Local recurrence rates after resection of large colorectal serrated lesions with or without margin thermal ablation.

INTRODUCTION: Serrated lesions (SLs) including traditional serrated adenomas (TSA), large hyperplastic polyps (HP) and sessile serrated lesions (SSLs) are associated with high incomplete resection rates. Margin ablation combined with EMR (EMR-T) has become routine to reduce local recurrence while cold snare polypectomy (CSP) is becoming recognized as equally effective for large SLs. Our aim was to evaluate local recurrence rates (LRR) and the use of margin ablation in preventing recurrence in a retrospective cohort study. METHODS: Patients undergoing resection of ≥15 mm colorectal SLs from 2010-2022 were identified through a pathology database and electronic medical records search. Hereditary CRC syndromes, first follow-up > 18 months or no follow-up, surgical resection were excluded. Primary outcome was LRRs (either histologic or visual) during the first 18-month follow-up. Secondary outcomes were LRRs according to size, and resection technique. RESULTS: 191 polyps in 170 patients were resected (59.8% women; mean age, 65 years). The mean size of polyps was 22.4 mm, with 107 (56.0%) ≥20 mm. 99 polyps were resected with EMR, 39 with EMR-T, and 26 with CSP. Mean first surveillance was 8.2 mo. Overall LRR was 18.8% (36/191) (16.8% for ≥20 mm, 17.9% for ≥30 mm). LRR was significantly lower after EMR-T when compared with EMR (5.1% vs. 23.2%; p = 0.013) or CSP (5.1% vs. 23.1%; p = 0.031). There was no difference in LRR between EMR without margin ablation and CSP (p = 0.987). CONCLUSION: The local recurrence rate for SLs ≥15 mm is high with 18.8% overall recurrence. EMR with thermal ablation of the margins is superior to both no ablation and CSP in reducing LRRs.

Serrated Polyps in Inflammatory Bowel Disease Indicate a Similar Risk of Metachronous Colorectal Neoplasia as in the General Population.

BACKGROUND: The risk of metachronous advanced neoplasia after diagnosing serrated polyps in patients with IBD is poorly understood. METHODS: A retrospective multicenter cohort study was conducted between 2010 and 2019 at three tertiary centers in Montreal, Canada. From pathology databases, we identified 1587 consecutive patients with serrated polyps (sessile serrated lesion, traditional serrated adenoma, or serrated epithelial change). We included patients aged 45-74 and excluded patients with polyposis, colorectal cancer, or no follow-up. The primary outcome was the risk of metachronous advanced neoplasia (advanced adenoma, advanced serrated lesion, or colorectal cancer) after index serrated polyp, comparing patients with and without IBD. RESULTS: 477 patients with serrated polyps were eligible (mean age 61 years): 37 with IBD, totaling 45 serrated polyps and 440 without IBD, totaling 586 serrated polyps. The median follow-up was 3.4 years. There was no difference in metachronous advanced neoplasia (HR 0.77, 95% CI 0.32-1.84), metachronous advanced adenoma (HR 0.54, 95% CI 0.11-2.67), and metachronous advanced serrated lesion (HR 0.76, 95% CI 0.26-2.18) risk. When comparing serrated polyps in mucosa involved or uninvolved with IBD, both groups had similar intervals from IBD to serrated polyp diagnosis (p > 0.05), maximal therapies (p > 0.05), mucosal inflammation, inflammatory markers, and fecal calprotectin (p > 0.05). CONCLUSION: The risk of metachronous advanced neoplasia after serrated polyp detection was similar in patients with and without IBD. Serrated polyps in IBD occurred independently of inflammation. This helps inform surveillance intervals for patients with IBD diagnosed with serrated polyps.

Large serrated polyps indicate a greater risk of advanced metachronous colorectal neoplasia than high-grade adenomas.

Background and study aims The risk of developing total metachronous advanced neoplasia (TMAN) in patients with index serrated lesions (SL) or adenoma with high-grade dysplasia (HGD) is unknown. We evaluated this risk in patients with either HGD, SL < 10 mm or SL ≥ 10 mm at index colonoscopy, who underwent surveillance colonoscopies. Patients and methods This retrospective cohort study evaluated all consecutive patients (n = 2477) diagnosed between 2010 and 2019 with colorectal HGD, SLs < 10 mm or SLs ≥ 10 mm. We excluded patients aged < 45 or > 75 years or those who had inflammatory bowel disease, hereditary colorectal cancer (CRC) syndromes, previous or synchronous CRC, or no follow-up colonoscopy. Descriptive variables were compared using analysis of variance or Pearson chi-squared tests. Multivariate Cox regressions were used to compare the risk of TMAN between the HGD, SL < 10 mm and SL ≥ 10 mm groups. Results Overall, 585 patients (mean age 63 years; 55% male; mean follow-up 3.67 years) were included (226 with SLs < 10 mm, 204 with SLs ≥ 10 mm, 155 with HGD). Compared with SLs < 10 mm, patients with HGD did not have a significantly different rate of TMAN (HR=0.75 [0.39-1.44]) and patients with SLs ≥ 10 mm had a higher rate of TMAN (HR=2.08 [1.38-3.15]). Compared with HGD, patients with SLs ≥ 10 mm had a higher rate of TMAN (HR=1.87 [1.04-3.36]). Conclusions The risk for TMAN was higher for patients with SLs ≥ 10 mm than with HGD or SLs < 10 mm. This risk should be considered when planning surveillance intervals for patients diagnosed with large SLs.