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| As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia |
| Parekh M, Fendrick A M, Ladabaum U |
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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. CRD summary This study determined the cost-effectiveness of faecal DNA testing every three years, annual faecal occult blood testing (FOBT), annual faecal immunochemical testing (FIT), and colonoscopy every 10 years, as screening strategies for colorectal cancer. Given the current reimbursement for cancer care, FOBT and FIT were the most cost-effective strategies. Generally, the study methodology was valid, although little information on the clinical sources was provided. The authors’ conclusions appear to be valid and enhanced by the comprehensive sensitivity analysis. Type of economic evaluation Cost-effectiveness analysis Study objective The objective was to determine the cost-effectiveness of alternative screening strategies for colorectal cancer (CRC) in individuals aged 50 years or more, focusing on stool-based strategies, in the light of changing test performance characteristics and increasing CRC care costs. Interventions The strategies were faecal deoxyribonucleic acid (F-DNA) testing every three years, annual guaiac-based faecal occult blood testing (FOBT), annual faecal immunochemical testing (FIT), and colonoscopy (COL) every 10 years. Three versions (1, 1.1, and 2) of the F-DNA test were considered, with each version being more accurate than the previous one. All the screening strategies were started in a 50-year-old individual and continued up to 80 years of age. A background strategy of no screening was also considered. Location/setting USA/primary care and hospital. Methods Analytical approach:This economic evaluation was based on a published Markov model with a lifetime horizon. The authors stated that a third-party payer perspective was adopted.
Effectiveness data:Most of the clinical data came from sources used in a previous analysis, which was published by the same authors and updated by this study. Updated clinical data on F-DNA and FIT were derived from a literature review and official submissions to national agencies. However, little information was given on the actual studies used to populate the model. US life tables were used to derive age- and sex-specific non-CRC mortality. An assumption of perfect adherence to the screening strategies was made in the base case. The key clinical endpoint was the screening accuracy.
Monetary benefit and utility valuations:Not relevant.
Measure of benefit:Life-years (LYs) were used as the summary benefit measure. They were discounted at an annual rate of 3%.
Cost data:The health services were FOBT, FIT, F-DNA testing, COL, COL with lesion removal, endoscopy complications, and treatment of CRC. The costs of cancer care and the screening strategies were based on Medicare reimbursement rates. The costs of CRC, by its stages, were taken from several published studies. The cost of F-DNA testing came from a specific laboratory list price. All costs were in US dollars ($) and the price year was 2006. A 3% annual discount rate was applied.
Analysis of uncertainty:One-way sensitivity analyses were carried out on all the model inputs using published ranges of values. Two-way sensitivity analyses were performed on the most influential parameters. Threshold analyses identified the critical values at which the most cost-effective strategy changed. A Monte Carlo simulation with 1,000 iterations was performed, sampling for the performance of the FOBT, FIT, and F-DNA testing. Finally, in an alternative scenario, imperfect adherence was considered. Results The expected LYs per person were 18.686 with no screening, 18.730 with F-DNA version 1, 18.739 with F-DNA version 1.1, 18.742 with FOBT, 18.744 with F-DNA version 2, 18.748 with COL, and 18.751 with FIT.
The average cost per person was $2,921 with no screening, $3,867 with F-DNA version 1, $3,821 with F-DNA version 1.1, $2,683 with FOBT, $3,833 with F-DNA version 2, $3,489 with COL, and $2,428 with FIT.
In comparison with no screening, all the strategies appeared to be reasonably cost-effective (between $9,200 and $21,200 per LY gained), with FOBT and FIT being dominant, which was more effective and less expensive than no screening. FIT was the dominant strategy in all comparisons. FOBT and COL were preferred over all F-DNA versions, which were either dominated (versions 1 and 1.1) or not cost-effective (version 2 for FOBT). COL was not cost-effective compared with FOBT ($144,000 per LY gained).
The deterministic sensitivity analysis did not significantly alter these findings. The cost-effectiveness of F-DNA improved as its cost was reduced and its sensitivity for large adenoma was improved. The probabilistic sensitivity analysis suggested that FOBT was dominant over no screening in more than 95% of the simulations, and FIT was dominant in 100% of the iterations. In all these scenarios, FIT remained the preferred strategy. In the scenarios with lower adherence, the cost-effectiveness of both FIT and FOBT was reduced, although they often remained economically attractive strategies. Authors' conclusions The authors concluded that, given the current reimbursement for cancer care, FOBT and FIT appeared to be the most cost-effective screening strategies for CRC. CRD commentary Interventions:The selection of the comparators was appropriate and included all the possible screening strategies for CRC. A description of each strategy, and the subsequent surveillance protocol for each strategy, was provided.
Effectiveness/benefits:The authors provided little information on the methodology used to derive the clinical inputs given that the bulk of the evidence had already been identified in a previous publication. The use of a systematic search should have ensured the selection of the best available published evidence, but the details on the methods and conduct of the literature review were not provided. Thus, it is not possible to judge the validity of the clinical inputs, although it is likely that the most recent and relevant studies were included. The derivation of the benefit measure was based on the modelling framework. LYs are a validated benefit measure and permit cross-disease comparisons.
Costs:The economic analysis was appropriately performed and was consistent with the viewpoint of the study. The unit costs were reported only for the screening strategies. The costs of cancer care were presented as macro-categories and were derived from published studies. Such an approach reduces the transparency of the economic analysis, but is commonly used when assessing the comprehensive cost of cancer. Other details of the study such as the price year, use of alternative assumptions, sources of costs, and discounting, were reported. However, no information on the resource consumption was provided.
Analysis and results:The use of an incremental analysis to combine the costs and benefits of the alternative strategies was appropriate. The issue of uncertainty was extensively investigated in the sensitivity analysis. The study findings were clearly presented. The authors noted some limitations of their analysis, mainly related to the use of a modelling framework which might not resemble the real-world management of CRC.
Concluding remarks:On the whole, the study was based on valid methodology, although little information on the clinical sources was provided. The authors’ conclusions appear to be valid and are enhanced by the comprehensive sensitivity analysis. Funding Supported by a grant from Exact Sciences Corp. and the NIH. Bibliographic details Parekh M, Fendrick A M, Ladabaum U. As tests evolve and costs of cancer care rise: reappraising stool-based screening for colorectal neoplasia. Alimentary Pharmacology and Therapeutics 2008; 27(8): 697-712 Other publications of related interest Pignone M, Saha S, Hoerger T, et al. Cost-effectiveness analyses of colorectal cancer screening: a systematic review for the U.S. Preventive Services Task Force. Ann Intern Med 2002;137:96-104.
Frazier AL, Colditz GA, Fuchs CS, et al. Cost-effectiveness of screening for colorectal cancer in the general population. JAMA 2000;284:1954-61.
Lieberman DA. Cost-effectiveness model for colon cancer screening. Gastroenterology 1995;109:1781-90.
Sonnenberg A, Delco F, Inadomi J. Cost-effectiveness of colonoscopy in screening for colorectal cancer. Ann Intern Med 2000;133:573-84. Indexing Status Subject indexing assigned by NLM MeSH Colonoscopy /economics; Colorectal Neoplasms /diagnosis /economics; Cost-Benefit Analysis; Feces /chemistry; Humans; Markov Chains; Mass Screening /economics /methods; Occult Blood; Quality-Adjusted Life Years AccessionNumber 22008100403 Date bibliographic record published 22/04/2009 Date abstract record published 03/06/2009 |
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