One in four cases of colorectal cancer (CRC) detected in a guiac faecal occult blood testing (gFOBT) programme are diagnosed within two years of a negative screening result, a study in the UEG Journal (1) has found, suggesting that gFOBT should be replaced by more sensitive screening methods to improve detection rates.
CRC is the most common type of digestive cancer in Europe (2) and annual incidence is predicted to rise by 12% by 2020 (3).
The observational study was carried out on 772,790 people during the first round of the Scottish Bowel Cancer Screening Programme, in which individuals aged 50-74 years were invited to participate in gFOBT screening over a two year study. Overall uptake of the screening was 54%, and of the 1,979 individuals who were diagnosed with CRC during the study period, 25% of the cases detected were within two years of a negative screening result (interval cancers).
Professor Evelien Dekker, United European Gastroenterology CRC screening expert, comments: "Although there are no universal guidelines on an acceptable interval cancer rate, this study supports the need to switch CRC screening with gFOBT to a more sensitive method, such as faecal immunochemical testing, to help reduce this figure".
Due to its superior analytical technique and adjustable cut-off levels, faecal immunochemical testing (FIT) offers substantial clinical benefits which could help increase CRC detection during screening. Comparative studies between the two faecal tests have been performed and have demonstrated the superiority of FIT over gFOBT screening (4,5). FIT has been fully implemented in some areas of Europe such as France and Slovenia, demonstrating robust results so far. A nationwide programme is currently being rolled out in the Netherlands and other nations are piloting the method too.
As well as its enhanced clinical benefits, utilising FIT has been shown to increase participation rates in CRC screening because the test is easier to perform and typically uses only a single faecal sample instead of the three required in gFOBT (6). "The simplicity of FIT should encourage a larger proportion of the public to undertake CRC screening, which also can help increase the levels early detection to improve survival rates" explains Professor Dekker. "With incidence of CRC expected to rise between now and 2020, implementing FIT across Europe should help increase screening participation rates. In the Netherlands we have experienced a participation rate that is 12% higher for FIT compared to gFOBT".
The Need for Screening:
With 355,436 people (46%) not participating in screening during the Scottish Bowel Cancer Screening Programme, the study also highlighted that 47% cases of CRC arose in these non-participants. This compares to just 28% of patients receiving diagnosis through a screening test, where the cancer is more likely to be detected at an earlier stage (see table below).
UEG - Interval Cancer in CRC Screening
| Stage | Screen-detected Cancer (%) | Interval Cancer (%) | Non-participant Cancer (%) |
| A | 33.9 | 18.7 | 11.3 |
| B | 25.6 | 25.5 | 25.3 |
| C | 25.2 | 28.5 | 29.3 |
| D | 6.3 | 18.9 | 21.5 |
| Unknown | 9 | 8.4 | 12.6 |
Distribution of screened-detected cancer, interval cancer and non-participant cancer by stage (A earliest stage; D latest stage)
Early detection of CRC results in a high survival rate, emphasising the requirement that both an effective screening process and a high uptake of screening should be targeted to identify and treat the disease as early as possible.
Professor Dekker adds: "These findings demonstrate that members of the public should be encouraged to participate in CRC screening and not ignore the potential symptoms of CRC after a negative screening result. Consultation with a doctor is strongly advised if symptoms occur, which include blood in the stool or a persistent change in bowel habits".
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Notes to Editors
About UEG
UEG, or United European Gastroenterology, is a professional non-profit organisation combining all the leading European societies concerned with digestive diseases. Together, its member societies represent over 22,000 specialists, working across medicine, surgery, paediatrics, gastrointestinal oncology and endoscopy. This makes UEG the most comprehensive organisation of its kind in the world, and a unique platform for collaboration and the exchange of knowledge. Find out more by visiting http://www.ueg.eu
To advance standards of gastroenterological care and knowledge across Europe and the world, UEG offers numerous activities and initiatives, including:
- UEG Week, the biggest congress of its kind in Europe, and one of the two largest in the world.
- UEG Education, the universal source of knowledge in gastroenterology, providing online and classroom courses, a huge online library and delivering the latest GI news, fostering debate and discussion
- Training Support, funding for innovative training and educational programmes, as well as international scientific and professional co-operations
- UEG Journal, published bi-monthly, covering translational and clinical studies from all areas of gastroenterology
- EU Affairs, promoting research, prevention, early diagnosis and treatment of digestive diseases, and helping develop an effective health policy for Europe
About Professor Dekker
Professor Evelien Dekker, UEG spokesperson and colorectal cancer screening expert, AMC Amsterdam Gastroenterology and Hepatology, Netherlands.
To interview Professor Dekker, or for further information, please contact Luke Paskins at UEG on 44-0-1444-811099 or media@ueg.eu
References
1. Steele RJC, Stanners G, et al. Interval cancers in a national colorectal cancer screening programme. UEG Journal. January 2016. http://ueg.sagepub.com/content/early/2016/01/06/2050640615624294.full
2. Roberts SE, Samuel DG, Williams JG, et al. Survey of Digestive Health across Europe. Part one: The burden of gastrointestinal diseases and the organisation and delivery of gastroenterology services across Europe. Report for United European Gastroenterology. October 2014.
3. International Agency for Research on Cancer (IARC)
4. Van Rossum L et al, Gastro 2008
5. Hol L et al, Gut 2010
6. Allison JE, Halloran SP, Population screening for colorectal cancer means getting FIT: The past, the present, and future of colorectal cancer screening using the faecal immunochemical test for haemoglobin (FIT). Gut and Liver. March 2014. http://www.gutnliver.org/journal/view.html?doi=10.5009/gnl.2014.8.2.117