this was reflected in the authors' conclusions. Implications of the study The study results support the routine use of FDG-PET for the staging of patients with NSCLC. Mediastinoscopy should be restricted to those cases in which FDG-PET suggests unresectable local disease, as a confirmatory diagnostic tool. Source of funding Supported in part by the National Health and Medical Research Council. Bibliographic details Yap K K, Yap K S, Byrne A J, Berlangieri S U, Poon A, Mitchell P, Knight S R, Clarke P C, Harris A, Tauro A, Rowe Page: 4 / 5
Powered by TCPDF (www.tcpdf.org) C C, Scott A M. Positron emission tomography with selected mediastinoscopy compared to routine mediastinoscopy offers cost and clinical outcome benefits for pre-operative staging of non-small cell lung cancer. European Journal of Nuclear Medicine and Molecular Imaging 2005; 32(9): 1033-1040 PubMedID 15875178 DOI 10.1007/s00259-005-1821-0 Other publications of related interest Verboom P, van Tinteren H, Hoekstra OS, et al. Cost-effectiveness of FDG-PET in staging non-small cell lung cancer: the PLUS study. Eur J Nucl Med Mol Imaging 2003;30:1444-9. Kelly RF, Tran T, Holmstrom A, et al. Accuracy and cost-effectiveness of 18F-2-fluorodeoxyglucose positron emission tomography scan in potentially resectable non-small cell lung cancer. Chest 2004;125:1413-23. Indexing Status Subject indexing assigned by NLM MeSH Adult; Aged; Aged, 80 and over; Australia; Carcinoma, Non-Small-Cell Lung /economics /pathology /radionuclide imaging /surgery; Cost-Benefit Analysis; Decision Support Systems, Clinical; Female; Health Care Costs /statistics & numerical data; Humans; Length of Stay /economics; Lung Neoplasms /economics /pathology /radionuclide imaging /surgery; Male; Mediastinoscopy /economics; Middle Aged; Models, Economic; Neoplasm Staging /economics; Positron-Emission Tomography /economics; Retrospective Studies; Treatment Outcome AccessionNumber 22005001608 Date bibliographic record published 31/07/2006 Date abstract record published 31/07/2006 Page: 5 / 5