Histology, Size, and Number of Advanced Polyps are Associated With Guideline-Discordant Surveillance Recommendations

Surveillance guidelines following polypectomy promote cost-effective reductions in future colorectal cancer (CRC) risk, but high nonadherence rates1 can have negative consequences on costs and effectiveness. Professional societies recommend a 3-year interval for patients with advanced colorectal polyps (ACPs), although few studies report provider adherence to surveillance intervals.2 This study evaluated rates and predictors of guideline-discordant recommendations for patients with ACPs.

Sessile serrated lesions: Clinicopathological characteristics, endoscopic diagnosis, and management

The 2019 World Health Organization (WHO) Classification of Tumours of the Digestive System (5th edition) introduced the term "sessile serrated lesion" (SSL) to replace the term "sessile serrated adenoma/polyp" (SSA/P). SSLs are early precursor lesions in the serrated neoplasia pathway that result in colorectal carcinomas with BRAF mutations, methylation for DNA repair genes, a CpG island methylator phenotype, and high levels of microsatellite instability. Some of these lesions can rapidly become dysplastic or invasive carcinomas that exhibit high lymphatic invasion and lymph node metastasis potential. The 2019 WHO classification noted that dysplasia arising in an SSL most likely is an advanced polyp, regardless of the morphologic grade of the dysplasia. Detecting SSLs with or without dysplasia is critical; however, detection of SSLs is challenging, and their identification by endoscopists and pathologists is inconsistent. Furthermore, indications for their endoscopic treatment have not been established. Moreover, SSLs are considered to contribute to the development of post-colonoscopy colorectal cancers. Herein, the clinicopathological and endoscopic characteristics of SSLs, including features determined using white light and image-enhanced endoscopy, therapeutic indications, therapeutic methods, and surveillance are reviewed based on the literature. This information may lead to more intensive research to improve detection, diagnosis, and rates of complete resection of these lesions and reduce post-colonoscopy colorectal cancer rates.

Head to head: should we adopt the term "sessile serrated lesion"?

The precursor lesion for the ~30% of colon carcinomas developing along the serrated pathway was first described in detail in 1996, and was named sessile serrated adenoma in 2003. Although the entity itself was controversial initially, over time the concept of a serrated pathway initiated by this lesion has become well accepted in the medical community. The name sessile serrated adenoma, however, has been controversial since the beginning and continues to be controversial. Alternative names, including serrated polyp with abnormal proliferation, sessile serrated polyp and, most recently, sessile serrated lesion, have been proposed. Despite the fact that the term sessile serrated lesion was adopted by the World Health Organization in 2019, none of these terms has received universal acceptance. In this article, arguments for and against adopting the term sessile serrated lesion are discussed in detail.

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.

Endocuff assisted colonoscopy significantly increases sessile serrated adenoma detection in veterans

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer related deaths in the United States. Colonoscopy is the gold standard for the detection of CRC. There are many colonoscopy quality measures and among these the adenoma detection rate (ADR) has demonstrated a significant impact in reducing mortality from CRC. The primary aim of our study was to compare ADR and distribution of polyp type in patients undergoing Endocuff-assisted colonoscopy (EAC) versus standard colonoscopy (SC) in a VA system.

METHODS

Retrospective data was collected from 496 patients who underwent routine screening, surveillance and diagnostic colonoscopies either via SC from January 6, 2014 through March 12, 2014 or EAC from September 24, 2014 through February 19, 2015. A total of 54 patients were excluded based on a personal history of CRC and prior resection, incomplete colonoscopy due to poor bowel preparation, and removal or loss of Endocuff (EC). Primary outcomes measured and compared were ADR and types of polyps found.

RESULTS

The overall ADR in the EAC group was higher at 59.91% versus 50.66% for SC, accounting for a 9% increase (P=0.0508). EAC was able to detect a total of 59 sessile serrated adenoma/polyps (SSA/Ps) compared to SC only detecting 8 (P≤0.0001). There was a significant increase in the SSA/P detection rate with EAC at 15% versus 3% in the SC group (P≤0.0001).

CONCLUSIONS

EAC significantly increases the detection of SSA/P and has shown a trend in improving ADR in our veteran population.

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.

Cyclooxygenase-2 immunohistochemical expression in serrated polyps of the colon

Aim of the study

Cyclooxygenase-2 (COX-2) expression has been observed in a substantial percentage of classical adenomas of the large bowel. The aim of the study was to assess and compare the expression of COX-2 in serrated polyps of the colon.

Material and methods

One hundred and nineteen serrated polyps were analyzed. There were 83 hyperplastic polyps (HP), 19 sessile serrated polyps (SSP) and 17 traditional serrated adenomas (TSA). COX-2 expression was assessed semi-quantitatively (0–2) and each lesion was fully characterized in terms of anatomical location, size, histology, age and sex of the patient. The general estimating equation (GEE) model with logit link was used in the statistical analysis.

Results

Epithelial expression of COX-2 was found in 85/119 serrated polyps (71.43%): 57/83 (68.67%) HP, 16/19 (84.21%) SSP, and 12/17 (70.59%) TSA. In HP and SSP it was predominantly of weak (49/83 HP, 12/19 SSP), whereas in TSA it was mainly of medium/strong intensity (8/17). The TSA category was associated with more frequent COX-2 expression (OR = 7.00, 95% CI: 1.49–32.88, p = 0.014) than HP, but such relation was not found for SSP vs. HP (p > 0.1). No associations between COX-2 expression and clinical parameters were found.

Conclusions

Immunohistochemical COX-2 expression cannot serve as a diagnostic adjunct to differentiate HP and SSP.

Risk factors for serrated polyps of the colorectum

Serrated pathway polyps are a relatively new area of interest in the field of colorectal cancer screening and prevention. Akin to conventional adenomas, some serrated polyps (SPs) have the potential to develop into malignant serrated neoplasms, yet little is known regarding risk factors for these lesions. Early epidemiological studies of hyperplastic polyps were performed without knowledge of the serrated pathway and likely included a mixture of SPs. More recently, studies have specifically evaluated premalignant SPs, such as the sessile serrated adenoma (SSA) or surrogates for these polyps such as large or proximally located SPs. SPs share some risk factors with conventional adenomas and have been associated with tobacco use, obesity, and age. Nonsteroidal anti-inflammatory drug (NSAID) use, fiber, folic acid, and calcium have been associated with reduced risk of SPs. Studies focused on SSAs specifically have reported associations with age, female sex, smoking, obesity, diabetes, and possibly diets high in fat, carbohydrates, and calories. Higher education has also been associated with risk of SSAs, while an inverse association between NSAID use and SSAs has been reported. Risk factors for traditional serrated adenomas are largely unknown. Studies are largely limited by varying inclusion criteria, as well as differences in pathological classification schemes. Further epidemiological studies of SPs are needed to aid in risk stratification and screening, and etiological research.

Germline mutations in oncogene-induced senescence pathways are associated with multiple sessile serrated adenomas

BACKGROUND & AIMS

Little is known about the genetic factors that contribute to the development of sessile serrated adenomas (SSAs). SSAs contain somatic mutations in BRAF or KRAS early in development. However, evidence from humans and mouse models indicates that these mutations result in oncogene-induced senescence (OIS) of intestinal crypt cells. Progression to serrated neoplasia requires cells to escape OIS via inactivation of tumor suppressor pathways. We investigated whether subjects with multiple SSAs carry germline loss-of function mutations (nonsense and splice site) in genes that regulate OIS: the p16-Rb and ATM-ATR DNA damage response pathways.

METHODS

Through a bioinformatic analysis of the literature, we identified a set of genes that function at the main nodes of the p16-Rb and ATM-ATR DNA damage response pathways. We performed whole-exome sequencing of 20 unrelated subjects with multiple SSAs; most had features of serrated polyposis. We compared sequences with those from 4300 subjects matched for ethnicity (controls). We also used an integrative genomics approach to identify additional genes involved in senescence mechanisms.

RESULTS

We identified mutations in genes that regulate senescence (ATM, PIF1, TELO2,XAF1, and RBL1) in 5 of 20 subjects with multiple SSAs (odds ratio, 3.0; 95% confidence interval, 0.9–8.9; P =.04). In 2 subjects,we found nonsense mutations in RNF43, indicating that it is also associated with multiple serrated polyps (odds ratio, 460; 95% confidence interval, 23.1–16,384; P = 6.8 x 10(-5)). In knockdown experiments with pancreatic duct cells exposed to UV light, RNF43 appeared to function as a regulator of ATMATRDNA damage response.

CONCLUSIONS

We associated germline loss-of-function variants in genes that regulate senescence pathways with the development of multiple SSAs.We identified RNF43 as a regulator of the DNA damage response and associated nonsense variants in this gene with a high risk of developing SSAs.