Each year, Europe’s second biggest cancer killer—colorectal cancer (CRC)—claims more than 200,000 lives in Europe alone; yet, early detection may result in a 90–95% survival rate. Implementation of CRC screening programmes across Europe is booming, but what are the nuts and bolts of a good CRC screening programme?
A press release issued by UEG in March 2014 warned that the annual incidence of CRC is predicted to have risen 12% by 2020, at which time it will potentially affect about half a million Europeans.1 CRC is currently the second and third most common cancer in European women and men, respectively, and accounts for 13% of all cancer-related deaths in Europe, resulting in one fatality every 3 minutes. Screening programmes have been implemented in several countries with a view to reducing morbidity and mortality by identifying and treating cases of early-stage CRC.
It’s almost a year since a nationwide CRC screening programme was launched in Denmark, with an annual budget of approximately €50M. Starting in March 2014, all Danish citizens aged 50–74 years old are invited to participate in biannual screening.2 Those individuals who are willing to participate receive a screening kit by regular mail, and the test is free and voluntary to complete. The CRC screening programme uses a faecal occult blood (FOB) test (FOBT), and individuals with a positive FOBT are offered a colonoscopy.
The Danish screening programme was implemented on the basis of a feasibility study carried out in 2005–2006, in which 2–3% of those screened tested positive for the presence of FOB; of these, 8% and 40% were found to have cancer and polyps, respectively, as demonstrated by colonoscopy.3 In the feasibility study, a chemical test with a sensitivity of only 60% was used. In the ongoing screening programme, however, the faecal immunochemical test (FIT; also known as an immunochemical FOBT) is being used, which is expected to increase sensitivity. Meanwhile, high FIT sensitivity and specificity may be difficult to achieve given the fact that not all CRCs bleed and there are causes of FOB other than cancer and polyps; hence, quite a few false-negatives and false-positives may still be expected with the FIT.
Of course, there’s more to achieving a successful screening programme than safeguarding best possible intervention options and optimizing diagnostic performance parameters, such as test cut-off and predictive values. The very nature of the test itself, how the screening programme is presented to the public and overall public health awareness are all factors potentially influencing the success of a screening programme. In the case of CRC, the mere thought of having a colonoscopy may scare people off, and public health awareness may differ substantially between countries, both of which are factors that may significantly affect uptake and thereby overall success rates. Sometimes there are differences in the willingness to participate within the same country that have no obvious explanation. For example, as pointed out by Björn Rembacken in his talk on CRC screening strategies in the West, a striking difference in the uptake rate has been observed in Belgium, where the Flemish appear much more keen on participating than the Walloons.4 In the Danish feasibility study, women were more likely to participate, as were those with higher education and higher income.5 Moreover, a study carried out by The Danish Cancer Society suggests that it takes time for a population to adjust to thinking and speaking of CRC.6 In this study, the most common barriers to accepting screening invitations included:
- Not wanting to know whether they have CRC
- Thinking that the test is too awkward to do
- The need for more information
- Developing a sense of being ill merely by being offered the test
- Feeling too old for the test to be relevant
Apart from mitigating issues that have to do with culture and tradition, by removing stigma and taboos through campaigns and the provision of information, what diagnostic tools can be developed to minimize the number of cases with a positive result for FOB but negative findings on colonoscopy? How far are we in terms of developing other non-invasive biomarkers, such as those based on microbiota signatures7 or DNA methylation, for the detection of both CRC and critical precursor lesions? To which extent may individual risk assessment replace invasive and semi-invasive diagnostic methods in terms of identifying patients with early CRC?
The UEG Education Library boasts a large catalogue of presentations, abstracts and syllabi focusing on early detection of CRC as a means of improving patient survival and widening the window of therapeutic intervention. For instance, if you want to familiarise yourself with the current status of CRC screening programmes throughout Europe, simply sign in to myUEG, go the Library and search for “CRC AND screening”. I also recommend listening to the presentations included in the session on “Colorectal cancer screening: the future” from UEG Week 2014 (see Further UEG Resources below).
References
- UEG Press Release. Europe is falling behind America in the fight against colorectal cancer due to low screening uptake. (March 2014, accessed February 2015).
- Danish Cancer Society. Screening for colon cancer. (2014, accessed February 2015)
- Research Centre for Prevention and Health—The Capital Region of Denmark. Screening for colorectal cancer in the counties of Vejle and Copenhagen—cross evaluation of pilot studies. [Article in Danish]
- Rembacken B. CRC screening strategies. Presentation in the East meets West: CRC Screening Strategies session at UEG Week 2013
- Frederiksen BL, Jørgensen T, Brasso K, et al. Socioeconomic position and participation in colorectal cancer screening. Br J Cancer 2010; 103: 1496—1501. http://www.nature.com/bjc/journal/v103/n10/abs/6605962a.html
- Meyer M. Department of Prevention and Documentation. The Danish Cancer Society. What were the barriers for participating in colorectal cancer screening? A qualitative and quantitative analysis of non-participant barriers to participating in a pilot colorectal cancer screening programme in Vejle and Copenhagen in 2005 and 2006. (April 2007) [Article in Danish].
- National Cancer Institute. Analyzing the gut microbiome to help detect colorectal cancer. (January 2015, accessed February 2015)
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Further UEG Resources
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About the Author
Dr Christen Rune Stensvold is a Senior Scientist and Public Health Microbiologist with specialty in parasitology. He has a Bachelor degree in Medical Sciences, an MSc in Parasitology, and a PhD in Health Sciences. He has been based at Statens Serum Institut, Copenhagen, since 2004. Since 2006, he has authored/co-authored more than 80 articles in international, peer-reviewed scientific journals. In 2013, he was awarded the Fritz Kauffmann Prize for his contribution to clinical microbiology in Denmark. For many years, he has been pursuing the role of common intestinal micro-eukaryotes in human health and disease. Follow Rune on Twitter @Eukaryotes.
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