Reporting trends of right-sided hyperplastic and sessile serrated polyps in a large teaching hospital over a 4-year period (2009-2012)

Adherence to the World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations throughout the life course and risk of colorectal cancer precursors

BACKGROUND

Despite the increasing incidence in colorectal cancer (CRC) among the young population, the involvement of modifiable early-life exposures is understudied.

METHODS

We prospectively investigated the association of lifestyle score, which measures adherence to the 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) cancer prevention recommendations, in adolescence and adulthood with risk of CRC precursors in 34,509 women enrolled in the Nurses' Health Study II. Participants reported adolescent diet in 1998 and subsequently underwent at least one lower gastrointestinal endoscopy between 1999 and 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression for clustered data.

RESULTS

During follow-up (1998-2015), 3036 women had at least one adenoma, and 2660 had at least one serrated lesion. In multivariable analysis, per unit increase in adolescent WCRF/AICR lifestyle score was not associated with risk of total adenoma or serrated lesions, in contrast to adult WCRF/AICR lifestyle score (OR = 0.92, 95% CI: 0.87-0.97, Ptrend = 0.002 for total adenoma; and OR = 0.86, 95% CI: 0.81-0.92, Ptrend < 0.001 for total serrated lesions).

CONCLUSION

Adherence to the 2018 WCRF/AICR recommendations during adulthood but not during adolescence was associated with a lower risk of CRC precursors.

Microvesicular hyperplastic polyp and sessile serrated lesion of the large intestine: a biological continuum or separate entities?

The range of lesions with a serrated appearance within the large intestine has expanded and become more complex over the last 30 years. The majority of these were previously known as metaplastic polyps but are today called hyperplastic polyps (HPs). HPs show two main growth patterns: microvesicular and goblet cell-rich. The former type shows morphological and molecular similarities (eg, BRAF mutations) to the more recently described sessile serrated lesion (SSL). In this review, we debate whether these lesions represent a biological spectrum or separate entities. Whichever view is held, microvesicular HPs and SSLs are distinct from the goblet cell-rich HP and the traditional serrated adenoma (TSA), which may themselves share molecular changes (eg, KRAS mutations), with the goblet cell-rich HP representing a precursor to the TSA. Both SSLs and the goblet cell-rich HP-TSA pathway are routes to colorectal cancer within the serrated pathway and overlaps between them can occur, for example, a (BRAF-mutated) TSA may arise from an SSL.

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.

A Polyp Worth Removing: A Paradigm for Measuring Colonoscopy Quality and Performance of Novel Technologies for Polyp Detection

Leaving no significant polyp behind while avoiding risks due to unnecessary resections is a commonsense strategy to safely and effectively prevent colorectal cancer (CRC) with colonoscopy. It also alludes to polyps worth removing and, therefore, worth finding. The majority of "worthy" precancerous polyps are adenomas, which for over 2 decades, have received the most attention in performance research and metrics. Consequently, the detection rate of adenomas is currently the only validated, outcome-based measure of colonoscopy demonstrated to correlate with reduced risk of postcolonoscopy CRC. However, a third or more of postcolonoscopy CRCs originate from sessile serrated polyps (SSPs), which are notoriously difficult to find, diagnose and completely resect. Among serrated polyps, the agreement among pathologists differentiating SSPs from non-neoplastic hyperplastic polyps is moderate at best. This lack of ground truth precludes SSPs from consideration in primary metrics of colonoscopy quality or performance of novel polyp detection technologies. By instead leveraging the distinct endoscopic and clinical features of serrated polyps, including those considered important due to proximal location and larger size, clinically significant serrated polyps represent serrated polyps worth removing, enriched with subtle precancerous SSPs. With the explosion of technologies to assist polyp detection, now is the time to broaden benchmarks to include clinically significant serrated polypss alongside adenomas, a measure that is relevant both for assessing the performance of endoscopists, and for assessing new polyp detection technologies.

Simple Sugar and Sugar-Sweetened Beverage Intake During Adolescence and Risk of Colorectal Cancer Precursors

BACKGROUND & AIMS

Recent increasing trends in early-onset colorectal cancer (CRC) strongly supports that early-life diet is involved in CRC development. However, data are lacking on the relationship with high sugar intake during early life.

METHODS

We prospectively investigated the association of adolescent simple sugar (fructose, glucose, added sugar, total sugar) and sugar-sweetened beverage (SSB) intake with CRC precursor risk in 33,106 participants of the Nurses' Health Study II who provided adolescent dietary information in 1998 and subsequently underwent lower gastrointestinal endoscopy between 1999 and 2015. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression for clustered data.

RESULTS

During follow-up, 2909 conventional adenomas (758 high-risk) and 2355 serrated lesions were identified (mean age at diagnoses, 52.2 ± 4.3 years). High sugar and SSB intake during adolescence was positively associated with risk of adenoma, but not serrated lesions. Per each increment of 5% of calories from total fructose intake, multivariable ORs were 1.17 (95% CI, 1.05-1.31) for total and 1.30 (95% CI, 1.06-1.60) for high-risk adenoma. By subsite, ORs were 1.12 (95% CI, 0.96-1.30) for proximal, 1.24 (95% CI, 1.05-1.47) for distal, and 1.43 (95% CI, 1.10-1.86) for rectal adenoma. Per 1 serving/day increment in SSB intake, ORs were 1.11 (95% CI, 1.02-1.20) for total and 1.30 (95% CI, 1.08-1.55) for rectal adenoma. Contrary to adolescent intake, sugar and SSB intake during adulthood was not associated with adenoma risk.

CONCLUSIONS

High intake of simple sugars and SSBs during adolescence was associated with increased risk of conventional adenoma, especially rectal adenoma.

The spectrum of serrated colorectal lesions-new entities and unanswered questions

Hyperplastic polyps (HPs) of the colon and rectum were historically thought not to be associated with an increased risk of development of colorectal cancer (CRC). The recognition of variants of serrated colorectal lesions that possessed relatively subtle but significant morphological differences from those of HPs and that could be associated with epithelial dysplasia and CRC led to the characterisation of sessile serrated lesions (SSLs) and traditional serrated adenomas (TSAs). These links were supported by the identification of genetic alterations that are commonly found in HPs, SSLs, TSAs, and CRC, e.g. BRAF and KRAS mutations. The 'serrated pathway' to CRC may progress faster than the traditional 'adenoma-carcinoma sequence', underlining the importance of identifying these lesions. The diagnostic histological criteria for SSLs have since been more clearly defined, in parallel with a drive to increase the recognition of these lesions at endoscopy. The existence of lesions showing overlapping morphological and molecular features with those of HPs, SSLs and TSAs has most recently been highlighted-including mucin-rich TSA, serrated tubulovillous adenoma, and those showing mixed histological features, e.g. comprising differing combinations of HP, SSL, and TSA. Morphological and molecular studies of this range of lesions are providing insights into the relationships of serrated colorectal lesions with each other and with CRC. This article provides an overview of the current understanding of serrated colorectal lesions, including a discussion of those with overlapping and mixed features.

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.

Long-term Risk of Colorectal Cancer After Removal of Conventional Adenomas and Serrated Polyps

BACKGROUND & AIMS

Endoscopic screening reduces incidence and mortality of colorectal cancer (CRC) because precursor lesions, such as conventional adenomas or serrated polyps, are removed. Individuals with polypectomies are advised to undergo colonoscopy surveillance to prevent CRC. However, guidelines for surveillance intervals after diagnosis of a precursor lesion, particularly for individuals with serrated polyps, vary widely, and lack sufficient supporting evidence. Consequently, some high-risk patients do not receive enough surveillance and lower-risk subjects receive excessive surveillance.

METHODS

We examined the association between findings from first endoscopy and CRC risk among 122,899 participants who underwent flexible sigmoidoscopy or colonoscopy in the Nurses' Health Study 1 (1990-2012), Nurses' Health Study 2 (1989-2013), or the Health Professionals Follow-up Study (1990-2012). Endoscopic findings were categorized as no polyp, conventional adenoma, or serrated polyp (hyperplastic polyp, traditional serrated adenoma, or sessile serrated adenoma, with or without cytological dysplasia). Conventional adenomas were classified as advanced (≥10 mm, high-grade dysplasia, or tubulovillous or villous histology) or nonadvanced, and serrated polyps were assigned to categories of large (≥10 mm) or small (<10 mm). We used a Cox proportional hazards regression model to calculate the hazard ratios (HRs) of CRC incidence, after adjusting for various potential risk factors.

RESULTS

After a median follow-up period of 10 years, we documented 491 incident cases of CRC: 51 occurred in 6161 participants with conventional adenomas, 24 in 5918 participants with serrated polyps, and 427 in 112,107 participants with no polyp. Compared with participants with no polyp detected during initial endoscopy, the multivariable HR for incident CRC in individuals with an advanced adenoma was 4.07 (95% confidence interval [CI] 2.89-5.72) and the HR for CRC in individuals with a large serrated polyp was 3.35 (95% CI 1.37-8.15). In contrast, there was no significant increase in risk of CRC in patients with nonadvanced adenomas (HR 1.21; 95% CI 0.68-2.16, P = .52) or small serrated polyps (HR 1.25; 95% CI 0.76-2.08; P = .38).

CONCLUSIONS

These findings provide support for guidelines that recommend repeat lower endoscopy within 3 years of a diagnosis of advanced adenoma and large serrated polyps. In contrast, patients with nonadvanced adenoma or small serrated polyps may not require more intensive surveillance than patients without polyps.

Colorectal polyp prevalence and aspirational detection targets determined using high definition colonoscopy and a high level detector in 2017

BACKGROUND

Colorectal adenoma prevalence can be determined by autopsy studies, or imaging studies such as colonoscopy. We describe the prevalence of colorectal adenomas determined by a single high detecting colonoscopist using high definition colonoscopes.

METHODS

We conducted a cross-sectional study of consecutive patients aged ≥18 years undergoing colonoscopy with a high level detector for the indications of screening, surveillance, and diagnostic reasons from December 29, 2016 to January 12, 2018.

RESULTS

During the study period, 1172 eligible patients underwent colonoscopy. Women comprised 55% (n = 646) and the majority (89%, n = 1038) were aged ≥50 years (mean age, 62.1 years). In persons aged ≥50 years undergoing screening, the prevalence of ≥1 conventional adenoma was 48.5% and ≥1 sessile serrated polyp was 15.3%. Diminutive polyps (1-5 mm in size) comprised three-quarters of all resected polyps (2236/2986). Among 246 patients (21%), 1050 hyperplastic appearing polyps were not resected from the recto-sigmoid. Adenoma prevalence was strongly associated with age and indication but serrated lesion prevalence was not.

CONCLUSIONS

The true prevalence of precancerous lesions in the colorectum determined by modern colonoscopy exceeds determination by autopsy studies. These data help define aspirational detection targets for colonoscopy. The economic burden associated with colonoscopic resection of tiny lesions is substantial.

A randomized clinical prospective trial comparing split-dose picosulfate/ magnesium citrate and polyethylene glycol for colonoscopy preparation

Background

Colonoscopy remains the gold standard for the investigation of abnormalities within the colon. However, its success is highly dependent on the quality of bowel preparation. The objective of this study was to compare the bowel preparation efficacy of picosulfate/magnesium citrate (PMC) vs polyethylene glycol (PEG) in a one-day vs two-day split dose regimen.

Methods

A prospective, randomized, controlled trial was conducted at the Forzani & MacPhail Colon Cancer Screening Centre in Calgary, Canada. 171 colonoscopy outpatients were randomized to split-dose PMC or PEG lavage as well as into one-day split or two-day split regimens in blocks of eight. Bowel preparation quality was recorded in a blinded manner by the endoscopist using the Ottawa Bowel Preparation Scale (OBPS) prior to washing or suctioning. The scale results were analyzed using a two-factor analysis of variance.

Results

141 patients received complete colonoscopies (PMC-71; PEG-70). PEG was found to be superior to PMC (mean OBPS: 4.14 ± 2.64 vs 5.11 ± 3.44, p = 0.019), when adjusted for administration regimen, leading to significantly more adequate bowel preparations (79.7% vs 59.7%, p = 0.007). A two-day split dose was superior to a one-day split dose regimen (mean OBPS: 3.68± 2.82 vs 5.69 ± 3.06, p<0.001). Two-day split dosing also resulted in a better right colon cleanliness score (right bowel OBPS 1.27±0.11 vs 2.10±0.12 for one-day split, P<0.001).

Conclusions

Optimal bowel preparation was achieved with the use of PEG lavage when administered in a two-day split dose regimen. This trial is registered with ClinicalTrials.gov under identifier NCT01415687.

Colorectal Serrated Neoplasia: An Institutional 12-Year Review Highlights the Impact of a Screening Programme

Background

As the malignant potential of sessile serrated lesions/polyps (SSL/Ps) and traditional serrated adenomas (TSAs) has been clearly demonstrated, it is important that serrated polyps are identified and correctly classified histologically.

Aim

Our aim was to characterize the clinicopathological features of a series of SSL/Ps & TSAs, to assess the accuracy of the pathological diagnosis, the incidence, and the rate of dysplasia in SSL/Ps & TSAs.

Methods

We identified all colorectal serrated polyps between 01/01/2004 and 31/05/2016, by searching the laboratory information system for all cases assigned a “serrated adenoma” SNOMED code. All available and suitable slides were reviewed by one pathologist, who was blinded to the original diagnosis and the site of the polyp. Subsequently discordant cases, SSL/Ps with dysplasia, and all TSAs were reviewed by a second pathologist.

Results

Over a 149-month period, 759 “serrated adenoma” polyps were identified, with 664 (from 523 patients) available for review. 41.1% were reviewed by both pathologists; 15.1% (100/664) were reclassified, with the majority being changed from SSL/P to hyperplastic polyp (HYP) (66/664; 9.9%). 80.3% of these HYPs were located in the left colon, and the majority exhibited prolapse effect. There were 520 SSL/Ps (92.2%) & 40 TSAs (7.1%). The majority of SSL/Ps were in the right colon (86.7%) and were small (64.5% <1 cm), while most TSAs were in the left colon (85.7%) and were large (73.1%≥1 cm). 6.7% of SSL/Ps exhibited dysplasia, the majority of which were large (66.7%≥1 cm). Following consensus review, 13/520 (2.5%) SSL/Ps were downgraded from SSL/P with dysplasia to SSL/P without dysplasia. Detection of SSL/Ps peaked in the most recent years reviewed (87.5% reported between 2013 and 2016, inclusive), coinciding with the introduction of “BowelScreen” (the Irish FIT-based colorectal cancer screening programme).

Conclusions

Awareness of, and adherence to, diagnostic criteria is essential for accurate classification of colorectal polyps.

Endoscopic diagnosis of sessile serrated polyp: A systematic review

The aim of the present review was to clarify how we should detect and diagnose sessile serrated polyps (SSP) endoscopically. A systematic search was conducted of MEDLINE from January 2004 through March 2018. Nine findings: (i) proximal location; (ii) size >10 mm; (iii) irregular shape; (iv) indistinctive border; (v) cloud-like surface; (vi) mucus cap; (vii) rim of debris in white-light endoscopy; (viii) dilated vessels; and (ix) dilated crypts (pits) in image-enhanced endoscopy were considered to be candidate discriminators of SSP from hyperplastic polyps. Prospective studies in a general setting are warranted to validate the above-mentioned endoscopic features of SSP during real-time colonoscopy and to determine whether these features are useful for the differential diagnosis of SSP.

Variation in Pathologist Classification of Colorectal Adenomas and Serrated Polyps

OBJECTIVES

Endoscopist quality measures such as adenoma detection rate (ADR) and serrated polyp detection rates (SPDRs) depend on pathologist classification of histology. Although variation in pathologic interpretation is recognized, we add to the literature by quantifying the impact of pathologic variability on endoscopist performance.

METHODS

We used natural language processing to abstract relevant data from colonoscopy and related pathology reports performed over 2 years at four clinical sites. We quantified each pathologist's likelihood of classifying polyp specimens as adenomas or serrated polyps. We estimated the impact on endoscopists' ADR and SPDR of sending their specimens to pathologists with higher or lower classification rates.

RESULTS

We observed 85,526 colonoscopies performed by 119 endoscopists; 50,453 had a polyp specimen, which were analyzed by 48 pathologists. There was greater variation across pathologists in classification of serrated polyps than in classification of adenomas. We estimate the endoscopist's average SPDR would be 0.5% if all their specimens were analyzed by the pathologist in our sample with the lowest classification rate and 12.0% if all their specimens were analyzed by the pathologist with the highest classification rate. In contrast, the endoscopist's average ADR would be 28.5% and 42.4% if their specimens were analyzed by the pathologist with lowest and highest classification rate, respectively.

CONCLUSIONS

There is significant variation in pathologic interpretation, which more substantially affects endoscopist SPDR than ADR.

Risk of colorectal polyps and of malignancies in asymptomatic carriers of mutations in the main DNA mismatch repair genes

OBJECTIVE

Mutation carriers (Mut+) in DNA mismatch repair genes are predisposed to cancer of various organs and to adenomatous polyps; however, they may remain asymptomatic and cancer or polyp-free for several years. We purposed to analyse the clinical follow-up of individuals carrying constitutional mutations in the MLH1, MSH2 or MSH6 genes who were unaffected by benign polyps or malignant tumours at diagnosis.

MATERIAL AND METHODS

Mut + subjects (n.81) were members of Lynch syndromes in whom mutations were detected between 1993 and 2015; all were asymptomatic at diagnosis. They were informed of the cancer risk and surveillance was suggested. As controls, 113 nongene carriers (Mut-) in the same Lynch families were identified.

RESULTS

About one-fourth of the mutation carriers developed polyps, mostly adenomas; polyps were less (12%, p < .05) in Mut - subjects, and hyperplastic lesions were the prevalent histology. More polyps were detected in MLH1 vs. MSH2 mutation carriers. In Mut+, 21 malignant tumours developed in 14 carriers vs. 4 tumours in 3 patients among Mut- (p < .001). Tumours were mostly of the Lynch spectrum; however, three glioblastomas were developed, together with neoplasms of various organs (duodenum, thyroid, skin, lung and cervix). Mean age of tumour occurrence was 43.0 years in Mut + vs. 53.0 among Mut-.

CONCLUSIONS

Cancer developed more often in Mut+, with no consistent difference between MLH1 and MSH2 carriers. More polyps (mostly adenomas) were detected in MLH1 carriers. The majority (13 of 21) of malignant tumours occurred in organs for which there is no recommended surveillance, and were lethal in three patients.

Proximal Aberrant Crypt Foci Associate with Synchronous Neoplasia and Are Primed for Neoplastic Progression

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion found within the human colon. Despite their relatively high frequency in the distal colon, few studies have examined the molecular characteristics of ACF within the proximal colon. In the following study, clinical participants (n = 184) were screened for ACF using high-definition chromoendoscopy with contrast dye-spray. Following pathologic confirmation, ACF biopsies were subjected to laser capture microdissection (LCM), and epithelial cells were evaluated for somatic mutations with a customized colorectal cancer mutation panel using DNA-mass spectrometry. Samples were further characterized for microsatellite instability (MSI). Logistic models were used to associate proximal ACF with synchronous (detected during the same procedure) neoplasia. Thirty-nine percent of participants had at least one histologically confirmed proximal ACF. Individuals with a proximal ACF were significantly more likely to present with a synchronous neoplasm (P = 0.001), and specifically, a proximal, tubular, or tubulovillous adenoma (multivariable OR = 2.69; 95% confidence interval, 1.12-6.47; P = 0.027). Proximal ACF were more likely to be dysplastic (52%) compared with distal ACF (13%; P < 0.0001). Somatic mutations to APC, BRAF, KRAS, NRAS, and ERBB2 were detected in 37% of proximal ACF. Hyperplastic ACF were more often MSI-high, but there were no differences in MSI status observed by colonic location. In summary, ACF are identified in the proximal colons of approximately 40% of individuals undergoing chromoendoscopy and more often in patients with synchronous proximal adenomas.Implications: This study provides the most complete set of data, to date, that ACF represent the earliest step in the adenoma-carcinoma sequence but remain below the detection limit of conventional endoscopy.Visual Overview: http//mcr.accrjournals.org/content/molcanres/16/3/486/F1.large.jpg Mol Cancer Res; 16(3); 486-95. ©2017 AACR.

Attenuated polyposis of the large bowel: a morphologic and molecular approach

Attenuated polyposis could be defined as a variant of familial adenomatous polyposis (FAP) in which synchronous polyps of the large bowel range between 10 and 99. We analysed all cases of attenuated polyposis observed over the last 30 years with the objectives: (A) to classify the disease according to different type and proportion of polyps; (B) To ascertain the contribution of APC and MutYH genes; (C) to discover features which could arise the suspicion of mutations; (D) To obtain indications for management and follow-up. 84 individuals in 82 families were studied. Polyps were classified into four groups as adenoma, hyperplastic, other serrated lesions or others; APC and MutYH mutations were assessed. Mean age at diagnosis was 54 ± 14 years in men and 48 ± 13 in women (P = 0.005). Polyps were more numerous in women (37 ± 26 vs 29 ± 22). Sixty % of patients underwent bowel resection, mainly for cancer; the remaining were managed through endoscopy. A total of 2586 polyps were detected at diagnostic endoscopy: 2026 (80 %) were removed and analysed. Adenomas were diagnosed in 1445 (70 %), hyperplastic polyps in 541 (26 %), other serrated lesions in 61 (2.9 %). Adenomas and hyperplastic lesions were detected in the majority of patients. In 68 patients (81 %) in whom studies were executed, APC mutations were found in 8 and MutYH mutations in 10. Genetic variants were more frequent in women (12 vs 6, P = 0.039). Taking into consideration the prevalent (>50 %) histology and presence of mutations, patients could be subdivided into four groups: (1) APC mutated polyposis (AFAP), when adenomas were >50 % and APC mutations detected (no. 8, 10 %); (2) MutYH mutated polyposis (MAP), adenomas >50 % and biallelic MutYH mutations (no. 10, 12 %); (1) attenuated polyposis without detectable mutations, prevalence of adenomas, 48 cases (57 %); (1) hyperplastic-serrated polyposis, with prevalence (>50 %) of hyperplastic/other serrated lesions and no constitutional mutation (no. 18, 21 %). Aggregation of tumors, cancer in probands, distribution of polyps and other clinical characteristics showed no difference among the four groups. In conclusions, AFAP and MAP, the polyposis labeled by constitutional mutations, represented about 25 % of all attenuated polyposis. Mutation-associated cases showed an earlier age of onset of polyps and were more frequent in the female sex.

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.

Attenuated adenomatous polyposis of the large bowel: Present and future

Attenuated adenomatous polyposis (AAP) is a poorly understood syndrome, that can be defined as the presence of 10-99 synchronous adenomas in the large bowel, and it is considered a phenotypic variant of familial adenomatous polyposis (FAP). This definition has the advantage of simplicity, but it may include sporadic multiple adenomas of the large bowel at an extreme, or FAP cases on the other side. AAP shows a milder phenotype than FAP, with an older age of onset of adenomas and cancer, and less frequent extracolonic manifestations. AAP may be diagnosed as a single case in a family or, less frequently, it may be present in other family members, and it shows distinct pattern of inheritance. In less than 50% of cases, it may be caused by adenomatous polyposis coli (APC) or MUTYH mutations, referred to as APC-associated polyposis, inherited as an autosomal dominant trait, or MUTYH-associated polyposis, which shows an autosomal recessive mechanism of inheritance, respectively. Surveillance should rely on colonoscopy at regular intervals, with removal of adenomas and careful histological examination. When removal of polyps is not possible or advanced lesions are observed, the surgical approach is mandatory, being subtotal colectomy with ileo-rectal anastomosis the treatment of choice. Studies on this syndrome are lacking, and controversies are still present on many issues, thus, other clinical and genetic studies are requested.

The clinical impact of serrated colorectal polyps

Serrated polyps (SPs) of the colorectum pose a novel challenge to practicing gastroenterologists. Previously thought benign and unimportant, there is now compelling evidence that SPs are responsible for a significant percentage of incident colorectal cancer worldwide. In contrast to conventional adenomas, which tend to be slow growing and polypoid, SPs have unique features that undermine current screening and surveillance practices. For example, sessile serrated polyps (SSPs) are flat, predominately right-sided, and thought to have the potential for rapid growth. Moreover, SSPs are subject to wide variations in endoscopic detection and pathologic interpretation. Unfortunately, little is known about the natural history of SPs, and current guidelines are based largely on expert opinion. In this review, we outline the current taxonomy, epidemiology, and management of SPs with an emphasis on the clinical and public health impact of these lesions.

Clinicopathological and molecular features of sessile serrated adenomas with dysplasia or carcinoma

OBJECTIVE

Sessile serrated adenomas (SSAs) are the precursors of at least 15% of colorectal carcinomas, but their biology is incompletely understood. We performed a clinicopathological and molecular analysis of a large number of the rarely observed SSAs with dysplasia/carcinoma to better define their features and the pathways by which they progress to carcinoma.

DESIGN

A cross-sectional analysis of 137 SSAs containing regions of dysplasia/carcinoma prospectively collected at a community GI pathology practice was conducted. Samples were examined for BRAF and KRAS mutations, the CpG island methylator phenotype (CIMP) and immunostained for MLH1, p53, p16, β-catenin and 0-6-methylguanine DNA methyltransferase (MGMT).

RESULTS

The median polyp size was 9 mm and 86.5% were proximal. Most were BRAF mutated (92.7%) and 94.0% showed CIMP. Mismatch repair deficiency, evidenced by loss of MLH1 (74.5%) is associated with older age (76.7 versus 71.0; p<0.0029), female gender (70% versus 36%; p<0.0008), proximal location (91% versus 72%; p<0.02), CIMP (98% versus 80%; p<0.02) and lack of aberrant p53 (7% versus 34%; p<0.001) when compared with the mismatch repair-proficient cases. Loss of p16 (43.1%) and gain of nuclear β-catenin (55.5%) were common in areas of dysplasia/cancer, irrespective of mismatch repair status.

CONCLUSIONS

SSAs containing dysplasia/carcinoma are predominantly small (<10 mm) and proximal. The mismatch repair status separates these lesions into distinct clinicopathological subgroups, although WNT activation and p16 silencing are common to both. Cases with dysplasia occur at a similar age to cases with carcinoma. This, together with the rarity of these 'caught in the act' lesions, suggests a rapid transition to malignancy following a long dwell time as an SSA without dysplasia.

Colorectal Cancer Risk Following Adenoma Removal: A Large Prospective Population-Based Cohort Study

BACKGROUND

Randomized controlled trials have demonstrated significant reductions in colorectal cancer incidence and mortality associated with polypectomy. However, little is known about whether polypectomy is effective at reducing colorectal cancer risk in routine clinical practice. The aim of this investigation was to quantify colorectal cancer risk following polypectomy in a large prospective population-based cohort study.

METHODS

Patients with incident colorectal polyps between 2000 and 2005 in Northern Ireland were identified via electronic pathology reports received to the Northern Ireland Cancer Registry. Patients were matched to the Northern Ireland Cancer Registry to detect colorectal cancer and deaths up to December 31, 2010. Colorectal cancer standardized incidence ratios (SIR) were calculated and Cox proportional hazards modeling applied to determine colorectal cancer risk.

RESULTS

During 44,724 person-years of follow-up, 193 colorectal cancer cases were diagnosed among 6,972 adenoma patients, representing an annual progression rate of 0.43%. Colorectal cancer risk was significantly elevated in patients who had an adenoma removed (SIR, 2.85; 95% CI, 2.61-3.25) compared with the general population. Male sex, older age, rectal site, and villous architecture were associated with an increased colorectal cancer risk in adenoma patients. Further analysis suggested that not having a full colonoscopy performed at, or following, incident polypectomy contributed to the excess colorectal cancer risk.

CONCLUSIONS

Colorectal cancer risk was elevated in individuals following polypectomy for adenoma, outside of screening programs.

IMPACT

This finding emphasizes the need for full colonoscopy and adenoma clearance, and appropriate surveillance, after endoscopic diagnosis of adenoma.

UK guidance for the pathological reporting of serrated lesions of the colorectum

Bowel cancer screening programmes have highlighted to endoscopists and clinicians the spectrum of serrated colorectal lesions. One of the most significant developments has been the recognition that sessile serrated lesions (SSLs), while bearing histological resemblance to hyperplastic polyps (HPs), may be associated with the enhanced development of epithelial dysplasia and colorectal adenocarcinoma. Different minimum criteria exist for the diagnosis of SSLs and their differentiation from HPs. Furthermore, the spectrum of terminology used to describe the entire range of serrated lesions is wide. This variability has impaired interobserver agreement during their histopathological assessment. Here, we provide guidance for the histopathological reporting of serrated lesions, including a simplified nomenclature system. Essentially, we recommend use of the following terms: HP, SSL, SSL with dysplasia, traditional serrated adenoma (TSA) and mixed polyp. It is hoped that this standardisation of nomenclature will facilitate studies of the biological significance of serrated lesions in terms of the relative risk of disease progression.

Sessile serrated adenoma: from identification to resection

Until the past two decades, almost all colorectal polyps were divided into two main groups: hyperplastic polyps and adenomas. Sessile serrated adenomas presented endoscopic, pathological and molecular profiles distinct from others polyps. Previously under-diagnosed, physicians now identified sessile serrated adenomas. The serrated neoplastic pathway is accounting for up to one-third of all sporadic colorectal cancers and sessile serrated adenomas have been identified as the main precursor lesions in serrated carcinogenesis. By analogy with the adenoma-adenocarcinoma sequence, the sessile serrated adenomas-adenocarcinoma sequence, has been identified. The development of endoscopic resection techniques permits the consideration of a non-surgical approach as the first option regardless of the size of the lesion. Sessile serrated adenoma warrants the watchfulness of physicians and requires an optimal quality of the colonoscopy procedure, a thorough evaluation of the lesion, an adequate endoscopic resection and follow-up colonoscopies in accordance with sessile serrated adenomas guidelines. We herein present a review on sessile serrated adenomas focusing on their pathological specificities, epidemiology, treatment modalities and follow-up.

Sessile serrated adenomas: an evidence-based guide to management

The concept of serrated colorectal neoplasia and a serrated pathway to colorectal cancer (CRC) is relatively new and continuing to evolve, but it has become highly relevant to gastroenterologists, pathologist, and oncologists alike. Sessile serrated adenomas (SSA) are now thought to be the major precursor lesion of serrated pathway cancers, which represent up to one-third of all sporadic CRC cases. However, despite their increasingly recognized importance, relatively little is known about the epidemiology and natural history of SSAs, and the molecular and epigenetic aspects are incompletely understood. Endoscopists must be aware of the unique features of SSAs so that the practice of colonoscopic screening for CRC can include optimized detection, removal, and appropriate surveillance of SSAs and other serrated precursor lesions. In this review, we discuss the history, epidemiology, and pathologic aspects of SSAs, as well as a recommended management approach and a discussion of uncertainties and opportunities for future research.

Management of sessile malignant polyps: is colonoscopic polypectomy enough?

BACKGROUND

The role of endoscopy in the management of malignant-pedunculated polyps has been well studied, but endoscopic management of malignant sessile polyps has not. Sometimes patients with malignant sessile polyps have comorbidities that make surgery exceptionally risky, and endoscopy beckons as a definitive management option. The aim of this study is to evaluate the potential role of endoscopy in the management of malignant sessile polyps.

METHODS

Patients undergoing colonoscopic polypectomy for malignant sessile polyps by a single endoscopist from 1997 to 2010 were evaluated. Demographic data, clinicopathological variables as well as long-term outcomes were recorded.

RESULTS

Sixteen patients had malignant sessile polyps. Six (37.5 %) were male and 10 (62.5 %) were female. Mean age at diagnosis was 72.9 ± 12.2 years. Six polyps were proximal to the splenic flexure (37.5 %) and 10 (62.5 %) were distal. The mean size of the polyps was 30.5 ± 15.9 mm. All polyps were removed endoscopically but 7 patients (43.8 %) had formal colectomy following colonoscopic resection. There were no demographic differences between patients with and without surgery. Piecemeal polypectomy was necessary in 8 patients, 4 from the surgery group, and 4 from the endoscopy group. More patients in the surgery group had poorly differentiated cancers (4/6 vs. 0/6) and incomplete margins (5/6 vs. 1/6) and more patients in the endoscopically treated group had serious comorbidity (5/9 vs. 3/7). There was no procedure-related morbidity or mortality. After a mean follow-up of 48.4 ± 27.2 months, one patient from the polypectomy group patient had a local recurrence and a liver metastasis, after originally declining surgery. In the surgery group, one patient had lung metastasis. The two patients who recurred with distant metastasis died.

CONCLUSION

Endoscopic management of sessile colorectal polyps appears to be feasible and safe in patients with well/moderately differentiated cancer and negative margins. Larger studies are needed to confirm these findings.

Pathology of serrated colorectal lesions

The concept of serrated colorectal neoplasia has become recognised as a key process in the development of colorectal cancer (CRC) and an important alternative pathway to malignancy compared with the long established ‘adenoma-carcinoma’ sequence. Increasing recognition of the morphological spectrum of serrated lesions has occurred in parallel with elucidation of the distinct molecular genetic characteristics of progression from normal mucosa, via the ‘serrated pathway’, to CRC. Some of these lesions can be difficult to identify at colonoscopy. Challenges for pathologists include the requirement for accurate recognition of the forms of serrated lesions that are associated with a significant risk of malignant progression and therefore the need for widely disseminated reproducible criteria for their diagnosis. Alongside this process, pathologists and endoscopists need to formulate clear guidelines for the management of patients with these lesions, particularly with respect to the optimal follow-up intervals. This review provides practical guidance for the recognition of these lesions by pathologists, a discussion of ‘serrated adenocarcinoma’ and an insight into the distinct molecular genetic alterations that are seen in this spectrum of lesions in comparison to those that characterise the classic ‘adenoma-carcinoma’ sequence.

Colorectal serrated pathway cancers and precursors

The serrated pathway (SP) can be viewed as two parallel, but partially overlapping, arrays of colorectal precursor lesions, and their respective endpoint carcinomas, that are distinct from those of the conventional adenoma-carcinoma sequence (APC-pathway). In this review we focus at the outset on the clinical impact, pathological features, molecular genetics and biological behaviours of the various SP cancers. Then we summarize the clinicopathological features, classification and molecular profiles of the two main precursor lesions that anchor the respective pathways: (i) sessile serrated adenoma/polyp (SSA/P), also called sessile serrated lesion (SSL), and (ii) traditional serrated adenoma (TSA). Activating mutations of the RAS-RAF-MAPK pathway initiate and sustain the lesions of the SP, and CpG island methylation of the promoter regions of tumour suppressor and DNA repair genes play the major role in their neoplastic progression. The SP includes microsatellite stable (MSS) carcinomas that are among the most biologically aggressive colorectal carcinomas (CRC), and also accounts for the great preponderance of sporadic hypermutated, mismatch repair (MMR)-deficient or microsatellite instable (MSI) CRC. The identification, removal and appropriate classification of at-risk SP precursors and surveillance of individuals who harbour these lesions present a challenge and opportunity for CRC prevention and mortality reduction.

Impact of the consideration of serrated polyps to the interval of colonoscopic surveillance in the NHS Bowel Cancer Screening Programme

AIM

Most international post polypectomy surveillance guidelines do not recommend surveillance for serrated polyps. In the present study the additional impact of serrated polyps on surveillance intervals from international adenoma surveillance guidelines was investigated.

METHOD

Endoscopic and pathology records were audited of participants in the NHS Bowel Cancer Screening Programme (guaiac faecal occult blood test, gFOBT) in 2011. Surveillance intervals were calculated for current guidelines and also for serrated polyps based on previously described aggressive and conservative strategies.

RESULTS

In total, 389 patients were included of whom 141 (36.2%) were high risk (advanced adenoma: adenoma ≥ 10 mm, villous elements, high grade dysplasia, or adenoma ≥ 3 in number) needing surveillance at ≤ 3 years. Thirty-three (8.5%) had significant serrated polyps, of whom 18 (4.6% of the total) had significant serrated lesions and simultaneous advanced adenoma or ≥ 3 adenomas. Adopting an aggressive surveillance strategy, the mean overall absolute additional proportion of all such patients in the surveillance group at 3 years or less was 4.0% (3.9% - 4.1%; 4.2% women; 3.8% men). These proportions varied according to endoscopist from 2.3% to 4.7%. For more conservative strategies the increase was only 1%.

CONCLUSION

The impact of including serrated polyps in current guidelines would result in a small increase in surveillance intervals for FOBT based bowel cancer screening. About half of those who might need surveillance for serrated polyps would already receive surveillance for being in a high risk adenoma group.

Comparison of faecal M2-PK and FIT in a population-based bowel cancer screening cohort

BACKGROUND

Screening for colorectal cancer improves outcomes and is cost effective. Stool-based tests have the highest participation rates in screening programmes. Their efficacy is limited by the relatively low sensitivity and specificity compared with colonoscopy. Stool levels of M2-PK, a dimeric form of the enzyme pyruvate kinase, correlate with colorectal cancer and neoplasia. A combination of stool markers may enhance screening performance; however, it remains to be determined whether an additional test would affect participation rates negatively.

AIMS

The aim of this study was to assess the performance of faecal M2-PK and faecal immunochemical test (FIT) and their combined effect in a screening programme.

MATERIALS AND METHODS

Within round 2 of our biennial FIT-based pilot, all invitations additionally included an M2-PK kit. A FIT greater than 100 ngHb/ml and/or an M2-PK greater than 4 U/ml were considered positive. FIT-positive or M2-PK-positive patients were offered a colonoscopy.

RESULTS

In all, 1800 combined M2-PK and FIT invites were sent out, and 879 (49%) samples were analysed. Overall positivity was 27% (n=245). Only 23 (2.6%) patients were positive for both tests. In all, 186 (88%) screening colonoscopies were performed. The adenoma detection rate for M2-PK-positive patients (n=157) was significant at 25% (n=40), and 3% (n=5) had advanced lesions. In FIT-positive patients (n=51), the adenoma detection rate was 29% (n=15), with significantly more, 21% (n=11), having advanced lesions (P<0.001, confidence interval 0.117-0.156). Had FIT only been tested, 70% (n=35) fewer patients would have had polyps removed.

CONCLUSION

The addition of M2-PK in a biennial bowel screening programme is acceptable to patients, feasible and detects additional adenomas, potentially at an earlier stage.

Who Needs Follow-Up after Endoscopic Resection of Colorectal Adenomas?

Background

Surveillance colonoscopy after endoscopic resection of colorectal adenomas is a crucial step in the concept of colorectal cancer screening. After identifying the patients at risk with screening and resection of adenomas, there has to be a tailored surveillance. Surveillance colonoscopy should detect recurrent and metachronal adenomas at a stage where they can be removed endoscopically. In the following, the criteria for a risk-adapted surveillance interval are presented.

Methods

A literature review based on American, European, and German guidelines for surveillance after polypectomy and the German guideline for the diagnosis and treatment of ulcerative colitis, as well as a selective literature search into hereditary colorectal cancer were performed.

Results

State of the art surveillance after endoscopic resection of colorectal adenomas is based on a focused anamnesis and the index colonoscopy. On the basis of existing guidelines, a risk-adapted surveillance strategy can be implemented.

Conclusions

Adherence to surveillance guidelines is a basic part of colorectal cancer screening and should be the starting point for further research.

A pathologist's survey on the reporting of sessile serrated adenomas/polyps

AIM

The purpose of this survey was to ascertain reporting habits of pathologists towards sessile serrated adenomas/polyps (SSA/P).

METHODS

A questionnaire designed to highlight diagnostic criteria, approach and clinical implications of SSA/P was circulated electronically to 45 pathologists in the UK and North America.

RESULTS

Forty-three of 45 pathologists agreed to participate. The vast majority (88%) had a special interest in gastrointestinal (GI) pathology, had great exposure to GI polyps in general with 40% diagnosing SSA/P at least once a week if not more, abnormal architecture was thought by all participants to be histologically diagnostic, and 11% would make the diagnosis if a single diagnostic histological feature was present in one crypt only, while a further 19% would diagnose SSA/P in one crypt if more than one diagnostic feature was present. The vast majority agreed that deeper sections were useful and 88% did not feel proliferation markers were useful. More than one-third did not know whether, or did not feel that, their clinicians were aware of the implications of SSA/P.

CONCLUSIONS

98% of pathologists surveyed are aware that SSA/P is a precursor lesion to colorectal cancer, the majority agree on diagnostic criteria, and a significant number feel that there needs to be greater communication and awareness among pathologists and gastroenterologists about SSA/P.