Risk of total metachronous advanced neoplasia at surveillance colonoscopy after detection of serrated lesions: a matched case-cohort study.

BACKGROUND : Serrated lesions are potential colorectal cancer precursors. This study evaluated the presence of total metachronous advanced neoplasia (T-MAN) at follow-up in patients with index serrated lesions compared with a matched cohort without serrated lesions. METHODS : Patients aged 45-74 years with serrated lesions were matched 2:1 by sex, age, synchronous polyps, and timing of index colonoscopy, to patients without serrated lesions. The primary outcome was T-MAN (advanced adenoma or high-risk serrated lesion) at follow-up. Secondary outcomes included presence of T-MAN stratified by synchronous polyps and serrated lesion characteristics. RESULTS : 1425 patients were included (475 patients, 642 serrated lesions; 950 controls; median follow-up 2.9 versus 3.6 years). Patients with serrated lesions had greater risk of T-MAN than those without (hazard ratio [HR] 6.1, 95 %CI 3.9-9.6). Patients with serrated lesions and high-risk adenoma (HRA) had higher risk of T-MAN than those with HRA alone (HR 2.6, 95 %CI 1.4-4.7); similarly, patients with serrated lesions plus low-risk adenoma (LRA) had higher risk than those with LRA alone (HR 7.0, 95 %CI 2.8-18.4), as did patients with serrated lesions without adenoma compared with no adenoma (HR 14.9, 95 %CI 6.5-34.0). Presence of proximal sessile serrated lesion (SSL; HR 9.3, 95 %CI 5.4-15.9), large SSL (HR 17.8, 95 %CI 7.4-43.3), and proximal large SSL (HR 25.0, 95 %CI 8.8-71.3), but not distal SSL, were associated with greater risk for T-MAN. CONCLUSION : Patients with serrated lesions had higher risk for T-MAN regardless of synchronous adenomas. Patients with serrated lesions and HRA, and those with large or proximal SSLs, were at greatest risk.

Rates of synchronous advanced neoplasia and colorectal cancer in patients with colonic serrated lesions.

BACKGROUND AND AIMS: Serrated lesions (SL) have been associated with significant risks of developing colorectal cancer (CRC). Data on synchronous findings after SL detection during colonoscopy is limited. Study aim was to evaluate the rate of synchronous advanced neoplasia (S-AN) and synchronous CRC (S-CRC) in colonoscopies where SLs were detected. METHODS: We conducted a retrospective study of screening aged patients 45-74year with colorectal SL (sessile serrated polyp [SSP] or traditional serrated adenoma [TSA]) detected during an elective colonoscopy. Primary outcome was risk of S-AN in patients with SL. Secondary outcomes included risk of S-AN or S-CRC stratified by SL characteristics. RESULTS: The study included 1262 patients with 1649 SLs (1214 with SSPs and 48 with TSAs). 47.2% were female and 22.9% of exams were screening colonoscopies, 48.2% surveillance, 28.9% diagnostic. The overall rates of S-AN and S-CRC were 15.1% and 1.3%, respectively. Presence of SSPs ≥ 10 mm was associated with higher rates of S-AN, (18.1 vs. 12.2%, Odds-Ratio [OR] = 1.61 [95% Confidence Interval [CI] 1.17-2.23], p = 0.004). SSP dysplasia was predictive of S-AN, (30.3 vs 14.1%, OR = 2.68 [95%CI 1.24-5.78], p = 0.012) but not S-CRC. SSP number (≥ 3) and location (proximal) were not predictors of S-AN or S-CRC. CONCLUSION: Patients with SLs are at high-risk of S-AN and S-CRC. Findings of SSPs ≥ 10 mm and SSP dysplasia are associated with high-risk of S-AN. Endoscopists should exercise heightened vigilance for synchronous findings when SLs are detected, especially SSPs ≥ 10 mm or when bowel preparation is suboptimal. Studies contrasting synchronous risk of other polyp types are needed to confirm these results.