Sessile serrated adenomas: an evidence-based guide to management

Dietary Inflammatory Potential and the Risk of Serrated and Adenomatous Colorectal Polyps

Studies of dietary inflammation potential and risks of colorectal cancer precursors are limited, particularly for sessile serrated lesions (SSLs). This study examines the association using the energy-adjusted dietary inflammatory index (E-DIITM), a measure of anti- and/or pro-inflammatory diet, in a large US colonoscopy-based case-control study of 3246 controls, 1530 adenoma cases, 472 hyperplastic polyp cases, and 180 SSL cases. Odds ratios (ORs) and 95% confidence intervals (CIs) were derived from logistic regression models. Analyses were stratified by participant characteristics, and urinary prostaglandin E2 metabolite (PGE-M) and high-sensitivity plasma C-reactive protein (hs-CRP) levels, inflammation biomarkers. Highest E-DII™ intake was associated with significantly increased risks of colorectal adenomas (OR 1.36, 95% CI 1.11, 1.67), and hyperplastic polyps (OR 1.43, 95% CI 1.06, 1.98), compared with participants consuming the lowest E-DII™ quartile. A similar, but non-significant, increased risk was also observed for SSLs (OR 1.41, 95% CI 0.82, 2.41). The positive association was stronger in females (pinteraction <0.001), normal weight individuals (ptrend 0.01), and in individuals with lower inflammatory biomarkers (ptrend 0.02 and 0.01 for PGE-M and hs-CRP, respectively). A high E-DII™ is associated with colorectal polyp risk, therefore promoting an anti-inflammatory diet may aid in preventing colorectal polyps.

Development and Validation of a Deep Learning-Based Histologic Diagnosis System for Diagnosing Colorectal Sessile Serrated Lesions

OBJECTIVES

The histopathologic diagnosis of colorectal sessile serrated lesions (SSLs) and hyperplastic polyps (HPs) is of low consistency among pathologists. This study aimed to develop and validate a deep learning (DL)-based logical anthropomorphic pathology diagnostic system (LA-SSLD) for the differential diagnosis of colorectal SSL and HP.

METHODS

The diagnosis framework of the LA-SSLD system was constructed according to the current guidelines and consisted of 4 DL models. Deep convolutional neural network (DCNN) 1 was the mucosal layer segmentation model, DCNN 2 was the muscularis mucosa segmentation model, DCNN 3 was the glandular lumen segmentation model, and DCNN 4 was the glandular lumen classification (aberrant or regular) model. A total of 175 HP and 127 SSL sections were collected from Renmin Hospital of Wuhan University during November 2016 to November 2022. The performance of the LA-SSLD system was compared to 11 pathologists with different qualifications through the human-machine contest.

RESULTS

The Dice scores of DCNNs 1, 2, and 3 were 93.66%, 58.38%, and 74.04%, respectively. The accuracy of DCNN 4 was 92.72%. In the human-machine contest, the accuracy, sensitivity, and specificity of the LA-SSLD system were 85.71%, 86.36%, and 85.00%, respectively. In comparison with experts (pathologist D: accuracy 83.33%, sensitivity 90.91%, specificity 75.00%; pathologist E: accuracy 85.71%, sensitivity 90.91%, specificity 80.00%), LA-SSLD achieved expert-level accuracy and outperformed all the senior and junior pathologists.

CONCLUSIONS

This study proposed a logical anthropomorphic diagnostic system for the differential diagnosis of colorectal SSL and HP. The diagnostic performance of the system is comparable to that of experts and has the potential to become a powerful diagnostic tool for SSL in the future. It is worth mentioning that a logical anthropomorphic system can achieve expert-level accuracy with fewer samples, providing potential ideas for the development of other artificial intelligence models.

Specific Targeting and Labeling of Colonic Polyps in CPC-APC Mice with Mucin 5AC Fluorescent Antibodies: A Model for Detection of Early Colon Cancer

Poor visualization of polyps can limit colorectal cancer screening. Fluorescent antibodies to mucin5AC (MUC5AC), a glycoprotein upregulated in adenomas and colorectal cancer, could improve screening colonoscopy polyp detection rate. Adenomatous polyposis coli flox mice with a Cdx2-Cre transgene (CPC-APC) develop colonic polyps that contain both dysplastic and malignant tissue. Mice received MUC5AC-IR800 or IRdye800 as a control IV and were sacrificed after 48 h for near-infrared imaging of their colons. A polyp-to-background ratio (PBR) was calculated for each polyp by dividing the mean fluorescence intensity of the polyp by the mean fluorescence intensity of the background tissue. The mean 25 μg PBR was 1.70 (±0.56); the mean 50 μg PBR was 2.64 (±0.97); the mean 100 μg PBR was 3.32 (±1.33); and the mean 150 μg PBR was 3.38 (±0.87). The mean PBR of the dye-only control was 2.22 (±1.02), significantly less than the 150 μg arm (p-value 0.008). The present study demonstrates the ability of fluorescent anti-MUC5AC antibodies to specifically target and label colonic polyps containing high-grade dysplasia and intramucosal adenocarcinoma in CPC-APC mice. This technology can potentially improve the detection rate and decrease the miss rate of advanced colonic neoplasia and early cancer at colonoscopy.

The Mucin Family of Proteins: Candidates as Potential Biomarkers for Colon Cancer

Mucins (MUC1-MUC24) are a family of glycoproteins involved in cell signaling and barrier protection. They have been implicated in the progression of numerous malignancies including gastric, pancreatic, ovarian, breast, and lung cancer. Mucins have also been extensively studied with respect to colorectal cancer. They have been found to have diverse expression profiles amongst the normal colon, benign hyperplastic polyps, pre-malignant polyps, and colon cancers. Those expressed in the normal colon include MUC2, MUC3, MUC4, MUC11, MUC12, MUC13, MUC15 (at low levels), and MUC21. Whereas MUC5, MUC6, MUC16, and MUC20 are absent from the normal colon and are expressed in colorectal cancers. MUC1, MUC2, MUC4, MUC5AC, and MUC6 are currently the most widely covered in the literature regarding their role in the progression from normal colonic tissue to cancer.

Sessile serrated lesion presenting as large pedunculated polyp in the rectum: A case report

RATIONALE

Sessile serrated lesions (SSLs) are serrated polyps (SP) with the typical serrated architecture of the crypt lining epithelium. SSL has an important clinical implication because they are recognized as precursor lesion of sporadic colorectal cancer (CRC) through "serrated pathway." SSLs usually appear flat to sessile, and are located in the right colon.

PATIENT CONCERNS

A 69-year-old man was referred to a tertiary medical center because of intermittent hematochezia for 2 years.

DIAGNOSIS

Colonoscopy revealed a large, pedunculated polyp in the rectum. The polyp surface was slightly reddish in color and the elongated stalk was covered with almost normal mucosa. Histopathological examination of the resected specimens revealed the typical features of SSL with low-grade dysplasia.

INTERVENTION

Endoscopic mucosal resection using a detachable snare was performed on the tumor for definite diagnosis and treatment.

OUTCOMES

There was no evidence of immediate or delayed bleeding after endoscopic mucosal resection, and the hemoglobin level normalized after a 1-year follow-up.

LESSONS

We report a rare case of a large pedunculated polyp with typical histological features of SSLs in the rectum. Endoscopists should always consider SSLs at any location even with unusual morphological findings.

Local recurrence after endoscopic resection of sessile serrated lesions: A multicenter prospective study by the Osaka Gut Forum

BACKGROUND AND AIM

Sessile serrated lesions (SSLs) act as precursors to colorectal cancer, sometimes harbor carcinomas, and are sometimes incompletely resected. We aimed to evaluate local recurrence after endoscopic resection of SSL ≥10 mm.

METHODS

This prospective, single-arm, observational study was performed at eight Japanese tertiary institutions. Colorectal lesions ≥10 mm were resected endoscopically, and the pathological diagnosis was either an SSL or hyperplastic polyp (HP). Follow-up colonoscopy was performed 1 year later, and the local recurrence was evaluated by biopsy.

RESULTS

From October 2018 to September 2021, 104 cases with 123 lesions were registered. Among the pathologically diagnosed 105 SSLs and 18 HPs, 95 and 7 lesions were diagnosed as SSLs and HPs, respectively, by central pathological review. Among the 104 endoscopically diagnosed SSLs, 86 were diagnosed as SSLs, whereas among the 11 endoscopically diagnosed HPs, two were diagnosed as HPs by central pathological review (the rest were SSLs). Among the 95 patients with 113 lesions who underwent follow-up colonoscopy, resection scars were identified in 95 (84%) lesions. Three (3.1%; 95% confidence interval 0.6-8.7%) local recurrences were diagnosed pathologically among 98 pathologically diagnosed SSLs. Two (6%) local recurrences were diagnosed in patients with SSLs ≥20 mm.

CONCLUSIONS

The local recurrence rate after endoscopic resection of SSLs ≥10 mm was 3.1%. Careful follow-up is recommended after endoscopic resection of large SSLs. Endoscopically diagnosed HPs ≥10 mm were sometimes pathologically diagnosed as SSL and should be considered for resection.

Single-cell Transcriptomics Reveals Early Molecular and Immune Alterations Underlying the Serrated Neoplasia Pathway Toward Colorectal Cancer

BACKGROUND & AIMS

Approximately one-third of colorectal cancers develop from serrated lesions (SLs), including hyperplastic polyp (HP), sessile serrated lesion (SSL), traditional serrated adenoma (TSA), and SSL with dysplasia (SSLD) through the serrated neoplasia pathway, which progresses faster than the conventional adenoma-carcinoma pathway. We sought to depict the currently unclarified molecular and immune alterations by the single-cell landscape in SLs.

METHODS

We performed single-cell RNA sequencing of 16 SLs (including 4 proximal HPs, 5 SSLs, 2 SSLDs, and 5 TSAs) vs 3 normal colonic tissues.

RESULTS

A total of 60,568 high-quality cells were obtained. Two distinct epithelial clusters with redox imbalance in SLs were observed, along with upregulation of tumor-promoting SerpinB6 that regulated ROS level. Epithelial clusters of SSL and TSA showed distinct molecular features: SSL-specific epithelium manifested overexpressed proliferative markers with Notch pathway activation, whereas TSA-specific epithelium showed Paneth cell metaplasia with aberrant lysozyme expression. As for immune contexture, enhanced cytotoxic activity of CD8⁺ T cells was observed in SLs; it was mainly attributable to increased proportion of CD103⁺CD8⁺ tissue-resident memory T cells, which might be regulated by retinoic acid metabolism. Microenvironment of SLs was generally immune-activated, whereas some immunosuppressive cells (regulatory T cells, anti-inflammatory macrophages, MDK⁺IgA⁺ plasma cells, MMP11-secreting PDGFRA⁺ fibroblasts) also emerged at early stage and further accumulated in SSLD.

CONCLUSION

Epithelial, immune, and stromal components in the serrated pathway undergo fundamental alterations. Future molecular subtypes of SLs and potential immune therapy might be developed.

Adenoma detection rate using narrow-band imaging is inferior to high-definition white light colonoscopy in screening and surveillance colonoscopies in daily clinical care: A randomized controlled trial

BACKGROUND

Despite recent advances in endoscopic technology adenoma miss rate still is up to 20% contributing to interval cancers. Improved imaging modalities have been introduced to increase adenoma detection rate (ADR). Recently, narrow-band imaging (NBI) (Exera II series, Olympus Corporation) was not significantly better than high-definition white light colonoscopy (HD-WLC). An improved second generation of NBI (190-NBI) is characterized by better illumination of the bowel lumen and may be associated with a higher ADR.

METHODS

We performed a prospective randomized study on patients referred to the Jena University Hospital for screening or surveillance colonoscopy between January 2015 and April 2017. Participating endoscopists were divided into 2 subgroups depending on their individual experience. Colonoscopy was performed by use of HD-WLC or 190-NBI upon withdrawal.

RESULTS

Five hundred fifty-three patients participated in the study. Eighty patients were excluded (insufficient bowel cleansing [n = 34], anticoagulation precluding polypectomy [n=15], partial colonic resection [n=9], other reasons [n = 22]). Mean age was 66.9 years (standard deviation 10.3 years), and 253 patients were male (53.5%). Bowel preparation and withdrawal time were not different. ADR among all subgroups was 39.4% using HD-WLC, but only 29.1% were using 190-NBI (P = .02). Number of polyps per patient was lower using 190-NBI than with HD-WLC (0.58 vs 0.86; P = .02). Subgroup analysis revealed that 190-NBI was inferior to HD-WLC only in unexperienced endoscopists.

CONCLUSION

In our stud,y ADR was lower by use of 190-NBI. These differences persisted only in unexperienced investigators. 190-NBI seems to be more challenging regarding ADR, requiring more intensive training prior to implementing this technology in daily clinical care.

REGISTRATION

ClinicalTrials.gov (identifier: NCT03081975).

Clip Closure Does Not Reduce Risk of Bleeding After Resection of Large Serrated Polyps: Results From a Randomized Trial

BACKGROUND & AIMS

Serrated polyps are important colorectal cancer precursors and are most commonly located in the proximal colon, where post-polypectomy bleeding rates are higher. There is limited clinical trial evidence to guide best practices for resection of large serrated polyps (LSPs).

METHODS

In a multicenter trial, patients with large (≥20 mm) non-pedunculated polyps undergoing endoscopic mucosal resection (EMR) were randomized to clipping of the resection base or no clipping. This analysis is stratified by histologic subtype of study polyp(s), categorized as serrated [sessile serrated lesions (SSLs) or hyperplastic polyps (HPs)] or adenomatous, comparing clip vs control groups. The primary outcome was severe post-procedure bleeding within 30 days of colonoscopy.

RESULTS

A total of 179 participants with 199 LSPs (191 SSLs and 8 HPs) and 730 participants with 771 adenomatous polyps were included in the study. Overall, 5 patients with LSPs (2.8%) experienced post-procedure bleeding compared with 42 (5.8%) of those with adenomas. There was no difference in post-procedure bleeding rates between patients in the clip vs control group among those with LSPs (2.3% vs 3.3%, respectively, difference 1.0%; P = NS). However, among those with adenomatous polyps, clipping was associated with a lower risk of post-procedure bleeding (3.9% vs 7.6%, difference 3.7%; P = .03) and overall serious adverse events (5.5% vs 10.6%, difference 5.1%; P = .01).

CONCLUSION

The post-procedure bleeding risk for LSPs removed via EMR is low, and there is no discernable benefit of prophylactic clipping of the resection base in this group. This study indicates that the benefit of endoscopic clipping following EMR may be specific for >2 cm adenomatous polyps located in the proximal colon.

CLINICALTRIALS

gov, Number: NCT01936948.

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.

The prevalence of sessile serrated lesion in the colorectum and its relationship to synchronous colorectal advanced neoplasia: a systemic review and meta-analysis

BACKGROUND

The aim of this systemic review and meta-analysis was to evaluate the prevalence of sessile serrated lesion (SSL) and its relationship to synchronous colorectal advanced neoplasia.

MATERIALS AND METHODS

Comprehensive, computerized research was performed on PubMed and published from 1 January 2010 to 6 July 2018 which searched relevant articles without any language limitations. Clinical trials were included in the narrative systemic review if they matched the following inclusion criteria: (1) published as a case-controlled study, cohort study or cross-sectional study; (2) defined objectively for diagnosis of SSL within the studies; (3) addressed the prevalence and characteristics of SSL. Within these trials, if they met additional criteria involving the reported outcome of risk regarding advanced neoplasia in relation to SSL, they were enrolled into meta-analysis.

RESULTS

Forty-one trials were enrolled for the systematic review, with a total of eight analyzed for the meta-analysis. The prevalence of all SSL ranged from 0.038 to 20.23% and the prevalence by pooled analysis was 2.7%. In a subgroup analysis, the overall prevalence of SSL during the periods of 2010-2014 and 2015-2018 was shown to be 2.7 and 2.8%, respectively. We calculated the pooled data on the cancer risk of SSL and the risk of synchronous advanced neoplasia in patients with SSL made available from the eight trials, which resulted in a pooled odds ratio of 3.53 (95% confidence interval 2.39-5.20, I2 = 4%, P = 0.40).

CONCLUSION

In this systemic review, SSL was found to be associated with an increased risk of synchronous advanced neoplasia in the colorectum.

Cold versus hot polypectomy/endoscopic mucosal resection-A review of current evidence

Background

Colonoscopy with polypectomy substantially reduces the risk of colorectal cancer (CRC) but interval cancers still account for 9% of all CRCs, some of which are due to incomplete resection.

Aim

The aim of this review is to compare the outcomes of cold and hot endoscopic resection and provide technical tips and tricks for optimizing cold snare polypectomy.

Results

Cold snare polypectomy (CSP) is the standard technique for small (≤10 mm) colorectal polyps. For large colonic polyps (>10 mm), hot resection techniques with use of electrocautery (polypectomy or endoscopic mucosal resection) were recommended until recently. However, the use of electrocoagulation brings serious adverse effects in up to 9% of the patients, such as delayed bleeding, post‐polypectomy syndrome and perforation. In recent years, efforts have been made to improve the polypectomy with cold snare in order to avoid these adverse effects of electrocoagulation without compromising the efficacy of the resection. Several authors have recently shown that the complication rates of CSP of polyps >10 mm is close to zero and recurrence rates varies between 5‐18%. Lower recurrence rates are found in serrated lesions (<8%).

Self-reported Metabolic Risk Factor Associations with Adenomatous, Sessile Serrated, and Synchronous Adenomatous and Sessile Serrated Polyps

Studies have found a positive association between metabolic risk factors, such as obesity and diabetes, and adenomatous polyps (AP). However, fewer studies have assessed the association between sessile serrated polyps (SSP) or synchronous diagnosis of APs and SSPs (synch polyps). Study participants (N = 1,370; ages 40-85) undergoing screening colonoscopy were enrolled between August 2016 and February 2020. Self-reported metabolic risk factors, including diabetes, hypertension, hyperlipidemia, and overweight/obesity, were evaluated for associations with new diagnoses of APs, SSPs, and synch polyps at the present colonoscopy. Average participant age was 60.73 ± 8.63 (SD) years; 56.7% were female and 90.9% white. In an assessment of individual metabolic risk factors, adjusted for age, sex, race, and smoking status, increased body mass index (BMI; overweight or obese vs. normal BMI of <25 kg/m2) was associated with an increased odds for new onset of colon APs (P trend < 0.001) as was a diagnosis of diabetes [adjusted conditional OR (aCOR) = 1.59 (1.10-2.29)]. No associations were seen between the metabolic risk factors and onset of SSPs. Being obese or hypertensive each increased the odds of new onset of synch polyps with aCOR values of 2.09 (1.01-4.32) and 1.79 (1.06-3.02), respectively. Self-reported risk factors may help assess polyp type risk. Because SSPs and synch polyps are rare, larger studies are needed to improve our understanding of the contribution of these factors to polyp risk. These data lead us to hypothesize that differences in observed metabolic risk factors between polyp types reflect select metabolic impact on pathways to colorectal cancer. PREVENTION RELEVANCE: Self-reported medical history provides valuable insight into polyp risk, potentially enabling the use of larger retrospective studies of colonoscopy populations to assess knowledge gaps. More aggressive colonoscopy screening, critical to colorectal cancer prevention, may be considered in populations of individuals with metabolic risk factors and modifiable lifestyle risk factors.

Risk of lower gastrointestinal bleeding and colorectal neoplasms following initiation of low-dose aspirin: a Danish population-based cohort study

OBJECTIVE

Aspirin may increase the risk of lower gastrointestinal bleeding (LGIB) from precursors of colorectal cancer (CRC). We investigated whether use of low-dose aspirin, through initiation of LGIB, may lead patients to undergo colonoscopy and polypectomy before manifest CRC.

DESIGN

We conducted a historical cohort study (2005-2013) of all Danish residents who initiated low-dose aspirin treatment (n=412 202) in a setting without screening for CRC. Each new aspirin user was matched with three non-users (n=1 236 560) by age, sex and region of residence on the date of their matched new user's first-time aspirin prescription (index date). We computed absolute risks (ARs), risk differences and relative risks (RRs) of LGIB, lower gastrointestinal endoscopy, colorectal polyps and CRC, comparing aspirin users with non-users.

RESULTS

The ARs were higher for new users than non-users for LGIB, lower gastrointestinal endoscopy, colorectal polyps and CRC within 3 months after index. Comparing new users with non-users, the RRs were 2.79 (95% CI 2.40 to 3.24) for LGIB, 1.73 (95% CI 1.63 to 1.84) for lower gastrointestinal endoscopy, 1.56 (95% CI 1.42 to 1.72) for colorectal polyps and 1.73 (95% CI 1.51 to 1.98) for CRC. The RRs remained elevated for more than 12 months after the index date, with the exception of CRC where the RRs were slightly decreased during the 3-5 years (RR 0.90, 95% CI 0.83 to 0.98) and more than 5 years (RR 0.91, 95% CI 0.82 to 1.00) following the index date.

CONCLUSION

These findings indicate that aspirin may contribute to reduce CRC risk by causing premalignant polyps to bleed, thereby expediting colonoscopy and polypectomy before CRC development.

Detection of Postcolonoscopy Colorectal Neoplasia by Multi-target Stool DNA

INTRODUCTION

Significant variability between colonoscopy operators contributes to postcolonoscopy colorectal cancers (CRCs). We aimed to estimate postcolonoscopy colorectal neoplasia (CRN) detection by multi-target stool DNA (mt-sDNA), which has not previously been studied for this purpose.

METHODS

In a retrospective cohort of patients with +mt-sDNA and completed follow-up colonoscopy, positive predictive value (PPV) for endpoints of any CRN, advanced adenoma, right-sided neoplasia, sessile serrated polyps (SSP), and CRC were stratified by the time since previous colonoscopy (0-9, 10, and ≥11 years). mt-sDNA PPV at ≤9 years from previous average-risk screening colonoscopy was used to estimate CRN missed at previous screening colonoscopy.

RESULTS

Among the 850 studied patients with +mt-sDNA after a previous negative screening colonoscopy, any CRN was found in 535 (PPV 63%). Among 107 average-risk patients having +mt-sDNA ≤9 years after last negative colonoscopy, any CRN was found in 67 (PPV 63%), advanced neoplasia in 16 (PPV 15%), right-sided CRN in 48 (PPV 46%), and SSP in 20 (PPV 19%). These rates were similar to those in 47 additional average risk persons with previous incomplete colonoscopy and in an additional 68 persons at increased CRC risk. One CRC (stage I) was found in an average risk patient who was mt-sDNA positive 6 years after negative screening colonoscopy.

DISCUSSION

The high PPV of mt-sDNA 0-9 years after a negative screening colonoscopy suggests that lesions were likely missed on previous examination or may have arisen de novo. mt-sDNA as an interval test after negative screening colonoscopy warrants further study.

Quality Control in the Slovenian National Colorectal Cancer Screening Program

OBJECTIVES

The objective of the study was to assess the impact of an internal quality indicator (QI) audit on the quality level of colonoscopies in the National Colorectal Cancer Screening Program (NCCSP).

DESIGN

Sixty-eight colonoscopists from 29 endoscopic centres participated in the NCCSP from April 2009 to January 2015. Controlled QIs were the percentage of total colonoscopies, adenoma detection rate (ADR), mean adenoma per procedure (MAP), mean adenoma per positive procedure (MAP+), right-sided ADR, sessile serrated lesion (SSL) detection rate, and patient responses to post-procedural questionnaires. A group of 3 expert endoscopists from the NCCSP Council performed 91 inspections and provided education.

RESULTS

A total of 891.364 (58.2%) Slovenian citizens participated in the first 3 screening rounds of the NCCSP. Among 46.552 (6%) positive individuals, 42.866 (92.1%) underwent first colonoscopies. Total colonoscopies were performed in 98% of endoscopies (p = 0.459 between cycles), mean ADR was 51.8% (p = 0.872 between cycles), mean percentage of adenoma in the right colon was 37.5% (p = 0.227 between cycles), mean MAP was 1.1 (p = 0.981 between cycles), mean MAP+ was 2.0 (p = 0.824 between cycles), and mean SSL detection rate was 3% (p < 0.001). We observed great difference in QIs between endoscopists and a significant increase in MAP, ADR in the right colon, and SSL per endoscopist during the 6-year period. Due to quality underperformance, 3 endoscopic centres (10.3%) and 13 endoscopists (19.1%) were excluded from the program.

CONCLUSIONS

The success of the NCCSP is related to the quality of colonoscopies performed. To ensure the proper quality level, regular audit and permanent education are needed.

Increased Sessile Serrated Adenoma Detection Rate With Mechanical New Technology Devices: A Systematic Review and Meta-Analysis

GOAL

This meta-analysis aims to compare the sessile-serrated adenoma detection rate (SSADR) of currently available mechanical new technology devices (NTDs) to conventional colonoscopy (CC).

BACKGROUND

NTDs including Endocuff, EndoRing, G-Eye, and AmplifEYE were developed with the aim of improving adenoma detection rate by enhancing colonic mucosal visualization. Increasing awareness of the risk of sessile-serrated adenoma progression to malignancy has ushered a need to increase the detection of these characteristically flat lesions.

STUDY

Embase and PubMed/Medline databases were searched from inception through January 2019 for published manuscripts or major conference abstracts reporting SSADR with Endocuff, EndoRing, G-Eye, AmplifEYE, and CC. Randomized controlled trials, high-quality case-control, cohort, and observational studies in adults with >10 subjects were included. The primary outcome was pooled SSADR odds ratio (ORs) with 95% confidence interval (95% CI) comparing CC with the NTDs. In addition, an analysis comparing each device to CC was performed.

RESULTS

Of 207 citations identified, a total of 14 studies with 12,655 subjects were included in our analysis (5931 subjects with NTDs and 6724 with CC). There were 12 studies with Endocuff, 2 with EndoRing, 1 with G-EYE, and 1 with AmplifEYE. The mean age was 62.4 years and 57.5% were males. Pooled SSADR with NTDs was 12.3% as compared with 6.4% with CC, with an OR of 1.81 (95% CI: 1.6-2.0, I2: 77%). Analysis of Endocuff alone yielded an OR 1.81 (95% CI: 1.6-2.1, I2: 79%).

CONCLUSION

Mechanical NTDs, notably Endocuff, are a safe and effective tool to increase the SSADR.

Prevalence of Colorectal Neoplasms and Mortality in New Users of Low-Dose Aspirin With Lower Gastrointestinal Bleeding

BACKGROUND

Aspirin inhibits platelet function and may therefore accelerate early lower gastrointestinal bleeding (LGIB) from colorectal cancer (CRC) precursor polyps. The bleeding may increase endoscopic polyp detection.

STUDY QUESTION

To estimate the prevalence of polyps and CRC comparing new users of low-dose aspirin with nonusers who all received a diagnosis of LGIB and to investigate the mortality among these patients.

STUDY DESIGN

Using Danish nationwide health registries, we conducted a cohort study (2006-2013) of all new aspirin users who also received a diagnosis of LGIB (n = 40,578). Each new user was matched with 5 nonusers with LGIB by gender and age at the LGIB diagnosis date.

MEASURES AND OUTCOMES

We computed the prevalence and prevalence ratios (PRs) of colorectal polyps and CRCs, and the mortality ratios within 6 months after the LGIB, comparing new users with nonusers.

RESULTS

We identified 1038 new aspirin users and 5190 nonusers with LGIB. We observed 220 new users and 950 nonusers recorded with endoscopically detected polyps. New aspirin users had a higher prevalence of conventional {PR = 1.28 [95% confidence interval (CI): 1.06-1.55]} and serrated [PR = 1.31 (95% CI: 0.95-1.80)] polyps. New users and nonusers had a similar prevalence of CRC [PR = 1.04 (95% CI: 0.77-1.39)]. However, after stratifying by location of CRC, the prevalence of proximal tumors was lower [PR = 0.71 (95% CI: 0.35-1.43)] in new users than in nonusers. No difference in mortality was observed.

CONCLUSIONS

These findings indicate that new use of low-dose aspirin is associated with an increased detection of colorectal polyps compared with nonuse.

Non-conventional dysplasia in inflammatory bowel disease is more frequently associated with advanced neoplasia and aneuploidy than conventional dysplasia

AIMS

Several different non-conventional morphological patterns of epithelial dysplasia have been recently described in inflammatory bowel disease (IBD), but there is limited information regarding their clinicopathological and molecular features, as well as potential risk for high-grade dysplasia (HGD) or colorectal cancer (CRC) compared with conventional dysplasia developing in IBD.

METHODS AND RESULTS

A total of 317 dysplastic lesions from 168 IBD patients were analysed. All lesions were re-reviewed and subtyped as either conventional [including tubular adenoma-like (n = 183) and tubulovillous/villous adenoma-like (n = 56)] or non-conventional dysplasia [including dysplasia with increased Paneth cell differentiation (DPD, n = 40), crypt cell dysplasia (CCD, n = 14), goblet cell deficient (GCD, n = 10), hypermucinous (n = 7), sessile serrated lesion (SSL)-like (n = 4) and traditional serrated adenoma (TSA)-like (n = 3)]. DNA flow cytometry was performed on 70 low-grade conventional (n = 24) and non-conventional (n = 46) dysplastic biopsies to determine their malignant potential and molecular pathways to HGD or CRC. Eleven sporadic tubular adenomas with low-grade dysplasia (LGD) were utilised as controls. Seventy-eight non-conventional dysplastic lesions were identified in 56 (33%) of the 168 patients, whereas 239 conventional dysplastic lesions were identified in 149 (89%) patients. Although both non-conventional and conventional dysplasias were most often graded as LGD at diagnosis (83% and 84%, respectively), non-conventional dysplasia (38%) was more likely to develop HGD or CRC in the same colonic segment than conventional dysplasia (19%) on follow-up (P < 0.001). Almost half (46%) of non-conventional dysplastic samples showed aneuploidy, whereas only 8% of conventional dysplasia (P = 0.002) and 9% of sporadic tubular adenomas (P = 0.037) did. Also, non-conventional dysplasia more frequently presented as a flat/invisible lesion (41%) compared with conventional dysplasia (18%) (P < 0.001). Among the non-conventional subtypes (n = 78), DPD was the most common (n = 40; 51%), followed by CCD (n = 14; 18%), GCD (n = 10; 13%), hypermucinous (n = 7; 9%), SSL-like (n = 4; 5%) and TSA-like (n = 3; 4%) variants. Hypermucinous dysplasia (mean = 2.1 cm) was significantly larger than DPD, SSL-like, TSA-like and GCD variants (mean = 1.0, 1.2, 1.2 and 1.9 cm, respectively) (P = 0.037). HGD or CRC was more likely to be associated with CCD (n = 13; 93%), hypermucinous (n = 4; 57%), GCD (n = 4; 40%) and SSL-like (n = 3; 75%) variants than DPD (n = 6; 15%) and TSA-like dysplasia (n = 0; 0%) on follow-up (P < 0.001). Furthermore, the rate of aneuploidy was significantly higher in CCD (100%), hypermucinous (80%) and GCD (25%) variants than in DPD (12%), SSL-like dysplasia (0%) and TSA-like dysplasia (0%) (P < 0.001).

CONCLUSIONS

Non-conventional morphological patterns of dysplasia are not uncommon in IBD, detected in 33% of the patients. The higher frequencies of advanced neoplasia (HGD or CRC) and aneuploidy in non-conventional dysplasia, in particular CCD, hypermucinous and GCD variants, suggest that they may have a higher malignant potential than conventional dysplasia or sporadic tubular adenomas, and thus need complete removal and/or careful follow-up. Greater than 40% of non-conventional dysplasia presented as a flat/invisible lesion, suggesting that IBD patients may benefit from random biopsy sampling in addition to targeted biopsies. The majority of non-conventional subtypes appear to develop via the chromosomal instability pathway, whereas an alternative serrated pathway may be responsible for the development of at least a subset of SSL-like and TSA-like dysplasias.

Hyperplastic polyp or sessile serrated lesion? The contribution of serial sections to reclassification

BACKGROUND

The histological discrimination of hyperplastic polyps from sessile serrated lesions can be difficult. Sessile serrated lesions and hyperplastic polyps are types of serrated polyps which confer different malignancy risks, and surveillance intervals, and are sometimes difficult to discriminate. Our aim was to reclassify previously diagnosed hyperplastic polyps as sessile serrated lesions or confirmed hyperplastic polyps, using additional serial sections.

METHODS

Clinicopathological data for all colorectal hyperplastic polyps diagnosed in 2016 and 2017 was collected. The slides were reviewed and classified as hyperplastic polyps, sessile serrated lesion, or other, using current World Health Organization criteria. Eight additional serial sections were performed for the confirmed hyperplastic polyp group and reviewed.

RESULTS

Of an initial 147 hyperplastic polyps from 93 patients, 9 (6.1%) were classified as sessile serrated lesions, 103 as hyperplastic polyps, and 35 as other. Of the 103 confirmed hyperplastic polyps, 7 (6.8%) were proximal, and 8 (7.8%) had a largest fragment size of ≥5 mm and < 10 mm. After 8 additional serial sections, 11 (10.7%) were reclassified as sessile serrated lesions. They were all less than 5 mm and represented 14.3% of proximal polyps and 10.4% of distal polyps. An average of 3.6 serial sections were required for a change in diagnosis.

CONCLUSION

Histopathological distinction between hyperplastic polyps and sessile serrated lesions remains a challenge. This study has uncovered a potential role for the use of additional serial sections in the morphological reappraisal of small hyperplastic polyps, especially when proximally located.

Detection and clinical characteristics of serrated polyps and conventional adenomas between patients in the outpatient and physical checkup unit receiving colonoscopy

PURPOSE

The sessile serrated adenoma/polyp detection rate (SSA/PDR) among different colonoscopy indications from daily practice has not been fully understood. This study aimed to evaluate the detection and clinical characteristics of serrated polyps and conventional adenomas between outpatient department (OPD) and physical checkup unit (PCU) patients receiving colonoscopy.

METHODS

The data for this retrospective study were collected between 2016 and 2017 at Kaohsiung Veterans General Hospital in Taiwan. A total of 7047 individuals were included, and information on polyp and adenoma detection was extracted from the colonoscopy reports.

RESULTS

The adenoma detection rate, the SSA/PDR, and the detection rate of traditional serrated adenoma (TSA) were 32.2%, 0.60%, and 0.50%, respectively. Risk analysis revealed no significant difference (p = 0.095) in SSA/PDR between individuals < 50 years and ≥ 50 years, and no trend of increased SSA/PDR as age increased was observed (p = 0.320). SSA/P and TSA had higher risks for synchronous advanced neoplasia than conventional adenoma, but with proximal hyperplastic polyps lower (p < 0.001, respectively). No significant difference of SSA/PDR between OPD and PCU patients was observed (p = 1.000); however, the age of SSA/P was significantly older in OPD than in PCU patients (p = 0.048).

CONCLUSION

The detection rates of CA and TSA were associated with age groups; however, SSA/PDR was insignificantly higher among individuals aged < 50 years than those with other age groups. In addition, SSA/PDR between OPD and PCU patients was not significantly found in daily practice of colonoscopies.

Significance of serrated epithelial change in inflammatory bowel disease

OBJECTIVES

The clinical significance of hyperplastic polyp-like histologic changes in random biopsy samples ('serrated epithelial change' or SEC) from patients with inflammatory bowel disease (IBD) remains uncertain, with some studies suggesting an increased risk of dysplasia and even carcinoma. Controlled studies are few. We studied the significance of SEC on the development of dysplasia in follow-up surveillance of IBD patients in our system.

METHODS

We identified 94 IBD patients with SEC and 187 IBD patients without SEC identified in index biopsy samples, and retrospectively collated results of follow-up surveillance samples in each group, with the development of dysplasia and/or adenocarcinoma as study endpoints.

RESULTS

IBD patients with SEC had a 12.8% likelihood of developing dysplasia of any type within IBD-affected areas vs a 4.3% likelihood in non-SEC patients (follow-up in the 1-4 year range for each group). This was significant in univariate analysis (p = 0.013) but not in multivariate analysis, likely due to increased frequency of follow-up sampling in the SEC patients. One cancer developed in each group (p = NS).

CONCLUSION

Our data, in the context of other studies, neither prove nor conclusively exclude an increased risk of dysplasia in IBD patients with SEC. But cancer risk appears low and continued surveillance at usual intervals seems reasonable.

Traditional serrated adenomas (TSA) and the company they keep: TSA presence predicts advanced neoplasm states

BACKGROUND

The association of TSAs with metachronous neoplasms is well established and suggests that TSAs would also have an association with synchronous neoplasms.

METHODS

We compared odds ratios and rates of synchronous neoplasms found in colonoscopies with and without TSAs.

RESULTS

There was a mean of 2.44 neoplasms among TSA cases in comparison with 1.72 in non-TSA cases. The odds ratio for advanced neoplasia was highest among cases with one or more TSAs relative to cases with one or more HPs (7.54 [CI, 4.23-13.44]) when compared with adenomas (1.95 [CI, 1.75-2.17]) and SSPs (2.98 [CI, 2.54-3.5]).

CONCLUSIONS

In this study population, there is a 7-fold higher risk of synchronous advanced neoplasms among cases with one or more TSAs.

Colorectal Cancer Screening for the Serrated Pathway

Serrated polyps are classified into hyperplastic polyps, sessile serrated adenomas/polyps, and traditional serrated adenomas. Although all serrated polyps share characteristic colonic crypts serrations, distinguishing hyperplastic polyps from sessile serrated adenomas/polyps is challenging. Traditional serrated adenomas are cytologically dysplastic lesions; sessile serrated adenomas/polyps develop cytologic dysplasia as they progress to colorectal cancer. A flat and pale appearance of serrated polyps may make detection difficult. Endoscopic mucosal resection has higher rates of complete resection. Close surveillance is recommended for sessile serrated adenomas/polyps, sessile serrated adenomas/polyp with dysplasia, hyperplastic polyps ≥10 mm, and traditional serrated adenomas.

Validation of serrated polyps (SPs) in Swedish pathology registers

Background

Little is known about the natural history of serrated polyps (SPs), partly due to the lack of large-scale epidemiologic data. In this study, we examined the validity of SP identification according to SNOMED (Systematised Nomenclature of Medicine) codes and free text from colorectal histopathology reports.

Methods

Through the ESPRESSO (Epidemiology Strengthened by histoPathology Reports in Sweden) study, we retrieved data on SPs from all pathology departments in Sweden in 2015–2017 by using SNOMED codes and free-text search in colorectal histopathology reports. Randomly selected individuals with a histopathology report of SPs were validated against patient charts using a structured, retrospective review.

Results

SPs were confirmed in 101/106 individuals with a histopathology report of SPs, yielding a positive predictive value (PPV) of 95% (95%CI = 89–98%). By year of diagnosis, the PPV was 89% (95%CI = 69–97%), 96% (95%CI = 81–99%) and 97% (95%CI = 89–99%) for individuals diagnosed before 2001 (n = 19), between 2001 and 2010 (n = 26) and after 2010 (n = 61), respectively. According to search method, the PPV for individuals identified by SNOMED codes was 100% (95%CI = 93–100%), and 93% (95%CI = 86–97%) using free-text search. Recorded location (colon vs. rectum) was correct in 94% of all SP histopathology reports (95%CI = 84–98%) identified by SNOMED codes. Individuals with SPs were classified into hyperplastic polyps (n = 34; 32%), traditional serrated adenomas (n = 3; 3%), sessile serrated adenomas/polyps (SSA/Ps) (n = 70; 66%), unspecified SPs (n = 3, 3%), and false positive SPs (n = 5, 5%). For individuals identified by SNOMED codes, SSA/Ps were confirmed in 49/52 individuals, resulting in a PPV of 94% (95%CI: 84–98%). In total, 57% had ≥2 polyps (1: n = 44, 2–3: n = 33 and ≥ 4: n = 27). Some 46% of SPs (n = 71) originated from the proximal colon and 24% were ≥ 10 mm in size (n = 37). Heredity for colorectal cancer, intestinal polyposis syndromes, or both was reported in seven individuals (7%). Common comorbidities included diverticulosis (n = 45, 42%), colorectal cancer (n = 19, 18%), and inflammatory bowel disease (n = 10, 9%).

Conclusion

Colorectal histopathology reports are a reliable data source to identify individuals with SPs.

Association Between Endoscopist Personality and Rate of Adenoma Detection

BACKGROUND & AIMS

There is significant variation among endoscopists in their adenoma detection rates (ADRs). We explored associations between ADR and characteristics of endoscopists, including personality traits and financial incentives.

METHODS

We collected electronic health record data from October 2013 through September 2015 and calculated ADRs for physicians from 4 health systems. ADRs were risk-adjusted for differences in patient populations. Physicians were surveyed to assess financial motivations, knowledge and perceptions about colonoscopy quality, and personality traits. Of 140 physicians sent the survey, 117 responded.

RESULTS

The median risk-adjusted ADR for all surveyed physicians was 29.3% (interquartile range, 24.1%-35.5%). We found no significant association between ADR and financial incentives, malpractice concerns, or physicians' perceptions of ADR as a quality metric. ADR was associated with the degree of self-reported compulsiveness relative to peers: among endoscopists who described themselves as much more compulsive, the ADR was 33.1%; among those who described themselves as somewhat more compulsive, the ADR was 32.9%; among those who described themselves as about the same as others, the ADR was 26.4%; and among those who described themselves as somewhat less compulsive, the ADR was 27.3%) (P = .0019). ADR was also associated with perceived thoroughness (much more thorough than peers, ADR = 31.5%; somewhat more, 31.9%; same/somewhat less, 27.1%; P = .0173). Physicians who reported feeling rushed, having difficulty pacing themselves, or having difficulty in accomplishing goals had higher ADRs. A secondary analysis found the same associations between personality and adenomas per colonoscopy.

CONCLUSIONS

We found no significant association between ADR and financial incentives, malpractice concerns, or perceptions of ADR as a quality metric. However, ADRs were higher among physicians who described themselves as more compulsive or thorough, and among those who reported feeling rushed or having difficulty accomplishing goals.

Curriculum review: serrated lesions of the colorectum

Colorectal cancer (CRC) is the second leading cause of death from cancer in the UK. Sporadic CRC evolves by the cumulative effect of genetic and epigenetic alterations. Typically, over the course of several years, this leads to the transformation of normal colonic epithelium to benign adenomatous polyp, low-grade to high-grade dysplasia and finally cancer-the adenoma-carcinoma sequence. Over the last decade, the serrated neoplasia pathway which progresses by methylation of tumour suppressing genes has been increasingly recognised as an important alternative pathway accounting for up to 30% of CRC cases. Endoscopists should be aware of the unique features of serrated lesions so that their early detection, appropriate resection and surveillance interval can be optimised.

CpG Island Methylation in Sessile Serrated Adenoma/Polyp of the Colorectum: Implications for Differential Diagnosis of Molecularly High-Risk Lesions among Non-dysplastic Sessile Serrated Adenomas/Polyps

Background

Although colorectal sessile serrated adenomas/polyps (SSA/Ps) with morphologic dysplasia are regarded as definite high-risk premalignant lesions, no reliable grading or risk-stratifying system exists for non-dysplastic SSA/Ps. The accumulation of CpG island methylation is a molecular hallmark of progression of SSA/Ps. Thus, we decided to classify non-dysplastic SSA/Ps into risk subgroups based on the extent of CpG island methylation.

Methods

The CpG island methylator phenotype (CIMP) status of 132 non-dysplastic SSA/Ps was determined using eight CIMP-specific promoter markers. SSA/Ps with CIMP-high and/or MLH1 promoter methylation were regarded as a high-risk subgroup.

Results

Based on the CIMP analysis results, methylation frequency of each CIMP marker suggested a sequential pattern of CpG island methylation during progression of SSA/P, indicating MLH1 as a late-methylated marker. Among the 132 non-dysplastic SSA/Ps, 34 (26%) were determined to be high-risk lesions (33 CIMP-high and 8 MLH1-methylated cases; seven cases overlapped). All 34 high-risk SSA/Ps were located exclusively in the proximal colon (100%, p = .001) and were significantly associated with older age (≥ 50 years, 100%; p = .003) and a larger histologically measured lesion size (> 5 mm, 100%; p = .004). In addition, the high-risk SSA/Ps were characterized by a relatively higher number of typical base-dilated serrated crypts.

Conclusions

Both CIMP-high and MLH1 methylation are late-step molecular events during progression of SSA/Ps and rarely occur in SSA/Ps of young patients. Comprehensive consideration of age (≥ 50), location (proximal colon), and histologic size (> 5 mm) may be important for the prediction of high-risk lesions among non-dysplastic SSA/Ps.

Clinical and endoscopic characteristics of sessile serrated adenomas/polyps with dysplasia/adenocarcinoma in a Korean population: A Korean Association for the Study of Intestinal Diseases (KASID) multicenter study

Sessile serrated adenomas/polyps (SSA/Ps) are precancerous lesions that account for one-third of colorectal cancers. The endoscopic and pathologic differentiation between SSA/Ps without dysplasia (SSA/POs) and SSA/Ps with dysplasia or adenocarcinoma (SSA/PDAs) can be difficult. This study aimed to assess the clinical characteristics of SSA/PDs. This multicenter retrospective cohort study included 532 patients who underwent endoscopic resection and were pathologically diagnosed with SSA/POs and SSA/PDAs. Initially, medical, endoscopic, and histopathological records of patients who underwent endoscopic resection of SSA/POs and SSA/PDAs at eight university hospitals in Korea between January 2005 and December 2015 were reviewed. A total of 307 (57.7%) patients were detected in men and 319 (60.0%) were located in the proximal colon. Most SSA/Ps had a flat, slightly elevated, or sessile morphology. The most prevalent endoscopic findings of SSA/Ps were nodular surface (244, 45.9%), disrupted vascular pattern (232, 43.6%), altered fold contour (141, 26.5%), dome-shaped morphology (135, 25.4%), and pale color (115, 21.6%). SSA/POs were more commonly found in the proximal colon, compared to SSA/PDAs. SSA/PDAs displayed 0-Ip, Isp, IIb or IIa + IIc morphologies more frequently, while SSA/POs displayed 0-Is or IIa morphology more frequently. The frequency of a rim of debris/bubbles was significantly higher in SSA/POs, while nodular surface and disrupted vascular pattern were significantly higher in SSA/PDAs. In the univariate analysis of endoscopic features, SSA/PDAs were significantly associated with the distal colon location, 0-Isp and IIb morphologies, nodular surface, and disrupted vascular pattern. In the multivariate analysis, 0-IIb, nodular surface, and disrupted vascular pattern were significantly associated with SSA/PDAs. SSA/Ps with 0-IIb morphology, nodular surface and disrupted vascular pattern are associated with an increased risk of dysplasia or adenocarcinoma.

Reasons why the diagnosis of serrated polyposis syndrome is missed

OBJECTIVES

Serrated polyposis syndrome (SPS) is a relatively new and under-recognized colorectal cancer (CRC) predisposition syndrome. Previous studies have reported miss-rates of SPS diagnosis varying from 40 to 82%. As SPS patients and their first-degree relatives have an increased risk of CRC, early recognition is important. We aimed to determine the miss-rate of SPS and to determine the reasons for missed diagnosis.

PATIENTS AND METHODS

We retrospectively identified all patients diagnosed with at least one colorectal polyp or carcinoma detected at our tertiary referral center between January 1986 and July 2013 using the nationwide pathology registry. On the basis of cumulative polyp count with size and location, SPS patients were identified. We checked whether the SPS diagnosis was made in the medical files and, if not, what might have been the reason for missing the diagnosis.

RESULTS

We randomly assessed 5000 patients, of whom 25 patients fulfilled the WHO criteria for SPS. In six patients, no previous SPS diagnosis had been made, leading to a miss-rate of 24.0% (95% confidence interval: 7.3-40.7). The reasons for missed diagnosis were polyps removed before establishment of the WHO criteria, unavailable pathology reports, and failure to apply the criteria by the clinician.

CONCLUSION

The miss-rate for the diagnosis of SPS is considerable, even during longer follow-up with repeated colonoscopies. A preventable reason for missing SPS cases is failure to apply the WHO criteria. Awareness of this CRC predisposition syndrome needs to be raised to decrease the miss-rate of SPS.

Calcium and vitamin D supplementation and increased risk of serrated polyps: results from a randomised clinical trial

OBJECTIVE

Serrated lesions such as sessile serrated adenomas or polyps (SSA/Ps) are important colorectal cancer precursors, but aetiological factors for these lesions are largely unknown. We aimed to determine the effects of calcium and vitamin D supplementation on the incidence of serrated polyps (SPs) in general and hyperplastic polyps and SSA/Ps specifically.

DESIGN

Participants with one or more adenoma at baseline were randomised to receive 1200 mg/day of elemental calcium, 1000 IU/day of vitamin D₃, both or neither agent. Treatment continued for 3 or 5 years, when risk of polyps was determined from surveillance colonoscopy (treatment phase). Outcomes after treatment ceased were also assessed (observational phase). Adjusted risk ratios (aRRs) of SPs were determined via multivariable generalised linear models.

RESULTS

SPs were diagnosed in 565 of 2058 (27.5%) participants during the treatment phase and 329/1108 (29.7%) during the observational phase. In total, 211 SSA/Ps were identified during follow-up. In the treatment phase, there was no effect of either calcium or vitamin D on incidence of SSA/Ps. However, during the later observational phase, we observed elevated risks of SSA/Ps associated with calcium alone and calcium+vitamin D treatment (aRR (95% CI): 2.65 (1.43 to 4.91) and 3.81 (1.25 to 11.64), respectively).

CONCLUSION

In a large multicentre chemoprevention study, we found evidence that calcium and vitamin D supplementation increased the risk of SSA/Ps. This appeared to be a late effect: 6-10 years after supplementation began. These possible risks must be weighed against the benefits of calcium and vitamin D supplementation. : Trial registration NUMBER: NCT00153816; Results.

Serrated Lesions of the Colon-Rectum: A Focus on New Diagnostic Tools and Current Management

Prompt diagnosis and correct management of the so called "serrated lesions" (SLs) of the colon-rectum are generally considered of crucial importance in the past years, mainly due to their histological heterogeneity and peculiar clinical and molecular patterns; sometimes, they are missed at conventional endoscopy and are possibly implicated in the genesis of interval cancers. The aim of this review is to focus on the diagnostic challenges of serrated lesions, underlying the role of both conventional endoscopy and novel technologies. We will show how an accurate and precise diagnosis should immediately prompt the most appropriate therapy other than defining a proper follow-up program. It will be emphasized how novel endoscopic techniques may provide better visualization of mucosal microsurface structures other than enhancing the microvascular architecture, in order to better define and characterize specific patterns of mucosal lesions of the gastrointestinal tract. Standard therapy of SLs of the colon-rectum is still very debated, also due to the relatively lack of studies focusing on treatment issues. The high risk of incomplete resection, together with the high rate of postcolonoscopy interval cancers, suggests the need of an extra care when facing this kind of lesions. Given this background, we will outline useful technical tips and tricks in the resection of SLs, taking aspects such as the size and location of the lesions, as well as novel available techniques and technologies, other than future perspectives, including confocal laser endomicroscopy into consideration. Follow-up of SLs is another hot topic, also considering that their clinical impact has been misunderstood for a long time. The incidence of the so called interval colorectal cancer underlines how some weaknesses exist in current screening and follow-up programs. Considering the lack of wide consensus for the management of some SLs, we will try to summarize and clarify the best strategies for their optimal management.

2017 Emily Couric Memorial Lecture: Colorectal Cancer: Polyps, Prevention, and Progress

Colorectal cancer remains the second‐leading cause of cancer death in the United States—but efforts over the past two decades have resulted in tremendous progress in understanding the biology of how this disease develops, increasing screening rates, and decreasing incidence and mortality in those age 50 years and older. The drivers of this movement have been outstanding leadership, innovation, and collaboration. As we move forward to tackle issues such as the increasing incidence of this disease in younger adults, the need to address disparities in care and outcomes, and our shared goal to reach 80% screening rates, it's important to understand and appreciate the story of our past success in order to advance our future efforts.

The clinical significance and synchronous polyp burden of large (≥ 20 mm) sessile serrated polyps in patients without serrated polyposis syndrome

BACKGROUND

Sessile serrated polyps (SSPs) are important precursors of colorectal carcinoma and interval cancer. Large SSPs (≥ 20 mm) outside the definition of serrated polyposis syndrome (SPS) have not been studied in comparison with SPS. We aimed to describe the characteristics of patients with large SSPs in this context.

METHODS

Patients with at least one SSP (≥ 20 mm) were eligible. Data from three consecutive colonoscopies were used to compare clinical and endoscopic characteristics in three patient groups: SPS, a solitary large SSP, and patients with at least two SSPs without fulfilling the criteria for SPS (oligo-SSP). Data on the diagnostic colonoscopy were collected retrospectively, whereas the remaining data was collected prospectively.

RESULTS

67/146 patients (45.9 %) had SPS, 53/146 (36.3 %) had a solitary SSP, and 26/146 (17.8 %) were categorized as oligo-SSP. Personal (16.4 %, 9.4 %, and 11.5 %, respectively) and family (17.9 %, 17.0 %, and 23.1 %, respectively) history of colorectal carcinoma did not differ significantly between groups. Polyp burden was greater in SPS compared with solitary SSP but was not different from oligo-SSP (advanced adenomas: SPS 32.8 % vs. solitary SSP 9.4 % [P = 0.002] vs. oligo-SSP 34.6 % [P = 0.87]; ≥ 10 conventional adenomas: 11.9 % vs. 0 % [P = 0.01] vs. 3.8 % [P = 0.44], respectively). Dysplasia in large SSPs was frequent in all groups (41.1 % overall). SPS was recognized by referring endoscopists in only 9.0 % of cases.

CONCLUSION

Patients with oligo-SSPs have similar synchronous polyp burden and clinical characteristics as patients with SPS and may require similar surveillance. Modification of the criteria for the diagnosis of SPS to include this group seems warranted. Patients with a solitary SSP have a lower risk of synchronous polyps, including advanced adenomas. Larger studies are warranted to determine whether these patients may return to standard surveillance following complete examination and clearance of the colon.

Impact of Changeover to Newer Endoscopic Systems on Quality and Efficiency of Screening and Surveillance Colonoscopy: Equipment or Endoscopist

GOALS

The goal of this study is to assess whether changeover to newer endoscopic systems impacts quality or efficiency, and quantify the relation between increased withdrawal time and detection rates of sessile serrated polyps (SSPDR) and adenomas (ADR) in real-world practice.

STUDY

Beginning 2 months after new endoscopic systems were implemented at 2 endoscopy units, we included all outpatients undergoing screening/surveillance colonoscopy for 4 months. Outpatients during the same 4-month period 1 year earlier comprised the control group. Quality endpoints included ADR, advanced ADR, SSPDR, polyp detection rate (PDR), and withdrawal time. The efficiency endpoint was procedure time. Statistical adjustment for potential confounding factors was performed with multivariable analysis.

RESULTS

Significant increases occurred in postchangeover (N=1122) versus prechangeover (N=1131) procedure time (difference=2.6 minutes; 1.6 to 3.6) and withdrawal time (difference=1.6 minutes; 0.8 to 2.5). Significant increases also occurred in ADR [435 (39%) vs. 380 (34%)], advanced ADR [82 (7%) vs. 50 (4%)], and PDR [664 (59%) vs. 611 (54%)], but these differences lost significance when withdrawal time was added to the multivariable model. For every minute increase in withdrawal time a significant increase was seen in ADR (OR=1.09; 1.08 to 1.11), advanced ADR (OR=1.10; 1.08 to 1.13), SSPDR (OR=1.07; 1.06 to 1.09), and PDR (OR=1.16; 1.14 to 1.18).

CONCLUSIONS

After changeover to newer endoscopy systems withdrawal times lengthened, resulting in increased procedure time, ADR, and advanced ADR. Regardless of endoscopic system, lengthening withdrawal time increased SSPDR, ADR, and advanced ADR: odds of detection increased 7% to 10% with every additional minute of withdrawal time. Greater attention to withdrawal time and endoscopist examination may be more productive than upgrading endoscopic systems.

Intestinal epithelial Notch-1 protects from colorectal mucinous adenocarcinoma

Increasing evidence links Notch-1 signaling with the maintenance of intestinal architecture and homeostasis. Dysfunction in the common Notch-1 pathway transcription factor recombinant binding protein suppressor of hairless (RBP-J) is associated with loss of epithelial barrier integrity and aberrant conversion of proliferative crypt cells into goblet cells. Furthermore, we have recently discovered that epithelial Notch-1 is indispensable in bridging innate and adaptive immunity in the gut and is required for supporting protective epithelial pro-inflammatory responses. Yet, the epithelial specific function of Notch-1 in intestinal tumorigenesis remains unknown. We generated Villin-Cre/Notch-1^fl/fl (VN^-/-) mice that are selectively deficient in Notch-1 in intestinal epithelial cells. Intestinal epithelial Notch-1 preserved barrier function and integrity, whereas lack of epithelial Notch-1 induced goblet cell hyperplasia, spontaneous serrated lesions, multifocal low- and high-grade dysplasia and colonic mucinous neoplasms in mice. Over time, VN^-/- mice displayed high occurrence of colorectal mucinous adenocarcinomas, which correlated with increased levels of mitogenic, angiogenic and pro-tumorigenic gene expression. Finally, we found that the expression of Notch-1 is significantly reduced in human colorectal mucinous adenocarcinoma when compared to colorectal adenocarcinoma. Taken together, our findings reveal a novel and critical protective role for Notch-1 in controlling intestinal tumorigenesis.

Sessile Serrated Adenomas: How to Detect, Characterize and Resect

Serrated polyps are important contributors to the burden of colorectal cancers (CRC). These lesions were once considered to have no malignant potential, but currently up to 30% of all CRC are recognized to arise from the serrated neoplasia pathway. The primary premalignant lesions are sessile serrated adenomas/polyps (SSA/Ps), although traditional serrated adenomas are relatively uncommon. Compared to conventional adenomas, SSA/Ps are morphologically subtle with indistinct borders, may be difficult to detect endoscopically, are more prevalent than previously thought, are associated with synchronous and metachronous advanced neoplasia, and have a higher risk of incomplete resection. Although many lesions remain “dormant,” progressive disease is associated with the development of dysplasia and more rapid progression to CRC. As a result, SSA/Ps are strongly implicated in the development of interval cancers. These factors represent unique challenges that require a meticulous approach to their management. In this review, we summarize the contemporary literature on the characterization, detection and resection of SSA/Ps.

Modifiable lifestyle factors associated with risk of sessile serrated polyps, conventional adenomas and hyperplastic polyps

OBJECTIVE

To identify modifiable factors associated with sessile serrated polyps (SSPs) and compare the association of these factors with conventional adenomas (ADs) and hyperplastic polyps (HPs).

DESIGN

We used data from the Tennessee Colorectal Polyp Study, a colonoscopy-based case-control study. Included were 214 SSP cases, 1779 AD cases, 560 HP cases and 3851 polyp-free controls.

RESULTS

Cigarette smoking was associated with increased risk for all polyps and was stronger for SSPs than for ADs (OR 1.74, 95% CI 1.16 to 2.62, for current vs never, ptrend=0.008). Current regular use of non-steroidal anti-inflammatory drugs was associated with a 40% reduction in SSP risk in comparison with never users (OR 0.68, 95% CI 0.48 to 0.96, ptrend=0.03), similar to the association with AD. Red meat intake was strongly associated with SSP risk (OR 2.59, 95% CI 1.41 to 4.74 for highest vs lowest intake, ptrend<0.001) and the association with SSP was stronger than with AD (ptrend=0.003). Obesity, folate intake, fibre intake and fat intake were not associated with SSP risk after adjustment for other factors. Exercise, alcohol use and calcium intake were not associated with risk for SSPs.

CONCLUSIONS

SSPs share some modifiable risk factors for ADs, some of which are more strongly associated with SSPs than ADs. Thus, preventive efforts to reduce risk for ADs may also be applicable to SSPs. Additionally, SSPs have some distinctive risk factors. Future studies should evaluate the preventive strategies for these factors. The findings from this study also contribute to an understanding of the aetiology and biology of SSPs.

Management of Serrated Polyps of the Colon

PURPOSE OF REVIEW

The purpose of this review is to summarize the management of serrated colorectal polyps (SPs), with a particular focus on the most common premalignant SP, sessile serrated adenoma or polyp (SSA/P). These lesions present a challenge for endoscopists with respect to detection and resection, and are also susceptible to pathologic misdiagnosis.

RECENT FINDINGS

Patients with SSA/Ps are at an increased risk of future colorectal neoplasia, including advanced polyps and cancer. Reasonable benchmarks for SP detection rates are 5-7% for SSA/Ps and 10-12% for proximal SPs. Certain endoscopic techniques such as chromoendoscopy, narrow band imaging, water immersion, and wide-angle viewing may improve SSA/P detection. Emerging endoscopic techniques such as underwater polypectomy, suction pseudopolyp technique, and piecemeal cold snare polypectomy are helpful tools for the endoscopist's armamentarium for removing SSA/Ps. Proper orientation of SSA/P specimens can improve the accuracy of pathology readings. Patients with confirmed SSA/Ps and proximal HPs should undergo surveillance at intervals similar to what is recommended for patients with conventional adenomas. Patients with SSA/Ps may also be able to lower their risk of future polyps by targeting modifiable risk factors including tobacco and alcohol use and high-fat diets. NSAIDs and aspirin appear to be protective agents. SPs and SSA/Ps in particular are important colorectal cancer precursors that merit special attention to ensure adequate detection, resection, and surveillance.

Mucins and associated O-glycans based immunoprofile for stratification of colorectal polyps: clinical implication for improved colon surveillance

Sessile serrated adenoma/polyps (SSA/P) are premalignant lesions of colorectal cancer that are difficult to distinguish histologically from hyperplastic polyps (HP) of minimal to no malignant potential. Specific markers for differentiating SSA/P from HP can aid clinicians for optimizing colon surveillance intervals. The present study investigates the potential of mucins and associated O-glycans to distinguish SSA/P from HP. Expression of colonic mucins (MUC1, MUC4, MUC17, MUC2, and MUC5AC) and O-glycans [Sialyl LewisA (CA19-9) and Tn/Sialyl-Tn on MUC1] were analyzed in HP (n=33), SSA/P (n=39), and tubular adenoma (TA) (n=36) samples by immunohistochemistry. A significantly reduced expression of MUC4 (p=0.0066), elevated expression of MUC17 (p=0.0002), and MUC5AC (p<0.0001) was observed in SSA/P cases in comparison to HP cases. Interestingly, significantly higher number of SSA/P cases (p<0.0001) exhibited MUC5AC expression in the goblet cells as well as filled the crypt lumen compared to only goblet cells in majority of the HP cases. Improved diagnostic potential was revealed by multivariate logistic regression analysis where combinatorial panel of MUC5AC/MUC17 discriminated SSA/P from HP (SN/SP=85/82%). Finally, the decision tree model based marker panel (CA19-9/MUC17/MUC5AC) predicted HP, SSA/P and TA with SN/SP of 58%/95%, 79%/90% and 97%/83%, respectively. Overall, the mucin and associated O-glycan based panel defined in the present study could aid in discriminating SSA/P from HP to devise better colon surveillance strategies.

Precision Medicine for CRC Patients in the Veteran Population: State-of-the-Art, Challenges and Research Directions

Colorectal cancer (CRC) accounts for ~9% of all cancers in the Veteran population, a fact which has focused a great deal of the attention of the VA's research and development efforts. A field-based meeting of CRC experts was convened to discuss both challenges and opportunities in precision medicine for CRC. This group, designated as the VA Colorectal Cancer Cell-genomics Consortium (VA4C), discussed advances in CRC biology, biomarkers, and imaging for early detection and prevention. There was also a discussion of precision treatment involving fluorescence-guided surgery, targeted chemotherapies and immunotherapies, and personalized cancer treatment approaches. The overarching goal was to identify modalities that might ultimately lead to personalized cancer diagnosis and treatment. This review summarizes the findings of this VA field-based meeting, in which much of the current knowledge on CRC prescreening and treatment was discussed. It was concluded that there is a need and an opportunity to identify new targets for both the prevention of CRC and the development of effective therapies for advanced disease. Also, developing methods integrating genomic testing with tumoroid-based clinical drug response might lead to more accurate diagnosis and prognostication and more effective personalized treatment of CRC.

The ethnic distribution of sessile serrated polyps in the United States is inversely associated with Helicobacter pylori prevalence

AIM

Little is known about the epidemiology of sessile serrated polyps (SSP). Our study aimed to investigate the influence of Helicobacter pylori gastritis and patient demographic characteristics (age, gender, ethnicity) on the prevalence of SSP using a large national database of patients undergoing bi-directional endoscopy.

METHOD

De-identified patient data were extracted from the Miraca Life Sciences electronic database of histopathological reports. Using multivariate logistic regression analysis, the influence of H. pylori gastritis and demographic characteristics on the occurrence of SSP were expressed as odds ratios (OR) with their 95% confidence intervals (CI).

RESULTS

The total study population comprised 228 506 subjects, of whom 28 890 carried a diagnosis of H. pylori gastritis and 11 285 SSP. Age (OR 4.35, 95% CI: 3.82-4.96), female gender (0.92, 0.88-0.95) and H. pylori gastritis (0.94, 0.88-0.99) exerted the strongest influence on the occurrence of SSP. In comparison with the population comprising Caucasians and African Americans, SSP were less common among subjects of Hispanic (0.67, 0.62-0.73), East Asian (0.59, 0.50-0.69), Indian (0.43, 0.27-0.64) or Middle Eastern descent (0.61, 0.41-0.87). All these ethnic subgroups were also characterized by a higher prevalence of H. pylori than the comparison group. A low prevalence of H. pylori was significantly associated with a high prevalence of SSP (R²  = 0.82, P < 0.001).

CONCLUSION

The prevalence of SSP within the United States is characterized by a marked ethnic variation. The inverse correlation between the prevalence of H. pylori and SSP suggests that gastric infection with H. pylori may be partly responsible for the observed ethnic distribution of SSP.

The Serrated Polyp Pathway: Is It Time to Alter Surveillance Guidelines?

PURPOSE OF REVIEW

In this manuscript, we review current surveillance guidelines for serrated polyps (SPs) and discuss how recent studies inform the selection of appropriate surveillance intervals for patients with SPs.

RECENT FINDINGS

Large and/or proximal SPs, particularly sessile serrated polyps (SSPs), are associated with increased risk of both synchronous and metachronous neoplasia, including advanced adenomas and colorectal cancer (CRC). Persons harboring multiple SSPs or dysplastic SSPs are at the highest risk. Moreover, a high percentage of large and/or proximal SPs are reclassified as SSPs when read by trained gastrointestinal pathologists, even if they were originally reported as hyperplastic polyps. These findings support the adoption of surveillance guidelines that prescribe closer surveillance of large and/or proximal SPs, regardless of subtype. SSPs remain a challenge to reliably identify, resect, and diagnose via histology. The increased risk of future neoplasia in patients with SSPs is likely driven by a combination of underdetection, inadequate removal, misclassification, and biology. Until further evidence emerges, we support guidelines that recommend close surveillance of patients with a history of large and/or proximal SPs and SSPs specifically in order to mitigate the threat of interval CRC.

Serrated lesions and serrated polyposis syndrome

The serrated pathway has been shown to be an alternative colorectal carcinogenetic route potentially accounting for up to one third of all CRCs. Serrated lesions, particularly SSPs, have been a focus of research during the past few years. They have well-established histological and molecular characteristics that account for their potential carcinogenetic risk through the accumulation BRAF, KRAS and methylator profile (CpG) mutations. Their endoscopic identification and resection represent a challenge because of their specific characteristics, and the need for an adequate specimen for histological diagnosis. Knowledge of these lesions is key, as is the adoption of established criteria for their endoscopic description and histological diagnosis. SPS is the maximum expression of involvement by serrated lesions, is associated with increased risk for CRC, and requires attentive endoscopic follow-up, as well as family screening. While the exact etiopathogenic mechanism remains unknown, current research will likely provide us with appropriate answers in the not too distant future.

Water Exchange Method Significantly Improves Adenoma Detection Rate: A Multicenter, Randomized Controlled Trial

OBJECTIVES

Adenoma detection rate (ADR) is a key colonoscopy quality indicator in Western clinical literature. Our low ADR prompted us to assess novel methods to improve performance. Western retrospective reports suggested that water exchange (WE) could increase ADR. However, most of these studies used pain score or intubation rate as the primary outcome. Here we test the hypothesis that WE significantly increases ADR among Chinese colonoscopists and design a prospective randomized controlled trial using ADR as our primary outcome.

METHODS

This prospective, randomized controlled trial was performed at six centers in China. Screening, surveillance, and diagnostic cases were randomized to be examined by WE or traditional air insufflation (AI) method. The primary outcome was ADR.

RESULTS

From April 2014 to July 2015, 3,303 patients were randomized to WE (n=1,653) and AI (n=1,650). The baseline characteristics were comparable. Overall ADR was 18.3% (WE) and 13.4% (AI) (relative risk 1.45, 95% confidential interval: 1.20-1.75, P<0.001). ADR in screening patients using AI was 25.8% (male) and 15.7% (female). ADR in screening patients aged >50 years old was 29.4% (WE) and 22.9% (AI) (relative risk 1.09, 95% confidential interval: 1.00-1.19, P=0.040). The increase by WE was reproducibly observed in all indication categories, and significant in screening and diagnostic cases. The limitation imposed by the unblinded investigators was mitigated by comparable inspection times in cases without polyps, similar adenoma per positive colonoscopy, and reproducible enhancement of ADR and adenoma per colonoscopy by WE across all eight investigators.

CONCLUSIONS

This prospective study confirms Western retrospective data that WE significantly improves ADR among Chinese colonoscopists. WE may be superior to AI for screening colonoscopy in China. Colonoscopists elsewhere with low ADR might consider evaluating WE for performance improvement.

Clinicopathological characteristics of serrated polyps as precursors to colorectal cancer: Current status and management

Serrated polyps have long been thought to lack malignant potential in the human colorectum. However, identification of the serrated pathway to colorectal cancer based on molecular biology has improved our understanding of the pathogenesis of colorectal cancers. Accordingly, serrated polyps such as traditional serrated adenoma and sessile serrated adenoma/polyps (SSA/P) are now considered to be precursor lesions of the serrated pathway. Recently, serrated polyps were classified into three subtypes, consisting of hyperplastic polyp, SSA/P, and traditional serrated adenoma, according to the World Health Organization classification. It has been suggested that SSA/P in the proximal colon are a precursor lesion of pathogenesis of colorectal cancer and are characterized by BRAF mutation and a CpG island methylator phenotype with or without microsatellite instability. However, SSA/P is more challenging to detect by colonoscopy and is likely to account for some interval cancers, particularly in the proximal colon because it presents flat or sessile, isochroous appearance, and occasionally has a mucous cap. Furthermore, the possibility has been raised that pathologists misclassify SSA/P as hyperplastic polyp. It is important for gastroenterologists to recognize the endoscopic features of serrated polyps to facilitate their detection and removal and also to establish postpolypectomy surveillance guidelines. In this review, we discuss the recent classification of serrated polyps; the molecular characteristics of the serrated pathway; appropriate diagnostic methods using endoscopy, including a new image-enhanced endoscopic technique; and management of these lesions.