COLONOSCOPY NOT ALWAYS NECESSARY, STUDY FINDS

A RECENT study found up to 20% of all procedures performed in a New South Wales hospital were either unhelpful or harmful. Some of these, which included performing a colonoscopy for constipation, were becoming more prevalent.

A colonoscopy is a test where a small, flexible tube is inserted into the bowel to check for abnormalities such as growths on the bowel, which can lead to bowel cancer.

Around 600 000 colonoscopies were performed in Australia in 20132014. This figure is expected to rise to more than a million a year by 2020, equivalent to one in every 25 Australians.

A colonoscopy is an invasive procedure and comes with risks, including bowel perforation. So it’s important to have the test only if you’re likely to benefit from it.

Bowel cancer is the second most common causes of cancer-related deaths in Australia. Current evidence suggests colonoscopy significantly reduces the risk of bowel cancers. This is where colonoscopy’s greatest benefit lies.

Bowel cancers start out as small growths in the bowel called polyps. These can be seen with a colonoscopy and cut out by doctors during the test.

So, colonoscopy is more worthwhile when done in people at an increased risk of bowel cancer. The most important risk factor is age, as cancer rates increase in people older than 50.

But some younger people can be at risk due to family history.

A doctor will usually recommend a colonoscopy if patients are at increased risk of bowel cancer due to family history, if their “poo test” is positive for blood, or if they have concerning symptoms such as bleeding.

An Australian study tried to determine which symptoms could best predict bowel cancer. The authors collected data on around 8 000 patients with a range of symptoms – including rectal bleeding and constipation – undergoing colonoscopy.

They followed them to see who was diagnosed with a cancer (or a large polyp) during the colonoscopy.

They found that, apart from age, rectal bleeding was the strongest predictor of bowel cancer. Other common symptoms such as abdominal pain or constipation alone were not associated with bowel cancer, suggesting colonoscopy in these cases was unnecessary. These findings have been replicated in other studies.

Small polyps grow slowly and may take 10 years or longer (if at all) to develop into bowel cancer. This is why it is considered inappropriate to continue screening in people aged over 75. |