Willingness-to-pay for colorectal cancer screening

A survey of individual preference for colorectal cancer screening technique

BACKGROUND

Due to the low participation in colorectal cancer screening, public preference for colorectal cancer screening modality was determined.

METHODS

A cross-sectional survey was performed of healthy ambulatory adults in a pediatrics primary care office and neighboring church. Overall preference was ranked for each of four colorectal cancer screening modalities: Faecal Occult Blood, Fiberoptic Sigmoidoscopy, Barium Enema and Colonoscopy. Four additional domains of preference also were ranked: suspected discomfort, embarrassment, inconvenience and danger of each exam.

RESULTS

80 surveys were analyzed, 57 of which were received from participants who had experienced none of the screening tests. Fecal Occult Blood Testing is significantly preferred over each other screening modality in overall preference and every domain of preference, among all subjects and those who had experienced none of the tests.

CONCLUSIONS

Efforts to increase public participation in colorectal cancer screening may be more effective if undertaken in the context of public perceptions of screening choices.

A perspective from countries using organized screening programs

Cancer screening may be offered to a population opportunistically, as part of an organized program, or as some combination of the preceding two options. Organized screening is distinguished from opportunistic screening primarily on the basis of how invitations to screening are extended. In organized screening, invitations are issued from centralized population registers. In opportunistic screening, however, due to the lack of central registers, invitations to screening depend on the individual's decision or on encounters with health care providers. The current article outlines key differences between organized and opportunistic screening. In the current study, literature searches were performed using PubMed and MEDLINE. Additional data were assembled from interviews with health officials in the five countries investigated and from the authors' personal files. Opportunistic screening was found to be distinguishable from organized screening on the basis of whether screening invitations were issued from centralized population registers. Organized screening programs also assumed centralized responsibility for other key elements of screening, such as eligibility requirements, quality assurance, follow-up, and evaluation. Organized programs focused on reducing mortality and morbidity at the level of the population rather than at the level of the individual. Thus, programs did not necessarily offer the most sensitive screening test for a particular cancer, and tests sometimes were offered at suboptimal intervals with respect to individual-level protection. Nonetheless, organized systems paid greater attention to the quality of screening, as measured by factors such as cancer detection rates, tumor characteristics, and false-positive biopsy rates. As a result, participants in organized screening programs received greater protection from the harmful effects associated with screening. In addition, organized programs worked more systematically toward providing value for money in an inevitably resource-limited environment. Although organized and opportunistic models of screening can yield similar uptake rates, organized programs exhibited greater potential ability to reduce cancer incidence and mortality, because of the higher levels of population coverage and centralized commitment to quality and monitoring; were more likely to be cost-effective; and offered greater protection against the harmful effects associated with poor quality or overly frequent screening.

Comparing willingness-to-pay: bidding game format versus open-ended and payment scale formats

The willingness-to-pay technique is being used increasingly in the economic evaluation of new health care technologies. Clinical trials of two methods of screening for colorectal cancer are currently being conducted in the UK and willingness-to-pay for screening has already been estimated by means of a questionnaire survey, using open-ended (OE) and payment scale (PS) formats. This paper addresses the same medical issue, although it elicits willingness-to-pay values by means of a bidding game in an interview setting. Interviews were conducted with 106 subjects in Nottingham. The bidding game format produced considerably higher valuations than had either of the previous questionnaire formats, whilst the significant differences between agreed valuations obtained using different initial bids supported the existence of starting-point bias in the bidding game. As with the questionnaire study, the majority of interview subjects offered relative valuations of tests at variance with their expressed preferences over the same tests. Given the significant difference in valuations generated by different formats, it follows that the economic case for preferring any one technology over others will depend considerably upon whichever format happens to have been used to generate the valuations.

Acceptability of diagnostic tests for breast cancer

PURPOSE

To assess the acceptability of new non-invasive breast cancer diagnostic tests intended to triage women in need of biopsy.

METHODS

Women who had abnormal screening tests and had been recommended to have a biopsy were invited to receive digital mammography, magnetic resonance imaging (MRI), and nuclear medicine evaluation (Tc-99m-sestamibi scanning) before biopsy. Participants completed a questionnaire about satisfaction and acceptability of the procedures. Satisfaction measured women's overall and test-specific satisfaction. Acceptability was measured by self-reported discomfort, embarrassment and women's preference in terms of willingness to pay to avoid a biopsy.

RESULTS

Women were satisfied with all of the potential diagnostic triage procedures. Most found the tests more comfortable than a routine mammogram (47, 50, and 66% undergoing MRI, digital mammography, and sestamibi scanning, respectively). Women who provided a response to willingness to pay questions (N = 43) were willing to pay an average of 611 dollars to have a test instead of a biopsy, if the test was as accurate as biopsy. The willingness to pay significantly decreased to 308 dollars if the test only had 95% accuracy. Those who had prior benign breast disease were less willing to pay for a test with 95% accuracy than those without this history.

CONCLUSION

Instead of immediate biopsy after an abnormal screening, these results suggest that women would find non-invasive triage tests acceptable, or preferable to biopsy if they were equally accurate or nearly equally accurate as a biopsy. New technologies to diagnose breast cancer should focus on decreasing discomfort as well as increasing test accuracy.

Eliciting willingness to pay: comparing closed-ended with open-ended and payment scale formats

Willingness to pay (WTP) is increasingly being used as a measure of valuation in health technology assessment. A variety of formats for eliciting values are available, although the relative virtues of each remain the subject of methodological controversy. This article compares valuation results obtained using a WTP survey instrument in a closed-ended format with those obtained from instruments using open-ended and payment scale formats. Samples of subjects were drawn from a general population, and all were asked to value the same intervention--alternative methods of screening for colorectal cancer. It was discovered that, whereas the open-ended and payment scale formats produced broadly similar valuations, the closed-ended format produced significantly higher WTP valuations and different justifications for those valuations. It is hypothesized that anchoring and yea-saying effects explain these differences and that the closed-ended format triggers a different response mode in subjects.

Update on the cost-effectiveness of screening for colorectal neoplasia

Colorectal cancer is an ideal target for population screening because it is a prevalent disease with an identifiable precursor lesion that, when treated, favorably alters the natural history of the disease. Several strategies for screening have illustrated efficacy, including fecal occult blood testing, sigmoidoscopy and colonoscopy. Cost-effectiveness analyses have been performed to determine whether the resources required to implement screening are justified by potential gains. The U.S. Preventive Services Task Force recently commissioned a study on the cost-effectiveness of colorectal cancer screening, which revealed that screening was cost-effective compared to no screening. However, it could not be confirmed which strategy would save the most life-years, nor which was most cost-effective. Since publication of this review, several additional cost-effectiveness analyses have been performed. These studies confirm that screening average risk patients at age 50 by a variety of available strategies is likely to be reasonable by current standards for resource utilization, and that either colonoscopy every 10 years (or once at age 65) or the combination of annual fecal occult blood testing with sigmoidoscopy every 5 years are viable alternatives. Additional economic analyses have examined the use of aspirin chemoprophylaxis to prevent colorectal cancer either alone or as an adjunct to screening strategies. These studies reaffirm the cost-effectiveness of colorectal cancer screening, but illustrate that aspirin chemoprophylaxis is unlikely to be associated with gains for which society would be willing to pay. At present, the decision to choose one colorectal screening strategy over another is based on availability of screening modalities, patient and provider preferences, and associated adherence to screening recommendations. Assessment of preference and development of interventions to increase adherence to screening should be a focus of research in the future.