Increasing Adenoma Detection Rate Could Reduce Risk of Colorectal Cancer


There was a 2.35-fold risk increase in PCCRC in the lowest ADR group compared to the highest.

Increasing Adenoma Detection Rate Could Reduce Risk of Colorectal Cancer

Investigators have identified an inverse association between adenoma detection rate (ADR) and postcolonoscopy colorectal cancer risk (PCCRC) following the utilization of a fecal immunochemical test (FIT).1

A team, led by Manuel Zorzi, MD, MSc, Veneto Tumor Registry, Azienda Zero, examined the association between adenoma detection rate and postcolonoscpy colorectal cancer risk in a fecal immunochemical test-based screening program in northeastern Italy.

Standard of Care

The current standard of care for colorectal cancer screening rely on fecal immunochemical tests. However, the benefits can depend on the identification of neoplasia at colonoscopy following FIT positivity. In addition, the quality of colonoscopy measured by adenoma detection rate could impact the effectiveness of screening programs.

In the retrospective, population-based cohort, the investigators examined patients with a positive FIT result following a colonoscopy using data from the regional cancer registry.

The team categorized endoscopists’ adenoma detection rate into 5 groups (20-39.9%, 40-44.9%, 45-49.9%, 50-54.9%, and 55-70%) and fitted Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) to examine the association of ADR with PCCRC incidence risk.

There were 110,109 initial colonoscopies, 49,626 of which were completed by 114 endoscopists between 2012-2017 and included in the final analysis with 328,778 person-years of follow-up. From this 277 cases of PCCRC were diagnosed.


The mean ADR was 48.3% (range, 23-70%) and the incidence rates of PCCRC from the lowest ADR group to highest were 13.13, 10.61, 7.60, 6.01, and 5.78 per 10,000 person-years.

The results show a significant inverse association between ADR and PCCRC incidence risk. There was a 2.35-fold risk increase in the lowest group (95% CI, 1.63-3.38) compared to the highest.

The adjusted HR for PCCRC associated with a 1% increase in ADR was 0.96 (95% CI, 0.95-0.98).

The investigators did identify some limitations in the study, mainly that ADR is partially determined by FIT positivity cutoff, but the exact values could vary in different settings.

“In a FIT-based screening program, ADR is inversely associated with PCCRC incidence risk, mandating appropriate colonoscopy quality monitoring in this setting,” the authors wrote. “Increasing endoscopists' ADR may significantly reduce PCCRC risk.”

Using Artificial Intelligence

Earlier this month, a study published in JAMA Network Open, shows that artificial intelligence (AI) could help detect colorectal cancer following a colonoscopy regardless of time the operation is performed.

A team, led by Zihua Lu, MD, Department of Gastroenterology, Renmin Hospital of Wuhan University, validated whether the assistance of an AI system could overcome time-related declines in ADR during colonoscopies.

Time of day has been linked in the past to a decline in adenoma detection for individuals undergoing colonoscopies.

In the study, the investigators compared detection rates based on time of coloscopy in a group of patients using an AI-assisted program with those who were unassisted.

The results show the ADR in the early session of the unassisted group was significantly higher compared to those in the late session (13.73% vs 5.70%; P = .005; odds ratio [OR], 2.42; 95% CI, 1.31-4.47).

However, after the investigators implemented the AI system, there was no statistically significant difference between the time of session (22.95% vs 22.06%, P = .78; OR, 0.96; 95% CI; 0.71-1.29) and the AI systems resulted in better assistance ability on ADR in late sessions compared to early sessions (OR, 3.81; 95% CI, 2.10-6.91 vs 1.60; 95% CI, 1.10-2.34).


Zorzi, M., Antonelli, G., Amidei, C. B., Battagello, J., Germanà, B., Valiante, F., Benvenuti, S., Tringali, A., Bortoluzzi, F., Cervellin, E., Giacomin, D., Meggiato, T., Rosa-Rizzotto, E., Fregonese, D., Dinca, M., Baldassarre, G., Scalon, P., Pantalena, M., Milan, L., … Hassan, C. (2023). Adenoma detection rate and colorectal cancer risk in fecal immunochemical test screening programs. Annals of Internal Medicine.

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