Improving participation in colorectal cancer screening: Targets for action

Abstract

Objective

Our aim was to determine whether physician-related factors influenced patient participation in colorectal cancer (CRC) screening programs and to identify patient characteristics associated with lower participation in order to facilitate the development of targeted actions to improve participation.

Method

A retrospective cohort study was conducted in a French department during its first CRC screening campaign from June 2007 to May 2010. Data for 157,766 patients followed by 903 general practitioners (GPs) were analyzed. Patient participation was assessed using multilevel logistic modeling.

Results

The overall participation rate was 30% (95% confidence interval [95% CI], 29.8–30.2) and varied across the 903 GPs from 0% to 75.5% (median, 30; interquartile range, 24–35). Inter-GP variance explained only 5.5% of the participation rate variance. Participation was significantly lower in males (odds ratio [OR], 0.79; 95% CI, 0.78–0.91), the youngest age group (55–59 years, OR, 0.61; 95% CI, 0.58–0.63), and patients living in socioeconomically deprived areas (OR, 0.82; 95% CI, 0.77–0.87).

Conclusion

Targeted actions to improve CRC screening participation should focus on patients younger than 60 years, males, and individuals living in deprived areas. Actions to enhance the influence of GPs on patient participation should be directed to the overall population of GPs.

Introduction

Colorectal cancer (CRC) ranks second among all cancers in terms of incidence and mortality in both men and women in Europe (Ferlay et al., 2010) and also constitutes a heavy economic burden (Chevreul, 2010). Although new technologies have improved diagnosis and treatment, early detection remains the key to reducing morbidity and mortality. A meta-analysis of trials of biennial CRC screening using the fecal occult blood test (FOBT) demonstrated a 15% relative reduction in CRC mortality (relative risk [RR], 0.85; 95% confidence interval [95% CI], 0.78–0.92) (Hewitson et al., 2008). As a result, most European countries have instituted population-based FOBT screening programs (Zavoral et al., 2009). A high level of participation in a screening program must be achieved and maintained to ensure clinical and cost effectiveness (Pignone et al., 2002). Participation rates vary widely across Europe (20%–52% in 2009) (Zavoral et al., 2009) and are generally considered insufficient when compared to the European guidelines for quality assurance in colorectal cancer screening that set a 45 to 65% participation rate (Segnan et al., 2010).

In France, a pilot FOBT campaign was started in 2002 and expanded into a national population-based program in 2009. Local organizations coordinate the program and send mailed invitations to individuals aged 50–74 years to visit their general practitioners (GPs) for a free FOBT kit and explanation of the screening program and test procedure. Two mailed reminders are sent to those who do not respond, with the second including an FOBT kit, instructions, and a pre-paid return envelope. The objective is a 50% participation rate (Grünfeld, 2009). The pilot campaign covering 21 departments achieved 42% participation (Goulard et al., 2008).

Factors affecting participation may be related to the patients or to the physicians (Subramanian et al., 2004). Regardless of their specific role in the screening program, GP involvement has been shown to improve patient participation (Federici et al., 2006, Ferreira et al., 2005, Myers et al., 2007, Nguyen-Oghalai and Wu, 2009). Several studies suggest that GP beliefs and practices regarding CRC screening may vary widely (Damery et al., 2010, Klabunde et al., 2003, Subramanian et al., 2004). While patient characteristics affecting willingness to participate in screening programs have been widely studied (Frederiksen et al., 2010, Pornet et al., 2010, Subramanian et al., 2004, Weller et al., 2007), to our knowledge no study has simultaneously evaluated the potential impact of both patient and GP characteristics on participation in a CRC screening program.

Our objective was to investigate whether actions targeting specific GP and patient populations could improve CRC screening participation. We therefore quantified the heterogeneity of GP average practices in influencing patient participation and identified GP and patient characteristics associated with lower participation. We modeled the probability of patient participation using a multilevel approach to differentiate sources of variability related to patients and GPs while simultaneously taking into account some of the characteristics of these two groups.