Expert weighs in on ADR-A as a colonoscopy quality metric

All-exam adenoma detection rate (ADR-A) — calculated across all colonoscopies regardless of indication in patients aged 45 years and older — performed similarly to screening-only adenoma detection rate (ADR-S) in predicting post-colonoscopy colorectal cancer (PCCRC) risk, according to a retrospective analysis recently published in the American Journal of Gastroenterology.

In discussions following publication, lead author Joseph C. Anderson, MD, of the Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, described the findings as further validation of ADR-A as a practical quality metric for colonoscopy. This article is based on publicly available summaries of the study and an interview conducted with GI & Hepatology News.

The analysis drew on data from more than 32,500 patients in the New Hampshire Colonoscopy Registry (NHCR). Eligible patients had an index colonoscopy and at least one follow-up event occurring six months or more after the procedure. A subset of patients developed PCCRC, defined as colorectal cancer diagnosed at least six months after the index examination.

According to Dr. Anderson, higher ADR-A values were generally associated with lower observed PCCRC risk. When endoscopists were grouped by detection rate performance, those in the highest ADR-A categories demonstrated lower PCCRC rates, with performance patterns comparable to those seen when using screening-only ADR.

Supporting ADR-A as a quality measure

Historically, ADR has been calculated using screening colonoscopies alone. Recent quality indicator updates from the American College of Gastroenterology (ACG) and the American Society for Gastrointestinal Endoscopy (ASGE) expanded measurement to include all examinations in patients aged 45 and older, establishing 35% as the current benchmark.

Dr. Anderson noted that using ADR-A offers several operational advantages. Measuring adenoma detection across all procedures reduces the need to distinguish colonoscopy indication and may limit the potential for indication misclassification. It also increases the number of procedures included in an endoscopist’s denominator, which may allow for more stable measurement over time.

“The New Hampshire Colonoscopy Registry data, as well as the Kaiser Permanente data published in Douglas Corley’s paper in Gastroenterology, validate the ADR-A as a quality metric,” Dr. Anderson said in the interview. He added, however, that additional validation in more diverse populations would be helpful.

He also cautioned that surveillance colonoscopies tend to have higher adenoma detection rates. Practices with a larger proportion of repeat examinations may therefore report higher overall ADRs, a consideration that should be taken into account when interpreting performance data.

Benchmarks: current standard and future targets

The current ACG/ASGE benchmark for ADR-A is 35%. In the NHCR analysis, this threshold fell within higher-performing detection groups associated with lower observed PCCRC risk.

“Our data support 35% as the current benchmark,” Dr. Anderson said. However, he observed that endoscopists with the highest ADR-A values in the registry demonstrated the lowest observed PCCRC risk.

“It is important to recognize that detection rates will be increasing with better technology and technique as they have been for several years,” he said. “Therefore, a higher benchmark for ADR-A, such as 45%, may be a future recommendation.”

Implications for clinical conversations

Asked whether the findings should influence patient discussions about interval cancer risk, Anderson emphasized transparency.

“Yes, quality should be the cornerstone for discussion between patients and endoscopists who are performing their colonoscopy,” he said. “The procedure is operator dependent, and it is important for patients to be informed about their endoscopist’s detection rates.”

He encouraged clinicians to proactively measure and share their detection rates and to adopt practices that optimize detection. In addition to ADR, he highlighted the importance of tracking serrated detection rates (SDRs), citing prior NHCR analyses.

In his own practice, Dr. Anderson uses split-dose bowel preparation and approaches each colonoscopy with the expectation that adenomas may be present. His unit tracks ADR, SDR, bowel preparation quality, and cecal intubation rates to ensure established benchmarks are met.

While ADR-A is increasingly endorsed as a comprehensive quality metric, questions remain about optimal benchmarks and how performance standards should evolve as technology and technique improve. For now, Dr. Anderson said, the emerging data support broader adoption of ADR-A measurement as part of routine quality monitoring in colonoscopy practice.

Dr. Anderson reported no conflicts of interest. Full disclosures for the remaining study authors are available in the published study.