'Flat' bowel lesions common and linked to bowel cancer

In collaboration with the Press Association

A study has revealed that flat bowel lesions are more common than previously thought, and may have a greater association with cancer than bowel polyps, which are more routinely diagnosed.

Looking for new and abnormal growths and polyps is one way of detecting bowel cancer.

Now a team at the Veterans Affairs Palo Alto Health Care System in California have examined data on 1,819 patients who were undergoing colonoscopy in order to estimate the prevalence of flat lesions - which are called non-polypoid colorectal neoplasms (NP-CRNs) - and determine the extent of their link with bowel cancer.

They found that 170 patients had NP-CRNs and that these lesions were nearly ten times more likely to contain cancerous tissue than polyps, regardless of size.

Writing in the Journal of the American Medical Association (JAMA), the researchers noted that non-polypoid bowel lesions are harder to detect and can appear either slightly elevated, slightly depressed or completely flat.

They wrote: "NP-CRNs were a relatively common finding during colonoscopy. They were more likely to contain carcinoma (cancerous tissue) compared with polypoid neoplasms, independent of lesion size.

"Recent studies have pointed out differences in the genetic mechanisms underlying non-polypoid and polypoid colorectal neoplasms. Future studies on NP-CRNs should further evaluate whether the diagnosis and removal of NP-CRNs has any effect on the prevention and mortality of colorectal cancer and particularly focus on their genetic and protein abnormalities," they concluded.

The UK has recently launched a bowel screening programme. The programme uses a test called the faecal occult blood test (FOBT) to check for early signs of bowel cancer. People can use this test themselves at home.