Colonoscopy quality indicators for colorectal cancer precursors: Sessile serrated lesion and adenoma detection rates from a large clinical study of a blood-based test for CRC screening.

10525 Background: Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally. Colonoscopy can reduce mortality by removing precancerous lesions or detecting cancer at an earlier, more treatable stage, with the adenoma detection rate (ADR) as the standard colonoscopy quality indicator. In 2024, the sessile serrated lesion detection rate (SSLDR) was introduced as a new multisociety colonoscopy quality indicator. Both quality indicators have associated performance targets, primarily based on benchmarking to colonoscopy registry data. Serrated lesions, which are precursors to 10-30% of CRC, are often missed due to their flat appearance, indistinct borders, and proximal locations. Published SSLDR data is limited, and to our knowledge, this is the first analysis of SSLDRs and ADRs in a large prospective, multicenter clinical study in an average-risk population. Methods: PREEMPT CRC, a clinical validation study of a blood-based test for CRC screening in adults aged 45-85, included 200 diverse U.S. sites. Based on thorough medical review of colonoscopy and pathology reports, SSLDRs and ADRs were calculated across 27,010 subjects that completed screening colonoscopy in the clinical validation. SSLDR and ADR were defined as the percentage of colonoscopies in which at least one SSL or adenoma was detected, respectively. Results were stratified by age and sex, and compared to established performance targets from colonoscopy quality guidelines. Results: The overall SSLDR in PREEMPT CRC was 7.2%, surpassing the newly recommended performance target of ≥ 6%. The overall ADR was 34.9%, aligning with the latest target of 35% overall (40% in males, 30% in females). The ADR increased significantly with age, from 26.9% in the 45-49 age group to 40.8% in the 75+ age group (p < 0.001). In contrast, the SSLDR remained consistent across age groups, with the 45-49 year age group (7.1%) similar to the overall SSLDR (7.2%) (p = 0.789). The ADR demonstrated a clear sex-dependence (41.9% in males, 29.4% in females, p < 0.001), while the SSLDR did not (7.4% in males, 7.1% in females, p = 0.433). Conclusions: The overall SSLDR and ADR in PREEMPT CRC were consistent with the updated colonoscopy quality guidelines, with the SSLDR exceeding the target, suggesting that the target could be updated from 6% to 7%. Our results underscore the age- and sex-independent risk of serrated lesions. Notably, even the SSLDR in the 45-49 year age group (7.1%, 6.2%-8.0%) exceeded the 6% performance target. Given the relatively high ADR of 26.9% observed among 45 to 49-year-olds, and the age-independence of the SSLDR, our findings highlight the importance of advocating for early CRC screening, especially in younger populations where screening adherence is generally poor. Clinical trial information: NCT04369053 .