Abstract
IntroductionColorectal cancer is the second leading cause of cancer deaths in France (HAS, 2013) but also the third most common cancer (INCa, 2014). An organized screening programme has been put in place since 2008, but participation rates remain low: 33.5% in France (Santé Publique France, 2018). According to the literature, the main barriers to participation in screening are the lack of confidence in the health care system (Clavarino et al, 2004) ; embarrassment, discomfort and dissatisfaction accompanying testing procedures (Varela et al, 2010); or lack of time. Finally, the lack of general practitioners’ recommendations is one of the most significant obstacles (Walsh et al, 2010, Powell et al, 2009). The Hemoccult II test, used as part of organized screening until March 2015, was replaced by a new immunological test, considered more sensitive, more specific and more reliable by the medical community (INCa, 2014).Objectives and methodFaced with the low screening rates and main obstacles identified in the literature, this thesis aims at analyzing the determinants of screening participation, with both patient and general practitioner points of view. Moreover, it appears necessary to evaluate issues with the arrival of the new immunological test.This doctoral work is based on the technique of triangulation (theoretical, methodological and data triangulation). More precisely, two validated and recognized theoretical frameworks in health and social psychology were employed, namely the Theory of Social Representations (Moscovici, 1984), and the Theory of Planned Behaviour (Ajzen et al, 1991), allowing the adoption of a comprehensive approach as well as a predictive approach to studying screening participation. Three studies have been set up:- A qualitative study through semi-structured interviews, conducted with 17 general practitioners, aimed at understanding their social representations of colorectal cancer screening and how it can be anchored in their practice of recommendation;- A qualitative study by focus groups, conducted with 29 participants from the general population. The objective was to apprehend their social representations of colorectal cancer screening as well as the obstacles and facilitators to screening participation.- A quantitative study by questionnaire, including 160 participants from the general population, endeavours to identify the key predictors of colorectal cancer screening intention and behaviour.Main resultsThe analysis of interviews revealed an inconsistency between the role general practitioners think they should play with patients in prevention and screening, and the reality of their practice which leaves them insufficient time to devote to it. The focus group analysis revealed that the main barriers to participation in screening are: the lack of accessibility of the test (needing to consult the general practitioner in order to obtain the screening kit), a low concern for prevention, but also the fact that colorectal cancer refers to a body part that is deemed taboo, and considered “dirty”. Finally, the analysis of questionnaires allowed the identification of several variables influencing intention and behaviour of screening, namely: previous screening behaviour, frequency of screening, denial, social proximity, social norms and perceived behavioural control. Analysis particularly emphasized the value of perceived behavioural control, which can directly influence behaviour without going through intention.ConclusionResults reveal the relevance of combining a comprehensive approach with a predictive approach. Our perspectives suggest the implementation of interventions aimed at improving the perceived level of control of the general population faced with this screening.