Quicker, safer test could accurately detect some bowel cancers

Patients with suspected bowel cancer could be offered a quicker test to assess their cancer risk.

This is the finding of new research from Imperial College London.

The study, which tracked 7375 patients referred to hospital with suspected bowel cancer, compared two methods of examining the inside of the bowel – whole colon investigation and flexible sigmoidoscopy.

These findings can help to inform guidelines for the best use of whole colon investigations Dr Amanda Cross Study author

Patients are referred for these tests by their GP when they develop symptoms such as blood in stools, or a change in bowel habit.

Both methods involve inserting a small flexible tube, with a light and camera on one end, into the rectum, and moving it through the bowel. This enables doctors to examine the lining of the bowel for any changes that may indicate cancer.

However, flexible sigmoidoscopy only looks at the lower part of the bowel; this procedure is generally quicker, carries a lower level of complications, such as perforation of the bowel, and is cheaper than whole colon investigation.

This study, published in the British Journal of Cancer, revealed patients with just rectal bleeding or increased stool frequency, but crucially, no anaemia or lump in the stomach, had a low risk (0.4%) of having cancer in the upper part of the bowel. Therefore, these patients could be examined safely by flexible sigmoidoscopy alone.

Changing guidelines 

The research team said that incorporating these findings into treatment guidelines would reduce the number of patients referred for whole colon investigation. Opting for flexible sigmoidoscopy where appropriate would also reduce burden on both patients and the NHS.

Dr Amanda Cross, lead author of the research from Imperial’s School of Public Health and the Department of Surgery and Cancer said: "These findings can help to inform guidelines for the best use of whole colon investigations at a time when endoscopy resources are extremely stretched."

Flexible sigmoidoscopy screening for bowel cancer was originally pioneered by Imperial’s Professor Wendy Atkin, who sadly passed away earlier this year.

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"Whole-colon investigation vs. flexible sigmoidoscopy for suspected colorectal cancer based on presenting symptoms and signs: a multicentre cohort study" by A.Cross et al. is published in the British Journal of Cancer.  https://doi.org/10.1038/s41416-018-0335-z

The work was funded by National Institute for Health Research (NIHR) Health Technology Assessment Programme and the Bobby Moore Fund for Cancer Research UK. Infrastructure support for this work was provided by the NIHR Imperial Biomedical Research Centre (BRC)