The study, published in the British Journal of Cancer, also adds to evidence that the test used in bowel screening – which looks for blood in stool samples – is better at finding bowel cancers in men, and in the lower part of the bowel.
While the blood test – known as FOBt – has been shown to be effective, it is not flawless. The study found that in people who attended screening nearly a quarter of cancers were diagnosed in between tests – suggesting these tumours were either missed by FOBt or these cancers were particularly fast-growing and developed in the two years between screening tests.
The study findings, based on north-east England, support Cancer Research UK’s calls to ensure the bowel screening programmes are as effective as possible.
This could be done by including a better stool blood test and implementing the Flexi-Scope bowel screening test swiftly.**
Using data from the Northern Colorectal Cancer Audit Group in north-east England, researchers looked at more than 1,300 bowel cancers diagnosed between April 2007 and March 2010.***
The results show that nearly 40 per cent of all screen-detected cancers are at an early stage with an improved survival rate compared to cancers found in patients who did not attend screening.****
Cancer Research UK figures show that when bowel cancer is found at the earliest stage, more than 90 per cent of people survive their disease at least five years.
Dr Michael Gill, lead author of the study based at the Wansbeck General Hospital in Northumberland and Durham University, said: “Compared to the trials which led to the introduction of the national bowel screening programme, our research shows that the proportion of bowel cancers detected through screening has improved with the roll-out of national screening.
“But too many bowel cancers are slipping through the net. We need to understand why the present blood test is failing to pick up cancers in certain parts of the bowel, and in women.”
The Scottish and English bowel screening programmes are considering a more effective blood test called Faecal Immunochemical Test (FIT) – which is more efficient at detecting hidden traces of blood in stool samples. And in 2012, the screening programme in England will also begin to include the new Flexi-Scope test.
Sarah Woolnough, Cancer Research UK’s director of policy, said: “There is persuasive evidence that the new blood test, FIT, is a more effective test for bowel screening. The test also requires patients to provide fewer stool samples and so is less complicated to complete and return – which we hope will improve take-up of bowel screening.
“Cancer Research UK is pleased that England will add the Flexi-Scope test to its bowel screening programme but the roll-out needs to be rapid. We need ongoing monitoring and resource to ensure the roll-out runs to time and plan.
“While we understand that Scotland, Wales and Northern Ireland will learn from the English pilots, we urge them to begin planning their own roll-out of the test to avoid undue delays and ultimately save more lives.
“Compared with breast and cervical screening, bowel screening uptake is worryingly low, particularly among men. This study is an important reminder for people to complete their bowel screening kit when it arrives in the post.”
Bowel cancer is the third most common cancer in the UK with more than 41,000 people diagnosed with the disease each year – over 100 people each day.
The bowel screening programme has only been fully up and running in England since 2010 but it is thought it will eventually save around 2,000 lives each year in the UK.
For media enquiries please contact the Cancer Research UK press office on 020 3469 8300 or, out-of-hours, the duty press officer on 07050 264 059.
Gill, M D et al. (2012). Comparison of screen detected and interval colorectal cancers in the bowel cancer screening programme. British Journal of Cancer DOI: 10.1038/bjc.2012.305
Notes to editors
The FOBt is available to men and women aged 60-74 in England, Wales and Northern Ireland and those aged 50-74 in Scotland.
**The UK government has committed to adding the Flexi-Scope test bowel screening test from next year in England. The new test uses a camera and light at the end of a flexible tube to detect and remove pre-cancerous growths from the lower parts of the bowel.
Cancer Research UK scientists led the trial which showed that the Flexi-Scope test has the potential to prevent a third of bowel cancer cases in people screened, as well as picking up the disease earlier.
***Diagnosed between 1st April 2007 and 31st March 2010. During this period around 950,000 screening invitations were sent out with an uptake of 56 per cent. These bowel cancer patients were followed up to see if they were dead (from any cause, not just their bowel cancer) or alive on 1st November 2011. So the mean study follow-up time was 29 months.
****The earliest stages here are defined as having Dukes Stage A bowel cancer and polyps which are cancerous. Dukes Stage A means that the cancer is only in the innermost lining of the bowel or growing slightly into the muscle layer. Polyps are growths in the bowel wall which can develop into cancer over a long period of time. The NHS Bowel Cancer Screening Programme aims to find and remove polyps in the general population before they become cancerous, but some of them become cancerous before they are found.
The Northern Colorectal Cancer Audit Group study showed that for patients whose bowel cancer was picked up through screening, nearly 90 per cent were alive at the end of the study follow-up period, compared to 65 per cent who did not attend screening and were diagnosed after symptoms developed.
FIT is a quantitative test that can give more accurate information about the amount of blood in a stool sample. It is more effective at finding bowel cancers and pre-cancers than FOBt. It could also be introduced without significant changes in the cost of the programme.
While more research is required to determine the absolute logistics of the test – relating to frequency and how it would fit with Flexi-Scope, Cancer Research UK believes that FIT will be a more effective test for bowel screening.
Scotland are looking at the effectiveness of FIT as a first line test for bowel screening. The Scottish government will await the results of this trial before making a decision on the introduction of the Flexi-Scope test.
FIT is currently used in Scotland as a second line test after a positive FOBt result.
In Northern Ireland FIT is currently used as a second-line test. Northern Ireland will be monitoring this and the modelling underway in Scotland before making a recommendation.
Uptake for each of the national bowel screening programmes is currently around 50 per cent, which is considerably lower than for breast (approximately 73 per cent in England) and cervical (around 78 per cent in England) screening.