A higher adenoma detection rate is associated with increased detection of colorectal cancer during screening colonoscopies, demonstrating that CRC incidence and mortality after index colonoscopy result not only from missed precancerous lesions but also from missed cancers, according to an analysis of the GI Quality Improvement Consortium (GIQuIC) database.
“We saw that ADR is associated with the detection of [advanced adenomas (AAs)] and [sessile serrated lesions (SSLs)], but that’s not terribly surprising. What was somewhat surprising was the difference in the cancer detection rate,” said lead author Jason A. Dominitz, MD, MHS, the national director of gastroenterology for the Veterans Health Administration and a professor of gastroenterology and medicine at the University of Washington, Seattle, who presented the findings at Digestive Disease Week 2023 (abstract Sa1067). Dr. Dominitz noted that endoscopists in the highest ADR quintile (>48%) detected 29% more CRCs than those in the lowest quintile.
“While well-established data support ADR as a quality metric inversely associated with the development of post-colonoscopy colorectal cancer, this is the first study to show an association with the detection of colorectal cancer during colonoscopy,” commented Trilokesh Kidambi, MD, a gastroenterologist and the director of the colon cancer screening program at City of Hope, in Duarte, Calif, who was not involved in the study.
Study Drew From 727 Endoscopy Suites
Post-colonoscopy CRC can arise when endoscopists miss CRC precursors or CRC itself during index colonoscopy. To better understand this risk, Dr. Dominitz and his co-investigators examined the association between ADR and detection of CRC, SSLs and AAs in colonoscopies performed either for screening or to evaluate an abnormal fecal test using GIQuIC data.
Using GIQuIC data for 2019 to 2022 from 727 endoscopy units, the investigators identified adults undergoing colonoscopy for screening or evaluation of abnormal fecal occult blood test (FOBT) or multitarget stool DNA (FIT-DNA). They excluded patients whose colonoscopy was performed for other indications, as well as those with inadequate bowel prep, incomplete exam or no pathology results, and those whose providers had performed fewer than 50 colonoscopies.
The final population included 1,681,231 patients being screened, 27,918 being evaluated for a positive FOBT and 25,205 being evaluated for a positive FIT-DNA test. The researchers looked for three outcomes: CRC, AAs and SSLs.
Mean endoscopist ADR was approximately 39%. The lowest ADRs (<30%) comprised quintile 1 while the highest (>48%) comprised quintile 5. Endoscopists with ADRs beyond 2 SDs of the mean were excluded from the analysis.
The findings from the more than 1.7 million colonoscopies included are shown in the Table.
| Table. Findings on Colonoscopy | |||
| Findings | Screening (n=1,681,231) | FOBT-positive (n=27,918) | FIT-DNA–positive (n=25,205) |
|---|---|---|---|
| Adenoma, % | 39.6 | 53.7 | 59.1 |
| AAs, % | 7.7 | 17.2 | 21.8 |
| SSLs, % | 8.2 | 8.6 | 15.8 |
| CRC, % | 0.3 | 1.5 | 1.5 |
| AAs, advanced adenomas; CRC, colorectal cancer; FIT-DNA, multitarget stool DNA; FOBT, fecal occult blood test; SSLs, sessile serrated lesions. Based on Digestive Disease Week 2023 (abstract Sa1067). | |||
As would be expected, the incidences of all the CRC precursors and CRC itself were significantly higher in patients undergoing evaluation for positive findings than for screening.
Association With ADR
With adjustment for age, sex, race, ethnicity, comorbidity and the indication for colonoscopy, the analysis showed endoscopists’ ADR to be independently associated with the detection of CRC, AAs and SSLs. The association was strongest for AAs and SSLs, he reported.
Compared with ADR quintile 1, the adjusted odds ratio (OR) for CRC detection increased steadily for for those in quintiles 2 through 5, reaching 1.29 for quintile 5. The association was even stronger for SSLs (quintile 5: OR, 4.12) and AAs (quintile 5: OR, 2.06).
When ADR was treated as a continuous variable, every 1% increase in ADR was associated with these increased odds of detection: 0.8% for CRC, 2.4% for AAs and 4.6% for SSLs.
In a stratified analysis by indication (screening vs. abnormal fecal test), the association for CRC detection appeared stronger after abnormal fecal tests (quintile 5: OR, 1.55) than for screening (quintile 5: OR, 1.25), but the result was not statisticallly significant.
Quality Improvement Initiatives Needed
“We need ongoing quality improvement interventions to minimize the operator dependence in colonoscopy,” Dr. Dominitz commented.
Dr. Kidambi added, “This important finding adds additional robust data supporting routine measurement of ADR and interventions to improve ADR in underperforming endoscopists to impact patient care.”
—Caroline Helwick
Drs. Dominitz and Kidambi reported no relevant financial disclosures.
This article is from the September 2023 print issue.