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Cost-effectiveness of positron emission tomography for the management of potentially operable non-small cell lung cancer in Quebec |
Nguyen V H, Peloquin S, Lacasse Y |
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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 use of computed tomography (CT) with positron emission tomography (PET) for the management of potentially operable non-small-cell lung cancer (NSCLC). In this intervention, all patients were first evaluated by CT. The use of PET was limited to detecting distant metastases when the CT findings were positive for mediastinal metastases, and to detecting mediastinal metastases when the CT findings were negative. To confirm the PET results, a biopsy and mediastinoscopy were performed to determine if there were any distant or mediastinal metastases, respectively.
This intervention strategy was compared with a strategy of CT alone. In this option, a mediastinoscopy was performed in patients with a positive result for mediastinal metastases to determine whether they would be candidates for surgery. In those cases where the CT results were negative, patients underwent surgery.
Economic study type Cost-effectiveness analysis.
Study population The study population comprised hypothetically medically fit-for-surgery 65-year-old men with histologically confirmed NSCLC in whom pre-operative staging using conventional detection techniques was negative for mediastinal and distant metastases.
Setting The setting was secondary care. The economic study was carried out in Quebec, Canada.
Dates to which data relate The effectiveness data were derived from studies published between 1999 and February 2001. The price year was 1998/1999.
Source of effectiveness data The effectiveness data were derived from a review of published studies.
Modelling A decision tree model was constructed to predict the cost and effects of using PET as a means of detecting mediastinal and distant metastases. The life time horizon was used.
Outcomes assessed in the review The outcomes assessed were:
the sensitivity and specificity of CT;
the life expectancy with palliative treatment;
the mortality rate associated with CT;
the surgical mortality rate;
the sensitivity and specificity of PET in detecting distant metastases;
the sensitivity and specificity of PET in detecting mediastinal metastases;
the probability of metastases detected by PET; and
the prevalence of mediastinal metastases.
Study designs and other criteria for inclusion in the review No inclusion criteria for a review of any of the parameters were reported. However, the data for PET and CT sensitivity and specificity came mainly from a prospective study.
Sources searched to identify primary studies A complete MEDLINE and Cancerlit search was conducted for studies from 1999 to February 2001.
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 Approximately 16 studies were included in the review.
Methods of combining primary studies Some of the effectiveness parameters derived from the primary studies were combined using a narrative method.
Investigation of differences between primary studies Results of the review The sensitivity of CT was 0.75 (range: 0.60 - 0.90) and the specificity was 0.66 (range: 0.55 - 0.77).
The life expectancy with palliative treatment was 1.0 (range: 0.1 - 2.0).
The mortality rate associated with CT was 0.000025 (range: 0.0 - 1.0).
The surgical mortality rate was 0.03 (range: 0.00 - 0.20).
The sensitivity PET in detecting distant metastases was 0.82 (range: 0.64 - 1.00) and the specificity was 0.93 (range: 0.88 - 0.98).
The sensitivity of PET in detecting mediastinal metastases was 0.91 (range: 0.81 - 1.00) and the specificity was 0.86 (range: 0.78 - 0.94).
The probability of metastases detected by PET was 0.07 (range: 0.05 - 0.11).
The prevalence of mediastinal metastases was 0.31 (range: 0.28 - 0.38).
Methods used to derive estimates of effectiveness The life expectancy with surgical treatment was calculated according to the Declining Exponential Approximation of Life Expectancy (DEALE) method.
Estimates of effectiveness and key assumptions The life expectancy with surgical treatment was 7.0 (range: 1.0 - 15.0).
Measure of benefits used in the economic analysis The measure of benefits used was the life-years gained (LYG). The health benefits were not discounted.
Direct costs The direct costs of the health care system were included in the analysis. These represented the costs of hospital stay for mediastinoscopy alone, surgery alone, or biopsy alone; hospital stay for mediastinoscopy, biopsy and surgery; the cost of a PET scan (including amortisation and capital cost) and the fee for biopsy, CT, mediastinoscopy and PET. The cost of a PET was derived from the costs of PET scanning at the Centre Hospitalier Universitaire de Sherbrooke, Quebec (written communication). The costs of hospital stay were determined by the Ministere de la Sante et des Services Sociaux's 1998-1999 diagnosis-related group database. The figures for physicians' fees were derived from the Medical Specialists' Manual (September 1999 edition). As the costs of biopsy varied considerably depending on the site and technique performed, an average cost was assumed. Discounting was unnecessary, as the costs were incurred during one year, and was therefore not performed. The study reported the average costs. The price year was 1998/1999.
Statistical analysis of costs The costs were treated as point estimates (i.e. the data were deterministic).
Indirect Costs The indirect costs were not included.
Sensitivity analysis To test the robustness of the model, univariate sensitivity and Monte Carlo analyses were performed. The costs of hospital stay, sensitivity and specificity of CT, life expectancy, surgical mortality rates, sensitivity and specificity of PET, prevalence, and the probability of metastases detected by PET were all varied in univariate sensitivity analyses. In the Monte Carlo simulation, a normal distribution with 20% variance was fitted to the cost variables, while a triangular distribution was fitted to sensitivity and specificity variables. All other variables were fitted with a uniform distribution.
Estimated benefits used in the economic analysis The LYG per patient were 4.551 with the CT strategy alone versus 4.823 when using the CT-PET strategy. The difference was 0.27 LYG with CT-PET.
Cost results The cost per patient was Can$8,455 with the CT strategy alone versus Can$9,723 when using the CT-PET strategy. The difference was an additional cost of Can$1,268 per patient with CT-PET.
Considering that 1,837 new patients a year could potentially benefit from the CT-PET strategy, the budget impact would be Can$8,613,693.
Synthesis of costs and benefits The costs and benefits were combined using an incremental cost-effectiveness ratio (i.e. the additional cost required per one additional LYG). The incremental cost-effectiveness ratio of CT-PET compared with CT alone was Can$4,689.
Varying the baseline values did not significantly affect the results. The incremental cost-effectiveness ratio of CT-PET ranged from Can$3,000 to Can$5,000 per LYG. Moreover, in approximately 50% of the Monte Carlo simulations, the cost per LYG was less than Can$5,000, and in 73% of the cases it was less than Can$10,000. If the standard cost-effectiveness ratio was set at less than Can$50,000 per LYG, the authors found that 95% of the simulation cases would be below this threshold.
Authors' conclusions The use of positron emission tomography (PET) to detect local and distant metastases in non-small-cell lung cancer (NSCLC) is an intervention that requires an acceptable investment for each life-year gained (LYG).
CRD COMMENTARY - Selection of comparators A justification was given for the comparator used. Diagnosis without PET represents current practice. You should decide if the comparator represents current practice in your own setting.
Validity of estimate of measure of effectiveness The authors stated that a systematic review of the literature had been undertaken to identify all relevant research. The effectiveness data were derived from recently published studies (i.e. 1999 - 2001), which will reflect current health technology use and practice. However, the authors failed to provide detailed methodology for the review of the literature, such as the study designs included, how the primary studies were combined and, in the case where more than one study was used to derive a particular effectiveness estimate, whether they investigated any potential differences between these studies. Therefore, it was difficult to assess the validity of the estimates. The authors undertook fairly exhaustive sensitivity analyses by undertaking univariate and Monte Carlo analyses. It would appear that the lower and upper bounds used in the univariate analyses were derived from the literature.
Validity of estimate of measure of benefit The estimation of benefits was modelled using a decision tree, which was appropriate. Life expectancy as a measure of benefit only permits partial cross health technology comparisons, as quality of life is not taken into consideration.
Validity of estimate of costs All the categories of cost relevant to the health care system perspective adopted were included in the analysis. Further, it appears that no major relevant cost have been omitted from the analysis. The costs of chemotherapy and radiation therapy were not included in the analysis since they were similar between the two strategies. The costs and the quantities were not reported separately, which will limit the generalisability of the authors' results, although the authors did provide the unit costs. The costs were derived from published sources, and appropriate and exhaustive sensitivity analyses were performed. Discounting was not relevant, as all the costs were during one year, and was therefore not performed. The price year was reported, which will aid any possible inflation exercises.
Other issues The authors reported that their results were similar to those compiled by the Australian Medicare Services Advisory Committee, which found that PET could lead to savings or require only a very small and very acceptable investment for each LYG. The issue of generalisability to other settings was addressed in the sensitivity analysis. The authors do not appear to have presented their results selectively, and their conclusions reflected the scope of the analysis.
The authors acknowledged several limitations of the study. The main ones were as follows. First, in the short term it is unlikely that PET would improve survival in patients with cancer per se. Instead, the efficacy of PET would reside in its ability to improve the patients' quality of life by sparing them unnecessary, debilitating intervention and providing them with quicker access to treatment. Second; given that PET would be used for clinical purposes other than detecting metastases in patients with NSCLC, the amortisation would probably be less than the amount considered in the study and, then, the incremental cost-effectiveness ratio could be overestimated.
Implications of the study The authors recommended that further prospective studies should be undertaken to measure quality of life and patient preference, to permit a more adequate assessment of the efficacy of this technology.
Source of funding This study was supported by and originated from the Agence'Evaluation des Technologies et des Modes d'Intervention en Sante (AETMIS).
Bibliographic details Nguyen V H, Peloquin S, Lacasse Y. Cost-effectiveness of positron emission tomography for the management of potentially operable non-small cell lung cancer in Quebec. Canadian Respiratory Journal 2005; 12(1): 19-25 Other publications of related interest Dietlein M, Weber K, Gandjour A, et al. Cost-effectiveness of FDG-PET for the management of potentially operable non-small cell lung cancer: priority for a PET-based strategy after nodal-negative CT results. European Journal of Nuclear Medicine 2000;27:1598-609.
Medical Services Advisory Committee (MSAC). Positron emission tomography. MSAC Assessment Report. Canberra: MSAC; 2000. Available from: URL: www.msac.gov.au/pdfs/reports/msacref02.pdf
Van Tinteren H, Hoekstra OS, Smit EF, et al. Effectiveness of positron emission tomography in the preoperative assessment of patient with suspected non-small cell lung cancer: the PLUS multicentre randomised trial. Lancet 2002;359:1388-93.
Indexing Status Subject indexing assigned by NLM MeSH Analysis of Variance; Carcinoma, Non-Small-Cell Lung /radiography /radionuclide imaging /surgery; Cost Savings; Cost-Benefit Analysis; Decision Trees; Evaluation Studies as Topic; Female; Humans; Lung Neoplasms /radiography /radionuclide imaging /surgery; Male; Neoplasm Staging; Positron-Emission Tomography /economics /methods; Probability; Quebec; Risk Assessment; Tomography, X-Ray Computed /economics /methods AccessionNumber 22005000566 Date bibliographic record published 31/10/2005 Date abstract record published 31/10/2005 |
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