Posted on April 15, 2026

SSLDR-A Calculated Using All Examinations Performs Similarly to Screening SSLDR-S in Predicting Post-Colonoscopy CRC

Joseph C. Anderson, MD, FACG1,2,3

 1VA Medical Center, White River Junction, VT; 2Geisel School of Medicine at Dartmouth, Hanover, NH; 3University of Connecticut School of Medicine, Farmington, CT

This article reviews Hagen R, Rex DK, MacKenzie TA, Amox CI, Butterly LF, Anderson JC. Higher sessile serrated lesion detection rates calculated using all examinations are associated with lower risk for post-colonoscopy colorectal cancer: Data from the New Hampshire Colonoscopy Registry. Clin Transl Gastroenterol. 2026; 17(4).

Access the article through Clinical and Translational Gastroenterology

Keywords: serrated polyps; colonoscopy; adenomas; surveillance

STRUCTURED ABSTRACT

Question: The goal was to examine the association between post-colonoscopy colorectal cancer (PCCRC) risk and sessile serrated lesion detection rate (SSLDR) which was calculated using exams with all indications (SSLDR-A), as compared to SSLDR restricted to data from screening exams (SSLDR-S).

Design: Retrospective analysis of data from the New Hampshire Colonoscopy Registry (NHCR) which is a prospective statewide colonoscopy registry.

Setting: Endoscopy centers across New Hampshire

Patients: The analysis included NHCR patients with an index exam and at least 1 follow-up event 6 months or longer after the colonoscopy, either a colonoscopy or a CRC diagnosis.

Exposure: The exposure variable was endoscopist-specific SSLDR-A, calculated for all indications, divided into quintiles. The SSLDR-A was also compared to a SSLDR-S.

SSLDR-A= The proportion of all colonoscopies in patients 45 years or older with an adequate bowel preparation performed by an endoscopist regardless of indication with at least 1 SSL divided by the total number of colonoscopies in patients 45 years or older with an adequate bowel preparation performed by that endoscopist regardless of indications.

SSLDR-S= The proportion of screening colonoscopies in patients 45 years or older with an adequate bowel preparation performed by an endoscopist with at least one SSL divided by the total number of screening colonoscopies in patients 45 years or older with an adequate bowel preparation performed by that endoscopist.

Outcomes: The primary outcome, PCCRC was any CRC diagnosed ≥ 6 months after an index exam.

Data Analysis: Cox regression was used to model the hazard of PCCRC on ADR, controlling for age, sex, and other covariates.

Funding: Division of Cancer Prevention, National Cancer Institute, 5R01CA243449, Optimizing colorectal cancer prevention: a multi-disciplinary, population-based investigation of serrated polyps using risk prediction and modeling; Grant Recipient: Lynn F. Butterly, M.D. and ACG 2023 clinical research grant (Anderson).

Results: There were 177 PCCRCs diagnosed in 115,762 patients with index colonoscopies. Procedures were performed by 126 endoscopists, with at least 50 exams recorded in the NHCR. Index exams were conducted between October 2004 and December 2020. Higher SSLDR-A and SSLDR-S rates were associated with lower PCCRC risks (Table 1). After adjusting for covariates, we observed that higher SSLDR-A rates were associated with lower hazard ratios (HR) as compared to the reference group (SSLDR-A: <1.5%; HR=1.0 vs SSLDR-A: 1.5-<3.0%; HR=0.53, 95% confidence interval (CI) 0.35-0.79; SSLDR-A: 3.0-<5.0%; HR=0.59, 95% CI 0.38-0.92; SSLDR: 5.0-<8.0%; HR=0.44, 95% CI 0.28-0.70; and SSLDR:8.0+% HR=0.20, 95% CI 0.08-0.46). The highest quintile of SSLDR-A (8.0%+) (HR=0.20, 95%CI 0.08-0.46) and SSLDR-S (8.0%+)(HR=0.20, 95% CI 0.09-0.44) provided similar protection from PCCRC. The 95% CI was narrower (median= 73%; IQR:0.09) for endoscopists when calculating SSLDR-A versus SSLDR-S. In contrast, when calculating the 95% CI for SSLDR-S compared to SSLDR-A, the CI increased nearly two-fold (median=137%; IQR 0.17).

Table 1. Unadjusted risks and adjusted hazard ratios for post-colonoscopy colorectal cancer for quintiles of endoscopist SSLDR-S and SSLDR-A. HR, hazard ratio; SSLDR-A, all-examination sessile serrated lesion detection rates; SSLDR-S, screening sessile serrated lesion detection rate.
a P<0.001 (X2 for trend).

COMMENTARY

Why Is This Important?
The detection and resection of precancerous polyps is important for colonoscopy to be effective in CRC prevention. Endoscopists have been monitoring their adenoma detection rates (ADR), which have been shown to be inversely associated with post-colonoscopy colorectal cancer (PCCRC) incidence.1, 2 Recent recommendations from the joint American College of Gastroenterology (ACG)/American Society of Gastrointestinal Endoscopy (ASGE) task force suggest that ADR can be calculated using data from all exams.3-6 Using data from examinations using all indications (ADR-A), rather than screening exams alone (ADR-S), can be beneficial by allowing a larger sample size, which may provide a more accurate assessment of an endoscopist’s overall performance. It can also mitigate potential gaming by endoscopists to manipulate their metrics.7

Serrated polyp detection is also crucial for CRC prevention since the serrated pathway may account for up to one-third of all CRCs and a large percentage of post-colonoscopy cancers. Serrated polyps include hyperplastic polyps (HPs), sessile serrated lesions, and traditional serrated adenomas of any size. New Hampshire Colonoscopy Registry data suggest that even if endoscopists achieve an adequate ADR, they could still have a low serrated detection rate.8-10 Therefore SSLDRs should be tracked by endoscopists. Sessile serrated lesion detection rate for screening exams (SSLDR-S) is defined as the number of screening colonoscopies with at least one SSL divided by the total number of screening colonoscopies for each endoscopist. An analysis of NHCR data suggests that a SSLDR-S of 6% may offer the most protection from PCCRC.10

As with ADR-A, a major advantage of using SSLDR-A (sessile serrated lesion detection rate using all exams) is its inclusion of all colonoscopies, regardless of the indication. This approach simplifies calculations by removing the need to distinguish between exam types, which in turn reduces endoscopist-level biases and prevents potential misclassification based on the reason for the exam. Furthermore, incorporating all colonoscopies increases the total sample size, resulting in higher statistical power, generalizability, and a noticeably narrower confidence interval as observed in this analysis, reflecting greater data precision and lower variability.

Key Study Findings 

In this study, the authors observed that SSLDR-A performed similarly to that of SSLDR-S. A striking observation was that the quintiles for both metrics were similar, suggesting no difference after including all examinations. This is in stark contrast to ADR in which ADR-A was higher than ADR-S. Both metrics observed optimal protection from PCCRC for endoscopists with SSLDRs in the highest quintile. Furthermore, the highest quintile for both metrics were an SSLDR of 8% or higher. These data suggest that an SSLDR-A of 8% be recommended as a possible new benchmark for endoscopists to achieve.

Caution
The low racial diversity in NH may decrease the generalizability of the findings. Thus, more data are needed in other more racially diverse populations.

My Practice
An important factor in optimizing serrated detection is the bowel preparation. All of my patients have a split bowel preparation.11 When performing a colonoscopy, I make the assumption that the patient has an SSL that I should be detecting. Thus, during inspection I carefully interrogate and wash every fold, adequately distending the lumen, utilizing an adequate withdrawal time, typically of 8 minutes or longer. I also re-intubate the proximal colon as highlighted in the recent ACG/ASGE recommendations.6, 12 In our endoscopy unit we track our ADR and SSLDRs as well as quality of bowel preparation and completion rates, ensuring that we are meeting established benchmarks.6, 11, 12 Although, current benchmark as per the recent ACG/ASGE latest recommendations on quality indicators for colonoscopy is 6%, I try to achieve an SSLDR-A of 8% or greater.

For Future Research
These data should be validated in other populations.

Conflict of Interest
Dr Anderson has no financial conflict of interest.

REFERENCES

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  2. 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.
  3. Anderson JC, Rex DK, Mackenzie TA, et al. Endoscopist adenomas-per-colonoscopy detection rates and risk for postcolonoscopy colorectal cancer: data from the New Hampshire Colonoscopy Registry. Gastrointest Endosc 2024;99:787–795.
  4. Anderson JC, Rex DK, Mackenzie TA, et al. Adenoma detection rates calculated using all examinations are associated with lower risk for postcolonoscopy colorectal cancer: Data from the New Hampshire Colonoscopy Registry. Am J Gastroenterol 2025.
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  9. Anderson JC, Hisey W, Mackenzie TA, et al. Clinically significant serrated polyp detection rates and risk for postcolonoscopy colorectal cancer: data from the New Hampshire Colonoscopy Registry. Gastrointest Endosc 2022;96:310–317.
  10. Anderson JC, Rex DK, Mackenzie TA, et al. Higher serrated polyp detection rates are associated with lower risk of postcolonoscopy colorectal cancer: Data from the New Hampshire Colonoscopy Registry. Am J Gastroenterol 2023;118:1927–1930.
  11. Jacobson BC, Anderson JC, Burke CA, et al. Optimizing bowel preparation quality for colonoscopy: Consensus recommendations by the US Multi-Society Task Force on colorectal cancer. Am J Gastroenterol 2025;120:738–764.
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