Abstract B12: To screen or not to screen: Examining components of the Extended Parallel Process Model in a tailored-risk communication intervention to promote colorectal cancer screening
Authors: Birmingham Wendy C. , Hung Man , Boonyasiriwat Watcharaporn , Walters Scott T. , Stroup Antoinette M. , Schwartz Marc D. , Franklin Jeremy D. , Kinney Anita Y. 
Published: October 2015

The Extended Parallel Process Model (EPPM) has been effectively used to promote healthy behaviors, but less is known about the effectiveness of the EPPM in promoting screening adherence in individuals at familial risk for colorectal cancer (CRC). The original EPPM model posits that an additive relationship exists between the constructs perceived severity and susceptibility (“threat”) and between perceived self- and response efficacy (“efficacy”). However, this model may not be as effective in predicting message acceptance in the context of CRC screening as these constructs may independently contribute to the model. For example, with CRC threat, there may be little variance in the perceived severity score as perceptions of cancer severity have been shown to be universally high. Likewise, one may have high levels of response efficacy (“Colonoscopy can save my life”) but low self-efficacy (“Without insurance I can't pay for a colonoscopy”) thus influencing efficacy scores. To determine the effectiveness of the EPPM in promoting CRC screening, we used data from the Family Colorectal Cancer Awareness and Risk Education Project (Family CARE), that tested a remote tailored-risk communication intervention aimed at individuals with familial risk for CRC. Intention-to-screen and medical record-verified colonoscopy (CS) were collected on 218 participants who received the personalized intervention. Using structural equation modeling (SEM), we examined associations of CRC threat and efficacy with greater message acceptance in a full additive model, and in an apriori alternative model in which perceived severity, susceptibility, self-efficacy and response efficacy acted as independent predictors. We considered indicators of good fit to be Root Mean Square Error of Approximation (RMSEA) &lt;.08, Standardized Root Mean Residual (SRMR) &lt;.08, and Comparative Fit Index (CFI) &gt;.90. We compared the two models based on model fit indices, Akaike Information Criterion (AIC) and Bayesian Information Criterion (BIC), with the preferred model having lower AIC and BIC. SEM results indicated poor fit for the full additive EPPM model (RMSEA=0.109; SRMR=0.137; CFI 0.800) while the alternative model showed good fit (RMSEA=0.068; SRMR=0.063; CFI=0.933). Additionally, comparison of the two models indicated that the alternative model was a better fit than the full additive model (RMSEA=0.071; SRMR=0.108; CFI 0.918; AIC=11021; BIC=11332). Further, we found perceptions of susceptibility (B =0.321, p &lt;.001) and self-efficacy (B=0.365, p&lt;0.001) to be significantly associated with intention to screen, while severity (B=0.059, p=0.454) and response efficacy (B=-0.189, p=0.101) showed no significant association. Importantly, intention to screen was significantly associated with medically verified CS behavior (B=0.728, p&lt;0.001).

Relatives of CRC patients are at increased risk for the disease, yet screening rates remain low among these individuals despite the effectiveness of CS in both early detection and cancer prevention. Theory-based communication such as the EPPM that addresses multiple determinates of behavior may help promote CRC screening yet few studies have tested conceptual models with regard to an intervention's effect on psychosocial pathways and actual cancer screening behavior. Our results indicate that focusing on individuals' perceptions of CRC susceptibility and screening self-efficacy may more effectively contribute to CRC screening behavior. Noteworthy, we measured both intentions to screen and actual screening behavior. These findings uniquely contribute to the literature by providing evidence of the underlying theoretical psychosocial pathways of how a personalized health promotion intervention works in motivating CRC screening among individuals at increased familial risk.

Citation Format: Wendy C. Birmingham, Man Hung, Watcharaporn Boonyasiriwat, Scott T. Walters, Antoinette M. Stroup, Marc D. Schwartz, Jeremy D. Franklin, Anita Y. Kinney. To screen or not to screen: Examining components of the Extended Parallel Process Model in a tailored-risk communication intervention to promote colorectal cancer screening. [abstract]. In: Proceedings of the Thirteenth Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2014 Sep 27-Oct 1; New Orleans, LA. Philadelphia (PA): AACR; Can Prev Res 2015;8(10 Suppl): Abstract nr B12.