Practical and low-cost strategies to increase the adenoma detection rate

The quality of colonoscopy is measured predominantly by the adenoma detection rate (ADR), defined as the proportion of procedures with at least one adenoma removed. Despite the fact that the ADR rewards the same credit to an endoscopist who finds one adenoma as another who consistently finds more than one adenoma, an increase in the ADR is an important proxy for an increase in quality and efficacy of colonoscopy, especially in screening. In fact, both retrospective and prospective studies have shown that ADR is inversely associated with the risk of interval colorectal cancer (CRC) and CRC death [1] [2].

Regrettably, the best and worst performers working within the same group of colonoscopists demonstrate a wide variation in ADR [3] [4]. Colonoscopy quality improvement programs strive to reduce this gap, moving poor performers toward high-end performance as efficiently as possible.

Into this background comes the observational study by Neilson et al. [5], which is published in this issue of Endoscopy. The study evaluated the effect of the implementation of a bundle of measures during colonoscopy (Quality Improvement in Colonoscopy [QIC]), which was introduced in the UK in 2011. The bundle included withdrawal time of ≥ 6 minutes, hyoscine butylbromide use, supine patient position for transverse colon examination, and rectal retroflexion. Data were collected for a 6-month period in 2014 from eight UK hospitals (28 615 colonoscopies, 188 endoscopists) 3 years following the QIC bundle implementation. Hyoscine butylbromide use was identified as a marker of bundle uptake, the effectiveness of which was measured by change in ADR. Data before and immediately after implementation of the bundle were compared. The increase in hyoscine butylbromide use indicated a consistent application of QIC measures and ADR was higher in the sustainability period compared with pre-intervention. Thus, the introduction of a simple and inexpensive bundle of interventions significantly changed practice; the effect on change in ADR was modest, but a significant increase was seen in poor performers.

“... the introduction of a simple and inexpensive bundle of interventions significantly changed practice; the effect on change in ADR was modest, but a significant increase was seen in poor performers.”

There are some limitations to this study, many of them correctly acknowledged by the authors: lack of a control group or analyses at individual endoscopist level (the trial was designed to look for change by group); factors associated with sustained change in practice were not individually evaluated (it would have been interesting to know which measures had the greatest impact on increasing the ADR); finally, caution should be exercised on the blanket administration of hyoscine butylbromide – it is not available in some countries and its use should probably not be directly linked to the improvement in ADR seen in the study.

Additionally, in recent years there has been a growing awareness of colon lesion location, morphology, and biology, along with sustained adoption of split-dose bowel preparation and recognition of the importance of the interval between the last dose of bowel preparation and the start of colonoscopy. These factors could have influenced the results.

With these considerations in mind, the strength of the study is that it was based on the bundle alone without a training component, which should make it easy to deliver.

Concerning the interventions of the QIC bundle, many studies suggest meeting a withdrawal time in the range of 6 – 8 minutes, or longer. However, the quality of withdrawal is not measured solely on the basis of reaching the goal of an appropriate length of time. Withdrawal should be done with adequate distension, washing, and accurate exploration between folds; these interventions are more important than time itself to improve lesion detection.

Position change is still underused probably due to a lack of awareness of its efficacy or to difficulty of implementation in sedated patients. The concept is to ensure the colon section currently being examined is at the apex, ensuring effective insufflation and distension.

In addition to rectal retroflexion, which should be routine, I also advise performing a repeat examination of the right side of the colon as this has been suggested to increase adenoma detection [6] [7]. It is still uncertain whether the best strategy is re-examination of the right colon with a second forward or retroflexed view [6] [7]. However, performing at least one of these two techniques should be strongly considered, especially if lesions have been found during the first pass.

On a different ground, there is a lot of enthusiasm for technology, but it comes at a financial cost and is not a substitute for good technique. Studies on device-assisted colonoscopy and/or some of the new technologies have shown contrasting results in terms of increasing ADR vs. standard forward-viewing colonoscopy. Most of the study findings are not generalizable to daily practice and include inherently high endoscopist bias. Finally, to date we do not know what effect a reduction in missed adenomas will have on interval CRC if there is not an increase in ADR.

A recent network meta-analysis compared the efficacy of a range of strategies in improving the ADR: low-cost optimization of existing resources (i. e. water-aided colonoscopy, second observer, dynamic position change), enhanced imaging techniques, add-on devices and new scopes, alone and in combination with high definition colonoscopy or each other [8]. Low-cost optimization of existing resources (odds ratio [OR] 1.29, 95 % confidence interval [CI] 1.17 – 1.43), enhanced imaging techniques (OR 1.21, 95 %CI 1.09 – 1.35), and add-on devices (OR 1.18, 95 %CI 1.07 – 1.29) were effective in increasing ADR compared with high definition colonoscopy. Use of newer scopes was not associated with a significant increase in ADR (OR 0.98, 95 %CI 0.79 – 1.21).

In summary, it seems that investigator-dependent skills remain the foundation of colon lesion detection. Assuming that all colonoscopists are aware of the distribution and morphology of adenomas and serrated lesions, and are consistent in finding and recognizing them, they should routinely apply low-cost interventions to improve ADR, as these methods have been proven effective. This approach might require just a marginal increase of time and effort. I personally suggest considering adopting an inexpensive method that works: perform water exchange colonoscopy; double check the right colon and rectum; use patient position change; use slow scope withdrawal to allow a careful inspection behind any fold along with adequate lumen distension. If resources are available, the addition of devices or technologies that might increase adenoma detection can also be considered.

Publication History

Article published online:
25 March 2020

• References

• 1 Kaminski MF, Wieszczy P, Rupinski M. et al. Increased rate of adenoma detection associates with reduced risk of colorectal cancer and death. Gastroenterology 2017; 153: 98-105
• 2 Corley DA, Jensen CD, Marks AR. et al. Adenoma detection rate and risk of colorectal cancer and death. N Engl J Med 2014; 370: 1298-306
• 3 Barclay RL, Vicari JJ, Doughty AS. et al. Colonoscopic withdrawal times and adenoma detection during screening colonoscopy. N Engl J Med 2006; 355: 2533-2541
• 4 Chen SC, Rex DK. Endoscopist can be more powerful than age and male gender in predicting adenoma detection at colonoscopy. Am J Gastroenterol 2007; 102: 856-861
• 5 Neilson LJ, East JE, Rajasekhar PT. et al. Sustained colonoscopy quality improvement using a simple intervention bundle. Endoscopy 2020; 52: 285-292
• 6 Clark BT, Parikh ND, Laine L. Yield of repeat forward-view examination of the right side of the colon in screening and surveillance colonoscopy. Gastrointest Endosc 2016; 84: 126-132
• 7 Desai M, Bilal M, Hamade N. et al. Increasing adenoma detection rates in the right side of the colon comparing retroflexion with a second forward view: a systematic review. Gastrointest Endosc 2019; 89: 453-459
• 8 Facciorusso A, Triantafyllou K, Murad MH. et al. Compared abilities of endoscopic techniques to increase colon adenoma detection rates: a network meta-analysis. Clin Gastroenterol Hepatol 2019; 17: 2439-2454