Earlier detection of colorectal cancer (CRC) can improve survival rates. A simple, effective blood test may help improve screening participation. The multi-target blood protein (MTBP; ColoSTAT®) test and algorithm uses concentrations of five protein biomarkers of CRC and patient’s sex and age to generate a CRC likelihood score. We compared the performance of the MTBP test in detecting CRC to colonoscopy, the ‘gold standard’. This cross-sectional, multicenter study enrolled participants into two cohorts: participants recently colonoscopically diagnosed with CRC and progressing to surgery or neoadjuvant treatment (Cohort 1), and participants with no CRC history who were scheduled for colonoscopy (Cohort 2). Due to COVID-19 pandemic-related recruitment delays, Cohort 1 was supplemented with bio-banked blood samples (BBS) from patients with clinically confirmed CRC. Performance goals for sensitivity and specificity of the MTBP test compared to colonoscopy were ≥ 73

BACKGROUND AND AIMS: Endoscopic submucosal dissection is increasingly promoted for the treatment of all large nonpedunculated colorectal polyps (LNPCPs) to cure potential low-risk cancers (superficial submucosal invasion without additional high-risk histopathologic features). The effect of a universal en bloc strategy on oncologic outcomes for the treatment of LNPCPs in the right colon is unknown. We evaluated this in a large Western population. METHODS: A prospective cohort of patients referred for endoscopic resection (ER) of LNPCPs was analyzed. Patients found to have cancer after ER and those referred directly to surgery were included. The primary outcome was to determine the proportion of right colon LNPCPs with low-risk cancer. RESULTS: Over 180 months until June 2023, 3294 sporadic right colon LNPCPs in 2956 patients were referred for ER at 7 sites (median size 30 [interquartile range 22.5-37.5] mm). A total of 63 (2.1%) patients were referred directly to surgery, and cancer was proven in 56 (88.9%). A total of 2851 (96.4%) of 2956 LNPCPs underwent ER (median size 35 [interquartile range 25-45] mm), of which 75 (2.6%) were cancers. The overall prevalence of cancer in the right colon was 4.4% (n [ 131 of 2956). Detailed histopathologic analysis was possible in 115 (88%) of 131 cancers (71 after ER, 44 direct to surgery). After excluding missing histopathologic data, 23 (0.78%) of 2940 sporadic right colon LNPCPs were low-risk cancers. CONCLUSIONS: The proportion of right colon LNPCPs referred for ER containing low-risk cancer amenable to endoscopic cure was <1%, in a large, multicenter Western cohort. A universal endoscopic submucosal dissection strategy for the management of right colon LNPCPs is unlikely to yield improved patient outcomes given the minimal impact on oncologic outcomes.

BACKGROUND:Small bowel capsule endoscopy (SBCE) and device-assisted enteroscopy (DAE) have an established role in the investigation and management of small bowel pathology. Previous studies have reported on the yield of SBCE (60%) and DAE (57%), but none have been in an Australian setting. AIMS:To determine the yield of SBCE and any DAE performed as a direct consequence of SBCE in an Australian referral centre. METHODS:A single-centre retrospective study was conducted at a tertiary hospital in Australia, enrolling consecutive patients between 1 January 2009 and 31 December 2021 undergoing SBCE. Data were collected with respect to demographics, procedural factors and findings, as well as findings and interventions of any DAE procedures performed after the SBCE. RESULTS:1214 SBCEs were performed, with a median age of 66 years old (60.8% men). The predominant indications were anaemia (n = 853, 70.2%) and overt gastrointestinal bleeding (n = 320, 26.4%). Of the complete small bowel studies (1132/1214, 93.2%), abnormal findings were detected in 588 cases (51.9%), most commonly angioectasias (266/588, 45.2%), erosions (106/588, 18.0%) and ulcers (97/588, 8.6%). 165 patients underwent a DAE (117 antegrade, 48 retrograde). Antegrade DAE had a higher yield than retrograde DAE (77.8% vs 54.2%; P = 0.002) and a higher rate of intervention (69.2% vs 37.5%; P < 0.001). CONCLUSION:In this largest single-centre cohort of patients undergoing SBCE to date, there is a similar yield of abnormal findings compared to existing literature. DAE, especially with an antegrade approach, had high diagnostic and therapeutic yield when pursued after a positive SBCE study.

AbstractBackground and AimSnare resection of nonlifting colonic lesions often requires supplemental techniques. We compared the success rates of neoplasia eradication using hot avulsion and argon plasma coagulation in colonic polyps when complete snare polypectomy had failed.MethodsPolyps that were not completely resectable by snare polypectomy were randomized to argon plasma coagulation or hot avulsion for completion of resection. Argon plasma coagulation was delivered using a forward shooting catheter, using a nontouch technique (flow 1.2 L, 35 watts). Hot avulsion was performed by grasping the neoplastic tissue with hot biopsy forceps and applying traction away from the bowel wall while using EndoCut I or soft coagulation for avulsion. Surveillance colonoscopies were performed at 6, 12, and 18 months.ResultsFrom November 2013 to July 2017, 59 patients were randomized to argon plasma coagulation (28) or hot avulsion (31). The median age was 69 (60–75), with 46% being female. The median residual tissue size was 10 mm (6–12). The residual adenoma rate at 6 months (hot avulsion 6% vs argon plasma coagulation 21% P = 0.09) and 18 months was not different between the groups (6.6% vs 3.6% P = 0.25). One patient in the argon plasma coagulation arm was diagnosed with metastatic cancer of likely colorectal origin despite benign histology in the original polypectomy specimen, supporting the importance of tissue acquisition.ConclusionBoth hot avulsion and argon plasma coagulation are effective and safe modalities to complete resection of non‐ensnarable colonic polyps.

Background and aims The efficacy of colorectal endoscopic mucosal resection (EMR) is limited by recurrence and the necessity for conservative surveillance. Margin thermal ablation (MTA) after EMR has reduced the incidence of recurrence at the first surveillance colonoscopy at 6 months (SC1). Whether this effect is durable to second surveillance colonoscopy (SC2) is unknown. We evaluated long-term surveillance outcomes in a cohort of LNPCPs that have undergone MTA. Methods LNPCPs undergoing EMR and MTA from four academic endoscopy centres were prospectively recruited. EMR scars were evaluated at SC1 and in the absence of recurrence, SC2 colonoscopy was conducted in a further 12 months. A historical control arm was generated from LNPCPs that underwent EMR without MTA. The primary outcome was recurrence at SC2 in all LNPCPs with a recurrence-free scar at SC1. Results 1152 LNPCPs underwent EMR with complete MTA over 90 months until October 2022. 854 LNPCPs underwent SC1 with 29/854 (3.4%) LNPCPs demonstrating recurrence. 472 LNPCPs free of recurrence at SC1 underwent SC2. 260 LNPCPs with complete SC2 follow-up formed the control arm from January 2012 to May 2016. Recurrence at SC2 was significantly less in the MTA arm versus controls (1/472 (0.2%) vs 9/260 (3.5%); p<0.001)). Conclusion LNPCPs that have undergone successful EMR with MTA and are free of recurrence at SC1 are unlikely to develop recurrence in subsequent surveillance out to 2 years. Provided the colon is cleared of synchronous neoplasia, the next surveillance can be potentially extended to 3-5 years. Such an approach would reduce costs and enhance patient compliance.

Background Cold snare polypectomy (CSP) is the standard of care for the resection of small (< 10mm) colonic polyps. Limited data exist for its efficacy for medium-sized (1019mm) nonpedunculated polyps, especially conventional adenomas. This study evaluated the effectiveness and safe-ty of CSP/cold endoscopic mucosal resection ( C-EMR) for medium-sized nonpedunculated colonic polyps. Methods A prospective multicenter observational study was conducted of all morphologically suitable nonpedunculated colonic polyps of 10-19mm removed by CSP/C- EMR between May 2018 and June 2021. Once resection was complete, multiple biopsies were taken of the margins circumferentially and centrally. The primary outcome was the incomplete resection rate (IRR), based on residual polyp in these biopsy specimens. Secondary outcomes were recurrence rate at first surveillance colonoscopy and rates of adverse events (AEs). Results CSP/C- EMR was performed for 350 polyps (median size 15 mm; 266 [ 76.0%] Paris 0-IIa classification) in 295 patients. Submucosal injection was used for 87.1% (n = 305) of polyps. Histology showed 68.6% adenomas, 26.0% sessile serrated lesions (SSLs) without dysplasia, 4.0% SSL with dys- plasia, and 1.4% hyperplastic polyps. The IRRs based on margin or central biopsies being positive were 1.7% (n = 6) and 0.3% (n = 1), respectively. The polyp recurrence rate was 1.7% (n = 4) at first surveillance colonoscopy - completed for 65.4% (n = 229) of polyps at a median interval of 9.7 months. AEs occurred in 3.4% (n = 10) of patients: four with post-polypectomy pain; three self-limiting post-polypectomy bleeds; two post-polypectomy-syndrome-like presentations; and one intraprocedural bleed treated with clips. There were no perforations. Conclusion CSP/ C-EMR for morphologically suitable nonpedunculated colonic polyps of 10- 19mm is effective and safe, including for conventional adenomas. Rates of incomplete resection and recurrence were low, with few AEs. Studies directly comparing this method with hot snare resection are required.

3529 Background: Colorectal cancer (CRC) survival rates could be improved if more cancers were detected early. The ColoSTAT blood test and algorithm combines concentrations of 5 protein biomarkers with age and sex to provide an alternative to current CRC screening methods like the faecal immunochemical test (FIT). We compared the performance of ColoSTAT to colonoscopy in detecting CRC. Methods: Patients in this Australian study were either recently diagnosed with CRC using colonoscopy and progressing to surgery or neoadjuvant treatment (Cohort 1) or had no CRC history and were scheduled for colonoscopy (Cohort 2). Due to COVID-19 pandemic-related recruitment delays, the samples from Cohort 1 were supplemented with bio-banked blood samples (BBS) from patients with clinically confirmed CRC. Patients provided a 17 mL blood sample and were followed until start of cancer treatment or colonoscopy. All blood samples were de-identified prior to testing by an independent laboratory. The primary endpoints were ColoSTAT sensitivity of ≥73% (lower 95% confidence limit [LCL] > 60%), and specificity ≥90% (LCL > 80%). Sensitivity by TNM stage was an exploratory endpoint (ACTRN12619000301167). Results: Cohort 1 enrolled 29 patients, Cohort 2 enrolled 768 patients and 192 BBS were included. Patient demographic characteristics were similar in Cohorts 1, 2 and BBS. Overall, the median age of the patients (n = 989) was 64 years (range 40 to 88) and 53.4% were female. Definitive ColoSTAT results were obtained for 22 patients in Cohort 1, 554 in Cohort 2 and 81 in BBS. Overall, the estimated sensitivity of ColoSTAT for detection of CRC compared with colonoscopy was 81.3% (95%CL 73.0%-87.4%) and estimated specificity 91.0% (95%CL 87.7%-93.5%) (Table). Conclusions: The ColoSTAT test met the primary endpoints of performance based on sensitivity and specificity in detecting CRC compared to colonoscopy. ColoSTAT sensitivity and specificity for CRC were comparable with published performance parameters for FIT which range from 74-93% (sensitivity) and 85-96% (specificity).1 Clinical trial information: ACTRN12619000301167 . Clinical trial information: ACTRN12619000301167 . [Table: see text]

AbstractAimsRadiofrequency (RF) ablation for pulmonary vein isolation (PVI) in atrial fibrillation (AF) is associated with the risk of oesophageal thermal injury (ETI). Higher power short duration (HPSD) ablation results in preferential local resistive heating over distal conductive heating. Although HPSD has become increasingly common, no randomized study has compared ETI risk with conventional lower power longer duration (LPLD) ablation. This study aims to compare HPSD vs. LPLD ablation on ETI risk.Methods and resultsEighty-eight patients were randomized 1:1 to HPSD or LPLD posterior wall (PW) ablation. Posterior wall ablation was 40 W (HPSD group) or 25 W (LPLD group), with target AI (ablation index) 400/LSI (lesion size index) 4. Anterior wall ablation was 40–50 W, with a target AI 500–550/LSI 5–5.5. Endoscopy was performed on Day 1. The primary endpoint was ETI incidence. The mean age was 61 ± 9 years (31% females). The incidence of ETI (superficial ulcers n = 4) was 4.5%, with equal occurrence in HPSD and LPLD (P = 1.0). There was no difference in the median value of maximal oesophageal temperature (HPSD 38.6°C vs. LPLD 38.7°C, P = 0.43), or the median number of lesions per patient with temperature rise above 39°C (HPSD 1.5 vs. LPLD 2, P = 0.93). Radiofrequency ablation time (23.8 vs. 29.7 min, P < 0.01), PVI duration (46.5 vs. 59 min, P = 0.01), and procedure duration (133 vs. 150 min, P = 0.05) were reduced in HPSD. After a median follow-up of 12 months, AF recurrence was lower in HPSD (15.9% vs. LPLD 34.1%; hazard ratio 0.42, log-rank P = 0.04).ConclusionHigher power short duration ablation was associated with similarly low rates of ETI and shorter total/PVI RF ablation times when compared with LPLD ablation. Higher power short duration ablation is a safe and efficacious approach to PVI.

BACKGROUND & AIMS: Large (& GE;20 mm) nonpedunculated colorectal polyps (LNPCPs) may have synchronous LNPCPs in up to 18% of cases. The nature of this relationship has not been investigated. We aimed to examine the relationship between individual LNPCP characteristics and synchronous colonic LNPCPs.METHODS: Consecutive patients referred for resection of LNPCPs over 130 months until March 2022 were enrolled. Serrated lesions and mixed granularity LNPCPs were excluded from analysis. Patients with multiple LNPCPs resected were identified, and the largest was labelled as dominant. The primary outcome was the identification of individual lesion characteristics associated with the presence of synchronous LNPCPs.RESULTS: There were 3149 of 3381 patients (93.1%) who had a single LNPCP. In 232 (6.9%) a synchronous lesion was detected. Solitary lesions had a median size of 35 mm with a predominant Paris 0-IIa morphology (42.9%) and right colon location (59.5%). In patients with & GE;2 LNPCPs, the dominant lesion had a median size of 40 mm, Paris 0-IIa (47.6%) morphology, and right colon location (65.9%). In this group, 35.8% of dominant LNPCPs were non-granular compared with 18.7% in the solitary LNPCP cohort. Non-granular (NG)-LNPCPs were more likely to demonstrate synchronous disease, with left colon NG-LNPCPs demonstrating greater risk (odds ratio, 4.78; 95% confidence interval, 2.95-7.73) than right colon NG-LNPCPs (odds ratio, 1.99; 95% confidence interval, 1.39-2.86).CONCLUSIONS: We found that 6.9% of LNPCPs have synchronous disease, with NG-LNPCPs demonstrating a greater than 4-fold increased risk. With post-colonoscopy interval cancers exceeding 5%, endoscopists must be cognizant of an individual's LNPCP phenotype when examining the colon at both index procedure and surveillance. ClinicalTrials.gov, NCT01368289; NCT02000141; NCT02198729.

Background and Aims: Optimal bowel preparation before capsule endoscopy (CE) is currently unknown. In this multicenter, blinded, randomized controlled trial, we assessed clinical effectiveness of 2 types of purgative regimen and a control arm of clear fluid only. Methods: Patients with suspected small intestinal bleeding were randomized into 3 arms: arm A, clear fluids only for 18 hours before CE and simethicone 200 mg in 150 mL water immediately before CE; arm B, same as A + 2 L of polyethylene glycol (PEG) 12 hours before CE; and arm C, same as A + 1 L PEG + sodium ascorbate 3 hours before CE. To assess diagnostic yield, lesions were classified either as highly relevant (P2) or less relevant (P0 or P1) lesions. Small-bowel visualization quality (SBVQ) was assessed using the Brotz score. Patient tolerability was assessed using the visual analog scale (0-10, with lower scores indicating better tolerability). Results: Two hundred twenty-nine patients completed the study. The mean age was 58.7 years (95% confidence interval, 29.3-87.9), and 47.2% were men. There was no significant difference in diagnosis of P2 lesions in arms A, B, and C (48.7%, 48.0%, and 45.9%, respectively; P=.94). Overall SBVQ and distal SBVQ were similar across the 3 arms (P =.94 and P =.68, respectively). Patients reported better tolerability in arm A (mean score, 1.5) compared with arms B and C (mean score, 3.5 and 2.6, respectively; P <.001). Conclusions: The use of a purgative bowel preparation before CE does not improve diagnostic yield or smallbowel visualization and is associated with lower patient tolerance.

ObjectiveManagement of covert submucosal invasive cancer (SMIC) discovered after piecemeal endoscopic mucosal resection (pEMR) of large (>20 mm) non-pedunculated colorectal polyps is challenging. The residual cancer risk is largely unknown. We sought to evaluate this in a large tertiary referral cohort.DesignCases of covert SMIC following pEMR were identified and followed. Oncological outcomes after surgery were divided based on residual intramural cancer, lymph node metastases (LNM) or both. Risk factors for residual intramural cancer and LNM were analysed based on the original pEMR histological variables. Risk parameters were analysed with respect to low and high-risk variables for residual intramural cancer and LNM.ResultsAmong 3372 cases of large non-pedunculated colorectal polyps, 143 cases of covert SMIC (4.2%) were identified. 109 underwent surgical resection. Histological analysis of pEMR histology was available in 98 of 109 (90%) cases. 62 cases (63%) had no residual malignancy. 36 cases had residual malignancy (residual intramural cancer n=24; LNM n=5; both n=7). All cases of residual intramural cancer could be identified by a R1 histological deep margin. Cases with poor differentiation (PD) and/or lymphovascular invasion (LVI) had a high risk of LNM (12/33), with a very low risk without these criteria (<1%; 0/65). Cases at low risk for LNM with R0 deep margin have a low risk of residual intramural cancer (<1%; 0/35).ConclusionThe majority of cases of large non-pedunculated colorectal polyps with covert SMIC following pEMR will have no residual malignancy. The risk of residual malignancy can be ascertained from three key variables: PD, LVI and R1 deep margin.

Mehul Lamba: NO financial relationship with a commercial interest | Kimberley Ryan: NO financial relationship with a commercial interest | Jason Hwang: NO financial relationship with a commercial interest | Florian Grimpen: NO financial relationship with a commercial interest | Gary Lim: NO financial relationship with a commercial interest | Dale Cornelius: NO financial relationship with a commercial interest | Alan Moss: YES financial relationship with a commercial interest;Janssen:Consulting;Pfizer:Consulting | Eu Jin Lim: NO financial relationship with a commercial interest | Gregor Brown: NO financial relationship with a commercial interest | Nam Nguyen: NO financial relationship with a commercial interest | Marcus Tippett: NO financial relationship with a commercial interest | Andrew Taylor: NO financial relationship with a commercial interest | Mark Appleyard: NO financial relationship with a commercial interest

[This corrects the article DOI: 10.1055/a-1813-1019.].