Snare tip soft coagulation (STSC) after endoscopic mucosal resection (EMR) of large (> 20 mm) non pedunculated colorectal polyps: a systematic review and meta-analysis

Background and study aims Endoscopic mucosal resection (EMR) of laterally spreading tumors (LSTs) > 20 mm in size can be challenging. Piecemeal EMR of these lesions results in high rates of adenoma recurrence at first surveillance colonoscopy (SC1). Snare tip soft coagulation (STSC) of post resection margins is a safe and effective technique to prevent adenoma recurrence. We conducted a systematic review and meta-analysis to evaluate the effectiveness and safety of this technique. Patients and methods Multiple databases were searched through April 2021 for studies that reported on outcomes of post EMR STSC for LSTs > 20 mm in size. Meta-analysis was performed to determine pooled odds of adenoma recurrence as well as pooled proportion of adverse events including intraprocedural and delayed bleeding as well as intraprocedural perforation events. Results Six studies including two randomized controlled trials (RCT) and four cohort studies with 2122 patients were included in the final analysis. Overall pooled odds of adenoma recurrence at SC1 with post EMR STSC compared to no STSC was 0.27 (95 % 0.18–0.42; I2 = 0 %), P < 0.001. Pooled rate of adenoma recurrence at SC1 in post EMR STSC cohort was 6 %. Rates of intraprocedural bleeding, delayed bleeding and intraprocedural perforation were 10.3 %, 6.5 % and 2 % respectively. Conclusions Our results show that thermal ablation of resection margins with STSC in LSTs > 20 mm is a safe and effective technique in reducing the incidence of adenoma recurrence.

P.168 Prediction of Pituitary Adenoma Recurrence using the SIPAP Classification

Background: Pituitary tumor recurrence following endoscopic endonasal transsphenoidal surgery (EETS) has been reported widely. We evaluated a modified score using the SIPAP classification system, combining the suprasellar and paraseller extension scores of the pituitary tumor, to determine its impact on adenoma recurrence. Methods: A retrospective cohort study design with patient characteristics, tumor type, endocrine, operation, imaging data collected. Preoperative MRI images were reviewed and SIPAP classification applied. Postoperative data were extracted for the follow-up period available for each patient.The suprasellar score and the highest parasellar scoring from both sides were numerically summed in a bilateral suprasellar and parasellar (SaP) score and combined to make 4 grades. Results: 276 patients were identified, 56.5% of the cohort was male. The mean cohort age was 54 years old.The mean follow up period was 32 months. Patient perioperative tumor grade according to SaP classification and recurrence rate was: Grade 1: 11%: Grade 2: 10%; Grade 3: 15%; Grade 4: 22%. The results followed a pattern of logarithmic curve. Conclusions: The SaP classification was useful in determining the pituitary tumor expected recurrence following EETS. The advanced tumors had the highest recurrence rates. Use of the SaP score may allow for more accurate preoperative counselling of patients with pituitary adenoma.

Adenoma Recurrence after Endoscopic Piecemeal Mucosal Resection of Colorectal Flat Lesions: Applicability of the Sydney EMR Recurrence Tool in a Non-Tertiary Centre

<b><i>Introduction:</i></b> Endoscopic mucosal resection (EMR) is the treatment of choice for non-invasive colorectal flat lesions. When endoscopic piecemeal mucosal resection (EPMR) is performed, endoscopic surveillance is necessary due to the risk of recurrence. The Sydney EMR Recurrence Tool (SERT) is a 0–4 scale that classifies lesions according to size, occurrence of intraprocedural bleeding (IPB) and presence of high-grade dysplasia (HGD). Our goal is to evaluate the applicability of SERT in predicting adenoma recurrence (AR) after EPMR. <b><i>Methods:</i></b> This is a retrospective single-centre study with inclusion of lateral spreading lesions ≥20 mm, consecutively resected by EPMR from March 2010 to February 2018, with at least 1 endoscopic re-evaluation. <b><i>Results:</i></b> A total of 181 lesions were included, corresponding to 174 patients with a mean age of 68 years and male gender predominance (61%; <i>n</i> = 106). The most frequent location was the ascending colon (34%; <i>n</i> = 62). Lesions were assessed according to Paris Classification (PC): 0-IIa: 39% (<i>n</i> = 71); 0-IIb: 24% (<i>n</i> = 43); 0-IIa + Is: 23% (<i>n</i> = 42); 0-IIa + IIb: 6% (<i>n</i> = 11); 0-IIa + IIc: 2% (<i>n</i> = 3). The mean size of the lesions was 33 ± 11 mm, with 25 (14%) being ≥40 mm. IPB occurred in 9 cases (5%), and 44 lesions (24%) displayed HGD. Sixty-six lesions (36.5%) were classified as SMSA (size, morphology, site, and access score) level 4. Adjunctive therapy with argon plasma coagulation (APC) was used in 37% (<i>n</i> = 67) of cases. The 6-month AR rate was 16% (<i>n</i> = 29). According to SERT groups, the AR rate was: SERT 0: 12% (14/120); SERT 1: 17% (6/35); SERT 2: 25% (3/12); SERT 3: 30% (3/10); SERT 4: 75% (3/4). Two of the three SERT variables (size ≥40 mm and IPB) were associated with recurrence at 6 months (<i>p</i> &#x3c; 0.05). HGD and the remaining tested variables (age, gender, localization, accessibility, PC, use of APC/biopsy forceps and occurrence of delayed bleeding) were not associated with AR. SERT 0 lesions showed an inferior risk of 6-month AR (adjusted OR = 2.62; <i>p</i> = 0.035), with a negative predictive value of 88%. SMSA correlated with SERT (<i>p</i> &#x3c; 0.001) and SMSA level 4 was associated with 6-month AR (<i>p</i> = 0.007). Lesions classified both as SERT 0 and SMSA level &#x3c;4 had the lowest 6-month recurrence rate (9.2%). The 24-month recurrence rate was 23% (<i>n</i> = 41). When applying the Kaplan-Meier method, cumulative recurrence was significantly lower in SERT 0 lesions (<i>p</i> = 0.006, log-rank test). <b><i>Discussion/Conclusion:</i></b> Resection of flat colorectal lesions by EPMR has a considerable risk of recurrence, mostly in SERT 1–4 lesions. SERT 0 lesions, especially with SMSA level &#x3c;4, show a lower risk of recurrent adenoma, which might allow longer intervals to first endoscopic surveillance in the future.

Risk factors associated with adenoma recurrence following cold snare endoscopic mucosal resection of polyps ≥ 20 mm: a retrospective chart review

Background and study aims Cold snare endoscopic mucosal resection (EMR) is being increasingly utilized for non-pedunculated polyps ≥ 20 mm due to adverse events associated with use of cautery. Larger studies evaluating adenoma recurrence rate (ARR) and risk factors for recurrence following cold snare EMR of large polyps are lacking. The aim of this study was to define ARR for polyps ≥ 20 mm removed by cold snare EMR and to identify risk factors for recurrence. Patients and methods A retrospective chart review of colon cold snare EMR procedures performed between January 2015 and July 2019 at a tertiary care medical center was performed. During this period, 310 non-pedunculated polyps ≥ 20 mm were excised using cold snare EMR with follow-up surveillance colonoscopy. Patient demographic data as well as polyp characteristics at the time of index and surveillance colonoscopy were collected and analyzed. Results A total of 108 of 310 polyps (34.8 %) demonstrated adenoma recurrence at follow-up colonoscopy. Patients with a higher ARR were older (P = 0.008), had endoscopic clips placed at index procedure (P = 0.017), and were more likely to be Asian and African American (P = 0.02). ARR was higher in larger polyps (P < 0.001), tubulovillous adenomas (P < 0.001), and polyps with high-grade dysplasia (P = 0.003). Conclusions Although cold snare EMR remains a feasible alternative to hot snare polypectomy for resection of non-pedunculated polyps ≥ 20 mm, endoscopists must also carefully consider factors associated with increased ARR when utilizing this technique.

Fecal Enterotoxigenic Bacteroides fragilis–Peptostreptococcus stomatis–Parvimonas micra Biomarker for Noninvasive Diagnosis and Prognosis of Colorectal Laterally Spreading Tumor

ObjectiveUp to now, non-invasive diagnosis of laterally spreading tumor (LST) and prediction of adenoma recurrence after endoscopic resection of LSTs is inevitable. This study aimed to identify a microbial signature with clinical significance of diagnosing LSTs and predicting adenoma recurrence after LSTs colectomy.MethodsWe performed 16S rRNA sequencing in 24 mucosal samples, including 5 healthy controls (HC), 8 colorectal adenoma (CRA) patients, and 11 LST patients. The differentiating microbiota in fecal samples was quantified by qPCR in 475 cases with 113 HC, 208 CRA patients, 109 LST patients, and 45 colorectal cancer (CRC) patients. We identified differentially abundant taxa among cases and controls using linear discriminant analysis effect size analysis. ROC curve was used to evaluate diagnostic values of the bacterial candidates. Pairwise comparison of AUCs was performed by using the Delong’s test. The Mantel-Haenszel hazard models were performed to determine the effects of microbial compositions on recurrence free survival.ResultsThe microbial dysbiosis of LST was characterized by relative high abundance of the genus Lactobacillus-Streptococcus and the species enterotoxigenic Bacteroides fragilis (ETBF)–Peptostreptococcus stomatis (P. stomatis)–Parvimonas micra (P. micra). The abundance of ETBF, P. stomatis, and P. micra were steadily increasing in LST and CRC groups. P. stomatis behaved stronger value on diagnosing LST than the other two bacteria (AUC 0.887, 95% CI 0.842–0.931). The combination of P. stomatis, P. micra, and ETBF (AUC 0.922, 95% CI 0.887–0.958) revealed strongest diagnostic power with 88.7% sensitivity and 81.4% specificity. ETBF, P. stomatis, and P. micra were associated with malignant LST (PP.stomatis = 0.0015, PP.micra = 0.0255, PETBF = 0.0169) and the abundance of IL-6. The high abundance of P. stomatis was related to the adenoma recurrence after LST resection (HR = 3.88, P = 0.008).ConclusionsFecal microbiome signature (ETBF–P. stomatis–P. micra) can diagnose LSTs with high accuracy. ETBF, P. stomatis, and P. micra were related to malignant LST and P. stomatis exhibited high predictive value on the adenoma recurrence after resection of LSTs. The fecal microbiome signature of LST may provide a noninvasive alternative to early detect LST and predict the adenoma recurrence risk after resections of LSTs.