Colorectal cancer is the third most common cancer worldwide and is the second leading cause of cancer-associated deaths. While colorectal cancer is on the decline in the United States (US), disparities still exist, despite the non-invasive screening modalities, such as stool-based tests have shown themselves to be effective in the detection of colorectal cancer. Many of the existing stool-based test interventions lack the use of a contemporary theory-based approach. Given the paucity of theory-based interventions intended to promote stool-based tests, this cross-sectional study utilizes the multi-theory model (MTM) of health behavior change to explain the seeking of stool-based tests for colorectal cancer (CRC) screening. An online 57-item questionnaire with an established psychometric validity was used to collect responses from the US-based sample (n = 640) of adults aged 45-75 years old. The data were analyzed using bivariate and multivariate statistical methods. Structural equation modeling (SEM) was conducted to test the construct validity of the survey instrument. In this nationwide sample, 39.2% (n = 251) of participants reported having received some form of a stool-based test. Among the participants who did not undergo stool-based CRC screening, the MTM subscales, including "participatory dialogue", "behavioral confidence", and "changes in the social environment", were significant predictors of initiating screening behavior and explained 48% of the variance in the initiation among this group (R2 = 0.579, F = 5.916, p < 0.001; adjusted R2 = 0.481). The MTM may be a useful framework with which to design educational, mass media, social media, and clinical interventions for the promotion of stool-based CRC screening among adults aged 45-75 years old.
Keywords: colorectal cancer; multi-theory model; polyps; screening.