Bowel growth removal questioned
Wednesday 9th October 2013, 2:51AM BST.
Too many people could be undergoing procedures to remove growths in their bowel that might never develop into cancer, according to experts.
Concerns about missing cases of bowel cancer could be putting people at unnecessary risk of bowel perforation or major bleeding, they said.
Bowel polyps are small growths on the inner lining of the colon or rectum and are common, affecting 15% to 20% of the UK population.
They do not usually cause symptoms but some can eventually turn into cancer if left untreated.
For this reason, they are generally removed in those having a colonoscopy as part of investigations for bowel symptoms.
Some polyps are a tiny raised area or bulge, called a sessile polyp, while others look like a grape on a stalk and some consist of many tiny bumps clustered together.
Professor Geir Hoff and colleagues in Norway, writing online in the British Medical Journal (BMJ), said more evidence was needed so that the risks of removing harmless polyps did not outweigh the benefits of screening.
They said the most common polyps found during screening are adenomas, and guidelines recommend that they are removed.
However, data shows that less than 5% of adenomas develop into bowel cancer, suggesting that 95% of procedures may be exposing patients to unnecessary risks, they went on.
This concern about malignancy has now been extended to sessile serrated polyps which are “less understood than adenomas and are more risky to remove”.
These polyps are often pale pink and covered by mucus, making them hard to distinguish, and t heir structure makes them difficult to remove. Sometimes they need to be cut into multiple pieces and removal can carry risks including major bleeding and perforation.
The authors said that with more polyps being detected as a result of screening, “we need to be able to quantify the gains and harms and share this information with screening participants”.
They added: “It is not enough simply to share a belief that we are doing good, partly motivated by fear of not doing enough.”
Mark Flannagan, chief executive of the charity Beating Bowel Cancer, said: “If bowel cancer is detected at an early stage, there is over a 90% chance of it being successfully treated.
“This is why taking part in the bowel cancer screening programme is so important. If you have an abnormal result you’ll be sent for a colonoscopy to detect polyps, which can develop into cancer over time.
“Whilst this study raises reasonable questions about the need to remove all polyps which are found, much more research needs to be done to refine the choice of which polyps should be routinely removed in the future. We await further studies with interest.”
Bowel cancer is the third most common cancer in the UK .
Professor Julietta Patnick, director of the NHS Cancer Screening Programmes, said: “We know that some benign polyps go on to develop into bowel cancer and some do not.
“However, leading experts do not yet know a sufficient amount about the disease to be able to determine which adenomas or sessile serrated polyps will become cancerous.
“The best available clinical advice from the British Society of Gastroenterology is therefore to remove polyps and send them for histological examination.
“Individuals are then recalled in one or three years, depending on their risk category.
“Consensus guidelines are important to ensure that all patients receive a high quality service. While watching and waiting might yield more information about the aetiology of bowel cancer, it represents a risk to the individual patient that many people will find unacceptable.
“Estimates suggest that the programme saves around 2,400 lives a year.”