AGA Clinical Practice Update on the Role of Artificial Intelligence in Colon Polyp Diagnosis and Management: Commentary.

DESCRIPTION: The purpose of this American Gastroenterological Association (AGA) Institute Clinical Practice Update (CPU) is to review the available evidence and provide expert commentary on the current landscape of artificial intelligence in the evaluation and management of colorectal polyps. METHODS: This CPU was commissioned and approved by the AGA Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. This Expert Commentary incorporates important as well as recently published studies in this field, and it reflects the experiences of the authors who are experienced endoscopists with expertise in the field of artificial intelligence and colorectal polyps.

Epithelial-specific ERBB3 deletion results in a genetic background-dependent increase in intestinal and colon polyps that is mediated by EGFR.

ERBB3 has gained attention as a potential therapeutic target to treat colorectal and other types of cancers. To confirm a previous study showing intestinal polyps are dependent upon ERBB3, we generated an intestinal epithelia-specific ERBB3 deletion in C57BL/6-ApcMin/+ mice. Contrary to the previous report showing a significant reduction in intestinal polyps with ablation of ERBB3 on a B6;129 mixed genetic background, we observed a significant increase in polyp number with ablation of ERBB3 on C57BL/6J compared to control littermates. We confirmed the genetic background dependency of ERBB3 by also analyzing polyp development on B6129 hybrid and B6;129 advanced intercross mixed genetic backgrounds, which showed that ERBB3 deficiency only reduced polyp number on the mixed background as previously reported. Increased polyp number with ablation of ERBB3 was also observed in C57BL/6J mice treated with azoxymethane showing the effect is model independent. Polyps forming in absence of ERBB3 were generally smaller than those forming in control mice, albeit the effect was greatest in genetic backgrounds with reduced polyp numbers. The mechanism for differential polyp number in the absence of ERBB3 was through altered proliferation. Backgrounds with increased polyp number with loss of ERBB3 showed an increase in cell proliferation even in non-tumor epithelia, while backgrounds showing reduced polyp number with loss of ERBB3 showed reduced cellular proliferation. Increase polyp number caused by loss of ERBB3 was mediated by increased epidermal growth factor receptor (EGFR) expression, which was confirmed by deletion of Egfr. Taken together, this study raises substantial implications on the use of ERBB3 inhibitors against colorectal cancer. The prediction is that some patients may have increased progression with ERBB3 inhibitor therapy, which is consistent with observations reported for ERBB3 inhibitor clinical trials.

Second-generation narrow-band imaging to detect colorectal adenomas: A prospective study including community hospitals.

BACKGROUND AND AIM: It is unclear whether second-generation narrow-band imaging (NBI) improves colorectal adenoma detection in clinical practice. We aimed to evaluate the ability of NBI to detect adenomas in academic and community hospitals. METHODS: This observational, multicenter study was conducted in four academic and four community hospitals between July 2018 and April 2019. We enrolled patients aged ≥ 20 years who underwent colonoscopy for screening, polyp surveillance, or diagnostic workup. The primary endpoint was the adenoma detection rate (ADR) between NBI (NBI group) and white-light imaging colonoscopies (WLI group) after propensity score (PS) matching. RESULTS: Of 1831 patients analyzed before PS matching, the NBI and WLI groups included 742 and 1089 patients, respectively. After PS matching, 711 pairs from both groups were analyzed. ADR and the mean number of adenomas per patient did not differ significantly between the NBI and WLI groups (43.5% vs 44.4%, P = 0.71; 0.90 ± 1.38 vs 0.91 ± 1.40, P = 0.95, respectively). Academic hospitals showed higher ADR in the NBI group (60.5% vs 53.8%), whereas community hospitals showed higher ADR in the WLI group (35.8% vs 40.5%). In the NBI group, ADR was significantly higher among NBI-screening-experienced endoscopists than among NBI-screening-inexperienced endoscopists (63.2% vs 39.2%, P < 0.001). The mean number of flat and depressed lesions detected per patient was significantly higher with NBI than with WLI (0.62 ± 1.34 vs 0.44 ± 1.01, P = 0.035). CONCLUSIONS: Second-generation NBI could not surpass WLI in terms of ADR based on patient recruitment from both academic and community hospitals but improved the detection of easily overlooked flat and depressed lesions.

Terminology, Molecular Features, Epidemiology, and Management of Serrated Colorectal Neoplasia.

In addition to the adenoma to carcinoma sequence, colorectal carcinogenesis can occur via the serrated pathway. Studies have focused on clarification of categories and molecular features of serrated polyps, as well as endoscopic detection and risk assessment. Guidelines from the World Health Organization propose assigning serrated polyps to categories of hyperplastic polyps, traditional serrated adenomas, and sessile serrated lesions (SSLs). Traditional serrated adenomas and SSLs are precursors to colorectal cancer. The serrated pathway is characterized by mutations in RAS and RAF, disruptions to the Wnt signaling pathway, and widespread methylation of CpG islands. Epidemiology studies of serrated polyps have been hampered by inconsistencies in terminology and reporting, but the prevalence of serrated class polyps is 20%-40% in average-risk individuals; most serrated polyps detected are hyperplastic. SSLs, the most common premalignant serrated subtype, and are found in up to 15% of average-risk patients by high-detecting endoscopists. Variations in rate of endoscopic detection of serrated polyps indicate the need for careful examination, with adequate bowel preparation and sufficient withdrawal times. Risk factors for SSLs include white race, family history of colorectal cancer, smoking, and alcohol intake. Patients with serrated polyps, particularly SSLs and traditional serrated adenomas, have an increased risk of synchronous and metachronous advanced neoplasia. Surveillance guidelines vary among countries, but SSLs and proximal hyperplastic polyps require special attention in assignment of surveillance interval-especially in light of concerns regarding incomplete detection and resection.

The efficacy of a leukotriene receptor antagonist in the treatment of human rectal aberrant crypt foci: a nonrandomized, open-label, controlled trial.

BACKGROUND: Leukotriene receptor antagonists (LTRAs) are broadly used for the management of allergic asthma and have recently been indicated to inhibit carcinogenesis and cancer cell growth. In colorectal cancer (CRC) chemoprevention studies, the occurrence of adenoma or CRC itself is generally set as the trial endpoint. Although the occurrence rate of CRC is the most confident endpoint, it is inappropriate for chemoprevention studies because CRC incidence rate is low in the general population and needed for long-term monitoring. Aberrant crypt foci (ACF), defined as lesions containing crypts that are larger in diameter and darker in methylene blue staining than normal crypts, are regarded to be a fine surrogate biomarker of CRC. Therefore, this prospective study was designed to explore the chemopreventive effect of LTRA on colonic ACF formation and the safety of the medicine in patients scheduled for a poly resection as a pilot trial leading the CRC chemoprevention trial. METHODS: This study is a nonrandomized, open-label, controlled trial in patients with colorectal ACF and polyps scheduled for a polypectomy. Participants meet the inclusion criteria will be recruited, and the number of ACF in the rectum will be counted at the baseline colonoscopic examination. Next, the participants will be assigned to the LTRA or no treatment group. Participants in the LTRA group will continue 10 mg of oral montelukast for 8 weeks, and those in the no treatment group will be observed without the administration of any additional drugs. At the end of the 8-week LTRA intervention period, a polypectomy will be conducted to evaluate the changes in the number of ACF, and cell proliferation in the normal colorectal epithelium will be analyzed. DISCUSSION: This will be the first study to investigate the effect of LTRAs on colorectal ACF formation in humans. TRIAL REGISTRATION: This trial has been registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry as UMIN000029926 . Registered 10 November 2017.

Endoscopic imaging techniques for detecting early colorectal cancer.

PURPOSE OF REVIEW: The detection of early colorectal cancer has improved notably since the introduction of bowel cancer screening programmes. This has created new challenges from endoscopic, histological and therapeutic perspectives. Here, we outline the limitations of current clinical practice and ways of implementing optical diagnosis to overcome these limitations. RECENT FINDINGS: Virtual chromoendoscopy without magnification for predicting or ruling out deep submucosal invasion is useful in real clinical practice for most lesions. However, magnifying virtual chromoendoscopy is needed to make an accurate diagnosis in nonulcerated narrow-band imaging international colorectal endoscopic (NICE) type 3 lesions or NICE type 2 lesions with depressed areas or of nodular mixed type. Finally, dye-based magnifying chromoendoscopy is needed in Japanese NBI Expert Team 2B lesions assessed with magnifying virtual chromoendoscopy. SUMMARY: A four-step strategy is proposed, combining white-light assessment, virtual chromoendoscopy without magnification, virtual chromoendoscopy with magnification and dye-based chromoendoscopy with magnification.

The dark side of the colon: current issues surrounding the significance, prevalence, detection, diagnosis and management of serrated polyps.

PURPOSE OF REVIEW: Hyperplastic polyps, once considered to have no malignant potential, are now recognized to be part of a larger group of polyps known as serrated polyps. Serrated polyps can progress to CRC through an epigenetic pathway known as CpG Island Methylator Phenotype (CIMP), characterized by hypermethylation of specific DNA regions such as the promoter regions of the DNA mismatch repair genes like MLH1. The CIMP pathway is tightly linked with mutations of the oncogene BRAF. There are three subtypes of serrated polyps - hyperplastic polyps, sessile serrated polyps (SSPs) and traditional serrated adenomas (TSAs). TSAs harbor cytologic dysplasia whereas hyperplastic polyps and SSPs are nondysplastic lesions. Currently, only SSPs and TSAs are believed to progress to CRC whereas hyperplastic polyps are thought to be benign with no malignant potential. This article will review the current evidence while highlighting some of the issues regarding serrated polyps. RECENT FINDINGS: One challenge has been pathologically distinguishing hyperplastic polyps from SSPs, which is an important distinction, given the potential for progression of SSPs to CRC. Other challenges regarding serrated polyps include adequate detection and resection. Surveillance guideline recommendations for some serrated polyps have been changed in current guidelines to reflect the malignant potential, recommending closer surveillance intervals than the 10-year follow-up that has been traditionally provided for hyperplastic polyps. SUMMARY: Given the difficulties in diagnosing as well as resecting, it is important for endoscopists to know how to detect, resect and manage follow-up in patients with serrated polyps.

Clinical usefulness of magnifying colonoscopy for the diagnosis of ulcerative colitis-associated neoplasia.

BACKGROUND AND AIM: The aim of this investigation was to evaluate the efficacy of Japanese magnifying colonoscopic classifications for ulcerative colitis-associated neoplasia (UCAN). METHODS: We reviewed the colonoscopy records from 2011 to 2018 at our institutions and identified cases of endoscopically or surgically resected UCAN observed by magnifying narrow-band imaging (NBI) endoscopy and magnifying chromoendoscopy. Association between magnifying endoscopic classification and histopathological findings was investigated retrospectively. Japan NBI expert team (JNET) classification and pit pattern classification were applied. RESULTS: There were 17 patients who had a diagnosis of UCAN. Tumors of types 2A, 2B and 3 by JNET classification correlated with the histopathological findings of low-grade dysplasia (LGD)/high-grade dysplasia (HGD), HGD, and massively submucosal invasive (mSM) carcinoma, respectively. Tumors of types III/IV, VI low irregularity, and VI high irregularity/VN by pit pattern classification were correlated with the histopathological findings of LGD/HGD, HGD, and mSM carcinoma, respectively. CONCLUSIONS: Japan NBI expert team classification and pit pattern classification may be predictive of the histological diagnosis and invasion depth of UCAN. This needs to be investigated prospectively in a large cohort or in a randomized clinical trial.

Management of complex polyps of the colon and rectum.

PUPRPOSE: Benign polyps that are technically challenging and unsafe to remove via polypectomy are known as complex polyps. Concerns regarding safety and completeness of resection dictate they undergo advanced endoscopic techniques, such as endoscopic mucosal resection or surgery. We provide a comprehensive overview of complex polyps and current treatment options. METHODS: A review of the English literature was conducted to identifyarticles describing the management of complex polyps of the colon and rectum. RESULTS: Endoscopic mucosal resection is the standard of care for the majority of complex polyps. Only polyps that fail endoscopic mucosal resection or are highly suspicious of invasive cancer but which cannot be removed endoscopically warrant surgery. CONCLUSION: Several factors influence the treatment of a complex polyp; therefore, there cannot be a "one-size-fitsall" approach. Treatment should be tailored to the lesion's characteristics, the risk of adverse events, and the resources available to the treating physician.

Effects of health-related quality of life on health service utilisation in patients with colorectal neoplasms.

This study was to assess the impact of HRQOL on health service utilisation using four different count data models. The HRQOL was measured using the Short-Form Six-Dimension instrument and the functional assessment of cancer therapy-colorectal whereas health service utilisation was measured by the number of monthly clinical consultations and the number of monthly hospitalisation. Different count data models (Poisson's regression, negative binomial regression, zero-inflated Poisson's regression and zero-inflated negative binomial regression) were used to assess the association between HRQOL and health service utilisation. A performance comparison was made between the models. Goodness-of-fit statistics (the Pearson's chi-squared test statistic, the Akaike and Bayesian information criteria) were used to determine the best-fitting model. The negative binomial model performed the best in assessing the association between HRQOL measures and health service utilisation in patients with colorectal neoplasm and thus recommended. Physical well-being of patients was negatively and significantly associated with the monthly rate of health service utilisation after controlling for patient demographics. Both physical and function well-beings of patients were negatively and significantly associated with the number of monthly hospitalisations. If the data for the condition-specific FACT-C are not available, SF-6D showed a very strong negative relationship with health service utilisation. Such models can be used to guide the allocation of clinical resources and funding for the care of colorectal cancer patients.

Screening for Colorectal Cancer With Fecal Immunochemical Testing With and Without Postpolypectomy Surveillance Colonoscopy: A Cost-Effectiveness Analysis.

BACKGROUND: Population-based screening to prevent colorectal cancer (CRC) death is effective, but the effectiveness of postpolypectomy surveillance is unclear. OBJECTIVE: To evaluate the additional benefit in terms of cost-effectiveness of colonoscopy surveillance in a screening setting. DESIGN: Microsimulation using the ASCCA (Adenoma and Serrated pathway to Colorectal CAncer) model. DATA SOURCES: Dutch CRC screening program and published literature. TARGET POPULATION: Asymptomatic persons aged 55 to 75 years without a prior CRC diagnosis. TIME HORIZON: Lifetime. PERSPECTIVE: Health care payer. INTERVENTION: Fecal immunochemical test (FIT) screening with colonoscopy surveillance performed according to the Dutch guideline was simulated. The comparator was no screening or surveillance. FIT screening without colonoscopy surveillance and the effect of extending surveillance intervals were also evaluated. OUTCOME MEASURES: CRC burden, colonoscopy demand, life-years, and costs. RESULTS OF BASE-CASE ANALYSIS: FIT screening without surveillance reduced CRC mortality by 50.4% compared with no screening or surveillance. Adding surveillance to FIT screening reduced mortality by an additional 1.7% to 52.1% but increased lifetime colonoscopy demand by 62% (from 335 to 543 colonoscopies per 1000 persons) at an additional cost of €68 000, for an increase of 0.9 life-year. Extending the surveillance intervals to 5 years reduced CRC mortality by 51.8% and increased colonoscopy demand by 42.7% compared with FIT screening without surveillance. In an incremental analysis, incremental cost-effectiveness ratios (ICERs) for screening plus surveillance exceeded the Dutch willingness-to-pay threshold of €36 602 per life-year gained. RESULTS OF SENSITIVITY ANALYSIS: When using a parameter set representing low colorectal lesion prevalence or when colonoscopy costs were halved or colorectal lesion incidence was doubled, screening plus surveillance became cost-effective compared with screening without surveillance. LIMITATION: Limited data on FIT performance and background CRC risk in the surveillance population. CONCLUSION: Adding surveillance to FIT screening is not cost-effective based on the Dutch ICER threshold and substantially increases colonoscopy demand. Extending surveillance intervals to 5 years would decrease colonoscopy demand without substantial loss of effectiveness. PRIMARY FUNDING SOURCE: Alpe d'HuZes, Dutch Cancer Society, and Stand Up To Cancer.

Obesity and Colorectal Cancer.

There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.

British Society of Gastroenterology/Association of Coloproctologists of Great Britain and Ireland guidelines for the management of large non-pedunculated colorectal polyps.

These guidelines provide an evidence-based framework for the management of patients with large non-pedunculated colorectal polyps (LNPCPs), in addition to identifying key performance indicators (KPIs) that permit the audit of quality outcomes. These are areas not previously covered by British Society of Gastroenterology (BSG) Guidelines.A National Institute of Health and Care Excellence (NICE) compliant BSG guideline development process was used throughout and the Appraisal of Guidelines for Research and Evaluation (AGREE II) tool was used to structure the guideline development process. A systematic review of literature was conducted for English language articles up to May 2014 concerning the assessment and management of LNPCPs. Quality of evaluated studies was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) Methodology Checklist System. Proposed recommendation statements were evaluated by each member of the Guideline Development Group (GDG) on a scale from 1 (strongly agree) to 5 (strongly disagree) with >80% agreement required for consensus to be reached. Where consensus was not reached a modified Delphi process was used to re-evaluate and modify proposed statements until consensus was reached or the statement discarded. A round table meeting was subsequently held to finalise recommendations and to evaluate the strength of evidence discussed. The GRADE tool was used to assess the strength of evidence and strength of recommendation for finalised statements.KPIs, a training framework and potential research questions for the management of LNPCPs were also developed. It is hoped that these guidelines will improve the assessment and management of LNPCPs.

Clinical indications for computed tomographic colonography: European Society of Gastrointestinal Endoscopy (ESGE) and European Society of Gastrointestinal and Abdominal Radiology (ESGAR) Guideline.

This is an official guideline of the European Society of Gastrointestinal Endoscopy (ESGE) and the European Society of Gastrointestinal and Abdominal Radiology (ESGAR). It addresses the clinical indications for the use of computed tomographic colonography (CTC). A targeted literature search was performed to evaluate the evidence supporting the use of CTC. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was adopted to define the strength of recommendations and the quality of evidence. Main recommendations 1 ESGE/ESGAR recommend computed tomographic colonography (CTC) as the radiological examination of choice for the diagnosis of colorectal neoplasia. ESGE/ESGAR do not recommend barium enema in this setting (strong recommendation, high quality evidence). 2 ESGE/ESGAR recommend CTC, preferably the same or next day, if colonoscopy is incomplete. Delay of CTC should be considered following endoscopic resection. In the case of obstructing colorectal cancer, preoperative contrast-enhanced CTC may also allow location or staging of malignant lesions (strong recommendation, moderate quality evidence). 3 When endoscopy is contraindicated or not possible, ESGE/ESGAR recommend CTC as an acceptable and equally sensitive alternative for patients with symptoms suggestive of colorectal cancer (strong recommendation, high quality evidence). 4 ESGE/ESGAR recommend referral for endoscopic polypectomy in patients with at least one polyp  ≥  6  mm in diameter detected at CTC. CTC surveillance may be clinically considered if patients do not undergo polypectomy (strong recommendation, moderate quality evidence). 5 ESGE/ESGAR do not recommend CTC as a primary test for population screening or in individuals with a positive first-degree family history of colorectal cancer (CRC). However, it may be proposed as a CRC screening test on an individual basis providing the screenee is adequately informed about test characteristics, benefits, and risks (weak recommendation, moderate quality evidence).

[Precancerous colorectal tumors]. / Präkanzerosen im Kolon.

Preneoplastic lesions of colorectal carcinoma can be divided in non-serrated and serrated lesions. Non-serrated lesions include conventional adenomas (tubular, tubulovillous and villous) and dysplasias associated with inflammatory bowel disease like flat intraepithelial neoplasia, dysplasia-associated lesions or masses (DALM) and adenoma-like masses (ALM). Conventional adenomas are mostly sporadic, but also found in hereditary adenomatous-polyposis syndromes. Hamartous polyposis syndromes are also associated with colorectal cancer. Serrated lesions include hyperplastic polyps, sessile serrated adenomas and traditional serrated adenomas. Based on these precancerous colorectal lesions different molecular subtypes were identified. Histological subtype, size and grade of dysplasia of polyps are essential for risk assessment of colorectal cancer.

Hyoscine N-butylbromide does not improve polyp detection during colonoscopy: a double-blind, randomized, placebo-controlled, clinical trial.

BACKGROUND: Colonoscopy is used for the detection of neoplastic polyps, although a significant miss rate has been reported. Limited data suggest that the administration of the antispasmodic hyoscine N-butylbromide during colonoscopy improves polyp detection. OBJECTIVE: To investigate whether the use of 20 mg hyoscine N-butylbromide intravenously during colonoscopy improves polyp detection or removal. DESIGN: A prospective, double-blind, placebo-controlled, randomized, clinical trial. SETTING: Nonacademic teaching hospital. PATIENTS: This study involved 674 patients who were routinely referred and accepted for either diagnostic or screening colonoscopy. INTERVENTION: Intravenous injection of either 1 mL hyoscine N-butylbromide (n = 340) or 0.9% NaCl solution (n = 334) when withdrawal was started. MAIN OUTCOME MEASUREMENTS: Polyp detection rate (PDR), adenoma detection rate (ADR), and the advanced lesion detection rate (ALDR), 5% trimmed mean number of polyps, mean withdrawal time. RESULTS: The cecal intubation rate was 96%. The PDR, ADR, and ALDR were 56% versus 60%, 30% versus 31%, and 14% versus 14% in the hyoscine N-butylbromide and placebo groups, respectively (all P values > .25). The means of the total number of detected, removed, and harvested polyps per patient were 1.13 versus 1.21, 1.03 versus 1.06, and 0.89 versus 0.89 in the hyoscine N-butylbromide and placebo groups, respectively (all P values > .37). Mean withdrawal time was 561 versus 584 seconds in the hyoscine N-butylbromide and placebo groups, respectively (P = .34). Multivariate analysis demonstrated no effect of hyoscine N-butylbromide on the investigated parameters. LIMITATIONS: Only experienced colonoscopists participated in the study. CONCLUSION: We found no evidence to support the use of hyoscine N-butylbromide during withdrawal of the colonoscope to improve polyp detection or removal. ( CLINICAL TRIAL REGISTRATION NUMBER: ISRCTN25405865.).

European guidelines for quality assurance in colorectal cancer screening and diagnosis. First Edition--Management of lesions detected in colorectal cancer screening.

Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on management of lesions detected in colorectal cancer screening includes 32 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of the screening process, including multi-disciplinary diagnosis and management of the disease.

Incidental focal colonic lesions found on (18)Fluorodeoxyglucose positron emission tomography/computed tomography scan: further support for a national guideline on definitive management.

AIM: (18)Fluorodeoxyglucose ((18)FDG) positron emission tomography/computed tomography (PET/CT) is an established part of staging in a wide variety of malignancies. Incidental abnormal uptake of (18)FDG of unknown significance is frequently encountered. Therefore, we investigated patients with abnormal colonic uptake of (18)FDG, determined by PET/CT images, using colonoscopy. METHOD: The radiology reports of all patients referred to a tertiary referral centre for a PET/CT scan were reviewed retrospectively. Patients with abnormal colonic uptake of (18)FDG were identified and the PET/CT findings were correlated with colonoscopic findings. RESULTS: Of 555 consecutive patients identified over a 26-month period, 53 had abnormal colonic uptake of (18)FDG, as determined by PET/CT images. Twenty-nine were not investigated following discussion in a specialist multidisciplinary (MDT) meeting, according to local protocol. Twenty out of 24 patients investigated by endoscopy had a colonic lesion correlating to the site identified on the PET/CT image: 16 patients had tubulovillous adenomas (nine of which were > 10 mm), two had invasive adenocarcinomas, two had diverticular disease and one had collagenous colitis; no colonic lesion was detected in three. These findings were incidental and not related to the primary diagnosis for which the scan was being performed. Accordingly, a positive predictive value of 83% is associated with the finding of abnormal uptake of (18)FDG on PET/CT images. CONCLUSION: Incidental abnormal colonic uptake of (18)FDG, determined by a PET/CT scan requires definitive colonic investigation in patients suitable for further treatment because significant colonic pathology is frequently identified. The benefit of this approach should be discussed in specialist MDT meetings and tailored to each patient; however, national guidelines for management are required.

Role of the serrated pathway in colorectal cancer pathogenesis.

The "serrated neoplastic pathway" describes the progression of serrated polyps, including sessile serrated adenomas and traditional serrated adenomas, to colorectal cancer. The recognition of this pathway during the last 15 years has led to a paradigm shift in our understanding of the molecular basis of colorectal cancer and significant changes in clinical practice. These findings are particularly relevant to prevention of interval cancers through colonoscopy surveillance programs-an important issue for colonoscopists. In the past, all serrated polyps were classified simply as hyperplastic polyps and were considered to have no malignant potential. Reappraisal of this view was largely driven by increasing recognition of the malignant potential of hyperplastic polyposis.

Polyp recurrence after endoscopic mucosal resection of sessile and flat colonic adenomas.

BACKGROUND: Endoscopic mucosal resection (EMR) is used for treatment of sessile and flat colonic adenomas. There is limited data comparing polyp recurrence between piecemeal and en-bloc resections. AIM: The purpose of this study was to evaluate the incidence density and predictive factors for polyp recurrence after piecemeal and en-bloc resections. METHODS: Patients undergoing EMR of flat or sessile adenomas≥10 mm were included. Incidence density (ID) and incidence rate ratio (IRR) of polyp recurrence were calculated. Predictive factors for recurrence were assessed by multivariate analysis using logistic regression. RESULTS: A total of 105 patients (males 54, mean age 68) with 121 polyps were included. Sixty-seven polyps (mean size±SD, 23.3±9.2 mm) were resected piecemeal and 54 polyps (mean size 14.7±5.1 mm) were resected en-bloc. There were 12 recurrences in the piecemeal group and two in the en-bloc group. The ID of polyp recurrence in the piecemeal group was 13.1 (95% CI 7.43-23.03) and in the en-bloc group was 2.7 (95% CI 0.67-10.78) per 100 person-years of follow-up. Piecemeal resections were 5.5 (95% CI 1.1-30.48, P=0.045) times and flat polyps were 6.6 (95% CI 1.22-35.53, P=0.028) times more likely to result in recurrence compared to en-bloc resections and sessile polyps, respectively. In the piecemeal group, additional use of argon plasma coagulation (APC) did not affect the recurrence (OR 0.46, P=0.29). CONCLUSIONS: Piecemeal resections and flat polyps are associated with higher recurrence following EMR. Additional use of APC did not affect the recurrence rates after piecemeal resection.