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Reducing pressures on the NHS: Using flexible sigmoidoscopy to investigate bowel cancer symptoms


Bowel cancer is the fourth most common cancer in the UK. Each year, there are approximately 42,000 new cases, representing more than 10% of all new cancer cases1. What’s more, someone dies from bowel cancer in the UK every 30 minutes, making it the country’s second most fatal cancer.

The shocking thing about these bleak statistics is that bowel cancer can be one of the most treatable cancers, if caught early enough. When bowel cancers are diagnosed at the earliest stage (stage I), over 90% of people will survive for five years or more. In stark comparison, less than 10% of people will survive this long if diagnosed at the latest stage (stage IV)1.  Unfortunately, too many cases are diagnosed at a late stage, when chances of successful treatment are low.

Diagnostic challenges

Early diagnosis of bowel cancer is no easy feat, however. Symptoms of the disease, such as a change in bowel habit, blood in stool, and abdominal pain, are common in the general population and are usually caused by other, less serious conditions such as haemorrhoids (piles) and irritable bowel syndrome. GPs will see many people with these kinds of symptoms but might only see a single case of bowel cancer each year. So how do they decide which patients require further investigation? 

Fearing that they will miss a cancer diagnosis, many GPs choose to refer patients with bowel cancer symptoms for a whole colon investigation to examine the entire length of the bowel. This usually involves a colonoscopy, a thin, flexible tube with a camera and light at the end, which is passed into the rectum to examine the lining of the bowel. Unsustainable numbers of patients are currently being examined in this way, placing enormous pressure on NHS resources and costing a huge amount of money. Bowel cancer costs the NHS more than £1 billion a year, with 25% of this spent on diagnostic investigations for people who are found not to have the disease2.

Flexible sigmoidoscopy – a cheaper, quicker, and effective alternative for some cases?

A potential solution to this problem is to offer some patients with symptoms suggestive of bowel cancer a cheaper and less resource-intensive test, such as flexible sigmoidoscopy. This procedure is similar to colonoscopy, but is often preferred by patients as it does not require sedation and is quicker and easier. It does, however, only examine the lower part of the bowel, but this is sufficient for patients unlikely to have cancer in the upper part of the bowel. 

Our study therefore aimed to determine which symptoms are associated with a low risk of cancer in the upper part of the bowel. We followed 7,375 patients who had been referred to hospital with suspected bowel cancer, collecting data from hospital records and cancer registries for three years following referral. This allowed us to identify all cancers arising in these patients, and spot associations between symptoms and cancer location.

The main findings of our study were that patients with rectal bleeding or increased stool frequency, but with no anaemia or lump in the abdomen, had a very low risk (0.4%) of having cancer in the upper part of the bowel. These patients could therefore safely undergo flexible sigmoidoscopy alone.

This study is significant because it allowed us to define, more specifically than in previous studies, which patients with suspected bowel cancer could be offered flexible sigmoidoscopy rather than a whole colon investigation. Incorporating these findings into guidelines would help GPs make better referral decisions and reserve whole colon investigations for patients who need them the most. This would help the NHS make best use of resources at a time when endoscopy departments are seriously overstretched.

You can read more about the study and our team at the Cancer Screening and Prevention Group (CSPRG) website and if you have any questions, feel free to ask us on Twitter at: @CSPRG_Imperial.

The study was funded by the NIHR's Health Technology Assessment (HTA) Programme and more information about the project is also available on the NIHR Journals Library.


(1) Cancer Research UK. Bowel Cancer Statistics. London: Cancer Research UK
(2) York Health Economics Consortium. Bowel Cancer Services: Costs and Benefits. Summary Report to the Department of Health. York: University of York; 2007

The views and opinions expressed in this blog are those of the authors and do not necessarily reflect those of the NIHR, NHS or the Department of Health and Social Care.