The impact of sample type and procedural attributes on relative acceptability of different colorectal cancer screening regimens

Joanne M Osborne,1,2 Ingrid Flight,1 Carlene J Wilson,1,3,4 Gang Chen,1 Julie Ratcliffe,1 Graeme P Young1 1Flinders Centre for Innovation in Cancer, Flinders University, Bedford Park, SA, Australia; 2Bowel Health Service, Repatriation General Hospital, Daw Park, SA, Australia; 3School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia; 4Olivia Newton John Cancer Wellness and Research Centre, Austin Hospital, Heidelberg, VIC, Australia Objective: In Australia and other countries, participation in colorectal cancer (CRC) screening using fecal occult blood testing is low. Previous research suggests that fecal sampling induces disgust, so approaches not involving feces may increase participation. This study aimed to determine population preferences for CRC screening tests that utilize different sample collections (stool, blood, and saliva) and the extent to which specific attributes (convenience, performance, and cost) impact this preference. Materials and methods: People aged 50–74 years completed a survey. Preference for screening for CRC through stool, blood, and saliva was judged through ranking of preference and attributes critical to preference and confirmed via a discrete choice experiment (DCE) where test attributes were described as varying by performance, cost, and sample type. Participants also completed a measure of aversion to sample type. Results: A total of 1,282 people participated in the survey. The DCE and ranking exercise confirmed that all test attributes had a statistically significant impact on respondents’ preferences (P < 0.001). Blood and saliva were equally preferred over stool; however, test performance was the most influential attribute. In multivariable analyses, those who preferred blood to stool collection exhibited higher aversion to fecal (OR = 1.17; P ≤ 0.001) and saliva (OR = 1.06; P ≤ 0.05) sampling and perceived that they had less time for home sample collection (OR = 0.72, P ≤ 0.001). Those who preferred saliva to stool had higher aversion to fecal (OR = 1.15; P ≤ 0.001) and blood (OR = 1.06, P ≤ 0.01) sampling and less time for home sample collection (OR = 0.81, P ≤ 0.5). Conclusion: Aversion to sample type and perceived inconvenience of sample collection are significant drivers of screening preference. While blood and saliva sampling were the most preferred methods, test performance was the most important attribute of a screening test, regardless of sample type. Efforts to increase CRC screening participation should focus on a test, or combination of tests, that combines the attributes of high performance, low aversion, and convenience of use. Keywords: quantitative study, preference, discrete choice experiment, ranking, home stool test, Australia