P0267 - Adenoma Detection Rate (ADR) and Risk of Colon Cancer: A Systematic Review

Ahmad G. Tarakji, MD¹, Mohamad Kalot, MD², Omar Shamaa, MD³, Shadi Hamdeh, MD^4
1University of Kansas Medical Center, Kansas City, KS; ²University at Buffalo, Buffalo, NY; ³Henry Ford Hospital, Detroit, MI; ⁴University of Kansas Medical Center, Lawrence, KS

Introduction: Adenoma detection rate (ADR) is the most important quality measure in screening colonoscopy. In this systematic review we aim to review and summarize the published literature and assess the association between ADR and interval CRC.

Methods: A comprehensive search of several databases from each database’s inception to March 14, 2021 was conducted. The databases included Ovid Medline In-Process & Other Non-Indexed Citations, Ovid MEDLINE, Ovid EMBASE, Ovid Cochrane Central Register of Controlled Trials, Ovid Cochrane Database of Systematic Reviews, and Scopus. The search strategy was designed and conducted by an experienced librarian. Controlled vocabulary supplemented with keywords was used to search for studies assessing the risk of developing CRC based on ADR. Two authors assessed methodological quality of the trials and independently extracted data in duplicate.

Results: Six Studies were included for data analysis. Pooling of the effect estimates was challenged by multiple factors pertaining to the study design and the heterogeneity in the reporting of effect estimates. First, different types of effect estimates were reported in the studies, including hazard ratio in four studies, odds ratio in one study, and relative risk in one study. Second, ADR was categorized differently in the studies with two studies reporting 5 categories, three studies reporting 4 categories, and one study reporting 3 categories. Third, the ADR percentage intervals were highly heterogenous with different start points and end points in the different categories. Additionally, among the studies reporting hazard ratio as the effect estimate, three studies used the first ADR category as reference, while one study used the fourth/last category as reference. Table 1 summarizes the included studies.

Due to above limitations, pooled effect estimates were not computed. With this methodological restraint in mind, we used the ADR reported percentages in an attempt to trend the CRC hazard ratio in the 4 studies with similar study design and effect estimates reporting.

As shown in figure 1, when ADR percentage increases, the hazard ratio of CRC tends to decrease when the four studies are evaluated separately, indicating a negative correlation between ADR percentage and CRC hazard ratio.

Discussion: Colon cancer incidence is inversely correlated with ADR. However, further studies with standardization of study design and categorization of ADR percentage intervals are needed in order to establish statistical correlations.


Figure: Figure 1: Pooling analysis of hazard ratio of colorectal cancer based on adenoma detection rate.

Study	Effect estimate	1st cat	EE	2nd cat	EE	3rd cat	EE	4th cat	EE	5th cat	EE
Kaminski, 2017	HR	11.21%	1	15.10%	0.9	19.17%	0.74	25%	0.64	>25%	0.27
Cross, 2020	HR	9.00%	0.72	12%	0.65	15%	0.58
Kaminski, 2010	HR	11%	12.5	15%	10.25	20%	10.94	>20%	1
Corley, 2014	HR	19.50%	1	23.85%	0.93	28.40%	0.85	33.50%	0.7	52.51%	0.52
Rogal, 2012	OR	9.30%	1	12.10%	0.44	14.30%	0.76	24.50%	0.35
Lam, 2020	RR	21.00%	1	25%	0.62	34%	0.52	52%	0.28

Table: Table 1: Studies evaluating the association between adenoma detection rate and colon cancer incidence.


Disclosures:
Ahmad Tarakji indicated no relevant financial relationships.
Mohamad Kalot indicated no relevant financial relationships.
Omar Shamaa indicated no relevant financial relationships.
Shadi Hamdeh indicated no relevant financial relationships.


Ahmad G. Tarakji, MD¹, Mohamad Kalot, MD², Omar Shamaa, MD³, Shadi Hamdeh, MD⁴. P0267 - Adenoma Detection Rate (ADR) and Risk of Colon Cancer: A Systematic Review, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.