# Appendix ICost-Effectiveness Analyses of Colorectal Cancer Screening: Results from a Pre-conference Modeling Exercise

Pignone M.

Publication Details

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Appendix I Cost-Effectiveness Analyses of Colorectal Cancer Screening: Results from a Pre-conference Modeling Exercise. SLIDE 1 NOTES: I would like to thank the following people for their work and advice on this exercise or on a previous review conducted (more...)

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Aims. SLIDE 2 NOTES: The aims of the pre-Workshop modeling exercise, as I see it, were two-fold: The first was to compare the several different cost-effectiveness analyses of colorectal cancer screening. Such a comparison has three motivations: to gain (more...)

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Background. SLIDE 3 NOTES: As with some other cancers, colorectal cancer is, of course, an important disease that is amenable to screening. However, unlike many conditions amenable to preventive interventions, there are several different screening tests (more...)

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Systematic Review - 2000. SLIDE NOTES 4: A precursor to this exercise was the work my colleagues and I did for the US Preventive Services Task Force in 2000 (Pignone et al., 2002). At that time, we reviewed seven published models. All seven found that (more...)

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Methods. SLIDE 5 NOTES: Here is a brief description of the methods used in the pre-workshop modeling exercise. Each modeler was asked to analyze 5 screening strategies, as well as no screening, as listed above.

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Methods. SLIDE 6 NOTES: We then specified standardized values for inputs in the four categories listed above. The modelers were asked to analyze each of the six strategies 10 times, with each run involving a different combination of original or standardized (more...)

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Calculation of C/E ratios. SLIDE 7 NOTES: For each run, we did the following: We ordered the years of life saved for every strategy from lowest to highest. We identified the strongly dominated strategies – those which were both less effective (more...)

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Basic Assumptions. SLIDE 8 NOTES: This and the next 5 slides review the standardized assumptions in each general area. Here are some basic assumptions that were common to all runs and all strategies.

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Assumptions: Costs. SLIDE 9 NOTES: No notes.

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Assumptions: Test performance. SLIDE 10 NOTES: No notes.

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Assumptions: Complications. SLIDE 11 NOTES: Note that we did not model more complex assumptions regarding complications, such as the possibility of bleeding (short of perforation) with colonoscopy, or other complications, such as a patient who is falls (more...)

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Assumptions: Follow-up and Surveillance. SLIDE 12 NOTES: All patients with positive FOBT tests would receive a follow-up colonoscopy. All patients with positive sigmoidoscopy would receive a follow-up colonoscopy.

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Assumptions: Compliance. SLIDE 13 NOTES: When we standardized on assumptions about compliance, we asked modelers to assume that all individuals would be fully compliant with all screening, follow-up and surveillance tests. That assumption is a poor description (more...)

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Standardization Analyses. SLIDE 14 NOTE: In this and the next chart, the rows depict the different assumptions and the columns depict the specific run. “S” means that the parameters in a specific run and input group (for example, in run (more...)

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Standardization Analyses - 2. SLIDE 15 NOTES: Run 6 standardizes across all parameter groups. We call that the fully standardized run.

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Results: Costs- Original Assumptions. SLIDE 16 NOTES: Now for the results of the exercise. The current chart shows – for the original assumptions (Run 1) -- the lifetime cost in a population of 100,000 50-year old individuals of screening, follow-up, (more...)

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Life-years – Original Assumptions. SLIDE 17 NOTES: This chart shows –for the original assumptions -- the years of life lived in a population of 100,000 50-year old individuals. Here, too, there is a substantial variation between the different (more...)

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Life Years c/w No Screening- Original. SLIDE 18 NOTES: This slide shows the years of life added, compared with the no-screening strategy, under the original assumptions (Run 1). Although the metric has changed (from total number of years of life lived (more...)

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Costs c/w No Screening- Original. SLIDE 19 NOTES: This chart shows extra lifetime costs compared with the no-screening strategy, under the original assumptions (Run 1). Substantial differences in cost persist across models for each of the different screening (more...)

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Average Cost-effectiveness- Original. SLIDE 20 NOTES: Here are the average cost-effectiveness ratios under the original assumptions (Run 1). By average, I mean the ratio of additional costs to additional effectiveness when each strategy is compared with (more...)

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Costs – All Standardized. SLIDE 21 NOTES: This and subsequent slides provide results under the fully standardized assumptions (Run 6). All four parameter groups are standardized in this run. The current slide shows – for the standardized (more...)

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Life-years – All Standardized. SLIDE 22 NOTES: This chart shows the years of life lived in a population of 100,000 50-year old individuals under the standardized assumptions. Rough visual inspection suggests that there is probably a little less (more...)

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Costs c/w Screening- Standard. SLIDE 23 NOTES: This slide shows extra lifetime costs compared with the no-screening strategy, under the standardized assumptions (Run 6). Now there is greater similarity across models in terms of costs once inputs are standardized. (more...)

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Life Years c/w No Screening - Standard. SLIDE 24 NOTES: This slide shows the years of life added, compared with the no-screening strategy, under the standardized assumptions (Run 6). Variation across models is now somewhat reduced, probably because some (more...)

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Life years c/w no screening: standardized and by model. SLIDE 25 NOTES: In this chart and the next, the same results are grouped by model instead of by strategy. You can see that there is some variation in terms of life years saved within each model by (more...)

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Costs c/w no screening: standardized and by model. SLIDE 26 NOTES: This slide groups lifetime costs by model. There are now some differences across strategies for all models, but they are relatively small across different tests, with FOBT generally less (more...)

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Average Cost-effectiveness- Standard. SLIDE 27 NOTES: Here is the average cost-effectiveness under the standardized assumptions (Run 6). The results are quite similar to what was seen under the original assumptions for average cost-effectiveness. The (more...)

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SLIDE 28 NOTES: The rest of this presentation is about incremental cost-effectiveness ratios (as opposed to average cost-effectiveness ratios) and preferred strategies. Recall that the incremental cost-effectiveness ratio (ICER) is calculated by eliminating (more...)

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ICERs: Original Assumptions. SLIDE 29 NOTES: Here are the ICERs under the original assumptions (Run 1). There are definite differences across models in which strategies are dominated and which are not. For example, flexible sigmoidoscopy every five years (more...)

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ICERs: All Standardized. SLIDE 30 NOTES: This chart shows the ICER's under the standardized assumptions (Run 6). With assumptions standardized, the first four models get very similar results. Under the specific set of standardized assumptions made about (more...)

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Most Effective Strategy- Original. SLIDE 31 NOTES: This slide shows – for the original assumptions -- the most effective strategy (i.e., the strategy that produces the largest number of additional years of life among all non-dominated strategies) (more...)

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Most Effective Strategy- Standardized. SLIDE 32 NOTES: This chart is the same as the previous chart, except that the assumptions are fully standardized (Run 6). Here, almost all of the differences across models disappear. The most effective strategy at (more...)

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Limitations. SLIDE 33 NOTES: This exercise had several limitations. Some were a function of the limited time we had to design and conduct the exercise and the amount of effort that the modelers could realistically expect to make to support the exercise. (more...)

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Conclusions. SLIDE 34 NOTES: In this chart and the next, the same results are grouped by model instead of by strategy. You can see that there is some variation in terms of life years saved within each model by the different strategies, suggesting that (more...)

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Implications. SLIDE 35 NOTES: Here are some preliminary thoughts about implications of this exercise. First, it would certainly be a good idea to establish some standard cost inputs, to eliminate this major source of variation across models. We also need (more...)

## REFERENCES

• Ness RM, Holmes A, Klein R, Greene J, Dittus R. Outcome states of colorectal cancer: Identification and description using patient focus groups. Am J Gastroenterol. 1998;93(9):1491–1497. [PubMed: 9732931]

• Pignone M, Saha S, Hoerger T, Mandelblatt J. Cost-effectiveness analyses of colorectal cancer screening: a systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2002;137(2):96–104. [PubMed: 12118964]