Defining phenotypes and cancer risk in hyperplastic polyposis syndrome

Serrated polyposis syndrome; epidemiology and management

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

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cancer Risk in Patients With and Relatives of Serrated Polyposis Syndrome and Sporadic Sessile Serrated Lesions

INTRODUCTION

Patients with serrated polyposis syndrome (SPS) and their first-degree relatives (FDRs) have increased colorectal cancer (CRC) risk. Patients with sporadic sessile serrated lesion (SSL) have risk for progression to CRC. Yet familial risks of common extracolonic cancers and even CRC in these cohorts are poorly understood. Our aim was to examine cancer risk for patients with SPS and sporadic SSL and their close and more distant relatives using a large population database.

METHODS

Patients with SPS (n = 59) from hereditary patient registries were eligible for study. Sporadic SSL (n = 754) and sex- and age-matched normal colonoscopy controls (n = 1,624) were selected from clinical data linked to the Utah Population Database. Cox models adjusting for the number of relatives, degree of relatedness, and person-years at risk were used to estimate CRC, extracolonic, and any-site adenocarcinoma/carcinoma cancer risk in patients and their relatives.

RESULTS

Compared with controls, CRC risk was elevated 10-fold in patients with SPS (P = 0.04) and 5-fold in their FDRs (P = 0.001). Any-site adenoma/carcinoma risk was increased 2.6-fold in FDRs of patients with SPS. No elevated risks of other common extracolonic cancers were observed in SPS and family members. The FDRs, second-degree relatives, and third-degree relatives of patients with both SSL and adenomatous polyps exhibited a 50% increased CRC risk.

DISCUSSION

Patients with SPS and their FDRs have an increased CRC risk, confirming other reports. Interestingly, patients with SSL were noted to have an increased risk of prostate cancer. Relatives of individuals with both sporadic SSL and adenomas, irrespective of size or dysplasia on examination, may have an elevated CRC risk, suggesting closer colonoscopy surveillance in this population.

Serrated polyps of the colon and rectum: a concise review

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

Will a flexi-sig' do? A retrospective review of colonoscopies indicated by diverticulitis alone

BACKGROUND

The incidence of colonic diverticulitis is increasing. In Australia the majority of diverticulitis occurs in the left colon and patients typically undergo colonoscopy following an attack. At present debate exists regarding the utility of this costly procedure and a flexible sigmoidoscopy has been proposed as a cheaper, less invasive alternative. This paper seeks to examine whether significant pathology is being detected in the right and transverse colon to warrant colonoscopy, as opposed to a flexible sigmoidoscopy.

METHODS

A retrospective review of colonoscopies performed between August 2016 and August 2018, indicated by diverticulitis alone, performed in a single Australian metropolitan hospital.

RESULTS

189 patient colonoscopies were reviewed in combination with the pathology forms. Only 1 primary colonic malignancy was detected, found in the left colon. 110 traditional adenomas and 35 sessile serrated adenomas were detected. 41.8% of patients had a polyp detected with an average of 1.9 polyps per patient. 38.6% of polyps were resected from the left colon while 61.4% were removed from the right and transverse colon. In total 30 polyps > 10 mm or with high-risk histological features were resected, 18 (60%) from the left colon and 12 (40%) from the right and transverse. 20 patients (10.6%) met the criteria for high-risk adenomas and 50% of those had > 40% of their polyps in the right and transverse colon. There was no significant difference in age between patients with polyps and those without.

CONCLUSION

Despite over half the patients having no polyps and only one left sided malignancy. This study demonstrates that the right and transverse colon is responsible for over 50% of the polyps removed and similar proportion of the advanced polyps. Where endoscopic surveillance after acute colonic diverticulitis is performed, this study supports the use of colonoscopy and cautions against flexible sigmoidoscopy alone.

Patterns of polyp histology: predictors of peril in the mucosa

BACKGROUND

Precursor colonic polyps of varied subtypes correlate with the known neoplastic pathways. When patients present with synchronous pre-malignant polyps of multiple histologies, multiple genetic mechanisms are likely to be active, potentially resulting in a more unstable, tumourigenic mucosa.

METHODS

We hypothesized that patients with a combination of sessile serrated adenomas/polyps (SSA/Ps), hyperplastic (HP) polyps and adenomas would be at highest risk of developing dysplasia/cancer compared to SSA/Ps alone, due to the synergistic effect of multiple active carcinogenic pathways. A prospective colonoscopy database was examined for patients with a history of SSA/P. Patients were placed into four groups based on patterns of polyp histology as follows: (i) only SSA/Ps; (ii) SSA/P + HP; (iii) SSA/Ps + adenomas; and (iv) SSA/Ps + HP + adenomas. These groups were compared in terms of the numbers, size, location and histology of polyps and personal or family history of colorectal cancer.

RESULTS

A total of 374 patients were included. The average age was 70 years (range 21-88), and 43% were male. There was a trend towards the most aggressive neoplastic pattern in group 4, associated with a tendency to larger SSA/Ps, more villous architecture in the adenomas and more high-grade dysplasia in both types of polyps. It was also associated with multiplicity of both SSA/Ps and adenomas. No SSA/Ps existing in the absence of adenomas had cytological dysplasia.

CONCLUSION

The combination of SSA/Ps, HP and adenomas in the colorectal epithelium seems to be a marker for aggressive carcinogenesis and suggests that accurate and effective surveillance is important to manage this risk.

Sessile Serrated Polyposis: Not an Inherited Syndrome?

BACKGROUND

Researchers are searching in vain for a coherent genetic explanation for serrated polyposis. We hypothesize that there is no consistent monogenetic inheritance.

OBJECTIVE

The purpose of this study was to describe the serrated polyposis phenotype, assessing features of mendelian inheritance, and to compare these features with patients with a solitary sessile serrated lesion.

DESIGN

This was a retrospective review of a prospectively maintained database comparing patients with serrated polyposis versus solitary sessile serrated lesions.

SETTINGS

The study was conducted at a single-institution tertiary referral center.

PATIENTS

Patients with serrated polyposis meeting World Health Organization criteria type I (≥5 serrated polyps proximal to the sigmoid, ≥2 of which are ≥10 mm in diameter) and isolated sessile serrated lesions were included MAIN OUTCOME MEASURES:: Disease phenotype was the main outcome measured.

RESULTS

A total of 46 serrated polyposis patients were identified. Median age of first sessile serrated lesion was 66 years (interquartile range, 42-70 y). A total of 60.3% were current or past smokers (mean = 38.6 packs per year). Serrated polyposis patients had a higher number of all types of polyps (26.3 vs 4.4) and a higher rate of high-grade dysplasia (19.6% vs 3.7%) compared with patients with a solitary sessile serrated lesion. A total of 36.2% of patients had personal history of noncolorectal cancers, including skin, prostate, breast, thyroid, and renal cell cancers and leukemia. In addition, 32.6% had a family history of colorectal cancer in first- or second-degree relatives; these cancers were not young age of onset. Breast and prostate cancers were also common (family history of any cancer, 83.0%). Ten patients underwent genetic testing: 4 had negative panels, 1 had a pathogenic variant in MSH2, 1 an IVS7 deletion in PTEN, 2 negative APC sequencing (1 negative MYH), and 1 a pathogenic variant in Chek2.

LIMITATIONS

RNF4 was not sequenced. Genetic analysis was performed on a subset of patients.

CONCLUSIONS

The rate of associated cancers suggests an underlying genetic predisposition to disordered growth, but serrated polyposis does not have typical features of dominant inheritance. The association with smoking suggests that familial/environmental factors play a role. See Video Abstract at http://links.lww.com/DCR/B84. POLIPOSIS SERRADA SÉSIL: ¿NO ES UN SÍNDROME HEREDITARIO?: Los investigadores están buscando en vano una explicación genética coherente para la póliposis serrados. Suponemos que no existe una herencia monogenética consistente.1) Describir el fenotipo de póliposis serrada, evaluando las características de la herencia mendeliana, 2) comparar estas características con pacientes con una lesión serrada sésil solitaria.Revisión retrospectiva de una base de datos mantenida prospectivamente que compara pacientes con póliposis serrada versus lesiones serradas sésiles solitarias.Institución única, centro de referencia terciario.Pacientes con póliposis serrada que cumplen con los Criterios de la Organización Mundial de la Salud Tipo I (≥ 5 pólipos serrados proximales al sigmoideo, ≥2 de los cuales tienen ≥10 mm de diámetro) y lesiones serradas sésiles aisladas.Fenotipo de la enfermedad.Se identificaron un total de 46 pacientes con póliposis serrada. La edad mediana de la primera lesión serrada sésil fue de 66 años (RIC: 42-70 años). El 60.3% eran fumadores actuales o pasados (medio 38.6 paquetes / año). Los pacientes con póliposis serrada tuvieron un mayor número de todos los tipos de pólipos (26.3 versus 4.4) y una mayor tasa de displasia de alto grado (19.6% versus 3.7%) en comparación con los pacientes con una lesión serrada sésil solitaria. El 36.2% de los pacientes tenían antecedentes personales de cánceres no colorectales, incluyendo los cánceres de piel, próstata, mama, tiroides, células renales y leucemia. El 32.6% tenía antecedentes familiares de cáncer colorectal en familiares de primer o segundo grado; estos cánceres no eran de inicio de edad temprana. El cáncer de mama y próstata también fue frecuente (antecedentes familiares de cualquier tipo de cáncer: 83.0%). 10 pacientes se sometieron a pruebas genéticas: 4 tenían paneles negativos, 1 tenía una variante patogénica en MSH2, 1 una eliminación IVS7 en PTEN, 2 secuenciación APC negativa (1 MYH negativa) y 1 variante patogénica en Chek2.RNF4 no fue secuenciado. El análisis genético se realizó en un subconjunto de pacientes.La tasa de cánceres asociados sugiere una predisposición genética subyacente al crecimiento desordenado, pero la póliposis serrada no tiene características típicas de herencia dominante. La asociación con el tabaquismo sugiere que los factores familiares / ambientales juegan un papel. Consulte Video Resumen en http://links.lww.com/DCR/B84. (Traducción-Dr. Yesenia Rojas-Khalil).

Hereditary or Not? Understanding Serrated Polyposis Syndrome

PURPOSE OF REVIEW

To present the current understanding of the diagnosis, management, and potential genetic causes of serrated polyposis syndrome.

RECENT FINDINGS

The clinical criteria for serrated polyposis syndrome was recently updated and now includes individuals with five or more serrated polyps proximal to the rectum that are 5 mm in size or greater and at least two that are 10 mm in size of greater as well as individuals with 20 or more serrated polyps throughout the colon with at least five proximal to the rectum. There is a significant risk for colon cancer in first-degree relatives of individuals with serrated polyposis syndrome. However, less than 3% of serrated polyposis syndrome cases are explained by identifiable germline mutations, with mutations in RNF43 being the only currently validated genetic cause. Serrated polyposis syndrome is rarely explained by identifiable germline mutations, but there remains an increased risk for colorectal cancer in first-degree relatives. Referral for genetic counseling and testing is recommended for individuals with serrated polyposis syndrome and a personal history of coexisting adenomatous polyposis or with a concerning family history and can be considered for all individuals with serrated polyposis syndrome. Close endoscopic surveillance of those with serrated polyposis syndrome and their first-degree relatives is recommended. Continued efforts at identifying hereditary causes of serrated polyposis are needed.

Panchromoendoscopy Increases Detection of Polyps in Patients With Serrated Polyposis Syndrome

BACKGROUND & AIMS

Serrated polyposis syndrome (SPS), characterized by multiple and/or large proximal serrated lesions, increases the risk of colorectal cancer. Serrated lesions often are missed during colonoscopy but panchromoendoscopy can increase their detection in an average-risk population. We performed a randomized controlled study to determine the efficacy of panchromoendoscopy in detection of polyps in patients with SPS.

METHODS

Patients with SPS (n = 86 patients) underwent tandem high-definition (HD) colonoscopies from February 2015 through July 2016 at 7 centers in Spain. Patients were assigned randomly to groups that received 2 HD white-light endoscopy examinations (HD-WLE group; n = 43) or HD-WLE followed by 0.4% indigo carmine panchromoendoscopy (HD-CE group; n = 43). For each procedure, polyps detected were described, removed, and analyzed by histology. The primary outcome was additional polyp detection rate, defined as the number of polyps detected during the second inspection divided by the total number of polyps detected during the first and the second examination.

RESULTS

A total of 774 polyps were detected (362 in the HD-WLE group and 412 in the HD-CE group); 54.2% were hyperplastic, 13.8% were adenomas, and 10.9% were sessile serrated polyps. There was a significantly higher additional polyp detection rate in the HD-CE group (0.39; 95% CI, 0.35-0.44) than in the HD-WLE group (0.22; 95% CI, 0.18-0.27) (P < .001). A higher additional rate of serrated lesions proximal to the sigmoid colon were detected in the second inspection with HD-CE (0.40; 95% CI, 0.33-0.47) than with HD-WLE (0.24; 95% CI, 0.19-0.31) (P = .001). Detection of adenomas and serrated lesions greater than 10 mm did not differ significantly between groups. In a multivariate logistic regression analysis, only use of HD-CE was associated independently with increased polyp detection throughout the colon.

CONCLUSIONS

In a randomized controlled trial, we found that panchromoendoscopy increases detection of polyps (mostly of small serrated lesions) and should be considered the standard of care in patients with SPS. Studies are needed to determine the effects of this strategy on the incidence of advanced neoplasia during long-term follow-up evaluation. ClinicalTrials.gov no: NCT03476434.

Can the rate and location of sessile serrated polyps be part of colorectal Cancer disparity in African Americans?

BACKGROUND

Up to 30% of colorectal cancers develop through the serrated pathway. African Americans (AAs) suffer a disproportionate burden of colorectal cancer. The aim of this study was to evaluate clinicopathological features of AA patients diagnosed with sessile serrated polyps (SSPs).

METHODS

We conducted a retrospective study of all colonoscopies (n = 12,085) performed at Howard University Hospital, from January 1st, 2010 to December 31st, 2015, of which 83% were in AA patients, (n = 10,027). Among AAs, pathology reports confirmed 4070 patients with polyps including 252 with SSPs. Demographic and clinical variables (i.e. sex, age, BMI, anatomic location, clinical symptoms, polyp size, and clinical indications were collected at colonoscopy.

RESULTS

In the AA population, the median age was 56 with interquartile range (IQR) of 51 to 62 years, 54% were female, and 48% had a BMI > 30. The most common reason for colonoscopy was screening (53%), whereas the prevalent reasons for diagnostic colonoscopies were changes in bowel habits (18%) and gastrointestinal bleeding (17%). The total number of SSPs among the 252 AA (diagnosed with SSPs) was 338. Of these, 9% (n = 29/338) had some degree of cytological dysplasia, primarily in the ascending colon (n = 6/42, 14%), Transverse colon (n = 2/16, 13%) and rectosigmoid (n = 19/233, 8%). About 24% of patients had more than 2 polyps. Most patients (76%) had distal SSPs (rectal and rectosigmoid), in comparison to 14% of proximal polyps and 10% of bilateral locations. Median SSA/P size for all locations was 0.6 cm.

CONCLUSION

The prevalence of SSPs accounts for 6% of all polyps in AA patients and was diagnosed in 2.5% of all colonoscopies (n = 252/10,027), which is higher than Caucasians in the US. SSPs were predominantly located in the left side, as compared to published literature showing the predominance in the right side of the colon. Screening of CRC will have the chance to detect high risk SSA/P in this population.

Update on genetic predisposition to colorectal cancer and polyposis

The present article summarizes recent developments in the characterization of genetic predisposition to colorectal cancer (CRC). The main themes covered include new hereditary CRC and polyposis syndromes, non-CRC hereditary cancer genes found mutated in CRC patients, strategies used to identify novel causal genes, and review of candidate genes that have been proposed to predispose to CRC and/or colonic polyposis. We provide an overview of newly described genes and syndromes associated with predisposition to CRC and polyposis, including: polymerase proofreading-associated polyposis, NTHL1-associated polyposis, mismatch repair gene biallelic inactivation-related adenomatous polyposis (including MSH3- and MLH3-associated polyposes), GREM1-associated mixed polyposis, RNF43-associated serrated polyposis, and RPS20 mutations as a rare cause of hereditary nonpolyposis CRC. The implementation of next generation sequencing approaches for genetic testing has exposed the presence of pathogenic germline variants in genes associated with hereditary cancer syndromes not traditionally linked to CRC, which may have an impact on genetic testing, counseling and surveillance. The identification of new hereditary CRC and polyposis genes has not deemed an easy endeavor, even though known CRC-related genes explain a small proportion of the estimated familial risk. Whole-genome sequencing may offer a technology for increasing this proportion, particularly if applied on pedigree data allowing linkage type of analysis. The final section critically surveys the large number of candidate genes that have been recently proposed for CRC predisposition.

The role of inherited genetic variants in colorectal polyposis syndromes

Colorectal carcinoma (CRC) is the third most common cancer in men and the second most common cancer in women across the world. Most CRCs occur sporadically, but in 15-35% of cases, hereditary factors are important. Some patients with an inherited predisposition to CRC will be diagnosed with a "genetic polyposis syndrome" such as familial adenomatous polyposis (FAP), MUTYH-associated polyposis (MAP), polymerase proofreading associated polyposis (PPAP), NTHL1-associated polyposis, MSH3-associated polyposis or a hamartomatous polyposis syndrome. Individuals with ≥10 colorectal polyps have traditionally been referred for genetic diagnostic testing to identify APC and MUTYH mutations which cause FAP and MAP respectively. Mutations are found in most patients with >100 adenomas but in only a minority of those with 10-100 adenomas. The reasons that diagnostic laboratories are not identifying pathogenic variants include mutations occurring outside of the open reading frames of genes, individuals exhibiting generalized mosaicism and the involvement of additional genes. It is important to identify patients with an inherited polyposis syndrome, and to define the mutations causing their polyposis, so that the individuals and their relatives can be managed appropriately.

Serrated Polyposis Syndrome in a Single-Center 10-Year Experience

Aims:

Serrated polyposis syndrome is a disease that is often missed in the clinical setting and is associated with colorectal cancer. We investigated the prevalence of SPS and the association between colorectal or other cancers in a 10-year, retrospective data analysis.

Methods:

We reviewed complete colonoscopy data obtained from January 2005 through January 2015 at a health-screening centre. Serrated polyposis syndrome was defined on the basis of the criteria established by the 2010 World Health Organization.

Results:

Of a total of 53.842 consecutive subjects who underwent complete colonoscopy, 12 (0.022%) patients had serrated polyposis syndrome. All of these cases were under-recognized by the endoscopist or referring physician. The mean patient age was 58.6 years; 67% of the patients were men and 33% were women. No serrated polyposis syndrome patients had a first-degree relative with serrated polyposis syndrome, and no serrated polyposis syndrome patients had colorectal cancer. Two cases (17%) had extra-colonic cancers (prostate cancer and thyroid cancer). Eight cases (67%) had a family history of cancer (stomach, breast, lung, pancreas, prostate and colorectal cancer).

Conclusion:

Serrated polyposis syndrome was a rare condition in a 10-year database, and it was diagnosed late in all cases. Serrated polyposis syndrome may be associated with an increased risk of extra-colonic cancer.

Serrated Polyps of Colon and Rectum: a Clinicopathologic Review

BACKGROUND

In the past decade, there have been significant changes in the classification and nomenclature of colorectal polyps. Previously, only two groups of lesions were widely recognized, the adenoma and the hyperplastic polyp. Adenomas were considered the only precursor of colorectal cancer, and hyperplastic polyps were considered innocent with no malignant potential. However, recent discoveries about molecular pathways of colorectal cancers have significantly changed our understanding of these neoplasms. Serrated polyps-previously uniformly called hyperplastic polyps-are now known to comprise a heterogeneous family of neoplasms united by their characteristic saw tooth morphology but differing in many important ways, including their malignant potential and molecular profile. This group of neoplasms includes both hyperplastic polyps and the more recently recognized serrated adenomas. Serrated adenomas can be subdivided into the traditional serrated adenoma and the sessile serrated adenoma/polyp. Both of these lesions show characteristic molecular changes, which differ from traditional colorectal adenomatous polyps.

OBJECTIVES

In this review, we will discuss the morphologic features of serrated colorectal lesions, the molecular alterations that characterize them, and their role in colorectal cancer development.

MATERIAL AND METHODS

The English literature regarding the new nomenclature will be reviewed and the key diagnostic points will be recorded.

RESULTS AND DISCUSSION

This large group of polyps has recently been better classified which needs specific attention by pathologists, gastroenterologists and even surgeons.

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.

Colorectal polyposis and inherited colorectal cancer syndromes

The majority of colorectal cancer (CRC) cases are sporadic, with hereditary factors contributing to approximately 35% of CRC cases. Less than 5% of CRC is associated with a known genetic syndrome. Although adenomatous polyposis syndromes, hamartomatous polyposis syndromes, and those previously classified as non-polyposis CRC syndromes are quite rare, it is important for clinicians to know the characteristics of each syndrome and to understand the differences in cancer risks between the different conditions. This information is very important when treatment and surveillance plans are formulated for each individual patient.

Hereditary Colorectal Polyposis and Cancer Syndromes: A Primer on Diagnosis and Management

Colorectal cancer (CRC) is the fourth most common cancer amongst men and women. Between 3 and 6% of all CRCs are attributed to well-defined inherited syndromes, including Lynch syndrome, familial adenomatous polyposis (FAP), MUTYH-associated polyposis (MAP), and several hamartomatous polyposis conditions. Identification of these patients through family history and appropriate genetic testing can provide estimates of cancer risk that inform appropriate cancer screening, surveillance and/or preventative interventions. This narrative review examines the hereditary colorectal cancer and polyposis syndromes, their genetic basis, clinical management, and evidence supporting cancer screening.

Increased Risk of Colorectal Cancer in Patients With Multiple Serrated Polyps and Their First-Degree Relatives

BACKGROUND & AIMS

We investigated whether patients with multiple serrated polyps, but not meeting the World Health Organization criteria for serrated polyposis syndrome, and their relatives have similar risks for colorectal cancer (CRC) as those diagnosed with serrated polyposis.

METHODS

We collected data from patients with more than 10 colonic polyps, recruited in 2008-2009 from 24 hospitals in Spain for a study of causes of multiple colonic polyps. We analyzed data from 53 patients who met the criteria for serrated polyposis and 145 patients who did not meet these criteria, but who had more than 10 polyps throughout the colon, of which more than 50% were serrated. We calculated age- and sex-adjusted standardized incidence ratios (SIRs) for CRC in both groups, as well as in their first-degree relatives.

RESULTS

The prevalence of CRC was similar between patients with confirmed serrated polyposis and multiple serrated polyps (odds ratio, 1.35; 95% confidence interval [CI], 0.64-2.82; P = .40). The SIR for CRC in patients with serrated polyposis (0.51; 95% CI, 0.01-2.82) did not differ significantly from the SIR for CRC in patients with multiple serrated polyps (0.74; 95% CI, 0.20-1.90; P = .70). The SIR for CRC also did not differ significantly between first-degree relatives of these groups (serrated polyposis: 3.28, 95% CI, 2.16-4.77; multiple serrated polyps: 2.79, 95% CI, 2.10-3.63; P = .50). Kaplan-Meier analysis showed no differences in the incidence of CRC between groups during the follow-up period (log-rank, 0.6).

CONCLUSIONS

The risk of CRC in patients with multiple serrated polyps who do not meet the criteria for serrated polyposis, and in their first-degree relatives, is similar to that of patients diagnosed with serrated polyposis.

Clinical characteristics of patients with serrated polyposis syndrome in Korea: comparison with Western patients

Background/Aims

Serrated polyposis syndrome (SPS) has been shown to increase the risk of colorectal cancer (CRC). However, little is known about the characteristics of Asian patients with SPS. This study aimed to identify the clinicopathological features and risk of CRC in Korean patients with SPS as well as the differences between Korean and Western patients based on a literature review.

Methods

This retrospective study included 30 patients with SPS as defined by World Health Organization classification treated at Samsung Medical Center, Korea, between March 1999 and May 2011.

Results

Twenty patients (67%) were male. The median patient age at diagnosis was 56 years (range, 39–76 years). A total of 702 polyps were identified during a median follow-up of 43 months (range, 0–149 months). Serrated polyps were noted more frequently in the distal colon (298/702, 55%). However, large serrated polyps and serrated adenomas were mainly distributed throughout the proximal colon (75% vs. 25% and 81% vs. 19%, respectively); 73.3% had synchronous adenomatous polyps. The incidence of CRC was 10% (3/30 patients), but no interval CRC was detected. A total of 87% of the patients underwent esophagogastroduodenoscopy and 19.2% had significant lesions.

Conclusions

The phenotype of SPS in Korean patients is different from that of Western patients. In Korean patients, SPS is more common in men, there were fewer total numbers of serrated adenoma/polyps, and the incidence of CRC was lower than that in Western patients. Korean patients tend to more frequently have abnormal gastric lesions. However, the prevalence of synchronous adenomatous polyps is high in both Western and Korean patients.

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.

Clinical risk factors of colorectal cancer in patients with serrated polyposis syndrome: a multicentre cohort analysis

OBJECTIVE

Serrated polyposis syndrome (SPS) is accompanied by an increased risk of colorectal cancer (CRC). Patients fulfilling the clinical criteria, as defined by the WHO, have a wide variation in CRC risk. We aimed to assess risk factors for CRC in a large cohort of patients with SPS and to evaluate the risk of CRC during surveillance.

DESIGN

In this retrospective cohort analysis, all patients with SPS from seven centres in the Netherlands and two in the UK were enrolled. WHO criteria were used to diagnose SPS. Patients who only fulfilled WHO criterion-2, with IBD and/or a known hereditary CRC syndrome were excluded.

RESULTS

In total, 434 patients with SPS were included for analysis; 127 (29.3%) were diagnosed with CRC. In a per-patient analysis ≥1 serrated polyp (SP) with dysplasia (OR 2.07; 95% CI 1.28 to 3.33), ≥1 advanced adenoma (OR 2.30; 95% CI 1.47 to 3.67) and the fulfilment of both WHO criteria 1 and 3 (OR 1.60; 95% CI 1.04 to 2.51) were associated with CRC, while a history of smoking was inversely associated with CRC (OR 0.36; 95% CI 0.23 to 0.56). Overall, 260 patients underwent surveillance after clearing of all relevant lesions, during which two patients were diagnosed with CRC, corresponding to 1.9 events/1000 person-years surveillance (95% CI 0.3 to 6.4).

CONCLUSION

The presence of SPs containing dysplasia, advanced adenomas and/or combined WHO criteria 1 and 3 phenotype is associated with CRC in patients with SPS. Patients with a history of smoking show a lower risk of CRC, possibly due to a different pathogenesis of disease. The risk of developing CRC during surveillance is lower than previously reported in literature, which may reflect a more mature multicentre cohort with less selection bias.

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.

Gastrointestinal tract cancers: Genetics, heritability and germ line mutations

Gastrointestinal (GI) tract cancers that arise due to genetic mutations affect a large number of individuals worldwide. Even though many of the GI tract cancers arise sporadically, few of these GI tract cancers harboring a hereditary predisposition are now recognized and well characterized. These include Cowden syndrome, MUTYH-associated polyposis, hereditary pancreatic cancer, Lynch syndrome, Peutz-Jeghers syndrome, familial adenomatous polyposis (FAP), attenuated FAP, serrated polyposis syndrome, and hereditary gastric cancer. Molecular characterization of the genes that are involved in these syndromes was useful in the development of genetic testing for diagnosis and also facilitated understanding of the genetic basis of GI cancers. Current knowledge on the genetics of GI cancers with emphasis on heritability and germ line mutations forms the basis of the present review.

Serrated Polyps and Serrated Polyposis Syndrome

Colorectal serrated polyps are intermediate lesions in the serrated neoplastic pathway, which account for up to 30% of colorectal cancers. This pathway is biologically distinct from the adenoma-to-carcinoma sequence, with associated cancers exhibiting mutations in the BRAF oncogene, DNA promoter hypermethylation, and microsatellite instability. An evolving understanding of these unique lesions has led to the development of a more accurate classification, improved endoscopic identification, and tailored clinical management guidelines. This article reviews serrated polyps and serrated polyposis syndrome.

Colorectal cancer risk factors in patients with serrated polyposis syndrome: a large multicentre study

OBJECTIVE

Serrated polyposis syndrome (SPS) is associated with an increased colorectal cancer (CRC) risk, although the magnitude of the risk remains uncertain. Whereas intensive endoscopic surveillance for CRC prevention is advised, predictors that identify patients who have high CRC risk remain unknown. We performed a multicentre nationwide study aimed at describing the CRC risk in patients with SPS and identifying clinicopathological predictors independently associated with CRC.

DESIGN

From March 2013 through September 2014, patients with SPS were retrospectively recruited at 18 Spanish centres. Data were collected from medical, endoscopy and histopathology reports. Multivariate logistic regression was performed to identify CRC risk factors.

RESULTS

In 296 patients with SPS with a median follow-up time of 45 months (IQR 26-79.7), a median of 26 (IQR 18.2-40.7) serrated polyps and 3 (IQR 1-6) adenomas per patient were detected. Forty-seven patients (15.8%) developed CRC at a mean age of 53.9±12.8, and 4 out of 47 (8.5%) tumours were detected during surveillance (cumulative CRC incidence 1.9%). Patients with >2 sessile serrated adenomas/polyps (SSA/Ps) proximal to splenic flexure and ≥1 proximal SSA/P with high-grade dysplasia were independent CRC risk factors (incremental OR=2, 95% CI 1.22 to 3.24, p=0.006). Patients with no risk factors showed a 55% decrease in CRC risk (OR=0.45, 95% CI 0.24 to 0.86, p=0.01).

CONCLUSIONS

Patients with SPS have an increased risk of CRC, although lower than previously published. Close colonoscopy surveillance in experienced centres show a low risk of developing CRC (1.9% in 5 years). Specific polyp features (SSA/P histology, proximal location and presence of high-grade dysplasia) should be used to guide clinical management.

Heritable Gastrointestinal Cancer Syndromes

Although almost all gastrointestinal cancers develop from sporadic genomic events, approximately 5% arise from germline mutations in genes associated with cancer predisposition. The number of these genes continues to increase. Tumor phenotypes and family history provide the framework for identifying at-risk individuals. The diagnosis of a hereditary cancer syndrome has implications for management of patients and their families. Systematic approaches that integrate family history and molecular characterization of tumors and polyps facilitate identification of individuals with this genetic predisposition. This article summarizes diagnosis and management of hereditary cancer syndromes associated with gastrointestinal cancers.

Serrated polyposis associated with a family history of colorectal cancer and/or polyps: The preferential location of polyps in the colon and rectum defines two molecular entities

Serrated polyposis (SPP) is characterized by the development of multiple serrated polyps and an increased predisposition to colorectal cancer (CRC). In the present study, we aimed to characterize, at a clinical and molecular level, a cohort of SPP patients with or without a family history of SPP and/or polyps/CRC (SPP-FHP/CRC). Sixty-two lesions from 12 patients with SPP-FHP/CRC and 6 patients with sporadic SPP were included. The patients with SPP-FHP/CRC presented with an older mean age at diagnosis (p=0.027) and a more heterogeneous histological pattern of lesions (p=0.032) than the patients with sporadic SPP. We identified two molecular forms of SPP-FHP/CRC, according to the preferential location of the lesions: proximal/whole-colon or distal colon. Mismatch repair (MMR) gene methylation [mutS homolog 6 (MSH6)/mutS homolog 3 (MSH3)] or loss of heterozygosity (LOH) of D2S123 (flanking MSH6) were detected exclusively in the former (p=3.0×10⁻⁷), in most early lesions. Proximal/whole-colon SPP-FHP/CRC presented a higher frequency of O-6-methylguanine-DNA methyltransferase (MGMT) methylation/LOH, microsatel-lite instability (MSI) and Wnt mutations (19/29 vs. 7/17; 16/23 vs. 1/14, p=2.2×10⁻⁴; 15/26 vs. 2/15, p=0.006; 14/26 vs. 4/20, p=0.02) but a lower frequency of B-raf proto-oncogene, serine/threonine kinase (BRAF) mutations (7/30 vs. 12/20, p=0.0089) than the distal form. CRC was more frequent in cases of Kirsten rat sarcoma viral oncogene homolog (KRAS)-associated proximal/whole-colon SPP-FHP/CRC than in the remaining cases (4/4 vs. 1/8, p=0.01). Thus, SPP-FHP/CRC appears to be a specific entity, presenting two forms, proximal/whole-colon and distal, which differ in the underlying tumor initiation pathways. Early MGMT and MMR gene deficiency in the former may underlie an inherited susceptibility to genotoxic stress.

The "Studded" Rectum: Phenotypic Evidence of MYH-Associated Polyposis

BACKGROUND

MYH-associated polyposis is a recessively inherited syndrome of colorectal cancer predisposition attributed to biallelic germline mutations in the base excision repair gene MYH. Clinically it overlaps with attenuated familial adenomatous polyposis, sporadic oligopolyposis, serrated polyposis, familial colorectal cancer type X, and Lynch syndrome. There is no specific phenotypic feature of MYH-associated polyposis. We have noticed that a proportion of patients with MYH-associated polyposis presenting for yearly colonoscopy surveillance have rectums that are studded with small hyperplastic polyps.

OBJECTIVE

We report this as a possible unique phenotypic feature of the syndrome.

DESIGN

This was a descriptive study.

SETTINGS

The study was conducted at a department of colorectal surgery in a tertiary referral center.

PATIENTS

Patients affected with oligopolyposis or MYH-associated polyposis presenting for endoscopic surveillance and polyp control were included.

INTERVENTIONS

Interventions included colonoscopy or proctoscopy with excision or biopsy of mucosal lesions.

MAIN OUTCOME MEASURES

The presence of rectal studding was measured.

RESULTS

There were 49 patients, 16 with biallelic germline mutations of MYH; 10 of these had rectal studding. A sampling of rectal polyps was biopsied and all were hyperplastic. Five patients with biallelic MYH mutations had no studding, and 1 had not been prospectively examined. The studding was independent of the nature of the MYH mutation(s). The 33 patients other patients included 21 with serrated polyposis, 2 with a germline APC mutation, 1 with a PTEN mutation, 2 with mixed polyposis, 3 with oligoadenomatous polyposis and no germline mutation, and 4 patients with oligoadenomatous polyposis who had not been genetically tested. Only 1 of these (oligoadenomatous polyposis, not tested) had studding.

LIMITATIONS

The study was limited by its small number of biallelic MYH mutation carriers.

CONCLUSIONS

Rectal studding may be a sign of MYH-associated polyposis and raises questions about the biology of abnormal base excision repair.

The molecular characteristics of colonic neoplasms in serrated polyposis: a systematic review and meta-analysis

Serrated polyposis is a rare disorder characterised by the presence of multiple serrated polyps in the large intestine, and an increased personal and familial risk of colorectal cancer. Knowledge of the molecular characteristics of colonic lesions which develop in this syndrome is fragmented, making it difficult to understand the underlying genetic basis of this condition. We conducted a systematic review and meta-analysis of all studies which evaluated the molecular characteristics of colorectal neoplasms found in individuals with serrated polyposis. We identified 4561 potentially relevant studies, but due to a lack of consensus in the reporting of findings, only fourteen studies were able to be included in the meta-analysis. BRAF mutation was found in 73% (95% CI 65-80%) of serrated polyps, 0% (95% CI 0-3%) of conventional adenomas and 49% (95%CI 33-64%) of colorectal cancers. In contrast, KRAS mutation was present in 8% (95% CI 5-11%) of serrated polyps, 3% (95% CI 0-13%) of conventional adenomas and 6% (95% CI 0-13%) of colorectal cancers. Absence of MLH1 immunostaining was found in 3% (95% CI 0-10%) of serrated polyps and 53% (95% CI 36-71%) of colorectal cancers. Overall, microsatellite instability was found in 40% (95% CI 18-64%) of colorectal cancers arising in the setting of serrated polyposis. Our results indicate that diverse molecular pathways are likely to contribute to the increased predisposition for colorectal cancer in individuals with serrated polyposis. We also propose a set of minimum standards for the reporting of future research in serrated polyposis as this is a rare syndrome and collation of research findings from different centres will be essential to identify the molecular mechanisms involved in the pathogenesis of this condition.

Diagnostic Approach to Hereditary Colorectal Cancer Syndromes

Approximately 5 to 10% of colorectal cancers develop within a known hereditary syndrome. Specific underlying genetic mutations drive the clinical phenotype and it is imperative to determine the genetic etiology to provide meaningful surveillance and intervention. Recognizing potential patients and families with a hereditary predisposition is the first step in management. Syndromes can be categorized according to polyp burden as polyposis or nonpolyposis. Clinical assessment should start with a personal and family medical history, physical examination, and evaluation for the presence and type of colorectal polyps or cancers. Key information is gained from these simple steps and should guide the specific genetic analysis for diagnosis. Genetic counseling is a critical component to any hereditary colorectal cancer program and should be conducted before genetic testing to provide education about the implications of test results. This review focuses on the thought process that drives initial clinical evaluation and guides genetic testing for patients with suspected hereditary colorectal cancer syndromes.

Genetics and Genetic Testing in Hereditary Colorectal Cancer

Colorectal cancer (CRC) remains the third most common cancer affecting men and women in the United States. Approximately one-third of CRCs are diagnosed in individuals who have family members also affected with the disease. Although the vast majority of colorectal neoplasms develop as a consequence of somatic genomic alterations arising in individual cells, approximately 5% of all CRCs arise in the setting of germline mutations in genes involved in key cellular processes. To date, multiple genes have been implicated in single-gene hereditary cancer syndromes, many of which are associated with increased risk for CRC, as well as other tumor types. This review outlines the clinical, pathologic, and genetic features of the hereditary cancer syndromes known to be associated with increased risk for CRC and delineates strategies for implementing genetic risk assessments in clinical settings.

Molecular and histologic considerations in the assessment of serrated polyps

CONTEXT : Colorectal cancer is a heterogeneous disease resulting from different molecular pathways of carcinogenesis. Recent data evaluating the histologic features and molecular basis of the serrated polyp-carcinoma pathway have significantly contributed to more comprehensive classifications of and treatment recommendations for these tumors.

OBJECTIVE

To integrate the most recent molecular findings in the context of histologic classifications of serrated lesions and their implications in diagnostic pathology and colorectal cancer surveillance.

DATA SOURCES

Published literature focused on serrated polyps and their association with colorectal cancer.

CONCLUSIONS

Three types of serrated polyps are currently recognized: hyperplastic polyps, sessile serrated adenomas/polyps, and traditional serrated adenomas. The BRAF V600E mutation is one of the most frequent molecular abnormalities identified in hyperplastic polyps and sessile serrated adenomas. In contrast, in traditional serrated adenomas, either BRAF V600E or KRAS mutations can be frequently identified. CpG methylation has emerged as a critical molecular mechanism in the sessile serrated pathway. CpG methylation of MLH1 often leads to reduced or lost expression in dysplastic foci and carcinomas arising in sessile serrated adenomas/polyps.

Risk of Colorectal and Other Cancers in Patients With Serrated Polyposis

Patients with serrated polyposis develop multiple colorectal hyperplastic and/or serrated sessile adenomas/polyps. We investigated the risk of colorectal and other cancers by analyzing data from 64 patients with serrated polyposis (mean age at diagnosis, 54 y; 41% men; 92% white) listed in the Johns Hopkins Polyposis Registry. Medical, endoscopic, and histopathology reports were evaluated. Six patients (9.4%) had a history of colorectal cancer, diagnosed at a mean age of 56 years; 6 additional patients (9.4%) had at least 1 advanced colorectal adenoma. Extracolonic cancers were found in 16% of the study population. The standard incidence ratio for colorectal cancer in patients with serrated polyposis was 18.72 (95% confidence interval, 6.87-40.74) and for extracolonic cancer was 31.20 (95% confidence interval, 14.96-57.37), compared with the Surveillance, Epidemiology, and End Results population. Patients with serrated polyposis therefore have a high risk for colorectal cancer and require vigilant colorectal surveillance, starting at the time of diagnosis of serrated polyposis. The risk of extracolonic cancer also appears to be increased, but this requires further evaluation.

Inherited predisposition to colorectal cancer: towards a more complete picture

Colorectal carcinoma (CRC) is the third most common cancer worldwide. Hereditary factors are important in 15%-35% of affected patients. This review provides an update on the genetic basis of inherited predisposition to CRC. Currently known genetic factors include a group of highly penetrant mutant genes associated with rare mendelian cancer syndromes and a group of common low-penetrance alleles that have been identified through genetic association studies. Additional mechanisms, which may underlie a predisposition to CRC, will be outlined, for example, variants in intermediate penetrance alleles. Recent findings, including mutations in POLE, POLD1 and NTHL1, will be highlighted, and we identify gaps in present knowledge and consider how these may be addressed through current and emerging genomic approaches. It is expected that identification of the missing heritable component of CRC will be resolved through evermore comprehensive cataloguing and phenotypic annotation of CRC-associated variants identified through sequencing approaches. This will have important clinical implications, particularly in areas such as risk stratification, public health and CRC prevention.

Three Colon Adenocarcinomas Arising in a Patient with Serrated Polyposis Syndrome: Case Report and Review of the Literature

Background

Serrated polyposis syndrome (SPS) is a rare entity mainly concerning the 6th decade of life and which is characterized by the presence of multiple large hyperplastic polyps, sessile serrated adenomas, and adenomas within the colon.

Case Report

We describe the case of a SPS patient with 3 synchronous adenocarcinomas. The morphologic features of serrated colorectal lesions, their characteristic molecular alterations, and their role in colorectal cancer development are discussed herein.

Conclusion

Our findings suggest that SPS is a rare condition with an increased risk for colon cancer. Patients suffering from SPS should have regular colonoscopic surveillance, and perhaps those with numerous dysplastic hyperplastic polyps should be treated with colectomy.

Clinicopathological Characteristics of Serrated Polyposis Syndrome in Korea: Single Center Experience

Background/Aim. Serrated polyposis syndrome (SPS) is a rare condition characterized by multiple serrated polyps throughout the colon and rectum. The aim of this study was to evaluate the clinicopathological characteristics of SPS in Koreans. Methods. This retrospective analysis of prospectively collected data was performed using information from the endoscopy, clinical records, and pathology database system of Uijeongbu St. Mary's Hospital. Consecutive patients satisfying the updated 2010 World Health Organization criteria for SPS between June 2011 and May 2014 were enrolled. Results. Of the 17,552 patients who underwent colonoscopies during the study period, 11 (0.06%) met the criteria for SPS. The mean age of these patients was 55.6 years. Ten patients (91%) were males. None had a family history of CRC or a first-degree relative with SPS. Seven patients (64%) had synchronous advanced adenoma. One patient had coexistence of SPS with CRC that was diagnosed at the initial colonoscopy. Five patients (45%) had more than 30 serrated polyps. One of the patients underwent surgery and 10 underwent endoscopic resection. Conclusion. The prevalence of SPS in this study cohort was comparable to that in Western populations. Considering the high risk of CRC, correct diagnosis and careful follow-up for SPS are necessary.

Colonic polyposis syndromes--an experience from a tertiary centre in South India

BACKGROUND

Several polyposis syndromes of the gastrointestinal tract have been recognized which carry increased risk for cancer and have a genetic predisposition. There is a paucity of literature regarding the occurrence and the burden of colonic polyposis syndromes in the Indian subcontinent. This study attempts to highlight this hitherto unaddressed burden and the associated increased risk for inherited colonic cancer in this geographical location.

METHODS

A retrospective study of various colonic polyposis syndromes encountered at a tertiary centre in South India over a period of 8 years (2005 to 2012) was performed. The diagnosis in each case was made histologically with clinicopathological correlation.

RESULTS

Fifty cases were identified as belonging to a colonic polyposis syndrome, during the study period. There were 27 males and 23 females with a median age of 36.5 years (range 19 months to 78 years). The commonest syndrome was familial adenomatous polyposis (n = 27; 54 %) followed by Peutz-Jeghers syndrome (n = 11), attenuated familial adenomatous polyposis (n = 7), juvenile polyposis syndrome (n = 3), hyperplasic polyposis syndrome (n = 1) and Cronkhite-Canada syndrome (n = 1). Colonic malignancy was documented at first presentation in 22 patients (44 %).

CONCLUSIONS

Our study highlights the various colonic polyposis syndromes encountered in a tertiary care institution in Southern India.

Yield of screening colonoscopy in first-degree relatives of patients with serrated polyposis syndrome

GOALS

We aimed to evaluate the diagnostic yield of screening colonoscopies in first-degree relatives (FDRs) of patients with serrated polyposis syndrome (SPS).

BACKGROUND

Patients with SPS are at an increased risk for colorectal cancer. Although inheritance patterns are unknown, FDRs of these patients have an increased risk for both colorectal cancer and SPS. Prospective studies evaluating the yield of screening colonoscopies in this group are however scarce. This information would be useful to evaluate a possible mode of inheritance and to investigate whether screening colonoscopies are justified in this group.

STUDY

FDR of patients with SPS were invited to undergo colonoscopy. The diagnostic yield was expressed by the number of FDRs with at least 1 significant polyp relative to the total number of included FDRs. Significant polyps were defined adenomas, traditional serrated adenomas, sessile serrated adenoma/polyp, or proximal hyperplastic polyp. Tissue specimens were reviewed by one expert pathologist.

RESULTS

Seventy-seven FDRs underwent colonoscopy (median age 52 y; interquartile range, 41 to 60). Colorectal cancer was not diagnosed. One or more significant polyps were detected in 43% of FDRs. No differences based on age, gender, or familial relationship were observed in the detection of polyps. Seven first-degree (9%) relatives had multiple polyps (≥5). Eleven (14%) FDRs fulfilled SPS WHO-criterion 2, of whom 1 sibling also met SPS WHO-criterion 3.

CONCLUSIONS

The yield of a single screening colonoscopy in FDRs of patients with serrated polyposis is substantial, warranting a colonoscopy screening program for these individuals.

A morphologic reappraisal of endoscopically but not histologically apparent polyps and the emergence of the overlooked goblet cell--rich hyperplastic polyp

Goblet cell--rich hyperplastic polyps (GCRHP) are morphologically subtle compared to microvesicular hyperplastic polyps (MVHP) and are believed to be the most commonly unrecognized serrated polyp, though this has not been systematically studied. We hypothesize that a gastrointestinal pathologist's review of endoscopically but not histologically apparent polyps will identify previously missed GCRHPs, a finding that may be clinically significant if the addition of this subtype of serrated polyp contributes to sufficient numeric criteria for a clinical diagnosis of serrated polyposis syndrome (SPS). Two blinded reviews were performed on 160 endoscopically but not histologically apparent polyps by a gastrointestinal pathologist, separated by a 6 month "washout period." A final review diagnosis of GCRHP was applied to all polyps with complete agreement on both reviews. Patient records were then searched to determine if the addition of a GCRHP resulted in sufficient numeric criteria for a clinical diagnosis of SPS. Fourteen (9%) polyps were reclassified as GCRHPs. The majority (n = 12, 86%) were originally called "colonic mucosa with surface hyperplastic change (CMWSHC)." Two polyps (1%) were re-classified as MVHPs. No other serrated or adenomatous polyps were identified. For each patient, the addition of a hyperplastic polyp did not result in a clinical diagnosis of SPS, though one patient fell short of this diagnosis by only one polyp. GCRHPs are the most commonly underdiagnosed serrated polyp and are often called CMWSHC. The addition of previously missed GCRHPs is unlikely to contribute to a diagnosis of SPS in an individual patient.

How does the serrated polyp pathway alter CRC screening and surveillance?

Screening and surveillance for colorectal cancer (CRC) reduces mortality through the detection of early-stage adenocarcinoma, and more importantly the detection and removal of premalignant polyps. While adenomas have historically been considered the most common and screening-relevant precursor lesions, there is accumulating evidence showing that the serrated pathway is an important contributor to CRC, and a disproportionate contributor to interval or postcolonoscopy CRC, particularly in the proximal colon. The serrated pathway is characterized by mutations in the BRAF gene, high levels of methylation of promoter CpG islands (CIMP-high), and the sessile serrated adenoma/polyp (SSA/P) is the most important precursor lesion. The study of serrated polyps has been complicated by evolving nomenclature, substantial variation among pathologists in the identification of SSA/Ps, high variability in endoscopic detection rates, and uncertainty regarding the relation to synchronous and metachronous colonic neoplasia. This paper presents an overview of the serrated polyp pathway and discusses its clinical implications including its impact on CRC screening.

Sessile serrated polyps: detection, eradication, and prevention of the evil twin

OPINION STATEMENT

The sessile serrated polyp (SSP), also known as sessile serrated adenoma, is the evil twin among the colorectal cancer precursors. As will be described, these lesions have multiple aliases (serrated adenoma, serrated polyp, or serrated lesion among others), they hang out in a bad neighborhood (the poorly prepped right colon), they hide behind a mask of mucus, they are difficult for witnesses (pathologists) to identify, they are difficult for police (endoscopists) to find, they are difficult to permanently remove from the society (high incomplete resection rate), they can be impulsive (progress rapidly to colorectal cancer (CRC)), and enforcers (gastroenterologists) do not know how best to control them (uncertain surveillance recommendations). There is no wonder that there is a need to understand these lesions well, learn how best to prevent the colonic mucosa from going down this errant path or, if that fails, detect these deviants and eradicate them from the colonic society. These lesions should be on endoscopists' most wanted list.

ACG clinical guideline: Genetic testing and management of hereditary gastrointestinal cancer syndromes

This guideline presents recommendations for the management of patients with hereditary gastrointestinal cancer syndromes. The initial assessment is the collection of a family history of cancers and premalignant gastrointestinal conditions and should provide enough information to develop a preliminary determination of the risk of a familial predisposition to cancer. Age at diagnosis and lineage (maternal and/or paternal) should be documented for all diagnoses, especially in first- and second-degree relatives. When indicated, genetic testing for a germline mutation should be done on the most informative candidate(s) identified through the family history evaluation and/or tumor analysis to confirm a diagnosis and allow for predictive testing of at-risk relatives. Genetic testing should be conducted in the context of pre- and post-test genetic counseling to ensure the patient's informed decision making. Patients who meet clinical criteria for a syndrome as well as those with identified pathogenic germline mutations should receive appropriate surveillance measures in order to minimize their overall risk of developing syndrome-specific cancers. This guideline specifically discusses genetic testing and management of Lynch syndrome, familial adenomatous polyposis (FAP), attenuated familial adenomatous polyposis (AFAP), MUTYH-associated polyposis (MAP), Peutz-Jeghers syndrome, juvenile polyposis syndrome, Cowden syndrome, serrated (hyperplastic) polyposis syndrome, hereditary pancreatic cancer, and hereditary gastric cancer.

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.

A rare case series of concomitant inflammatory bowel disease, sporadic adenomas, and serrated polyposis syndrome

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) involving the colon is associated with an increased risk of colon cancer. Patients may develop sporadic adenomas further increasing their risk of colorectal cancer. Current knowledge of IBD with concomitant serrated polyposis syndrome (SPS) is limited. We describe four patients with both IBD and SPS.

METHODS

Four patients with inflammatory bowel disease and hyperplastic polyps referred to Beth Israel Deaconess Medical Center meeting the World Health Organization (WHO) criteria for SPS were identified.

RESULTS

Four patients with long standing IBD involving the colon were identified. All of these patients' IBD were in clinical remission. Additionally, 2 of the 4 patients were also noted to have sporadic adenomas. Each patient was also found to have multiple sessile serrated adenomas and hyperplastic polyps meeting the WHO criteria for SPS. Two of the patients had colonoscopy with chromoendoscopy which improved polyp detection. Discussions were held with each patient regarding the potentially increased risk of colorectal cancer with the combination of IBD and SPS. Patients were advised that colectomy would be the safest method to reduce the risk of cancer. None of the patients opted for colectomy and instead planned on a repeat colonoscopy with chromoendoscopy at 3-12 month intervals.

CONCLUSION

Serrated polyposis syndrome develops in patients with IBD. It is unclear how high the risk of colon cancer is in patients who have both IBD and SPS and what the recommendations should be regarding the frequency of surveillance or surgery. Further studies are necessary to identify the optimal management of these patients.

Prevalence of serrated polyposis syndrome and its association with synchronous advanced adenoma and lifestyle

We assessed the clinicopathological characteristics of patients with serrated polyposis syndrome (SPS) and the incidence of advanced adenoma/colorectal cancer (CRC). We prospectively enrolled 249 consecutive patients who underwent colonoscopy at the National Cancer Center Hospital over a 6-month period. All the polyps were diagnosed using magnification colonoscopy and resection/biopsy. The enrolled patients were divided into two groups, i) those with ≥5 histologically diagnosed hyperplastic polyps (HPs) proximal to the sigmoid colon, with at least 2 polyps >10 mm in diameter and ii) those with ≥20 HPs distributed throughout the colon. The clinical characteristics of the two groups were compared, including lifestyle, family history of CRC and colonoscopic findings. HPs were identified in 228 patients, of whom 21 (8.4%) had SPS. All 21 patients had ≥20 HPs distributed throughout the colon, with none having >2 HPs ≥1 cm in diameter in the right colon. Synchronous advanced adenoma/CRC was diagnosed in 76/249 (30.5%) patients. The prevalence of advanced adenoma/CRC was higher among patients with compared to those without SPS (P=0.075). SPS was also associated with older age and higher body mass index (BMI). Our results suggested that older age and higher BMI are independent risk factors for SPS. Advanced adenoma/CRC tended to occur more frequently among patients with compared to those without SPS, although the difference was not statistically significant.

Genetic predisposition to colorectal cancer: Where we stand and future perspectives

The development of colorectal cancer (CRC) can be influenced by genetic factors in both familial cases and sporadic cases. Familial CRC has been associated with genetic changes in high-, moderate- and low-penetrance susceptibility genes. However, despite the availability of current gene-identification techniques, the genetic causes of a considerable proportion of hereditary cases remain unknown. Genome-wide association studies of CRC have identified a number of common low-penetrance alleles associated with a slightly increased or decreased risk of CRC. The accumulation of low-risk variants may partly explain the familial risk of CRC, and some of these variants may modify the risk of cancer in patients with mutations in high-penetrance genes. Understanding the predisposition to develop CRC will require investigators to address the following challenges: the identification of genes that cause uncharacterized hereditary cases of CRC such as familial CRC type X and serrated polyposis; the classification of variants of unknown significance in known CRC-predisposing genes; and the identification of additional cancer risk modifiers that can be used to perform risk assessments for individual mutation carriers. We performed a comprehensive review of the genetically characterized and uncharacterized hereditary CRC syndromes and of low- and moderate-penetrance loci and variants identified through genome-wide association studies and candidate-gene approaches. Current challenges and future perspectives in the field of CRC predisposition are also discussed.