Unacceptable variation in screening colonoscopy

McFerran and colleagues’ editorial rightly warned about heterogeneity in the quality of colonoscopies,(1) when highlighting differences in the incidence of post-colonoscopy cancers.(2)

However, relying on the Consensus statements from the World Endoscopy Organisation overlooked an enduring inertia. The Organization just issued a report regarding quality of colonoscopy but failed to reach a consensus for “Adenoma Detection Rate”, the obvious mandatory quality metric for relevance.(3) Indeed, colonoscopy has been endorsed in the US as the preferred strategy for colorectal cancer screening as soon as 2000. However, adenoma Detection Rate is still a bazaar: when reported its range is too wide and can also varies from one report to another with the same team.(4) Further adjustments too rarely take into account relevant variables which are most basic: age, sex (RR being twice higher in man), life style (BMI, tobacco and alcohol use, use of aspirin/nonsteroidal anti-inflammatory drugs) and family history. Similarly, no analysis according: a) to sites despite colonoscopy provides less protection from cancer in the right colon than from the left; b) to indications (positive fecal test or first intention)

The lack of concern about quality metric for screening is global. For fecal tests, uptake for one round is a poor surrogate used to mask a shipwreck (e.g. 1/3 in France despite a national program since 2003). Indeed, early randomized controlled trials in the 90’s showed that mortality was reduced at best after 8 to 13 years of screening in two trials and not until after 15 to 18 years of screening in another two trials, conditions where compliance was optimal. The Taiwanese FIT Screening Program showed no effectiveness with a 6 years follow-up when adjusting for self-selection biases.(Figure 2B in 5)

Screening is not a performing a test (fecal or endoscopy) but about a public health program with quality assurance. This means funding, competence and dedication.

1 McFerran E, O'Mahony JF, Goodall E, Lawler M. Unacceptable variation in screening colonoscopy. BMJ. 2019;367:l6384.

2 Burr NE, Derbyshire E, Taylor J, etal . Variation in post-colonoscopy colorectal cancer across colonoscopy providers in English National Health Service: population based cohort study. BMJ 2019;367:l6090.

3 Jover R, Dekker E, Schoen RE, et al. Colonoscopy quality requisites for selecting surveillance intervals: A World Endoscopy Organization Delphi recommendation. Dig Endosc 2018;30:750-759.

4 Braillon A. Quality indicators for colonoscopy: Missing the wood for the trees? Gastroenterology. 2017;153:1695-1696.

5 Chiu HM, Chen SL, Yen AM, Chiu SY, Fann JC, Lee YC et al. Effectiveness of fecal immunochemical testing in reducing colorectal cancer mortality from the One Million Taiwanese Screening Program. Cancer 2015,121:3221-9.