British Society of Gastroenterology position statement on serrated polyps in the colon and rectum

Calibrating Natural History of Cancer Models in the Presence of Data Incompatibility: Problems and Solutions

The calibration of cancer natural history models is often challenged by a lack of representative calibration targets, forcing modellers to rely on potentially incompatible datasets. Using a microsimulation colorectal cancer model as an example, the purposes of this paper are to (1) highlight the reasons for uncertainty in calibration targets, (2) illustrate practical and generalisable approaches for dealing with incompatibility in calibration targets, and (3) discuss the importance of future research in the area of incorporating uncertainty in calibration. The low quality of data and differences in populations, outcome definitions, and healthcare systems may result in incompatibility between the model and the data. Acknowledging reasons for data incompatibility allows assessment of the risk of incompatibility before calibrating the model. Only a few approaches are available to address data incompatibility, for instance addressing biases in calibration targets and their adjustment, relaxing the goodness-of-fit metric, and validation of the calibration targets to the data not used in the calibration. However, these approaches lack explicit comparison and validation, and so more research is needed to describe the nature and causes of indirect uncertainty (i.e. uncertainty that cannot be expressed in absolute quantitative forms) and identify methods for managing this uncertainty in healthcare modelling.

Colorectal carcinoma occurring via the adenoma-carcinoma pathway in patients with serrated polyposis syndrome

BACKGROUND

Although serrated polyposis syndrome (SPS) is associated with an increased colorectal cancer (CRC) risk, the carcinogenic mechanisms remain unknown. We investigated clinicopathological characteristics and genetic abnormalities in colorectal polyps and CRC to elucidate carcinogenic mechanisms in SPS.

METHODS

We retrospectively analyzed clinicopathological features of colorectal polyps in 44 SPS patients, and examined mutations of genes including APC, RAS, BRAF, and TP53, and microsatellite instability (MSI) in CRC tissues.

RESULTS

Of the 44 patients, 25 (56%) fulfilled WHO criterion 1, 11 (25%) fulfilled criterion 2, and 8 (18%) fulfilled both. A total of 956 polyps were observed; 642 (67%) hyperplastic polyps (HP), 204 (21%) sessile serrated lesions (SSL), 10 (1%) traditional serrated adenoma (TSA), and 100 (11%) adenomas. The median numbers of polyps (/patient) were 10.5 (IQR 2.75-23) HPs, 4.0 (2.0-6.0) SSLs, 0 (0-0) TSA, and 1 (0-3.3) adenoma. SSL and HP located preferentially in the proximal and distal colon, respectively. Twenty-two CRCs were found in 18 patients. Based on the histological coexistence of SSL/TSA, BRAF mutation and MSI, 5 CRCs (26%) were classified as serrated-neoplasia pathway. Conversely, based on the coexistence of adenoma, APC/RAS and TP53 mutations, 11 CRCs (58%) were classified as adenoma-carcinoma pathway. The remaining three were unclassifiable. Most CRCs through adenoma-carcinoma pathway were located in the left-side colorectum and patients bearing those met criterion 2, characterized by many HP and advanced adenomas. Adenoma was a significant risk factor for CRC.

CONCLUSIONS

Our results suggest that more than half of the CRCs, particularly those in the left-side colorectum, developed through the adenoma-carcinoma pathway in SPS patients. Adenoma was a risk factor for CRCs, suggesting its importance in colorectal carcinogenesis.

Omega-3 polyunsaturated fatty acids: moving towards precision use for prevention and treatment of colorectal cancer

Data from experimental studies have demonstrated that marine omega-3 polyunsaturated fatty acids (O3FAs) have anti-inflammatory and anticancer properties. In the last decade, large-scale randomised controlled trials of pharmacological delivery of O3FAs and prospective cohort studies of dietary O3FA intake have continued to investigate the relationship between O3FA intake and colorectal cancer (CRC) risk and mortality. Clinical data suggest that O3FAs have differential anti-CRC activity depending on several host factors (including pretreatment blood O3FA level, ethnicity and systemic inflammatory response) and tumour characteristics (including location in the colorectum, histological phenotype (eg, conventional adenoma or serrated polyp) and molecular features (eg, microsatellite instability, cyclooxygenase expression)). Recent data also highlight the need for further investigation of the effect of O3FAs on the gut microbiota as a possible anti-CRC mechanism, when used either alone or in combination with other anti-CRC therapies. Overall, these data point towards a precision approach to using O3FAs for optimal prevention and treatment of CRC based on mechanistic understanding of host, tumour and gut microbiota factors that predict anticancer activity of O3FAs.

Clinicopathological Correlates of Dysplastic Sessile Serrated Lesion: A Prospective Cohort Study With a High Detection Rate

Background and Aims

Sessile serrated lesions (SSLs) develop colorectal cancer (CRC), through a critical intermediary stage of SSL with dysplasia (SSLd). In this prospective observational study, we aimed to assess clinicopathological correlates of SSLd in the setting of a high lesion-detection rate.

Methods

Patients diagnosed with SSL and SSLd from February 2018 until January 2020 were prospectively recruited, and SSLd specimens were re-evaluated by 2 expert pathologists in a blinded manner. Associations were analyzed using multivariate logistic regression models.

Results

A total of 6425 patients underwent 7423 colonoscopies, and 2671 SSLs were resected from 1047 patients. The overall SSL detection rate per colonoscopy was 15.9%. The median age of patients with SSL was 54 years (interquartile range, 39-66), and 43.3% were male. After pathologist review, 24 SSLds were confirmed in 20 patients. The median size of SSLd was 8 mm (interquartile range, 5.75-15.25), and 13 of 24 SSLds were <10 mm in size. After multivariate analysis, older age (odds ratio = 1.07, 95% confidence interval = 1.03-1.1) and higher number of synchronous SSLs (odds ratio = 1.12, 95% confidence interval = 1.02-1.23) were associated with the presence of dysplasia. Patient sex and number and size of synchronous adenomas were not associated with the presence of SSLd. Seven of 20 patients with SSLd had synchronous or metachronous SSLd. Six of 20 patients with SSLd met the diagnostic criteria for serrated polyposis syndrome.

Conclusion

The overall SSL detection rate was 15.9%, and 0.9% of SSLs were dysplastic. Older age and higher number of synchronous SSL were risk factors for the presence of dysplasia in SSLs. Thirty percent of patients with SSLd had serrated polyposis syndrome, and 35% had multiple SSLd.

ERBB2 Mutations as Potential Predictors for Recurrence in Colorectal Serrated Polyps by Targeted Next-Generation Sequencing

Background

Follow-up guidelines for serrated polyps (SPs) are mainly based on factors such as histology and size with limited evidence. The underlying genomic mechanism of SPs in relation to recurrence risks is utterly unknown.

Methods

We applied targeted next-generation sequencing (NGS) approach on two groups of SPs [polyp-relapsed SPs (PRSPs) vs. polyp-free SPs (PFSPs)] based on the surveillance outcomes to compare differences of DNA variants in 71 colorectal cancer-associated genes. A multicenter validation cohort was established longitudinally from 2016 to 2019 to confirm the relevant results.

Results

Among the 96 NGS samples, at least one mutant after filtration was detected in 90 samples (94%). Molecular profiling presented BRAF, KRAS, and APC as top 3 mutated genes. FBXW7, MSH2, and ERBB2 might be recurrence-relevant, while DMD, BRCA1, and BRCA2 might be negatively correlated with recurrence. Notably, ERBB2 mutants (R678Q and V842I) (n = 5) had higher risks of polyp recurrence than the wild types (n = 85), with a median polyp-free interval of 15 months compared to 26 months [P &lt; 0.001; hazard ratio (HR) = 4.9; 95% confidence interval (CI) = 1.9–12.8]. Furthermore, a multicenter cohort composed by 321 SPs verified that ERBB2-mutated SPs had increased risks of polyp recurrence (P &lt; 0.001; HR = 3.7; 95% CI = 2.3–6.0) and advanced neoplastic lesion (ANL) recurrence (P &lt; 0.001; HR = 10.0; 95% CI = 2.7–36.9) compared with wild-type SPs, respectively.

Conclusions

Our results are emphasizing that SP individuals with ERBB2 mutants are at higher risks of subsequent colorectal neoplasms. ERBB2 mutants might work as facilitated markers for prediction of high-risk SPs and might implicate a potential mechanism in the serrated pathway to colorectal carcinoma (CRC).

Improving sessile serrated adenoma detection rates with high definition colonoscopy: A retrospective study

BACKGROUND

Sessile serrated adenomas (SSAs) are important premalignant lesions that are difficult to detect during colonoscopy due to poor definition, concealment by mucous caps, and flat appearance. High definition (HD) colonoscopy may uniquely aid in the detection of these inconspicuous lesions compared to standard definition (SD) colonoscopes. In the absence of existing clinical guidelines to obligate the use of HD colonoscopy for colorectal cancer screening in average-risk patients, demonstrating the benefit of HD colonoscopy on SSA detection rate (SSADR) may help strengthen the evidence to recommend its use in all settings.

AIM

To evaluate the benefit of HD colonoscopy compared to SD colonoscopy on SSADR in average-risk patients undergoing screening colonoscopy.

METHODS

Data from screening colonoscopies for patients aged 50-76 years two years before and two years after the transition from SD colonoscopy to HD colonoscopy at our large, academic teaching center were collected. Patients with symptoms of colorectal disease, positive occult blood test, history of colon polyps, cancer, polyposis syndrome, inflammatory bowel disease or family history of colon cancer or polyps were excluded. Patients whose endoscopists did not perform colonoscopies both before and after scope definition change were also excluded. Differences in individual endoscopist SSADR, average SSADR, and overall SSADR with SD colonoscopy vs HD colonoscopy were also evaluated for significance.

RESULTS

A total of 3657 colonoscopies met eligibility criteria with 2012 colonoscopies from the SD colonoscopy period and 1645 colonoscopies from the HD colonoscopy period from a pool of 11 endoscopists. Statistically significant improvements of 2.30% in mean SSADR and 2.53% in overall SSADR were noted with HD colonoscopy (P = 0.00028 and P = 0.00849, respectively). On the individual level, three endoscopists experienced statistically significant benefit with HD colonoscopy (+5.74%, P = 0.0056; +4.50%, P = 0.0278; +4.84%, P = 0.03486).

CONCLUSION

Our study suggests that HD colonoscopy statistically significantly improves sessile serrated adenoma detection rate in the screening of average risk patients during screening colonoscopy. By improving the detection and removal of these lesions, adoption of HD colonoscopy may reduce the significant premalignant burden of sessile serrated adenomas.

Serrated polyposis syndrome; epidemiology and management

Serrated colorectal polyps, long considered innocent, are currently recognized as the precursors to one-third of all colorectal cancers (CRC). Serrated polyposis syndrome (SPS), characterized by accumulation of multiple and/or large serrated polyps, symbolizes the highest expression of serrated pathway of carcinogenesis, leading to a high risk of CRC when it is not detected or treated on time. Although previously considered uncommon, SPS is now acknowledged as the most prevalent colorectal polyposis. This syndrome has attracted increasing interest over the past decade and has become a hot topic in the field of gastrointestinal oncology. Besides a small proportion of cases caused by germline mutations in RNF43, no clear genetic cause has been identified. Both epigenetic and environmental factors, especially smoking, have been related to this syndrome, but the etiology of SPS remains uncertain and diagnosis is based on endoscopic criteria. Recent studies on SPS have focused on identifying the underlying risk-factors for CRC, defining the best endoscopic techniques for surveillance and establishing optimal preventive strategies aimed at reducing CRC-incidence without exposing patients to unnecessary procedures. The purpose of this chapter is to review, from a practical perspective, current knowledge and future directions in the diagnosis and management of serrated polyposis syndrome.

Total polyp number may be more important than size and histology of polyps for prediction of metachronous high-risk colorectal neoplasms

BACKGROUND

To evaluate whether the risk of metachronous high-risk colorectal neoplasm (HR-CRN) differs according to the indication for surveillance colonoscopy.

METHODS

Patients who underwent polypectomy or endoscopic resection of colorectal neoplasms were enrolled and classified into three groups according to the indication for surveillance colonoscopy: advanced colorectal neoplasm (ACRN: adenoma ≥ 10 mm, adenoma with high-degree dysplasia and/or villous component), advanced serrated polyps (ASP: hyperplastic polyp or sessile serrated lesion ≥ 10 mm, traditional serrated polyp), and high-risk polyps (HRP: 3 or more adenomas or serrated polyps). The primary outcome was the development of metachronous HR-CRN, defined as ACRN, ASP, or HRP at the first follow-up colonoscopy.

RESULTS

In total, 367 patients were enrolled (ACRN group: N = 264; ASP group: N = 33; HRP group: N = 70). Among the 160 patients who underwent follow-up colonoscopy, 28 (18%) had HR-CRN. In univariable analysis, indication for surveillance colonoscopy was not found to be associated with the development of metachronous HR-CRN. Instead, the total polyp number at index colonoscopy showed a positive association with the risk of metachronous HR-CRN in trend analysis (p = 0.001). In multivariable analysis, the presence of 5 or more polyps at index colonoscopy was found to be associated with the risk of metachronous HR-CRN (OR, 2.575, p = 0.049) after adjusting for risk factors, such as obesity, diabetes, and smoking.

CONCLUSIONS

The risk of metachronous HR-CRN did not differ according to the main indications for surveillance colonoscopy. The presence of 5 or more polyps at index colonoscopy was the only risk factor for metachronous HR-CRN.

Risk of Colorectal Cancer in Serrated Polyposis Syndrome: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Serrated polyposis syndrome (SPS) is characterized by development of numerous serrated lesions throughout the colorectum and increased risk of colorectal cancer (CRC). However, SPS has been an underrecognized CRC predisposition syndrome, and the true risk of CRC in SPS, both overall and in surveillance, is not known. The aim of this systematic review and meta-analysis is to describe the risk of CRC in patients with SPS.

METHODS

Electronic databases were searched on March 25, 2021, for studies describing CRC risk in SPS. Random-effects meta-analysis was performed to assess pooled risk of CRC among SPS patients. Primary outcomes were risk of CRC at time of SPS diagnosis and during surveillance following diagnosis of SPS. Secondary outcomes included risk of CRC prior to diagnosis of SPS and effect of World Health Organization subtype on CRC risk.

RESULTS

Thirty-six studies including 2788 patients with SPS were included in the analysis. Overall risk of CRC in SPS was 19.9% (95% confidence interval [CI], 15.3%-24.5%). CRC risk at the time of diagnosis was 14.7% (95% CI, 11.4%-18.8%), while risk during surveillance was 2.8% (95% CI, 1.8%-4.4%), or 7 cases per 1000 person-years. SPS patients also had a high incidence of history of CRC prior to SPS diagnosis (7.0%; 95% CI, 4.6%-11.7). Subgroup analysis did not reveal any significant differences based on World Health Organization subtype.

CONCLUSIONS

Our meta-analysis demonstrated that patients with SPS have an elevated risk of CRC, which is highest at the time of diagnosis and suggests the importance of early SPS recognition and screening to modify CRC risk. The persistently elevated CRC risk during surveillance supports current guidelines recommending heightened surveillance protocols.

Adenoma and serrated lesion detection with distal attachment in screening colonoscopy: a randomized controlled trial

BACKGROUND

Adenoma detection rate (ADR) is the single most important measure of quality in colonoscopy, but little is known about the detection rate of serrated lesions (SLDR). To improve ADR, Endocuff Vision (EV) can be used. Studies have shown differing results as to the effect on ADR; an effect on SLDR has not been shown. To investigate the effect of Endocuff Vision on ADR in a screening population, this randomized controlled open label trial with concealed allocation was performed. Randomization to trial group was carried out by the endoscopist using prepared numbered envelopes.

METHODS

Patients referred as part of the national bowel screening program at Regional Hospital Herning, Denmark were recruited and allocated to one of two groups: Endocuff Vision colonoscopy (EVC) and standard colonoscopy (SC). Outcomes were ADR, mean number, site, and size of lesions per procedure. SLDR as outcome was added after inclusion had begun.

RESULTS

A total of 1178 participants were included, with 1166 (EVC 583 and SC 583) available for analysis. There was no clinical relevant difference in ADR (59.2% [CI 55.1; 63.1] v 60.5% [CI 56.5; 64.4]) or SLDR (13.0% [CI 10.5; 16.0] v 10.3% [CI 8.0; 13.0]) between groups. More serrated lesions were found per procedure (MSP) (0.2 v 0.1, IRR 57% [CI 17; 109]. Removal rate of EV was similar in the two study groups.

CONCLUSION

We found no significant effects of the use of Endocuff Vision on ADR, when compared to standard colonoscopy, but more serrated lesions were detected in the Endocuff group.

TRIAL REGISTRATION

Clinical Trials NCT04651062.

Current Approaches in Managing Colonic Serrated Polyps and Serrated Polyposis

For decades, conventional adenomas were the only known precursor lesions of colorectal cancer (CRC). Accordingly, education and research regarding CRC prevention were mainly focused on adenomas. The groundbreaking discovery that serrated polyps (SPs) also have the potential to develop into CRCs, and seem to account for a considerable proportion of sporadic CRCs, has led to a paradigm shift in the prevention, diagnosis, and treatment of CRC. Studies in recent years have led to our current understanding of SPs and associated CRC, but a lot of work is still to be done to further improve knowledge about this serrated neoplasia pathway and the clinical management of SPs and serrated polyposis syndrome (SPS). In this review, we reflect on the current understanding of SPs with respect to terminology, detection, resection, and surveillance and reflect on the management of SPS.

A Metabolomics-Based Screening Proposal for Colorectal Cancer

Colorectal cancer (CRC) is a high incidence disease, characterized by high morbidity and mortality rates. Early diagnosis remains challenging because fecal occult blood screening tests have performed sub-optimally, especially due to hemorrhoidal, inflammatory, and vascular diseases, while colonoscopy is invasive and requires a medical setting to be performed. The objective of the present study was to determine if serum metabolomic profiles could be used to develop a novel screening approach for colorectal cancer. Furthermore, the study evaluated the metabolic alterations associated with the disease. Untargeted serum metabolomic profiles were collected from 100 CRC subjects, 50 healthy controls, and 50 individuals with benign colorectal disease. Different machine learning models, as well as an ensemble model based on a voting scheme, were built to discern CRC patients from CTRLs. The ensemble model correctly classified all CRC and CTRL subjects (accuracy = 100%) using a random subset of the cohort as a test set. Relevant metabolites were examined in a metabolite-set enrichment analysis, revealing differences in patients and controls primarily associated with cell glucose metabolism. These results support a potential use of the metabolomic signature as a non-invasive screening tool for CRC. Moreover, metabolic pathway analysis can provide valuable information to enhance understanding of the pathophysiological mechanisms underlying cancer. Further studies with larger cohorts, including blind trials, could potentially validate the reported results.

Serrated neoplasia in the colorectum: gut microbiota and molecular pathways

Colorectal cancer (CRC) is a heterogeneous disease with different gene expression patterns. There are two major colorectal carcinogenesis pathways: conventional adenoma-carcinoma pathway and alternative serrated neoplasia pathway. Apart from the conventional pathway that is typically initiated by characteristic APC mutation and chromosomal instability, the serrated neoplasia pathway is mainly characterized by mutations of BRAF or KRAS, microsatellite instability (MSI), and CpG island methylator phenotype (CIMP). Despite the malignant potential of serrated lesions, they can be easily overlooked during endoscopy screening and even in pathological assessment due to its anatomical location, morphology, and histological features. It has been shown that environmental factors especially the gut microbial composition play a key role in CRC pathogenesis. Thus, the preferential localization of serrated lesions in specific intestine areas suggest that niche-specific microbiota composition might intertwined with host genetic perturbations during the development of serrated lesions. Although serrated lesions and conventional adenomas are biologically different, most studies have focused on conventional adenomas, while the pathophysiology and role of microorganisms in the development of serrated lesions remain elusive. In this review, we discuss on the role of gut microbiota in the serrated neoplasia pathway of colorectal carcinogenesis and its specific clinical and molecular features, and summarize the potential mechanisms involved.

Impact of comprehensive optical diagnosis training using Workgroup serrAted polypS and Polyposis classification on detection of adenoma and sessile serrated lesion

OBJECTIVES

Many interventions have been attempted to improve adenoma detection rate (ADR) and sessile serrated lesion detection rate (SDR), and one of these interventions is educational training to recognize polyp characteristics. This study aimed to investigate the change in polyp detection rates of endoscopists before and after comprehensive training through the Gangnam-Real Time Optical Diagnosis (Gangnam-READI) program.

METHODS

Fifteen gastroenterologists participated in a 1-year comprehensive training program that consisted of ex vivo and in vivo training that encompasses knowledge and skills in endoscopic characterization of colonic polyps using the Workgroup serrAted polypS and Polyposis (WASP) classification. We evaluated the impact of the training program by comparing the overall and individual ADR and SDR 6 months before and after the training.

RESULTS

Overall, 18,280 polyps (9337 adenomas and 855 sessile serrated lesion) were collected. The optical diagnosis training had no significant impact on the difference in ADR after training compared to before training (47.7% vs. 46.5%, P = 0.608). A tendency for a decrease in ADR variance was noted among the endoscopists after training (74.9 vs. 32.7, P = 0.121). The overall pre-training period SDR was 4.5% and showed a statistically significant increase to 5.6%, 8.0%, and 7.1% in the first and second half of the training period, and post-training period, respectively (P = 0.003). The optical diagnosis training did not decrease variance in SDR (8.9 vs. 8.8, P = 0.985).

CONCLUSION

Comprehensive optical diagnosis training with WASP classification has a significant impact on increasing the overall SDR of expert endoscopists.

Small sessile serrated polyps might not be at a higher risk for future advanced neoplasia than low-risk adenomas or polyp-free groups

BACKGROUND

Polypectomy surveillance colonoscopy is recommended according to the risk stratification of initially removed polyps. This study aimed to evaluate the risk of advanced neoplasia following low-risk SSPs compared with that following LRAs and polyp-free groups.

MATERIALS AND METHODS

From September 2013 to August 2017, asymptomatic Koreans aged 50-75 years who underwent surveillance colonoscopy post-baseline colonoscopy were enrolled. The 1314 participants who met the study design criteria were stratified into three groups according to the presence of LRAs or low-risk SSPs. The rate of advanced neoplasia was then compared between groups by surveillance colonoscopy.

RESULTS

A total of 1314 participants were classified according to baseline colonoscopy findings: no polyp (n = 551), LRA (n = 707), and low-risk SSP (n = 56). All participants underwent surveillance colonoscopy after an average of 28.1 ± 8.7 months. The rate of advanced neoplasia at surveillance was not different between groups: no polyp group (13/551, 2.4%), LRA group (27/707, 3.8%), and low-risk SSP group (0/56, 0%). The LRA group exhibited a significantly higher rate of low- and high-risk polyps (47.5, 13.4%) than did the no polyp (35.6, 7.4%, p < .001, p = .001), but no significant differences to the low-risk SSP group (35.7, 7.1%, p = .117, p = .253), respectively.

CONCLUSIONS

Patients with low-risk SSPs were not at a higher risk of advanced neoplasia than LRA patients, even in the polyp-free group. We suggest that surveillance colonoscopy after the removal of low-risk SSPs is not required more often than for LRAs.

A Systematic Review on HOX Genes as Potential Biomarkers in Colorectal Cancer: An Emerging Role of HOXB9

Emerging evidence shows that Homeobox (HOX) genes are important in carcinogenesis, and their dysregulation has been linked with metastatic potential and poor prognosis. This review (PROSPERO-CRD42020190953) aims to systematically investigate the role of HOX genes as biomarkers in CRC and the impact of their modulation on tumour growth and progression. The MEDLINE, EMBASE, Web of Science and Cochrane databases were searched for eligible studies exploring two research questions: (a) the clinicopathological and prognostic significance of HOX dysregulation in patients with CRC and (b) the functional role of HOX genes in CRC progression. Twenty-five studies enrolling 3003 CRC patients, showed that aberrant expression of HOX proteins was significantly related to tumour depth, nodal invasion, distant metastases, advanced stage and poor prognosis. A post-hoc meta-analysis on HOXB9 showed that its overexpression was significantly associated with the presence of distant metastases (pooled OR 4.14, 95% CI 1.64–10.43, I² = 0%, p = 0.003). Twenty-two preclinical studies showed that HOX proteins are crucially related to tumour growth and metastatic potential by affecting cell proliferation and altering the expression of epithelial-mesenchymal transition modulators. In conclusion, HOX proteins may play vital roles in CRC progression and are associated with overall survival. HOXB9 may be a critical transcription factor in CRC.

Colonoscopy may be weak link in organised colorectal cancer screening programme with faecal immunochemical test

OBJECTIVE

To evaluate the quality of colonoscopies performed after a positive faecal immunochemical test in the French colorectal cancer screening programme.

METHODS

Retrospective analysis of all colonoscopies performed between 2015 and 2019 after a positive quantitative faecal immunochemical test in the population-based colorectal cancer screening programme organised in Alsace, part of the French programme. The following indicators were evaluated: annual colonoscopy volume, caecal intubation rate, adenoma detection rate, proximal serrated lesion detection rate and proportion of patients referred directly to surgery for benign polyp management. Endoscopists who performed <30 faecal immunochemical test positive colonoscopies were non-assessable.

RESULTS

Overall, 13,455 faecal immunochemical test-positive colonoscopies performed by 116 community gastroenterologists were included, 13,067 of them by 80 assessable endoscopists. The overall caecal intubation, adenoma detection and proximal serrated lesion detection rates were 97.9%, 57.6% and 7.6%, respectively. They were <90%, <45% and <1% for 1.3%, 12.5% and 6.3% of the endoscopists, respectively. Overall, 1028 (7.9%) individuals were examined by 13 low-performing endoscopists and 328 (2.4%) individuals by 33 low-volume non-assessable endoscopists. Among 9133 individuals harbouring polyps, 155 (1.7%) had unwarranted surgery for a benign polyp. Overall, 1487 individuals (11.1%; 95% confidence interval 10.5-11.6) were not given the best possible chances, whereas 5545 individuals (41.2%; 95% confidence interval 40.4-42.0) were offered the best possible chances by 37 endoscopists.

CONCLUSIONS

At programme level, the key performance indicators evaluated largely exceeded the target standards. At individual level, at least one in nine individuals was not given the best possible chances during faecal immunochemical test-positive colonoscopies by a minority of poor-performing and/or low-volume endoscopists.

Colorectal cancer risk following polypectomy in a multicentre, retrospective, cohort study: an evaluation of the 2020 UK post-polypectomy surveillance guidelines

OBJECTIVE

Colonoscopy surveillance aims to reduce colorectal cancer (CRC) incidence after polypectomy. The 2020 UK guidelines recommend surveillance at 3 years for 'high-risk' patients with ≥2 premalignant polyps (PMPs), of which ≥1 is 'advanced' (serrated polyp (or adenoma) ≥10 mm or with (high-grade) dysplasia); ≥5 PMPs; or ≥1 non-pedunculated polyp ≥20 mm; 'low-risk' patients without these findings are instead encouraged to participate in population-based CRC screening. We examined the appropriateness of these risk classification criteria and recommendations.

DESIGN

Retrospective analysis of patients who underwent colonoscopy and polypectomy mostly between 2000 and 2010 at 17 UK hospitals, followed-up through 2017. We examined CRC incidence by baseline characteristics, risk group and number of surveillance visits using Cox regression, and compared incidence with that in the general population using standardised incidence ratios (SIRs).

RESULTS

Among 21 318 patients, 368 CRCs occurred during follow-up (median: 10.1 years). Baseline CRC risk factors included age ≥55 years, ≥2 PMPs, adenomas with tubulovillous/villous/unknown histology or high-grade dysplasia, proximal polyps and a baseline visit spanning 2-90 days. Compared with the general population, CRC incidence without surveillance was higher among those with adenomas with high-grade dysplasia (SIR 1.74, 95% CI 1.21 to 2.42) or ≥2 PMPs, of which ≥1 was advanced (1.39, 1.09 to 1.75). For low-risk (71%) and high-risk (29%) patients, SIRs without surveillance were 0.75 (95% CI 0.63 to 0.88) and 1.30 (1.03 to 1.62), respectively; for high-risk patients after first surveillance, the SIR was 1.22 (0.91 to 1.60).

CONCLUSION

These guidelines accurately classify post-polypectomy patients into those at high risk, for whom one surveillance colonoscopy appears appropriate, and those at low risk who can be managed by non-invasive screening.

Proliferation, apoptosis and their regulatory protein expression in colorectal adenomas and serrated lesions

BACKGROUND

Adenomas and serrated lesions represent heterogeneous sets of early precursors in the colorectum with varying malignant potential. They are often distinguished by their histopathologic differences, but little is known about potential differences in regulation of epithelial proliferation and apoptosis.

METHODS

We conducted a protein expression analysis using tissue microarrays of 625 colorectal adenomas and 142 serrated lesions to determine potential differences in regulation of epithelial proliferation and apoptosis. We quantitated proliferation with Ki-67; apoptosis with activated caspase-3 (CASP3); up- and down-regulators of proliferation with cyclin D1, p16INK2, and p21Cip1; and apoptosis regulators with BAX, BCL2, and survivin. Linear mixed effects models and circos diagrams were used to determine relationships among expression and lesion characteristics.

RESULTS

Adenomas had a significantly higher CASP-3 labeling index (LI) than serrated lesions, resulting in a lower net growth ratio (Ki-67 LI/activated CASP-3 LI, p-value<0.0001). Cyclin D1 LI, p16 LI and p21 LI were lower in adenomas compared to serrated lesions, while expression of both BCL2 and BAX were higher (p <0.001). Among adenomas, cyclin D1 LI and p16 LI levels increased with greater villous component, and the highest BAX expression was detected in adenomas larger than 2 cm (both p<0.0001). Right-sided adenomas had higher CASP3 LI than left colorectal adenomas (p = 0.008). Significant differences in cyclin D1 LI, p21 LI and survivin LI were also observed across histopathologic subtypes of serrated lesions.

CONCLUSIONS

Our findings demonstrate different patterns of regulatory protein expression in adenomas than serrated lesions, especially involving apoptosis. ClinicalTrials.gov Identifier: NCT00272324.

Effectiveness and safety of the different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps: A systematic review and pooled analysis

BACKGROUND

We performed a systematic review and pooled analysis to assess the effectiveness and safety of different endoscopic resection methods for 10- to 20-mm nonpedunculated colorectal polyps.

METHODS

Articles in PubMed, EMBASE, and the Cochrane Library related to the common endoscopic treatment of 10- to 20-mm nonpedunculated polyps published as of April 2020 were searched. Primary outcomes were the R0 resection rate and en bloc resection rate. Secondary outcomes were safety and the recurrence rate. Meta-regression and subgroup analysis were also performed.

RESULTS

A total of 36 studies involving 3212 polyps were included in the final analysis. Overall, the effectiveness of resection methods with a submucosal uplifting effect, including endoscopic mucosal resection (EMR), cold EMR and underwater EMR (UEMR), was better than that of methods without a nonsubmucosal uplifting effect [R0 resection rate, 90% (95% confidence interval (CI) 0.81-0.94, I² = 84%) vs 82% (95% CI 0.78-0.85, I² = 0%); en bloc resection rate 85% (95% CI 0.79-0.91, I² = 83%) vs 74% (95% CI 0.47-0.94, I² = 94%)]. Regarding safety, the pooled data showed that hot resection [hot snare polypectomy, UEMR and EMR] had a higher risk of intraprocedural bleeding than cold resection [3% (95% CI 0.01-0.05, I² = 68%) vs 0% (95% CI 0-0.01, I² = 0%)], while the incidences of delayed bleeding, perforation and post-polypectomy syndrome were all low.

CONCLUSIONS

Methods with submucosal uplifting effects are more effective than those without for resecting 10- to 20-mm nonpedunculated colorectal polyps, and cold EMR is associated with a lower risk of intraprocedural bleeding than other methods. Additional research is needed to verify the advantages of these methods, especially cold EMR.

Evaluation of the Serrated Lesions Detection Rate and Its Role as a Colonoscopy Quality Criteria

Objectives To evaluate the serrated lesion detection rate in colonoscopy at a specialized clinic and its role as quality criteria for endoscopic examination.

Methods This is an observational cross-sectional study with all patients that underwent colonoscopy between October 2018 and May 2019, performed by an experimented physician. A questionnaire was answered before the examination by the patient, and another questionnaire after the colonoscopy was answered by the medical team. All polyps identified were removed and sent to the same pathologist for analysis.

Results A total of 1,000 colonoscopies were evaluated. The average age of the patients was 58.9 years old, and most of them were female (60.6%). In 62.5% of the procedures, polyps were removed, obtaining a total of 1,730 polyps, of which 529 were serrated lesions, being 272 sessile serrated lesions (SSL). This data resulted in a serrated lesion detection rate (SDR) of 29.2%, and of 14% when considering only the SSL detection rate (SSLDR). The right colon had higher rates, with 22.3% SDR and 15.3% SSLDR. Screening colonoscopies also presented a higher serrated detection rate, of 20%, followed by diagnostics and follow-up exams. Smoking was the only risk factor associated with higher serrated detection rate.

Conclusions The serrated lesion detection rate is higher than the ones already previously suggested and the have the higher rates were stablished in the right colon and on screening exams.

Screening and prevention of colorectal cancer

Mortality from colorectal cancer is reduced through screening and early detection; moreover, removal of neoplastic lesions can reduce cancer incidence. While understanding of the risk factors, pathogenesis, and precursor lesions of colorectal cancer has advanced, the cause of the recent increase in cancer among young adults is largely unknown. Multiple invasive, semi- and non-invasive screening modalities have emerged over the past decade. The current emphasis on quality of colonoscopy has improved the effectiveness of screening and prevention, and the role of new technologies in detection of neoplasia, such as artificial intelligence, is rapidly emerging. The overall screening rates in the US, however, are suboptimal, and few interventions have been shown to increase screening uptake. This review provides an overview of colorectal cancer, the current status of screening efforts, and the tools available to reduce mortality from colorectal cancer.

Evaluation of novel LCI CAD EYE system for real time detection of colon polyps

Background

Linked color imaging (LCI) has been shown to be effective in multiple randomized controlled trials for enhanced colorectal polyp detection. Recently, artificial intelligence (AI) with deep learning through convolutional neural networks has dramatically improved and is increasingly recognized as a promising new technique for enhancing colorectal polyp detection.

Aim

This study aims to evaluate a newly developed computer-aided detection (CAD) system in combination with LCI for colorectal polyp detection.

Methods

First, a convolutional neural network was trained for colorectal polyp detection in combination with the LCI technique using a dataset of anonymized endoscopy videos. For validation, 240 polyps within fully recorded endoscopy videos in LCI mode, covering the entire spectrum of adenomatous histology, were used. Sensitivity (true-positive rate per lesion) and false-positive frames in a full procedure were assessed.

Results

The new CAD system used in LCI mode could process at least 60 frames per second, allowing for real-time video analysis. Sensitivity (true-positive rate per lesion) was 100%, with no lesion being missed. The calculated false-positive frame rate was 0.001%. Among the 240 polyps, 34 were sessile serrated lesions. The detection rate for sessile serrated lesions with the CAD system used in LCI mode was 100%.

Conclusions

The new CAD system used in LCI mode achieved a 100% sensitivity per lesion and a negligible false-positive frame rate. Note that the new CAD system used in LCI mode also specifically allowed for detection of serrated lesions in all cases. Accordingly, the AI algorithm introduced here for the first time has the potential to dramatically improve the quality of colonoscopy.

Cold snare polypectomy without submucosal injection: safety and efficacy in 615 large serrated lesions

Background and study aim  Cold resection is becoming the standard of care for the resection of nonpedunculated colon lesions up to 10 mm in diameter. Sessile serrated adenomas/polyps (SSA/Ps), including those ≥ 10 mm, present various characteristics that make them ideal candidates for cold snare polypectomy (CSP). Patients and methods  A prospectively maintained database was searched retrospectively for consecutive patients with lesions ≥ 10 mm resected between March 2013 and March 2018. During that period, all SSA/P-appearing lesions were resected using CSP without submucosal injection, except for lesions with endoscopic suspicion of dysplasia or submucosal invasion. Patients with a pathological diagnosis of SSA/P were included in the analysis. Adverse events were recorded up to 21 days following colonoscopy. Results  615 SSA/Ps ≥ 10 mm were resected during 452 colonoscopy procedures in 379 patients (mean age 54.1 years; standard deviation [SD] 11.9 years). Mean polyp size was 13.7 (SD 5.2) mm; 122 lesions (19.8 %) were ≥ 20 mm and 479 lesions (77.9 %) underwent piecemeal resection. Immediate adverse events included persistent abdominal pain that resolved spontaneously within 2 hours in three patients (0.8 %; 95 % confidence interval [CI] 0.2 %-2.3 %). One patient with persistent intraprocedural bleeding was successfully treated with a hemostatic clip. No late adverse events were detected. Surveillance colonoscopy was performed in 293 patients (77.3 %) at 23.4 (SD 11.6) months following index colonoscopy; residual/recurrent lesions were diagnosed in 23 patients (7.8 %; 95 %CI 5.0 %-11.6 %). Conclusion  CSP without submucosal injection appeared to be safe and effective for the resection of large SSA/Ps.

NTRK oncogenic fusions are exclusively associated with the serrated neoplasia pathway in the colorectum and begin to occur in sessile serrated lesions

Neurotrophic tropomyosin receptor kinase (NTRK) gene fusions are emerging tissue-agnostic drug targets in malignancies including colorectal carcinomas (CRCs), but their detailed landscape in the context of various colorectal carcinogenesis pathways remains to be investigated. In this study, pan-tropomyosin receptor kinase (TRK) protein expression was assessed by immunohistochemistry (IHC) in retrospectively collected colorectal epithelial tumor tissues, including 441 CRCs [133 microsatellite instability-high (MSI-high) and 308 microsatellite stable (MSS)] and 595 premalignant colorectal lesions (330 serrated lesions and 265 conventional adenomas). TRK-positive cases were then subjected to next-generation sequencing and/or fluorescence in situ hybridization to confirm NTRK rearrangements. TRK IHC positivity was not observed in any of the MSS CRCs, conventional adenomas, traditional serrated adenomas, or hyperplastic polyps, whereas TRK positivity was observed in 11 of 58 (19%) MLH1-methylated MSI-high CRCs, 4 of 23 (17%) sessile serrated lesions with dysplasia (SSLDs), and 5 of 132 (4%) sessile serrated lesions (SSLs). The 11 TRK-positive MSI-high CRCs commonly harbored CpG island methylator phenotype-high (CIMP-high), MLH1 methylation, BRAF/KRAS wild-type, and NTRK1 or NTRK3 fusion (TPM3-NTRK1, TPR-NTRK1, LMNA-NTRK1, SFPQ-NTRK1, ETV6-NTRK3, or EML4-NTRK3). Both NTRK1 or NTRK3 rearrangement and BRAF/KRAS wild-type were detected in all nine TRK-positive SSL(D)s, seven of which demonstrated MSS and/or CIMP-low. TRK expression was selectively observed in distorted serrated crypts within SSLs and was occasionally localized at the base of serrated crypts. NTRK fusions were detected only in SSLs of patients aged ≥50 years, whereas BRAF mutation was found in younger age-onset SSLs. In conclusion, NTRK-rearranged colorectal tumors develop exclusively through the serrated neoplasia pathway and can be initiated from non-dysplastic SSLs without BRAF/KRAS mutations prior to full occurrence of MSI-high/CIMP-high. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Serrated Polyposis Syndrome with a Synchronous Colon Adenocarcinoma Treated by an Endoscopic Mucosal Resection

Serrated polyposis syndrome (SPS) can transform to malignant lesions through the sessile serrated pathway and traditional serrated pathway. These pathways may cause rapid neoplastic progression compared to the adenoma-carcinoma sequence, which may cause interval colorectal cancer. The authors experienced a case of SPS with a synchronous colon adenocarcinoma that was treated with an endoscopic mucosal resection. In pathology reviews, other parts of the adenocarcinoma showed sessile serrated adenoma. Therefore, patients with SPS have a potential for malignant transformation, highlighting the need for strict colonoscopy surveillance starting at the time of SPS diagnosis.

Reducing adenoma miss rate of colonoscopy assisted by artificial intelligence: a multicenter randomized controlled trial

BACKGROUND

We have developed the computer-aided detection (CADe) system using an original deep learning algorithm based on a convolutional neural network for assisting endoscopists in detecting colorectal lesions during colonoscopy. The aim of this study was to clarify whether adenoma miss rate (AMR) could be reduced with CADe assistance during screening and surveillance colonoscopy.

METHODS

This study was a multicenter randomized controlled trial. Patients aged 40 to 80 years who were referred for colorectal screening or surveillance at four sites in Japan were randomly assigned at a 1:1 ratio to either the "standard colonoscopy (SC)-first group" or the "CADe-first group" to undergo a back-to-back tandem procedure. Tandem colonoscopies were performed on the same day for each participant by the same endoscopist in a preassigned order. All polyps detected in each pass were histopathologically diagnosed after biopsy or resection.

RESULTS

A total of 358 patients were enrolled and 179 patients were assigned to the SC-first group or CADe-first group. The AMR of the CADe-first group was significantly lower than that of the SC-first group (13.8% vs. 36.7%, P < 0.0001). Similar results were observed for the polyp miss rate (14.2% vs. 40.6%, P < 0.0001) and sessile serrated lesion miss rate (13.0% vs. 38.5%, P = 0.03). The adenoma detection rate of CADe-assisted colonoscopy was 64.5%, which was significantly higher than that of standard colonoscopy (53.6%; P = 0.036).

CONCLUSION

Our study results first showed a reduction in the AMR when assisting with CADe based on deep learning in a multicenter randomized controlled trial.

Risk of metachronous neoplastic lesions during post-polypectomy surveillance in individuals with advanced colorectal neoplasia at initial screening colonoscopy

BACKGROUND AND AIM

The evidence of associations between some types of advanced colorectal neoplasia (ACN) at baseline and the risk of metachronous neoplasia is inconsistent. This study aimed to elucidate the incidence of metachronous neoplasia during post-polypectomy surveillance in individuals with ACN at baseline and examine the risk factors for its high incidence.

METHODS

Data from individuals who underwent endoscopic resection for ACN and received surveillance colonoscopy were analyzed. Data from individuals with no neoplastic lesions at baseline were used as reference. The incidence of metachronous ACN and clinically significant neoplasia (ACN and nonadvanced adenomas sized ≥ 5 mm) were evaluated. Risk factors for the higher incidence of these lesions were examined in individuals with ACN at baseline.

RESULTS

During the median follow-up period of 61.8 months, metachronous ACN and nonadvanced adenomas sized ≥ 5 mm were detected in 9.6% and 32.4% of individuals with ACN at baseline (n = 136), respectively. The cumulative incidence of metachronous ACN and clinically significant neoplasia in individuals with ACN at baseline (3-year incidence: 5.5% and 16.9%, respectively) was higher than that in individuals with no neoplastic lesions at baseline (P < 0.01 for both). The presence of advanced histology at baseline, ≥ 5 neoplastic lesions at baseline, and family history of colorectal cancer were identified as risk factors for the higher incidence of clinically significant neoplasia.

CONCLUSIONS

The relatively high incidence of metachronous neoplasia in individuals with ACN at baseline was confirmed; careful surveillance is required for these individuals, particularly in those with the risk factors.

Correlation between proximal serrated polyp detection and clinically significant serrated polyps: inter-endoscopist variability

INTRODUCTION AND AIMS

The adenoma detection rate (ADR) is the most important quality indicator for the prevention of colorectal cancer but serrated polyps are also precursor lesions of the disease. The aim of our study was to compare the detection rate of proximal serrated polyps (PSPs) and that of clinically significant serrated polyps (CSSPs) between endoscopists and analyze the relation of those parameters to the ADR.

METHODS

An observational, prospective, cross-sectional study was conducted on all patients that underwent colonoscopy at the Policlínico Peruano Japonés within the time frame of July 2015 and August 2016. The ADR and PSP and CSSP detection rates between endoscopists were compared through multivariate logistic regression and the association between those parameters was calculated through the Pearson correlation coefficient.

RESULTS

The study included 15 endoscopists and 1,378 colonoscopies. The PSP detection rate ranged from 1.8-17% between endoscopists and had an almost perfect correlation with the CSSP detection rate (p = 0.922), as well as strongly correlating with the ADR (p = 0.769).

CONCLUSIONS

There was great variability in the PSP detection rate between endoscopists. It also had an almost perfect correlation with the CSSP detection rate and strongly correlated with the ADR. Those results suggest a high CSSP miss rate at endoscopy and a low PSP detection rate.

Unveiling the Roles of Low-Density Lipoprotein Receptor-Related Protein 6 in Intestinal Homeostasis, Regeneration and Oncogenesis

Intestinal epithelial self-renewal is tightly regulated by signaling pathways controlling stem cell proliferation, determination and differentiation. In particular, Wnt/β-catenin signaling controls intestinal crypt cell division, survival and maintenance of the stem cell niche. Most colorectal cancers are initiated by mutations activating the Wnt/β-catenin pathway. Wnt signals are transduced through Frizzled receptors and LRP5/LRP6 coreceptors to downregulate GSK3β activity, resulting in increased nuclear β-catenin. Herein, we explored if LRP6 expression is required for maintenance of intestinal homeostasis, regeneration and oncogenesis. Mice with an intestinal epithelial cell-specific deletion of Lrp6 (Lrp6^IEC-KO) were generated and their phenotype analyzed. No difference in intestinal architecture nor in proliferative and stem cell numbers was found in Lrp6^IEC-KO mice in comparison to controls. Nevertheless, using ex vivo intestinal organoid cultures, we found that LRP6 expression was critical for crypt cell proliferation and stem cell maintenance. When exposed to dextran sodium sulfate, Lrp6^IEC-KO mice developed more severe colitis than control mice. However, loss of LRP6 did not affect tumorigenesis in Apc^Min/+ mice nor growth of human colorectal cancer cells. By contrast, Lrp6 silencing diminished anchorage-independent growth of BRaf^V600E-transformed intestinal epithelial cells (IEC). Thus, LRP6 controls intestinal stem cell functionality and is necessary for BRAF-induced IEC oncogenesis.

Simple feedback of colonoscopy performance improved the number of adenomas per colonoscopy and serrated polyp detection rate

Background and study aims  High-quality endoscopy requires improvement of not only the adenoma detection rate (ADR) but also the serrated polyp (SP) detection rate and the mean number of adenomas per positive procedure (MAP +). We evaluated whether a simple feedback of colonoscopy performance improves those quality indicators using propensity-score matching. Patients and methods  Eleven endoscopists were evaluated regarding colonoscopy performance including ADRs, SP detection rates, mean numbers of adenomas per procedure (MAPs), and MAPs + with their ranking in the clinic. Endoscopic performance was compared before and after the feedback. Results  Colonoscopies were performed for 874 patients before the feedback and 1,272 patients after the feedback. Using propensity-score matching, 803 patients before the feedback and 803 patients after the feedback were matched. ADR after the feedback was significantly higher than that before the feedback (50.8 % and 40.8 %, respectively). MAP after feedback was significantly larger than that before the feedback (0.92 and 0.69, respectively), as well as MAP + (1.96 and 1.69, respectively). Clinically significant SP detection rate was also improved from 10.0 % to 14.9 %. Conclusions  Feedback including ADR, MAP, MAP +, and clinically significant SR detection rate could improve on those quality indicators. Further studies are needed to effectively prevent colorectal cancer in colonoscopy practice.

Diagnosis, epidemiology and management of serrated polyposis syndrome: a comprehensive review of the literature

Serrated polyp associated colorectal cancer (CRC) develops from an alternative mechanism of colorectal carcinogenesis and accounts for 10-15% of all CRC. Serrated polyposis syndrome (SPS) occurs infrequently and is characterized by the occurrence of multiple serrated polyps (hyperplastic polyps, sessile serrated lesions and traditional serrated adenomas) throughout the colon and/or rectum and has been strongly associated with development of CRC. However, SPS is frequently unrecognized, due to application failure of the WHO criteria regarding diagnosis and/or missed serrated polyps during endoscopy. The management of SPS requires surveillance at regular intervals and removal of large serrated polyps. Endoscopic resection suitability and technique depends on lesion size and the endoscopist's experience. In this manuscript, we present an update regarding SPS epidemiology, molecular characteristics, management, surveillance strategies and endoscopic resection techniques.

Serrated polyps of the colon and rectum: a concise review

"Serrated polyps" is the term used for epithelial lesions of the colon and rectum that have a "sawtooth" pattern on the polyp's surface and crypt epithelium. The so-called serrated pathway describes the progression of sessile serrated adenomas and traditional serrated adenomas to colorectal cancer. Said pathway is well recognized as an alternative mechanism of carcinogenesis and accounts for 15-30% of the cases of colorectal cancer. It also explains a large number of the cases of interval colorectal cancer. Thus, due to their usually aggressive and uncertain behavior, serrated polyps are of the utmost importance in colorectal cancer screening. Our aim was to review the history, current nomenclature, pathophysiology, morphology, treatment, and surveillance of serrated polyps.

Colonoscopy screening and surveillance guidelines

The Colonoscopy Screening and Surveillance Guidelines were developed by the Japan Gastroenterological Endoscopy Society as basic guidelines based on the scientific methods. The importance of endoscopic screening and surveillance for both detection and post-treatment follow-up of colorectal cancer has been recognized as essential to reduce disease mortality. There is limited high-level evidence in this field; therefore, we had to focus on the consensus of experts. These clinical practice guidelines consist of 20 clinical questions and eight background knowledge topics that have been determined as the current guiding principles.

First case of serrated lesion of the duodenal papilla in a patient with serrated colonic polyposis

A serrated polyposis syndrome was diagnosed in a 26-year-old female presenting with gastrointestinal symptoms. Screening for other lesions of the gastrointestinal tract showed a serpiginous looking papilla, described as possibly dysplastic. Histological analysis of biopsies showed a serrated lesion. This case describes the first known association between a duodenal serrated lesion and serrated polyposis syndrome. Upper GI screening is probably of little interest in this setting. In patients with upper GI serrated lesions, we recommend screening colonoscopy.

Revising the European Society of Gastrointestinal Endoscopy (ESGE) research priorities: a research progress update

BACKGROUND

One of the aims of the European Society of Gastrointestinal Endoscopy (ESGE) is to encourage high quality endoscopic research at a European level. In 2016, the ESGE research committee published a set of research priorities. As endoscopic research is flourishing, we aimed to review the literature and determine whether endoscopic research over the last 4 years had managed to address any of our previously published priorities.

METHODS

As the previously published priorities were grouped under seven different domains, a working party with at least two European experts was created for each domain to review all the priorities under that domain. A structured review form was developed to standardize the review process. The group conducted an extensive literature search relevant to each of the priorities and then graded the priorities into three categories: (1) no longer a priority (well-designed trial, incorporated in national/international guidelines or adopted in routine clinical practice); (2) remains a priority (i. e. the above criterion was not met); (3) redefine the existing priority (i. e. the priority was too vague with the research question not clearly defined).

RESULTS

The previous ESGE research priorities document published in 2016 had 26 research priorities under seven domains. Our review of these priorities has resulted in seven priorities being removed from the list, one priority being partially removed, another seven being redefined to make them more precise, with eleven priorities remaining unchanged. This is a reflection of a rapid surge in endoscopic research, resulting in 27 % of research questions having already been answered and another 27 % requiring redefinition.

CONCLUSIONS

Our extensive review process has led to the removal of seven research priorities from the previous (2016) list, leaving 19 research priorities that have been redefined to make them more precise and relevant for researchers and funding bodies to target.

A Review of Colorectal Cancer in Terms of Epidemiology, Risk Factors, Development, Symptoms and Diagnosis

This review article contains a concise consideration of genetic and environmental risk factors for colorectal cancer. Known risk factors associated with colorectal cancer include familial and hereditary factors and lifestyle-related and ecological factors. Lifestyle factors are significant because of the potential for improving our understanding of the disease. Physical inactivity, obesity, smoking and alcohol consumption can also be addressed through therapeutic interventions. We also made efforts to systematize available literature and data on epidemiology, diagnosis, type and nature of symptoms and disease stages. Further study of colorectal cancer and progress made globally is crucial to inform future strategies in controlling the disease's burden through population-based preventative initiatives.

Endoscopic diagnosis for colorectal sessile serrated lesions

BACKGROUND

Hyperplastic polyps are considered non-neoplastic, whereas sessile serrated lesions (SSLs) are precursors of cancer via the ‘‘serrated neoplastic pathway’’. The clinical features of SSLs are tumor size (> 5 mm), location in the proximal colon, coverage with abundant mucus called the ‘‘mucus cap’’, indistinct borders, and a cloud-like surface. The features in magnifying narrow-band imaging are varicose microvascular vessels and expanded crypt openings. However, accurate diagnosis is often difficult.

AIM

To develop a diagnostic score system for SSLs.

METHODS

We retrospectively reviewed consecutive patients who underwent endoscopic resection during colonoscopy at the Toyoshima endoscopy clinic. We collected data on serrated polyps diagnosed by endoscopic or pathological examination. The significant factors for the diagnosis of SSLs were assessed using logistic regression analysis. Each item that was significant in multivariate analysis was assigned 1 point, with the sum of these points defined as the endoscopic SSL diagnosis score. The optimal cut-off value of the endoscopic SSL diagnosis score was determined by receiver-operating characteristic curve analysis.

RESULTS

Among 1288 polyps that were endoscopically removed, we analyzed 232 diagnosed as serrated polyps by endoscopic or pathological examination. In the univariate analysis, the location (proximal colon), size (> 5 mm), mucus cap, indistinct borders, cloud-like surface, and varicose microvascular vessels were significantly associated with the diagnosis of SSLs. In the multivariate analysis, size (> 5 mm; P = 0.033), mucus cap (P = 0.005), and indistinct borders (P = 0.033) were independently associated with the diagnosis of SSLs. Size > 5 mm, mucus cap, and indistinct borders were assigned 1 point each and the sum of these points was defined as the endoscopic SSL diagnosis score. The receiver-operating characteristic curve analysis showed an optimal cut-off score of 3, which predicted pathological SSLs with 75% sensitivity, 80% specificity, and 78.4% accuracy. The pathological SSL rate for an endoscopic SSL diagnosis score of 3 was significantly higher than that for an endoscopic SSL diagnosis score of 0, 1, or 2 (P < 0.001).

CONCLUSION

Size > 5 mm, mucus cap, and indistinct borders were significant endoscopic features for the diagnosis of SSLs. Serrated polyps with these three features should be removed during colonoscopy.

Open-access colonoscopy quality indicators and patient perception using split-dose bowel preparation

Background and Aim

Open-access (OA) colonoscopies are defined as those scheduled without a gastrointestinal (GI) office visit. Past research has not focused on split preparation use and patient perception within OA. We aim to identify differences in bowel preparation (BP) adequacy, adenoma detection rate (ADR), self-reported compliance, and patient perception between OA and GI providers using split prep.

Methods

This was a cross-sectional study using split BP for colonoscopies. Patients completed a survey, and demographics, BP adequacy, and ADR were recorded. BP compliance was self-reported. Patients were asked three questions qualifying the BP instructions. Data were analyzed using chi square and Mann-Whitney tests by SPSS.

Results

BP adequacy was reported for 56 of 60 patients. Twenty-one participants (38%) were scheduled on OA, and 35 participants (62%) were scheduled after a GI office visit. Adequate BP was more frequent in 86% (18/21) of OA patients compared to 60% (21/35) in the GI group (P = 0.043). OA patients reported better review and explanation of the BP instructions compared to GI patients. There was no statistical difference between the demographics of the OA and GI groups or self-reported compliance and patient understanding of instructions.

Conclusion

OA scheduled colonoscopies were associated with more adequate BP. This could be explained by patients' self-motivation or an explanation of the importance of completing BP. This study supports the use of OA procedures as a standard of care.

Colorectal Cancer Screening and Surveillance for Non-Hereditary High-Risk Groups—Is It Time for a Re-Think?

Purpose of review

Colorectal cancer (CRC) is the second most common cause of cancer death worldwide, killing approximately 900,000 people each year. An individual’s risk of developing CRC is multi-factorial with known risk factors including increasing age, male sex, family history of CRC and raised body mass index. Population-based screening programmes for CRC exist in many countries, and in the United Kingdom (UK), screening is performed through the NHS Bowel Cancer Screening Programme (BCSP). Screening programmes offer a population-based approach for those at “average risk”, and do not typically offer enhanced screening for groups at increased risk. In the UK, such patients are managed via non-screening symptomatic services but in a non-systematic way.

Recent findings

There is growing evidence that conditions such as cystic fibrosis and a history of childhood cancer are associated with higher risk of CRC, and surveillance of these groups is advocated by some organizations; however, national recommendations do not exist in most countries.

Summary

We review the evidence for screening “high risk” groups not covered within most guidelines and discuss health economic issues requiring consideration acknowledging that the demand on colonoscopy services is already overwhelming.

Predictors of Metachronous Risk Polyps After Index Colonoscopy

INTRODUCTION

Guidelines for surveillance after polypectomy are lacking in strong evidence. Our aim was to identify some precursors of colorectal cancer lesions at 3 years after polypectomy to improve stratification and surveillance programs.

METHODS

We included patients with high-risk lesions (HRLs), defined as advanced adenoma (AA), large serrated polyps (SPs), and multiplicity (≥3 of any adenomas/SPs). Data on age, sex, cardiovascular risk factors, pharmacological treatment, and the histological characteristics in each individual, and mutations in genes involved in the most advanced index polyp, were collected. Parameters independently associated with a metachronous HRL diagnosis were evaluated through univariate and multivariate analyses. The results are reported as odds ratios and 95% confidence intervals along with P values.

RESULTS

A total of 537 cases (median age: 60.7 years; 66% male) were included. Dyslipidemia and smoking correlated with metachronous HRLs. Multivariate logistic regression analysis showed that the presence of multiplicity with ≥3 polyps on the index colonoscopy was significantly associated with metachronous HRL, AA, proximal AA, and ≥3 polyps at 3 years. In addition, independent predictors of metachronous proximal AA were increasing age, female sex, and the loss of expression of the MLH1 protein.

DISCUSSION

Multiplicity was a strong predictor of HRLs at 3 years, although the inclusion of other clinical variables (age, sex, smoking status, and dyslipidemia) improves surveillance recommendations. Without these risk factors, the surveillance could be extended to 5 years; we propose examining the somatic expression of MHL1 in all patients.

Piloting gender-oriented colorectal cancer screening with a faecal immunochemical test: population-based registry study from Finland

OBJECTIVE

To assess the feasibility and evaluate the performance of a relaunched colorectal cancer (CRC) screening programme with different cut-offs for men and women.

DESIGN

Population-based registry study.

SETTING

Nine municipalities in Finland which started CRC screening with faecal immunochemical test (FIT) in April 2019 with cut-off levels 70 µg Hg/g faeces for men and 25 µg Hg/g faeces for women.

PARTICIPANTS

Men (n=13 059) and women (n=14 669) aged 60-66 years invited to screening during the first programme year.

OUTCOME MEASURES

Participation rates, positivity rates, detection rates of CRC and advanced adenoma (AA), and positive predictive values (PPV) of FIT for CRC and AA.

RESULTS

Altogether 21 993 invitees returned stool samples. The participation rate of women (83.4%; 95% CI 82.8 to 84.0) was significantly higher than that of men (74.7%; 95% CI 73.9 to 75.4). The positivity rates were 2.4% (2.2 to 2.7) and 2.8% (2.5 to 3.1), respectively. In total, 37 CRCs and 116 AAs were detected. The detection rates of CRC and AA per 1000 participants were 1.8 (1.1 to 2.9) and 7.2 (5.6 to 9.1) for men and 1.6 (0.9 to 2.4) and 3.8 (2.8 to 5.0) for women. The PPVs per 100 positive tests were 6.6 (4.0 to 10.3) and 25.7 (20.6 to 31.4) for men and 6.4 (3.9 to 9.8) and 15.5 (11.6 to 20.2) for women.

CONCLUSIONS

The chosen FIT strategy narrowed the gap in the diagnostic performance between men and women especially in the detection of CRC. The participation rates were excellent. The levels of positivity and detection rates were moderate and need further action. The results indicate that gender-specific protocols can be introduced to organised CRC screening. It is yet to be seen whether they are more effective than a uniform screening protocol.

Oncological outcome after local treatment for early stage rectal cancer

BACKGROUND

Treatment of early rectal cancer is evolving towards organ-preserving therapy which includes endoscopic resection and transanal approaches. We aimed to explore the role of local treatments such as endoscopic polypectomy (Endoscopic Mucosal Resection (EMR) or Endoscopic submucosal dissection (ESD)) and transanal endoscopic microsurgery/ transanal minimal invasive surgery (TEM/TAMIS) in patients who had early rectal cancer. We considered these outcomes alongside conventional major surgery using total mesorectal excision (TME) for early stage disease.

METHODS

All patients identified at MDT with early stage rectal cancer at our institution between 2010 and 2019 were included. Long-term outcomes in terms of local recurrence, survival and procedure-specific morbidity were analysed.

RESULTS

In total, 536 patients with rectal cancer were identified, of which 112 were included based on their pre-operative identification at the MDT on the basis that they had node-negative early rectal cancer. Among these, 30 patients (27%) had the lesion excised by flexible endoscopic polypectomy techniques (EMR/ESD), 67 (60%) underwent TEM/TAMIS and 15 (13%) had major surgery. There were no differences in patient demographics between the three groups except for TEM/TAMIS patients being more likely to be referred from another hospital (p < 0.001) and they were less active (WHO performance status p = 0.04). There were no significant differences in overall survival rates and cancer-specific survival between the three treatment groups. The 5-year overall survival rate for endoscopic polypectomy, TEM/TAMIS or major resection was 96% versus 90% and 88%, respectively (p = 0.89). The 5- year cancer-specific survival rate was 96%, versus 96% and 100%, respectively (p = 0.74).

CONCLUSION

Endoscopic polypectomy by EMR/ESD is an appropriate local treatment for early stage rectal cancer in selected patients. It is possible to achieve good oncological outcomes with a polypectomy similar to TEM/TAMIS and major surgery; however, a multidisciplinary approach is necessary enabling close surveillance and the use of adjuvant radiotherapy.

The 2019 World Health Organization Classification of appendiceal, colorectal and anal canal tumours: an update and critical assessment

The recently published 5th edition 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System brings significant changes from the 2010 4th edition. An emphasis on uniformity in nomenclature and grading for tumours across all organ systems is a particular feature of the 5th edition blue book series that is reflected in the gastrointestinal tract (GIT) classification. For example, simplified two tiered grading is reinforced for preinvasive lesions throughout the GIT, with dysplasia at all sites now being considered either low or high grade. Similarly, a uniform approach to classification and grading of GIT neuroendocrine neoplasms has been consolidated, with an emphasis on distinguishing grade 3 neuroendocrine tumours from neuroendocrine carcinomas. In this review, we discuss and critically assess the important and sometimes controversial changes made to the classification of tumours of the lower GIT, comprising the colorectum, vermiform appendix and anal canal. The particularly controversial decision to endorse the term 'sessile serrated lesion' for lesions previously termed 'sessile serrated polyp/adenoma' is explored. The morphological, molecular, and clinical insights behind the substitution of the term 'goblet cell adenocarcinoma' for 'goblet cell carcinoid' are assessed. The evolution of the classification of appendiceal mucinous neoplasms is considered. Inflammatory bowel disease related dysplasia and its evolving subtypes, with major implications for pathologists in routine practice, is explained.

Molecular Features of the Serrated Pathway to Colorectal Cancer: Current Knowledge and Future Directions

Serrated lesions are the precursor lesions of a new model of colorectal carcinogenesis. From a molecular standpoint, the serrated pathway is thought to be responsible for up to 30% of all colorectal cancer cases. The three major processes of this molecular mechanism are alterations in the mitogen-activated protein kinase pathway, production of the CpG island methylation phenotype, and generation of microsatellite instability. Other contributing processes are activation of WNT, alterations in the regulation of tumor suppressor genes, and alterations in microRNAs or in MUC5AC hypomethylation. Although alterations in the serrated pathway also contribute, their precise roles remain obscure because of the various methodologies and definitions used by different research groups. This knowledge gap affects clinical assessment of precursor lesions for their carcinogenic risk. The present review describes the current literature reporting the molecular mechanisms underlying each type of serrated lesion and each phenotype of serrated pathway colorectal cancer, identifying those areas that merit additional research. We also propose a unified serrated carcinogenesis pathway combining molecular alterations and types of serrated lesions, which ends in different serrated pathway colorectal cancer phenotypes depending on the route followed. Finally, we describe some key issues that need to be addressed in order to incorporate the newest technologies in serrated pathway research and to improve overall knowledge for developing specific prevention strategies and new therapeutic targets.