Full-Spectrum Endoscopy Outweighs Standard Forward-Viewing Colonoscopy

Full-spectrum endoscopy offers clearer visualisation of the colonic mucosa compared with standard forward-viewing colonoscopy, increasing colorectal cancer detection rates

medwireNews: Researchers have found that full-spectrum colonoscopy has a significantly lower adenoma miss rate than standard forward-viewing colonoscopy.

Moreover, in their study, full-spectrum endoscopy detection of adenomas previously missed with forward-viewing colonoscopy led to changes in patient management in line with US and European guidelines.

Seventy percent of these missed adenomas were in the right colon, the researchers, led by Ian Gralnek, from Rambam Health Care Campus in Haifa, Israel, note.

“This finding might have clinical significance in view of the known reduced protective effect of colonoscopy for proximal, compared with distal, colon cancers,” they add.

The researchers randomly assigned 88 participants to receive standard forward-viewing colonoscopy followed by full-spectrum colonoscopy and 97 to receive the two procedures in the reverse order.

Standard forward-viewing colonoscopy detected 29 adenomas in 25 patients, and full-spectrum colonoscopy detected a further 20 adenomas in 15 patients, giving a miss rate of 41% for forward-viewing colonoscopy.

By comparison, when full-spectrum colonoscopy was used first it detected 60 adenomas and two cancers in 33 patients, and forward-viewing colonoscopy detected an additional five adenomas, giving a miss rate of just 7% for full-spectrum colonoscopy.

The researchers report in The Lancet Oncology that the five adenomas initially missed by full-spectrum colonoscopy were not advanced adenomas and were detected in patients who had other adenomas detected by full-spectrum colonoscopy.

This meant that none of the adenomas missed by full-spectrum colonoscopy would have changed the post-polypectomy surveillance colonoscopy recommendations according to US or European guidelines. One patient was reclassified as high risk according to European guidelines due to the total number of small adenomas increasing from four to five.

Of the adenomas missed by forward-viewing colonoscopy, three (15%) were advanced adenomas, and subsequent detection of adenomas by full-spectrum colonoscopy led to the shortening of the post-polypectomy surveillance interval for eight patients based on US guidelines and five patients based on European guidelines.

“These data suggest that full-spectrum colonoscopy improves visualisation of the colonic mucosa during colonoscopy and could improve the efficacy of screening of colorectal cancer and surveillance,” say the researchers.

But in a related comment, David Ransohoff, from the University of North Carolina at Chapel Hill, USA, points out that the improved detection of adenomas with full-spectrum colonoscopy in the current study primarily concerned small (1–5 mm) tubular adenomas.

He therefore stresses the need to consider how the management of such small adenomas affects patients’ outcomes, so that the negative and positive impact of more intensive surveillance is balanced.

“The challenge for the future is now to maximise benefit while minimising harm and effort,” he concludes.

References

Gralnek IM, Siersema PD, Halpern Z, et al. Standard forward-viewing colonoscopy versus full-spectrum endoscopy : an international, multicentre, randomised, tandem colonoscopy trial. Lancet Oncol; Advanced online publication February 20, 2014. doi.org/10.1016/S1470-2045(14)70020-8

David F Ransohoff. What is the effect of more sensitive diagnostic technology? Lancet Oncol; Advanced online publication February 20, 2014. doi:10.1016/S1470-2045(14)70065-8

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