Psychosocial determinants of participation in colorectal cancer screening: issues in the arrival of the new immunological test.

Summary IntroductionColorectal cancer is the 2nd leading cause of cancer mortality in France (HAS, 2013) but also the 3rd most common cancer (INCa, 2014). Organized screening has existed since 2008, yet participation rates remain low: 33.5% in France (Santé Publique France, 20018). According to the literature, the main barriers to participation in screening are lack of trust in the health care system (Clavarino et al, 2004) . embarrassment, discomfort and unpleasantness accompanying the testing procedures (Varela et al, 2010) . or lack of time. Finally, the lack of recommendations from the physician is one of the most important barriers (Walsh et al, 2010 . Powell et al, 2009). The Hemoccult II test, used in organized screening until March 2015, has been replaced by a new immunological test, considered more sensitive, more specific and more reliable by the medical community (INCa, 2014).Objectives and methodIn view of the low screening rates and the main obstacles identified in the literature, the aim of this thesis work is to analyze the determinants of participation in screening both from the point of view of patients and general practitioners. This doctoral work is based on the triangulation technique (theoretical, methodological and data). More precisely, two validated and recognized theoretical frameworks in social psychology of health were mobilized, namely the Theory of Social Representations (Moscovici, 1984), and the Theory of Planned Behavior (Ajzen et al., 1991), allowing the adoption of a comprehensive as well as predictive approach to screening. Three studies were developed:- A qualitative study by semi-directive interviews, conducted with 17 general practitioners, with the aim of understanding their social representations of colorectal cancer screening as well as the way in which it can be anchored in their recommendation practice. A quantitative study by questionnaires, carried out with 160 participants from the general population, aimed at identifying the main predictors of the intention and behaviour of colorectal cancer screening.Main resultsThe analysis of the interviews revealed an inconsistency between the role that doctors think they should play with patients in prevention and screening, and the reality of their practice which leaves them little time to devote to it. The analysis of the focus groups revealed that the main obstacles to participation in screening are: the lack of accessibility of the test (need to consult the general practitioner to obtain the screening kit), a low level of concern for prevention, but also the fact that colorectal cancer refers to a part of the body that is taboo and considered dirty Finally, analysis of the questionnaires identified several variables that influenced screening intention and behavior, namely: previous screening behavior, screening frequency, denial, social proximity, social norms, and perceived behavioral control. The analyses particularly highlighted the importance of perceived behavioural control, which can directly influence behaviour without going through intention.ConclusionThe findings reveal the relevance of combining a comprehensive approach with a predictive approach. Our perspectives propose the implementation of interventions aiming at improving the level of perceived control of the general population towards this screening.