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Background and Aims: There are limited data regarding the morphology, histopathology, and anatomical distribution of sporadic colorectal polyps in Chinese patients. We evaluated these characteristics of sporadic polyps to guide the endoscopic detection and excision of colorectal polyps. Methods: This was a retrospective single-center observational study involving 7381 patients with sporadic colorectal polyps. All polyps were removed endoscopically. The morphology and histopathology of polyps were evaluated according to the Paris classification and the World Health Organization classification, respectively. Results: A total of 22,174 polyps removed endoscopically from 7322 patients were included. In the sigmoid colon, 24.70% of colorectal polyps occurred, followed by the transverse colon (18.58%) in frequency. 0-Is type polyps accounted for 60.60% of all sporadic colorectal polyps. Polyps with 0-Ip, 0-Isp, and 0-IIa types were frequently found in the sigmoid colon, but laterally spreading lesions usually occurred in the ascending colon (24.61%) and rectum (20.51%). Irrespective of the Paris classification and anatomical location, as the polyps enlarge, the proportion of adenomatous polyps gradually increases while the proportion of serrated lesions decreases. Polyps with size ≥1 cm located in the left-sided colon were more likely to have villous/tubulovillous or high-grade dysplasia histology than those located in the right-sided colon, and about 1% of them were demonstrated with adenocarcinoma. Conclusion: Sigmoid colon should be detected adequately during colonoscopy, and polyps with size ≥1 cm should be treated carefully, especially in the left-sided colon.

Objective: Computer-aided diagnosis (CAD) using artificial intelligence (AI) is expected to support the characterisation of colorectal lesions, which is clinically relevant for efficient colorectal cancer prevention. We conducted this study to assess the diagnostic performance of commercially available CAD systems., Methods: This was a multicentre, prospective performance evaluation study. The endoscopist diagnosed polyps using white light imaging, followed by non-magnified blue light imaging (non-mBLI) and mBLI. AI subsequently assessed the lesions using non-mBLI (non-mAI), followed by mBLI (mAI). Eventually, endoscopists made the final diagnosis by integrating the AI diagnosis (AI+endoscopist). The primary endpoint was the accuracy of the AI diagnosis of neoplastic lesions. The diagnostic performance of each modality (sensitivity, specificity and accuracy) and confidence levels were also assessed., Results: Overall, 380 lesions from 139 patients were included in the analysis. The accuracy of non-mAI was 83%, 95% CI (79% to 87%), which was inferior to that of mBLI (89%, 95% CI (85% to 92%)) and mAI (89%, 95% CI (85% to 92%)). The accuracy (95% CI) of diagnosis by expert endoscopists using mAI (91%, 95% CI (87% to 94%)) was comparable to that of expert endoscopists using mBLI (91%, 95% CI (87% to 94%)) but better than that of non-expert endoscopists using mAI (83%, 95% CI (75% to 90%)). The level of confidence in making a correct diagnosis was increased when using magnification and AI., Conclusions: The diagnostic performance of mAI for differentiating colonic lesions is comparable to that of endoscopists, regardless of their experience. However, it can be affected by the use of magnification as well as the endoscopists' level of experience., Competing Interests: Competing interests: We received research funding from Fujifilm Japan. There are no other conflicts of interest., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: Conventional hot snare endoscopic mucosal resection (H-EMR) is effective for the management of large (≥20 mm) non-pedunculated colon polyps (LNPCPs) however, electrocautery-related complications may incur significant morbidity. With a superior safety profile, cold snare EMR (C-EMR) of LNPCPs is an attractive alternative however evidence is lacking. We conducted a randomised trial to compare the efficacy and safety of C-EMR to H-EMR., Methods: Flat, 15-50 mm adenomatous LNPCPs were prospectively enrolled and randomly assigned to C-EMR or H-EMR with margin thermal ablation at a single tertiary centre. The primary outcome was endoscopically visible and/or histologically confirmed recurrence at 6 months surveillance colonoscopy. Secondary outcomes were clinically significant post-EMR bleeding (CSPEB), delayed perforation and technical success., Results: 177 LNPCPs in 177 patients were randomised to C-EMR arm (n=87) or H-EMR (n=90). Treatment groups were equivalent for technical success 86/87 (98.9%) C-EMR versus H-EMR 90/90 (100%); p=0.31. Recurrence was significantly greater in C-EMR (16/87, 18.4% vs 1/90, 1.1%; relative risk (RR) 16.6, 95% CI 2.24 to 122; p<0.001).Delayed perforation (1/90 (1.1%) vs 0; p=0.32) only occurred in the H-EMR group. CSPEB was significantly greater in the H-EMR arm (7/90 (7.8%) vs 1/87 (1.1%); RR 6.77, 95% CI 0.85 to 53.9; p=0.034)., Conclusion: Compared with H-EMR, C-EMR for flat, adenomatous LNPCPs, demonstrates superior safety with equivalent technical success. However, endoscopic recurrence is significantly greater for cold snare resection and is currently a limitation of the technique., Trial Registration Number: NCT04138030., Competing Interests: Competing interests: MJB: Research Support: Olympus Medical, Cook Medical, Boston Scientific. The remaining authors have no financial, professional or personal conflicts of interest to disclose., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Endoscopic submucosal dissection (ESD) is the 'gold standard' for large flat polyps; nevertheless, the rate of adoption in the USA is low. In ESD, the polyp is 'surgically' detached with a needle knife after a submucosal lift; gravity and the dissection cap are used for retraction. ESD would be easier if active retraction were possible. In an ex vivo bovine colon model, this study assessed an overtube system (Boston Scientific ORISE Tissue Retraction System, TRS) that permits retraction and creates 'an operative field' for removal of rectal/sigmoid lesions. Method: Classic ESD (C-ESD) was compared to TRS-facilitated ESD (TRS-ESD). Cleaned/preserved bovine large bowel was used, and two 2-cm 'lesions'/colon were branded onto the mucosal surface 25 and 35 cm from the anus. Submucosal saline lifts were made using a thin catheter and a standard needle knife. We tracked case length, number of instrument exchanges (to refresh lift), the volume of lift solution, the fullness of resection, and deep muscle injuries. Results: Fifty ESDs were carried out in 25 colons (25 C-ESD, 25 TRS-ESD). Complete resections were noted in all cases. The TRS method required fewer instrument exchanges (median 5) vs C-ESD (median 9, p < 0.0001) and less lift solution (median 39 ml) than the C-ESD cases (median 55 ml, p = 0.0003). TRS-ESD was associated with fewer deep muscle injuries (median 2) than C-ESD (median 3, p = 0.0191). Finally, the TRS group's median case length (34.5 min) was shorter than that of C-ESD (41 min, p = 0.0543). Conclusion: The TRS system provides retraction and facilitates ESD regarding the number of lift injections, the volume of lift solution needed, and avoidance of muscle injuries. Of note, there is an apparent TRS learning curve, and the device mandates a distal-to-proximal approach and initial 360 degree mucosal incision. Further study is warranted. [ABSTRACT FROM AUTHOR]

Background: Tumourigenesis in right-sided and left-sided colons demonstrated distinct features., Objective: We aimed to characterise the differences between the left-sided and right-sided adenomas (ADs) representing the early stage of colonic tumourigenesis., Design: Single-cell and spatial transcriptomic datasets were analysed to reveal alterations between right-sided and left-sided colon ADs. Cells, animal experiments and clinical specimens were used to verify the results., Results: Single-cell analysis revealed that in right-sided ADs, there was a significant reduction of goblet cells, and these goblet cells were dysfunctional with attenuated mucin biosynthesis and defective antigen presentation. An impairment of the mucus barrier led to biofilm formation in crypts and subsequent bacteria invasion into right-sided ADs. The regions spatially surrounding the crypts with biofilm occupation underwent an inflammatory response by lipopolysaccharide (LPS) and an apoptosis process, as revealed by spatial transcriptomics. A distinct S100A11 + epithelial cell population in the right-sided ADs was identified, and its expression level was induced by bacterial LPS and peptidoglycan. S100A11 expression facilitated tumour growth in syngeneic immunocompetent mice with increased myeloid-derived suppressor cells (MDSC) but reduced cytotoxic CD8+ T cells. Targeting S100A11 with well-tolerated antagonists of its receptor for advanced glycation end product (RAGE) (Azeliragon) significantly impaired tumour growth and MDSC infiltration, thereby boosting the efficacy of anti-programmed cell death protein 1 therapy in colon cancer., Conclusion: Our findings unravelled that dysfunctional goblet cells and consequential bacterial translocation activated the S100A11-RAGE axis in right-sided colon ADs, which recruits MDSCs to promote immune evasion. Targeting this axis by Azeliragon improves the efficacy of immunotherapy in colon cancer., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells that accumulate in circulation of cancer patients and at tumor sites where they suppress anti-tumor immunity. We previously reported that in a colon cancer prevention trial of a MUC1 vaccine tested in individuals at increased risk for colon cancer, those who did not mount immune response to the vaccine had higher pre-vaccination levels of circulating MDSC compared to those who did. We also reported that individuals with pancreatic premalignancy, Intraductal Papillary Mucinous Neoplasm (IPMN), had increased circulating levels of MDSC that inversely correlated with spontaneous antibody responses against the pancreatic tumor associated antigen MUC1, abnormally expressed on IPMN. Accumulation of MDSC in cancer and their immunosuppressive role had been well established but their presence in premalignancy was unexpected. In this study we compared MDSC in premalignancy with those in cancer with the hypothesis that there might be differences in the composition of various MDSC subpopulations and their immunosuppressive functions due to different lengths of exposure to disease and/or different tissue microenvironments. In cohorts of patients with premalignant polyps, colon cancer, premalignant IPMN, and pancreatic cancer, we confirmed higher levels of MDSC in premalignancy compared to healthy controls, higher levels of MDSC in cancer compared to premalignancy, but no difference in their subpopulation composition or immunosuppressive capacity. We show that levels of MDSC in premalignancy correlate negatively in vivo with spontaneous MUC1-specific antibody responses and in vitro with polyclonal T cell proliferation and IFN-γ secretion.

Objective: Colorectal cancer (CRC) has a significant role in cancer-related mortality. Colonoscopy, combined with adenoma removal, has proven effective in reducing CRC incidence. However, suboptimal colonoscopy quality often leads to missed polyps. The impact of artificial intelligence (AI) on adenoma and polyp detection rate (ADR, PDR) is yet to be established., Design: We conducted a randomised controlled trial at Sahlgrenska University Hospital in Sweden. Patients underwent colonoscopy with or without the assistance of AI (AI-C or conventional colonoscopy (CC)). Examinations were performed with two different AI systems, that is, Fujifilm CADEye and Medtronic GI Genius. The primary outcome was ADR., Results: Among 286 patients, 240 underwent analysis (average age: 66 years). The ADR was 42% for all patients, and no significant difference emerged between AI-C and CC groups (41% vs 43%). The overall PDR was 61%, with a trend towards higher PDR in the AI-C group. Subgroup analysis revealed higher detection rates for sessile serrated lesions (SSL) with AI assistance (AI-C 22%, CC 11%, p=0.004). No difference was noticed in the detection of polyps or adenomas per colonoscopy. Examinations were most often performed by experienced endoscopists, 78% (n=86 AI-C, 100 CC)., Conclusion: Amidst the ongoing AI integration, ADR did not improve with AI. Particularly noteworthy is the enhanced detection rates for SSL by AI assistance, especially since they pose a risk for postcolonoscopy CRC. The integration of AI into standard colonoscopy practice warrants further investigation and the development of improved software might be necessary before enforcing its mandatory implementation., Trial Registration Number: NCT05178095., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Aims: Colectomy is the current approach for patients with endoscopically unresectable benign polyps but risks considerable morbidity. Full‐thickness laparoendoscopic excision (FLEX) is a novel procedure, specifically developed to treat endoscopically unresectable benign colonic polyps, which could reduce the treatment burden of the current approach and improve outcomes. However, traditional evaluations of surgical innovations lack methodological rigour. This study reports the development and feasibility of the FLEX procedure in selected patients. Method: A prospective development study using the Idea, Development, Evaluation, Assessment, Long‐term study (IDEAL) framework was undertaken, by one surgeon, of the FLEX procedure in selected patients with endoscopically unresectable benign colonic polyps. Three‐dimensional (3D)‐CT colonography reconstructions were used preoperatively to rehearse patient‐specific, critical manoeuvres. Targetted, full‐thickness excision was performed: after marking the margin of the caecal polyp using circumferential endoscopic argon plasma coagulation, transmural endoscopic sutures were used to evert the bowel and resection was undertaken by laparoscopic linear stapling. Feasibility outcomes (establishing 'local success') included evidence of complete polyp resection without adverse events (especially safe closure of the excision site). Results: Ten patients [median (interquartile range) age: 74 (59‐78) years] with polyp median diameters of 35 (30–41) mm, were referred for and consented to receive the FLEX procedure. During the same time frame, no patient underwent colectomy for benign polyps. One further patient received FLEX for local excision of a presumed malignant polyp because severe comorbidity prohibited standard procedures. The FLEX procedure was successfully performed locally, with complete resection of the polyp and safe closure of the excision site, in eight patients. Three noncompleted procedures were converted to laparoscopic segmental colectomy under the same anaesthetic because of endoscopic inaccessibility (two patients) and transcolonic suture failure (one patient). Conclusions: The FLEX procedure is still under development. Early data demonstrate that it is safe for excision of selected benign polyps. Modifications to transcolonic suture delivery are now required and there is a need for wider adoption before more definitive evaluation can be performed. [ABSTRACT FROM AUTHOR]

Myeloid derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells that accumulate in circulation of cancer patients and at tumor sites where they suppress anti-tumor immunity. We previously reported that in a colon cancer prevention trial of a MUC1 vaccine tested in individuals at increased risk for colon cancer, those who did not mount immune response to the vaccine had higher pre-vaccination levels of circulating MDSC compared to those who did. We also reported that individuals with pancreatic premalignancy, Intraductal Papillary Mucinous Neoplasm (IPMN), had increased circulating levels of MDSC that inversely correlated with spontaneous antibody responses against the pancreatic tumor associated antigen MUC1, abnormally expressed on IPMN. Accumulation of MDSC in cancer and their immunosuppressive role had been well established but their presence in premalignancy was unexpected. In this study we compared MDSC in premalignancy with those in cancer with the hypothesis that there might be differences in the composition of various MDSC subpopulations and their immunosuppressive functions due to different lengths of exposure to disease and/or different tissue microenvironments. In cohorts of patients with premalignant polyps, colon cancer, premalignant IPMN, and pancreatic cancer, we confirmed higher levels of MDSC in premalignancy compared to healthy controls, higher levels of MDSC in cancer compared to premalignancy, but no difference in their subpopulation composition or immunosuppressive capacity. We show that levels of MDSC in premalignancy correlate negatively in vivo with spontaneous MUC1-specific antibody responses and in vitro with polyclonal T cell proliferation and IFN-γ secretion. [ABSTRACT FROM AUTHOR]

Objective: Residual or recurrent adenoma (RRA) after endoscopic mucosal resection (EMR) of large non-pedunculated colorectal polyps (LNPCPs) of ≥20 mm is a major limitation. Data on outcomes of the endoscopic treatment of recurrence are scarce, and no evidence-based standard exists. We investigated the efficacy of endoscopic retreatment over time in a large prospective cohort., Design: Over 139 months, detailed morphological and histological data on consecutive RRA detected after EMR for single LNPCPs at one tertiary endoscopy centre were prospectively recorded during structured surveillance colonoscopy. Endoscopic retreatment was performed on cases with evidence of RRA and was performed predominantly using hot snare resection, cold avulsion forceps with adjuvant snare tip soft coagulation or a combination of the two., Results: 213 (14.6%) patients had RRA (168 (78.9%) at first surveillance and 45 (21.1%) thereafter). RRA was commonly 2.5-5.0 mm (48.0%) and unifocal (78.7%). Of 202 (94.8%) cases which had macroscopic evidence of RRA, 194 (96.0%) underwent successful endoscopic therapy and 161 (83.4%) had a subsequent follow-up colonoscopy. Of the latter, endoscopic therapy of recurrence was successful in 149 (92.5%) of 161 in the per-protocol analysis, and 149 (73.8%) of 202 in the intention-to-treat analysis, with a mean of 1.15 (SD 0.36) retreatment sessions. No adverse events were directly attributable to endoscopic therapy. Further RRA after endoscopic therapy was endoscopically treatable in most cases. Overall, only 9 (4.2%, 95% CI 2.2% to 7.8%) of 213 patients with RRA required surgery.Thus 159 (98.8%, 95% CI 95.1% to 99.8%) of 161 cases with initially successful endoscopic treatment of RRA and follow-up remained surgery-free for a median of 13 months (IQR 25.0) of follow-up., Conclusions: RRA after EMR of LNPCPs can be effectively treated using simple endoscopic techniques with long-term adenoma remission of >90%; only 16% required retreatment. Therefore, more technically complex, morbid and resource-intensive endoscopic or surgical techniques are required only in selected cases., Trial Registration Numbers: NCT01368289 and NCT02000141., Competing Interests: Competing interests: MJB: research support from Olympus Medical, Cook Medical and Boston Scientific. DJT: research support from Olympus Medical., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To develop an interpretable artificial intelligence algorithm to rule out normal large bowel endoscopic biopsies, saving pathologist resources and helping with early diagnosis., Design: A graph neural network was developed incorporating pathologist domain knowledge to classify 6591 whole-slides images (WSIs) of endoscopic large bowel biopsies from 3291 patients (approximately 54% female, 46% male) as normal or abnormal (non-neoplastic and neoplastic) using clinically driven interpretable features. One UK National Health Service (NHS) site was used for model training and internal validation. External validation was conducted on data from two other NHS sites and one Portuguese site., Results: Model training and internal validation were performed on 5054 WSIs of 2080 patients resulting in an area under the curve-receiver operating characteristic (AUC-ROC) of 0.98 (SD=0.004) and AUC-precision-recall (PR) of 0.98 (SD=0.003). The performance of the model, named Interpretable Gland-Graphs using a Neural Aggregator (IGUANA), was consistent in testing over 1537 WSIs of 1211 patients from three independent external datasets with mean AUC-ROC=0.97 (SD=0.007) and AUC-PR=0.97 (SD=0.005). At a high sensitivity threshold of 99%, the proposed model can reduce the number of normal slides to be reviewed by a pathologist by approximately 55%. IGUANA also provides an explainable output highlighting potential abnormalities in a WSI in the form of a heatmap as well as numerical values associating the model prediction with various histological features., Conclusion: The model achieved consistently high accuracy showing its potential in optimising increasingly scarce pathologist resources. Explainable predictions can guide pathologists in their diagnostic decision-making and help boost their confidence in the algorithm, paving the way for its future clinical adoption., Competing Interests: Competing interests: SG, DS and NR are co-founders of Histofy. DS reports personal fees from Royal Philips, outside the submitted work. NR and FM report research funding from GlaxoSmithKline., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: There are limited data regarding the morphology, histopathology, and anatomical distribution of sporadic colorectal polyps in Chinese patients. We evaluated these characteristics of sporadic polyps to guide the endoscopic detection and excision of colorectal polyps., Methods: This was a retrospective single-center observational study involving 7381 patients with sporadic colorectal polyps. All polyps were removed endoscopically. The morphology and histopathology of polyps were evaluated according to the Paris classification and the World Health Organization classification, respectively., Results: A total of 22,174 polyps removed endoscopically from 7322 patients were included. In the sigmoid colon, 24.70% of colorectal polyps occurred, followed by the transverse colon (18.58%) in frequency. 0-Is type polyps accounted for 60.60% of all sporadic colorectal polyps. Polyps with 0-Ip, 0-Isp, and 0-IIa types were frequently found in the sigmoid colon, but laterally spreading lesions usually occurred in the ascending colon (24.61%) and rectum (20.51%). Irrespective of the Paris classification and anatomical location, as the polyps enlarge, the proportion of adenomatous polyps gradually increases while the proportion of serrated lesions decreases. Polyps with size ≥1 cm located in the left-sided colon were more likely to have villous/tubulovillous or high-grade dysplasia histology than those located in the right-sided colon, and about 1% of them were demonstrated with adenocarcinoma., Conclusion: Sigmoid colon should be detected adequately during colonoscopy, and polyps with size ≥1 cm should be treated carefully, especially in the left-sided colon., (© 2023 The Authors.)

Objetivo: analizar la evolución de la mucosa rectal y del reservorio así como idoneidad de los intervalos de seguimiento y del tratamiento realizado para evitar la aparición del cáncer, en una serie de pacientes con poliposis adenomatosa familiar (PAF), intervenidos. Método: estudio prospectivo de 28 pacientes con PAF intervenidos mediante anastomosis íleo-rectal (20 pacientes) y anastomosis íleo-anal con reservorio (8 pacientes). A todos se les había realizado un control endoscópico dos veces al año y análisis del número y características macroscópicas e histológicas de los pólipos antes y después de la cirugía así como del tratamiento realizado, de sus complicaciones y de la adecuación del intervalo de seguimiento. El seguimiento medio fue de 6,47 años (DE = 4,59; rango = 0,72-16,75 años). Resultados: ninguno de los 26 pacientes que cumplimentaron correctamente el protocolo de seguimiento desarrolló cáncer. Sólo dos pacientes lo desarrollaron al 1,75 y los 3 años, respectivamente del abandono del protocolo. Los pacientes que desarrollaron adenomas durante el seguimiento fueron tratados con éxito mediante polipectomía endoscópica, salvo en dos casos que se indicó cirugía. Conclusiones: en nuestra serie, el incumplimiento de las revisiones ha sido el factor que ha condicionado la aparición de cáncer.Objective: the study was to assess changes in the rectal mucosa and pouch in a series of patients with familial adenomatous polyposis (FAP) who underwent either subtotal colectomy and ileorectal anastomosis (IRA) or proctocolectomy and ileal pouch-anal anastomosis (IPAA), and to evaluate the suitability of the follow-up interval and postoperative treatment employed to prevent the development of cancer. Method: this study involved 28 patients with FAP who underwent IRA (n=20) or IPAA (n=8), and were followed endoscopically over a mean period of 7.47 years. The number and both macroscopic and histological features of polyps before and after surgery, the treatment, and complications were all analyzed. The suitability of the follow-up interval was assessed. Results: none of the 26 patients who complied with follow-up developed rectal cancer. Two patients developed rectal cancer at 21 and 36 months after withdrawing from the protocol. Except in two cases in which surgery was indicated, patients who developed adenomas during follow-up were treated by endoscopic polypectomy. Conclusions: in our series, the failure to comply with follow-up examinations was associated with cancer development.

Familial adenomatous polyposis (FAP) is a dominantly inherited syndrome caused by germline mutations in the APC gene and characterized by the development of multiple colorectal adenomas and a high risk of developing colorectal cancer (CRC). The severity of polyposis is correlated with the site of the APC mutation. However, there is also phenotypic variability within families with the same underlying APC mutation, suggesting that additional factors influence the severity of polyposis. Genome-wide association studies identified several single nucleotide polymorphisms (SNPs) that are associated with CRC. We assessed whether these SNPs are associated with polyp multiplicity in proven APC mutation carriers. Sixteen CRC-associated SNPs were analysed in a cohort of 419 APC germline mutation carriers from 182 families. Clinical data were retrieved from the Dutch Polyposis Registry. Allele frequencies of the SNPs were compared for patients with <100 colorectal adenomas versus patients with ≥100 adenomas, using generalized estimating equations with the APC genotype as a covariate. We found a trend of association of two of the tested SNPs with the ≥100 adenoma phenotype: the C alleles of rs16892766 at 8q23.3 (OR 1.71, 95 % CI 1.05-2.76, p = 0.03, dominant model) and rs3802842 at 11q23.1 (OR 1.51, 95 % CI 1.03-2.22, p = 0.04, dominant model). We identified two risk variants that are associated with a more severe phenotype in APC mutation carriers. These risk variants may partly explain the phenotypic variability in families with the same APC gene defect. Further studies with a larger sample size are recommended to evaluate and confirm the phenotypic effect of these SNPs in FAP. [ABSTRACT FROM AUTHOR]

Background: Epidemiologic data suggest that colonic adenomas have an increased tendency to occur in patients who are obese, African American, or have a positive family history of colon cancer, or diabetes mellitus. Recent data suggest that impaired glucose tolerance, dyslipidemia, and metabolic syndrome are associated with a higher risk for colonic adenomas. Patients with nonalcoholic fatty liver disease (NAFLD) often share several of the aforementioned risk factors for colonic adenomas. However, data are lacking about the relationship between NAFLD and colonic adenomas. The aim of this study was to systematically evaluate whether NAFLD is an independent risk factor for colonic adenomas.Methods: We performed a retrospective cohort observational study on 233 patients who underwent screening colonoscopies at Brooke Army Medical Center from November 2007 to March 2010 to assess for the association between NAFLD and colonic adenomas. Patients who had previously been found to have biopsy-proven simple steatosis (n = 65) or nonalcoholic steatohepatitis (NASH) (n = 29) were compared with a control group without fatty liver disease on sonographic imaging (n = 139). Patients were stratified based on gender, race, body mass index (BMI), and family history and adjusted for variables previously known to be associated with increased adenoma risk.Results: The mean age was 54.7 ± 6.0 years (48.5% women). Racial demographics were: 62.7% White, 18.5% Hispanic, 13.7%, African American, and 5.2% other. The mean BMI was 29.7 ± 5.8. The prevalence of colonic adenomas was 25.1% in the control group and 24.4% in the NAFLD group to include simple steatosis and NASH (p = 1.00). Furthermore, when adjusting for known confounders to include race, BMI, and family history no significant differences were found (p = 0.33). However, the ultrasound-negative patients ranked lower in the number of adenomas per person (p = 0.016).Conclusions: There was no difference in the prevalence of colonic adenomas when comparing the NAFLD group who had undergone colonoscopy with a group of control patients without NAFLD who had undergone colonoscopy. However, patients with negative ultrasounds appeared to have a lower polyp burden. [ABSTRACT FROM PUBLISHER]

Aim This study was designed to assess the relationship between diverticulitis and the development of colorectal cancer (CRC) and colonic adenomas. Method A retrospective study was longitudinally conducted. Patients who had been admitted to the hospital between 1990 and 2000 with diverticulitis were retrieved and the incidence of CRC and prevalence of colonic adenomas in these patients was determined. Data were collected from the electronic clinical and pathology records. The incidence of CRC and prevalence of adenomas in this patient cohort was compared with the general population. The patients were followed until 2008. Results A total of 288 patients with diverticulitis were included (167 of whom were female patients [58%]). The mean age of patients at admittance for diverticulitis was 66 years (range: 27-92). CRC was detected in five patients (1.7%) (95% CI 0.8-3.5) with a mean age of 77 years; colonic adenomas were found in 18 patients (6.3%) (95% CI 4.3-9.0) with a mean age of 62 years. The lifetime risks of developing CRC and adenomas were presumed to be 4% and 20% respectively. Expected rates for CRC and adenomas in our patients were calculated as 17 (95% CI 4.0-8.6) and 69 patients (95% CI 20.1-28.3) respectively. Conclusion This study showed a lower prevalence of CRC and colonic adenomas in patients with diverticulitis compared with the lifetime risk which means that diverticulitis is not a risk factor for development of CRC and adenomas. Long-term colonic screening after a negative colonoscopy for diverticulitis (generally performed several weeks after recovery) does not seem to be justified. [ABSTRACT FROM AUTHOR]

We aimed to study the intracellular expression of 5-lipoxygenase (5-LOX), the primary competitor with cyclooxygenase-2 in arachidonic acid metabolism, as inflammatory enzymes may be involved in blocking apoptosis and promoting cancer growth by changing arachidonic acid metabolism within cells. Our purpose was to investigate the possible connection between 5-LOX expression and colon carcinogenesis by characterizing 5-LOX expression in histologically different colonic adenomas, determining the relationship between high expression of 5-LOX and various conventional clinicopathological features of adenomas, and finally characterizing the histological localization of cells with 5-LOX overexpression. A total of 111 patients were examined and 120 histologically different colonic adenomas analyzed (including four cases of intramucosal adenocarcinoma in a polyp). Immunohistochemical staining with polyclonal anti-5-LOX antibodies was performed. There was a significant correlation between high 5-LOX expression and patient age, increased polyp size, high grade of intraepithelial neoplasia, villous and tubulovillous adenoma, and histological epithelial localization. We observed a strong positive correlation between 5-LOX overexpression and the appearance of typical high-risk factors for malignant transformation in adenomatous polyps. The results support the role of 5-LOX in early stages of colon carcinogenesis. [ABSTRACT FROM AUTHOR]

Abstract: Background and study aims: Despite the growing understanding of the involvement of protooncogenes and tumour suppressor genes in the oncogenesis of CRC, the exact biological and molecular mechanisms underpinning this process remain poorly understood. The signal transducer and activator of transcription (STAT3) has been implicated in the regulation of growth and malignant transformation. Accumulating evidences have come to indicate that abnormalities in the Janus kinase (JAK)/STAT pathway are involved in oncogenesis of several cancers. The aim of this study was to investigate the expression of JAK3 and STAT3 in both normal and activated forms by immunohistochemistry in adenomas of the colon, ulcerative colitis and CRC compared to normal colonic mucosa. Patients and methods: Tissues from 30 cases with primary CRC and seven cases with ulcerative colitis (UC), removed by colectomy, were included. In addition, tissues from 10 colonic adenomas, 15 CRC and eight cases with UC, obtained by endoscopic biopsies, were examined histopathologically. Immunohistochemical evaluation of STAT3, p-STAT3, JAK3 and p-JAK3 expression in tissue sections was completed. Statistical analysis and correlation of data were then performed. Results: Normal colonic mucosa showed expression of STAT3 only. Immunoreactivity of p-JAK3 increased significantly (p <0.05) and correlated with the degree of dysplasia in colonic adenomas. Immunoreactivity of p-STAT3 increased significantly (p <0.05) and correlated with the degree of dysplasia in cases with UC. In CRC a significant positive correlation was found between p-STAT3 expression and grading, STAT3, JAK3 and p-JAK3 and TNM or Dukes’ staging, and p-STAT3 and nodal status excluding distant metastasis (p <0.05). Conclusion: JAK3 and STAT3, and particularly their activated forms, were found to correlate significantly with the degree of dysplasia in adenomas and UC, indicating their potential role in colorectal carcinogenesis. They also correlate with anaplasia and invasion, suggesting a definitive role in progression of CRC. [Copyright &y& Elsevier]

Abstract: Background: Azoxymethane (AOM) is a potent carcinogen that induces colorectal cancer and adenomas in rats. [18F]FDG-PET is a molecular imaging technique that is based on the elevated uptake and retention of radiolabeled glucose. At present, it is unknown at which stage FDG accumulation occurs during the adenoma carcinoma sequence. To address this issue, we studied the FDG uptake in AOM-induced rat colorectal adenocarcinoma (CRC) and correlated this with histopathological findings. Methods: Seventy Fischer 344 rats were injected with AOM. Terminal autopsy took place 20–38 weeks after the first AOM injection. After [18F]FDG PET scanning, the rats were sacrificed, tissue [18F]FDG uptake was measured, followed by histopathological examination. Results: Macroscopic examination revealed 21 tumors (7 located in the small bowel and 14 in the colon) in 19 rats. On histological examination, we found 10 colonic adenocarcinomas (the first being observed at Week 22) and 7 adenocarcinoma in the small bowel. In total, seven colon adenomas were found in five rats, six of which expressed high-grade dysplasia. The [18F]FDG accumulation in small intestine carcinomas was well beyond background accumulation (P<.0001). On PET scanning, two rats showed focal accumulation of the abdominal area, corresponding to small intestine carcinomas. Conclusion: Adenocarcinomas had a significantly higher [18F]FDG uptake than background bowel uptake. [18F]FDG uptake was lower in adenomas than in carcinomas. These data suggest that the AOM model allows the evaluation of intervention strategies with [18F]FDG uptake as a valid outcome measure. [Copyright &y& Elsevier]

PURPOSE: This study was designed to assess the predictive value for advanced proximal neoplasms (cancer, adenoma ≤ 10 mm, or villous component ≤20 percent, or severe dysplasia) of the characteristics of distal polyps. METHODS: The study was conducted among patients, aged 55 to 64 years, referred for colonoscopy in the Italian trial of sigmoidoscopy screening for colorectal cancer. Patients reporting a history of colorectal cancer, adenomas, inflammatory bowel disease, recent colorectal endoscopy, or two first-degree relatives with colorectal cancer were excluded. We compared the prevalence of advanced proximal neoplasia in patients with ‘low-risk’ (1–2 tubular adenomas, >10 mm, with low-grade dysplasia, or hyperplastic polyp) and in those with ‘high-risk’ (size, ≤10 mm, or ≤3 adenomas, or villous component <20 percent, or severe dysplasia) polyps in the distal colon. RESULTS: Of 426 patients with polyps < 5 mm, 29 (6.9 percent) were detected with an advanced proximal neoplasm (including 4 colorectal cancers). The prevalence of proximal advanced neoplasia was 9.4 percent among patients with high-risk distal polyps and 2.5 percent among those with low-risk lesions (adjusted odds ratio, 3.19; 95 percent confidence interval, 1.06-9.59). Approximately 40 people with low-risk distal polyps 6 to 9 mm should undergo colonoscopy to detect one proximal advanced neoplasm; the corresponding number for patients with high-risk distal polyps is 10. CONCLUSIONS: The 2.5 percent prevalence of proximal advanced neoplasms among people with low-risk 6-mm to 9-mm distal polyps is similar to the prevalence observed among people without distal polyps. Restricting colonoscopy referral to patients with high-risk distal polyps might represent a cost-effective strategy in a screening context. [ABSTRACT FROM AUTHOR]

Objective: Monitoring of key performance indicators (KPIs) is a vital element of endoscopy quality improvement. Adenoma detection rate (ADR) is considered the best marker for colonoscopic quality as it inversely correlates with subsequent colonic cancer incidence and mortality, while polyp detection rate (PDR) is an easier-to-calculate surrogate for ADR. This study assessed whether regular feedback to individual endoscopists about their KPIs improved departmental performance., Methods: Individual KPIs were calculated for a period of 8 years (January 2012-December 2019) and fed back to all endoscopists at 6 monthly intervals, alongside anonymised indicators for other endoscopists, aggregate departmental performance data and benchmarks. An automated natural language processing software (EndoMineR) was used to identify adenomas in pathology reports and calculate ADR. Linear regressions were calculated for departmental ADR, PDR and other KPIs at 6 monthly intervals., Results: 39 359 colonoscopies (average 2460 in every 6-month period, range 1799-3059) were performed by an average of 42 (range 34-50) endoscopists. A continuous improvement in collective performance including ADR (12.7%-21.0%, R 2 0.92, p<0.001) and PDR (19.0%-29.6%, R 2 0.77, p<0.001) was observed throughout the study. Other KPIs showed similar improvement. The detection of non-neoplastic polyps did not increase. When analysed separately, ADR and PDR appeared to improve for gastroenterologists and nurse endoscopists but not for surgeons., Conclusion: Regular feedback with individual and departmental KPIs was associated with improved ADR and overall performance throughout the 8-year study period. Concomitant monitoring of ADR and PDR may prevent 'gaming' behaviour and ensure that genuine improvement is achieved., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Five hundred eighty-two patients with colorectal adenomas or early cancers were polypectomized from 1974 to 1985. In 100 patients, total colonoscopy was performed more than twice after the initial polypectomies. These patients were divided into three groups: group A patients underwent total colonoscopy at 1-year intervals; group B patients underwent total colonoscopy at 2-year intervals, group C patients underwent total colonoscopy at 3-year or more than 3-year intervals. The frequency and location of newly developed adenomas were investigated. The detection rate for new adenomas was 13% in group A and 50% in group B; thus, there was a significant difference between group A and group B ( P<0.01). The transverse colon is the only segment where the topological proportion of newly developed adenomas increased in comparison with that of index adenomas ( P<0.05). The detection rate for new adenomas was significantly higher in patients who had carcinoma in situ at the time of initial polypectomy ( P<0.05). Questionnaires about colonoscopy and colonic adenomas were therefore mailed to the patients who were lost to follow-up after the polypectomy. [ABSTRACT FROM AUTHOR]

Intravenously injected haematoporphyrin derivative localizes in malignant tissue more than it does in the surrounding normal tissues; this allows cancer to be treated photodynamically. The aim of this study is to determine whether adenomas of the large bowel, which are benign precarcinomatous lesions, accumulate HPD as well as does malignant tissue, and whether such accumulation occurs to a greater extent than it does in the surrounding normal mucosa. For this purpose, microspectrofluorometric analysis was performed on biopsy samples of adenomas, on adenocarcinomas, and on normal mucosa, and the data were compared. The samples were obtained from patients affected by histologically proven adenocarcinomas and synchronous adenomas of the bowel 48h after intravenous injection of HPD (3 mg/kg bodyweight), that is, the time interval usually required for photodynamic therapy. The intensity of fluorescence of the adenomas was a little lower than that observed from adenocarcinomas, but was higher than that from the surrounding mucosa. The fluorescence spectra from adenomas and from adenocarcinomas showed three main emission bands centred at about 630, 670 and 700 nm. The relative amplitudes of the band at 630 and 670 nm in benign and malignant colorectal tumours varied with the excitation wavelength, depending on the different physicochemical state of the accumulated drug. A further analysis, performed 72 h after administration, indicated the existence of an intratissue turnover of the porphyrins. [ABSTRACT FROM AUTHOR]

Colonic adenocarcinomas evolve through a multistep process from tubular adenomas to invasive adenocarcinomas. Matrix metalloproteinases (MMPs) have been implicated in proteolysis of basement membrane for initiation of metastatic cascade.By immunocytochemical staining, hyperplastic polyps, tubular adenomas, tubovillous adenomas, villous adenomas to adenocarcinomas were systematically examined for the presence of MMP-2 (gelatinase A) and MMP-9 (gelatinase B) and tissue inhibitor of MMP (TIMP)-1 and TIMP-2, respectively.MMP-2 and MMP-9, and TIMP-1 and TIMP-2 were immunolocalized in scattered stromal cells, whereas epithelial cells of normal mucosa and hyperplastic polyps were weakly stained. From tubular adenomas to villous adenomas, immunolocalization of gelatinases and TIMPs showed increasing gradually, and in situ carcinomas showed a definite positive, immunolocalization of gelatinases and TIMPs.Increasing immunolocalization of gelatinases and TIMPs from tubular adenomas to adenocarcinomas coincides with a multistep process of colonic tumorigenesis. [ABSTRACT FROM AUTHOR]

The association of endoscopic resection with Nd:YAG laser photocoagulation was used to treat benign colorectal villous adenomas. Eighty-five patients were included: 49 with surgical contraindications, 35 for whom surgical resection appeared to be too hazardous, and 1 who refused surgery. Forty-five tumors had an axial extension between 1 and 3 cm, and 40 tumors had an axial extension of at least 4 cm. Diathermic snare resection was performed to remove large tumoral fragments prior to laser photocoagulation of the residual flat lesions. Treatments were repeated every 15 days until total tumor destruction was achieved. A carcinoma was detected in biopsy specimens obtained during endoscopic treatment of five patients. Two patients were lost to follow-up. Treatment results could be analyzed in 78 patients. Successful treatment was achieved in 67 patients. Tumor destruction was complete in 77 percent of patients who had lesions of at least 4 cm diameter and in 93 percent of patients with smaller lesions. The axial extension of the tumor was the main factor affecting the results of treatment. No major complications occurred. During the average 103-week follow-up period, 21 percent of the patients with total tumor destruction had a recurrence. The risk of recurrence was correlated with the number of initial treatment sessions and previous surgery treatment. It would appear that the treatment with endoscopic resection prior to Nd:YAG laser photocoagulation is a safe and effective method in the destruction of colorectal villous adenomas. [ABSTRACT FROM AUTHOR]

Background: Low-volume preparations for colonoscopy have shown similar efficacy compared to high-volume ones in randomized controlled trials (RCT). However, most RCTs do not provide data about clinical outcomes including lesions detection rate. Moreover, real-life comparisons are lacking., Aim: To compare efficacy (both in terms of adequate bowel preparation and detection of colorectal lesions) and tolerability of a high-volume (HV: 4 L polyethylene glycol, PEG) and a low-volume (LV: 2 L PEG plus bisacodyl) bowel preparation in a real-life setting., Methods: Consecutive outpatients referred for colonoscopy were prospectively enrolled between 1 December 2014 and 31 December 2016. Patients could choose either LV or HV preparation, with a day-before schedule for morning colonoscopies and a split-dose for afternoon procedures. Adequate bowel preparation according to Boston Bowel Preparation Scale (BBPS), clinical outcomes including polyp detection rate (PDR), adenoma detection rate (ADR), advanced adenoma detection rate (AADR), sessile/serrated lesion detection rate (SDR) and cancer detection rate and self-reported tolerability of HV and LV were blindly assessed., Results: Total 2040 patients were enrolled and 1815 (mean age 60.6 years, 50.2% men) finally included. LV was chosen by 52% of patients (50.8% of men, 54.9% of women). Split-dose schedule was more common with HV (44.7% vs 38.2%, P = 0.005). High-definition scopes were used in 33.4% of patients, without difference in the two groups ( P = 0.605). HV and LV preparations showed similar adequate bowel preparation rates (89.2% vs 86.6%, P = 0.098), also considering the two different schedules (HV split-dose 93.8% vs LV split-dose 93.6%, P = 1; HV day-before 85.5% vs LV day-before 82.3%, P = 0.182). Mean global BBPS score was higher for HV preparations (7.1 ± 1.7 vs 6.8 ± 1.6, P < 0.001). After adjustment for sex, age and indications for colonoscopy, HV preparation resulted higher in PDR [Odds ratio (OR) 1.32, 95%CI: 1.07-1.63, P = 0.011] and ADR (OR 1.29, 95%CI 1.02-1.63, P = 0.038) and comparable to LV in AADR (OR 1.51, 95%CI 0.97-2.35, P = 0.069), SDR and cancer detection rate. The use of standard-definition colonoscopes was associated to lower PDR (adjusted OR 1.59, 95%CI: 1.22-2.08, P < 0.001), ADR (adjusted OR 1.71, 95%CI: 1.26-2.30, P < 0.001) and AADR (adjusted OR 1.97, 95%CI: 1.09-3.56, P = 0.025) in patients receiving LV preparation. Mean Visual Analogue Scale tolerability scored equally (7, P = 0.627) but a ≥ 75% dose intake was more frequent with LV (94.6% vs 92.1%, P = 0.003)., Conclusion: In a real-life setting, PEG-based low-volume preparation with bisacodyl showed similar efficacy and tolerability compared to standard HV preparation. However, with higher PDR and ADR, HV should still be considered as the reference standard for clinical trials and the preferred option in screening colonoscopy, especially when colonoscopy is performed with standard resolution imaging., Competing Interests: Conflict-of-interest statement: The authors declare that there is no conflict of interest., (©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.)

Objective: Colon capsule endoscopy (CCE) has shown promise for colorectal neoplasia detection compared with optical colonoscopy (OC), but has not been compared with other screening tests in average risk screening patients., Design: Patients 50 to 75 years of age (African Americans, 45-75 years) were randomised to CCE or CT colonography (CTC) and subsequent blinded OC. The primary endpoint was diagnostic yield of polyps ≥6 mm with CCE or CTC. Secondary endpoints included accuracy for size and histology, examination completeness, number/proportion of subjects with polyps and adenomas ≥6 mm and ≥10 mm, subject satisfaction and safety., Results: From 320 enrolled subjects, data from 286 (89.4%) were evaluable. The proportion of subjects with any polyp ≥6 mm confirmed by OC was 31.6% for CCE versus 8.6% for CTC (pPr non-inferiority and superiority=0.999). The diagnostic yield of polyps ≥10 mm was 13.5% with CCE versus 6.3% with CTC (pPr non-inferiority=0.9954). The sensitivity and specificity of CCE for polyps ≥6 mm was 79.2% and 96.3% while that of CTC was 26.8% and 98.9%. The sensitivity and specificity of CCE for polyps ≥10 mm was 85.7% and 98.2% compared with 50% and 99.1% for CTC. Both tests were well tolerated/safe., Conclusion: CCE was superior to CTC for detection of polyps ≥6 mm and non-inferior for identification of polyps ≥10 mm. CCE should be considered comparable or superior to CTC as a colorectal neoplasia screening test, although neither test is as effective as OC., Trial Registration Number: ClinicalTrials.gov no: NCT02754661., Competing Interests: Competing interests: These authors disclose the following: BDC: Consultant to Medtronic, Salix, Allergan, Takeda; Speakers’ Bureau for Salix, Allergan, Takeda, AlfaSigma, RedHill, QOL. ER: Consultant to Olympus; IP with Medtronic. DMK: Consultant to Medtronic, Ferring, Salix, MotusGI; Research support from Medtronic, MotusGI. DP: Speakers’ Bureau: Gilead Life Sciences, Merck; Advisory Boards: Gilead, Novartis, Intercept. NPP: Consultant to Medtronic. IF-U received honorarium from Medtronic. IJS: Consultant to Medtronic. DKR: Consultant to Olympus Corporation, Boston Scientific, Medtronic, Aries Pharmaceutical, Braintree Laboratories, Lumendi Ltd, Norgine, Endokey, GI Supply; Research support: EndoAid, Olympus Corporation, Medivators, Erbe USA Inc.; Ownership: Satisfai Health., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Competing Interests: Competing interests: JEE has served on clinical advisory boards for Lumendi, Boston Scientific and Paion; has served on the clinical advisory board and has share options in Satisfai Health; and reports speaker fees from Falk. He is an associate editor for the Journal of Gastroenterology and Hepatology.

Objective: Postscreening colorectal cancer (PSCRC) after screening colonoscopy is associated with endoscopists' performance and characteristics of resected lesions. Prior studies have shown that adenoma detection rate (ADR) is a decisive factor for PSCRC, but correlations with other parameters need further analysis and ADR may change over time., Design: Cohort study including individuals undergoing screening colonoscopy between 1/2008 and 12/2019 performed by physicians participating in a quality assurance programme in Austria. Data were linked with hospitalisation data for the diagnosis of PSCRC (defined as CRC diagnosis >6 months after colonoscopy). ADR was defined dynamically in relation to the time point of subsequent colonoscopies; high-risk groups of patients were those with an adenoma ≥10 mm, or with high-grade dysplasia, or villous or tubulovillous histology, or a serrated lesion ≥10 mm or with dysplasia, or colonoscopies with ≥3 lesions. Main outcome was PSCRC for each risk group (negative colonoscopy, hyperplastic polyps, low-risk and high-risk group of patients) after colonoscopy by endoscopists with an ADR <20% compared with endoscopists with an ADR ≥20%., Results: 352 685 individuals were included in the study (51.0% women, median age 60 years) of which 10.5% were classified as high-risk group. During a median follow-up of 55.4 months, 241 (0.06%) PSCRC were identified; of 387 participating physicians, 19.6% had at least one PSCRC (8.4% two or more). While higher endoscopist ADR decreased PSCRC incidence (HR per 1% increase 0.97, 95% CI 0.95 to 0.98), affiliation to the high-risk group of patients was also associated with higher PSCRC incidence (HR 3.27, 95% CI 2.36 to 4.00). Similar correlations were seen with regards to high-risk, and advanced adenomas. The risk for PSCRC was significantly higher after colonoscopy by an endoscopist with an ADR <20% as compared with an endoscopist with an ADR ≥20% in patients after negative colonoscopy (HR 2.01, 95% CI 1.35 to 3.0, p<0.001) and for the high-risk group of patients (HR 2.51, 95% CI 1.49 to 4.22, p<0.001)., Conclusion: A dynamic calculation of the ADR takes into account changes over time but confirms the correlation of ADR and interval cancer. Both lesion characteristics and endoscopists ADR may play a similar role for the risk of PSCRC. This should be considered in deciding about appropriate surveillance intervals in the future., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aims: Adenoma detection rate (ADR) has been shown to correlate with interval cancers after screening colonoscopy and is commonly used as surrogate parameter for its outcome quality. ADR improvements by various techniques have been studied in randomised trials using either parallel or tandem methodololgy., Methods: A systematic literature search was done on randomised trials (full papers, English language) on tandem or parallel studies using either adenoma miss rates (AMR) or ADR as main outcome to test different novel technologies on imaging (new endoscope generation, narrow band imaging, iScan, Fujinon intelligent chromoendoscopy/blue laser imaging and wide angle scopes) and mechanical devices (transparent caps, endocuff, endorings and balloons). Available meta analyses were also screened for randomised studies., Results: Overall, 24 randomised tandem trials with AMR (variable definitions and methodology) and 42 parallel studies using ADR (homogeneous methodology) as primary outcome were included. Significant differences in favour of the new method were found in 66.7% of tandem studies (8222 patients) but in only 23.8% of parallel studies (28 059 patients), with higher rates of positive studies for mechanical devices than for imaging methods. In a random-effects model, small absolute risk differences were found, but these were double in magnitude for tandem as compared with parallel studies (imaging: tandem 0.04 (0.01, 0.07), parallel 0.02 (0.00, 0.04); mechanical devices: tandem 0.08 (0.00, 0.15), parallel 0.04 (0.01, 0.07)). Nevertheless, 94.2% of missed adenomas in the tandem studies were small (<1 cm) and/or non-advanced., Conclusions: A tandem study is more likely to yield positive results than a simple parallel trial; this may be due to the use of different parameters, variable definitions and methodology, and perhaps also a higher likelihood of bias. Therefore, we suggest to accept positive results of tandem studies only if accompanied by positive results from parallel trials., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: Adenoma detection rate (ADR) is an important quality marker at lower GI endoscopy. Higher ADRs are associated with lower postcolonoscopy colorectal cancer rates. The English flexible sigmoidoscopy (FS) screening programme (BowelScope), offers a one-off FS to individuals aged 55 years. However, variation in ADR exists. Large studies have demonstrated improved ADR using Endocuff Vision (EV) within colonoscopy screening, but there are no studies within FS. We sought to test the effect of EV on ADR in a national FS screening population., Design: BowelScope: Accuracy of Detection Using ENdocuff Optimisation of Mucosal Abnormalities was a multicentre, randomised controlled trial involving 16 English BowelScope screening centres. Individuals were randomised to Endocuff Vision-assisted BowelScope (EAB) or Standard BowelScope (SB). ADR, polyp detection rate (PDR), mean adenomas per procedure (MAP), polyp characteristics and location, participant experience, procedural time and adverse events were measured. Comparison of ADR within the trial with national BowelScope ADR was also undertaken., Results: 3222 participants were randomised (53% male) to receive EAB (n=1610) or SB (n=1612). Baseline demographics were comparable between arms. ADR in the EAB arm was 13.3% and that in the SB arm was 12.2% (p=0.353). No statistically significant differences were found in PDR, MAP, polyp characteristics or location, participant experience, complications or procedural characteristics. ADR in the SB control arm was 3.1% higher than the national ADR., Conclusion: EV did not improve BowelScope ADR when compared with SB. ADR in both arms was higher than the national ADR. Where detection rates are already high, EV is unable to improve detection further., Trial Registration Numbers: NCT03072472, ISRCTN30005319 and CPMS ID 33224., Competing Interests: Competing interests: CJR has received grant funding from ARC medical, Norgine and Olympus medical. He was an expert witness for ARC Medical. PB has received grant funding from Norgine., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Diathermy practice in colonic polypectomy has a poor evidence base. We surveyed endoscopists across the UK to gain an insight in current diathermy practice., Methods: An eight-question survey was designed to be compact, easy to complete, while still capturing the relevant data. This national survey was circulated by the endoscopy committees of the British Society of Gastroenterology and Association of Coloproctology of Great Britain and Ireland., Results: The survey was open between February and October 2016. Analysis showed: (1) 250/348 (71.8%) completed the full survey, 159 gastroenterologists (63.6%), 36 surgeons (14.4%), 34 gastroenterology trainees (13.6%), 21 others (8.4%); (2) predominant use of coagulation current for small pedunculated polypectomy, high rates of cold snare polypectomy for small sessile polyps (right 43.2% > left 34.4%); (3) a combination of coagulation and cutting current, or Endo Cut , was most popular for larger polypectomy; (4) low use of Endo Cut mode irrespective of size/location of polyp (17.2%-32.0%); (5) 204/250 (81.6%) used reduced current settings for right colon polypectomy; and (6) 208/250 (83.2%) were confident on knowledge and use of diathermy., Conclusion: This national survey exposes a wide variation in practice suggesting that colonoscopists employ diathermy modalities that they are comfortable with. As many complications are as direct result of thermal injury and polypectomy is the most frequent therapeutic intervention, appropriate training and formal guidance is lacking., Competing Interests: Competing interests: None declared.

Objective: Low adenoma detection rates (ADR) are linked to increased postcolonoscopy colorectal cancer rates and reduced cancer survival. Devices to enhance mucosal visualisation such as Endocuff Vision (EV) may improve ADR. This multicentre randomised controlled trial compared ADR between EV-assisted colonoscopy (EAC) and standard colonoscopy (SC)., Design: Patients referred because of symptoms, surveillance or following a positive faecal occult blood test (FOBt) as part of the Bowel Cancer Screening Programme were recruited from seven hospitals. ADR, mean adenomas per procedure, size and location of adenomas, sessile serrated polyps, EV removal rate, caecal intubation rate, procedural time, patient experience, effect of EV on workload and adverse events were measured., Results: 1772 patients (57% male, mean age 62 years) were recruited over 16 months with 45% recruited through screening. EAC increased ADR globally from 36.2% to 40.9% (P=0.02). The increase was driven by a 10.8% increase in FOBt-positive screening patients (50.9% SC vs 61.7% EAC, P<0.001). EV patients had higher detection of mean adenomas per procedure, sessile serrated polyps, left-sided, diminutive, small adenomas and cancers (cancer 4.1% vs 2.3%, P=0.02). EV removal rate was 4.1%. Median intubation was a minute quicker with EAC (P=0.001), with no difference in caecal intubation rate or withdrawal time. EAC was well tolerated but caused a minor increase in discomfort on anal intubation in patients undergoing colonoscopy with no or minimal sedation. There were no significant EV adverse events., Conclusion: EV significantly improved ADR in bowel cancer screening patients and should be used to improve colonoscopic detection., Trial Registration Number: NCT02552017, Results; ISRCTN11821044, Results., Competing Interests: Competing interests: CJR has received research grants from ARC Medical, Olympus Medical, Aquilant Endoscopy, Norgine and travel grants from Boston Scientific and Cook Medical. He is an advisory board member for Ai4Gi. BPS has received speaker grants from Olympus Medical and research support from Norgine, Aquilant and Diagmed. He is an advisory board member for Creo Medical. ZPT was a non-paid speaker for Norgine Pharmaceutical. He has received research and educational grants from Norgine Pharmaceutical and medical equipment support from Olympus. He holds a Consultant Agreement for Creo Medical., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2019. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Colonoscopy is a commonly used modality for screening and surveillance of colorectal cancer (CRC). Therefore, it is essential to have adequate bowel preparation (prep) for the procedure which depends on type of bowel regimens, diet before colonoscopy and timing of the procedure., Aims: The purpose of this study is to analyse the effect of multiple factors on adenoma detection rate (ADR) and prep quality of colonoscopy. This is the also the first study determining outcomes based on various combinations of diet, timing of the procedure and bowel prep regimens., Methods: This is a retrospective single-centre observational study. Data about diet before procedure, bowel prepprep regimen and timing of the procedure was collected for patients coming for screening colonoscopy., Results: Patients with split prep had higher good prep rates (73.8% vs 56.2%) and higher ADRs (34.2 % vs 29.9%) as compared with non-split prep. The good prep quality (65.8% vs 62.1%) and ADRs (31.9% vs 31.5%) were comparable in patients who received clear liquid diet as compared with low residue diet. The good results of bowel prep were obtained with split prep with either clear liquids or low residue diet irrespective of the timing of procedure. The poor prep was noticed in patients who underwent procedure in afternoon, with a low restrictive diet and non-split bowel regimen., Conclusions: The current study adds to our knowledge about the combined effect of multiple variables affecting the bowel prep quality and ADR. It is imperative to opt for the best combination required for colonoscopy, as this will influence the effectiveness of colonoscopies regarding timely cancer detection and prevention., Competing Interests: Competing interests: None declared.