Distribution and prevalence of colorectal hyperplastic polyps using magnifying pan-mucosal chromoendoscopy and its relationship with synchronous colorectal cancer: prospective study

Prospective evaluation of the proportion of sessile serrated adenoma/polyps in endoscopically diagnosed colorectal polyps with hyperplastic features

BACKGROUND AND STUDY AIMS

Sessile serrated adenoma/polyps (SSA/Ps) are considered precursors of colorectal cancers with microsatellite instability. However, it is still difficult to differentiate SSA/Ps from hyperplastic polyps endoscopically; therefore, the prevalence of SSA/Ps remains uncertain in clinical practice. This study aimed to clarify the proportion of SSA/Ps in endoscopically diagnosed colorectal polyps with hyperplastic features (E-HPs).

PATIENTS AND METHODS

Patients aged ≥ 40 years undergoing colonoscopy for standard clinical indications at our center were prospectively enrolled between June 2013 and May 2014. During colonoscopy, 0.05 % indigo carmine dye was sprayed throughout the colorectum to highlight lesions. All detected lesions were diagnosed by high definition magnifying narrow-band imaging and were resected endoscopically or surgically, apart from rectosigmoid E-HPs ≤ 5 mm. The number of rectosigmoid E-HPs ≤ 5 mm was recorded, and some were resected for use as tissue samples.

RESULTS

A total of 343 patients (male: 42.9 %; mean age: 61.5 years) were included. Among 3838 E-HPs (distal: 96.4 %) detected in 294 patients, 792 were resected and analyzed. All of 21 SSA/Ps identified in 17 patients were included in E-HPs, and the overall proportion of SSA/Ps in E-HPs was 2.7 %. However, this proportion increased with the size of E-HPs (≤ 5 mm: 0.7 %; 6 - 9 mm: 29.0 %; ≥ 10 mm: 70 %) and was higher in the proximal colon than in the distal colorectum (10.9 % vs. 0.9 %). In addition, no SSA/P was found in the rectum, and no SSA/P had cytological dysplasia.

CONCLUSIONS

The overall proportion of SSA/Ps in E-HPs was 2.7 %, although this proportion was higher in the proximal colon and increased with the size of E-HPs. SSA/Ps were common in routine colonoscopy, with a prevalence of at least 5.0 %.

STUDY REGISTRATION

UMIN000010832.

The prevalence and associated factors of colorectal neoplasms in acromegaly: a single center based study

PURPOSE

Colorectal neoplasms are well known to be a complication in cases of acromegaly; however, data on the prevalence of colorectal neoplasms in Asian patients with acromegaly are limited. Further, the factors associated with colorectal neoplasms in cases of acromegaly are controversial. Therefore, we aimed to clarify the prevalence of and factors associated with colorectal neoplasms in Japanese patients with acromegaly in a single center.

METHODS

We analyzed consecutive 57 patients who had undergone full-length colonoscopy at the time of diagnosis at Kobe University Hospital between 1986 and 2012.

RESULTS

Of the 57 patients, 22 (38.6%), 18 (31.6%) and 3 (5.3%) patients were diagnosed with hyperplastic polyps, adenomas, and adenocarcinomas, respectively and the prevalence was significantly higher than in a historical control group, Chinese patients with irritable bowel syndrome (The odds ratio was 4.0, 8.7, and 17.5, respectively). The prevalence of adenocarcinomas was also significantly higher in these patients than in the general Japanese population (odds ratio 14.5). Patients with acromegaly who had colorectal neoplasms had longer disease duration than those without colorectal neoplasms. Of note, the area under the growth hormone (GH) concentration-time curve (GH AUC) during the oral glucose tolerance test was significantly higher in patients with adenocarcinomas than in those with no colonic lesion or those with hyperplastic polyps.

CONCLUSION

Japanese patients with acromegaly exhibited an increased risk of colorectal neoplasms, especially colorectal adenocarcinomas. An increased GH AUC was associated with an increased risk for colon adenocarcinomas in patients with acromegaly.

Serrated and non-serrated precursor lesions of colorectal cancer

Although often viewed as a single disease, colorectal cancer more accurately represents a family of diseases with different precursor lesions. Conventional (tubular, tubulovillous and villous) adenomas are the most common neoplastic lesions occurring in the large intestine. They have adenomatous polyposis coli (APC) mutations and arise from dysplastic aberrant crypt foci, initially as polyclonal lesions. In sporadic tumours, neoplastic progression follows the traditional pathway (chromosomal instability pathway), resulting in CpG island methylator phenotype (CIMP)-negative, microsatellite-stable (MSS), BRAF and KRAS wild-type cancers. Germline mutations in the APC gene lead to familial adenomatous polyposis. Conventional adenomas are also the precursors of Lynch syndrome-associated microsatellite-instable (MSI-high) cancers. Sessile serrated adenoma/polyp (SSA/P) is the principal precursor lesion of the serrated pathway, in which BRAF mutation can lead to colorectal cancer with MSI-high CIMP-high or MSS CIMP-high phenotype. SSA/Ps have been associated with synchronous and metachronous invasive adenocarcinomas as well as so-called interval carcinomas. Serrated polyposis is rare but most likely underdiagnosed. Affected individuals bear an increased but unspecified risk for the development of colorectal cancer; close endoscopic surveillance is warranted. Traditional serrated adenomas (TSAs) are much less common than the other serrated lesions. Cancers originating from TSAs may show KRAS mutation with a CIMP-high MSS phenotype.

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.

Serrated polyposis syndrome and the role of serrated polyps in colorectal cancer development

SUMMARY Serrated polyposis syndrome is characterized by the presence of multiple colorectal serrated polyps and is associated with an increased colorectal cancer risk. The mixture of distinct precursor lesion types and malignancies in serrated polyposis syndrome provides a unique model to study the recently proposed serrated neoplasia pathway. This pathway involves the progression of serrated polyps, that is, hyperplastic polyps, sessile serrated adenoma/polyps and/or traditional serrated adenomas, to colorectal cancer. The early genetic events of this route, as currently identified, are BRAF or KRAS mutations and an enhanced CPG island methylation status of multiple genes. There is evidence to suggest that a proportion of sporadic colorectal cancers originate from serrated polyps, which encompass molecular sequences of events such as hypermethylation of different genes and BRAF mutations. This review discusses the characteristics and clinical relevance of serrated polyps and provides an overview of the clinical aspects and treatment of serrated polyposis syndrome.

Proximal and large hyperplastic and nondysplastic serrated polyps detected by colonoscopy are associated with neoplasia

BACKGROUND & AIMS

The family of serrated lesions includes hyperplastic polyps and sessile serrated adenomas without dysplasia, as well as traditional serrated adenoma with dysplasia. We investigated whether detection of proximal nondysplastic serrated polyps (ND-SP) at screening and surveillance colonoscopies is associated with advanced neoplasia.

METHODS

The study included 3121 asymptomatic patients (aged 50-75 years) who had screening colonoscopies; 1371 had subsequent surveillance. The proximal colon was defined as segments proximal to the descending colon. Large ND-SP were defined as ≥ 10 mm. We compared rates of detection of any neoplasia and advanced neoplasia at screening and surveillance colonoscopies (within 5.5 years) in patients with and without proximal or large ND-SP.

RESULTS

At baseline screening, 248 patients (7.9%) had at least 1 proximal ND-SP. They were more likely than patients with no proximal ND-SP to have advanced neoplasia (17.3% vs 10.0%; odds ratio [OR], 1.90; 95% confidence interval [CI], 1.33-2.70). Patients with large ND-SP (n = 44) were also more likely to have synchronous advanced neoplasia (OR, 3.37; 95% CI, 1.71-6.65). During surveillance, 39 patients with baseline proximal ND-SP and no neoplasia were more likely to have neoplasia compared with subjects who did not have polyps (OR, 3.14; 95% CI, 1.59-6.20). Among patients with advanced neoplasia at baseline, those with proximal ND-SP (n = 43) were more likely to have advanced neoplasia during surveillance (OR, 2.17; 95% CI, 1.03-4.59).

CONCLUSIONS

Detection of proximal and large ND-SP at a screening colonoscopy is associated with an increased risk for synchronous advanced neoplasia. Detection of proximal ND-SP in a baseline colonoscopy is associated with an increased risk for interval neoplasia during surveillance.

Filiform polyposis in the sigmoid colon: A case series

Filiform polyposis is a rare condition of uncertain pathogenesis that is usually found in association with Crohn’s disease, ulcerative colitis, intestinal tuberculosis or histiocytosis X. We report seven interesting cases of polyposis with various pathologic components, mainly located in the left side of the colon with no associated inflammatory bowel disease, intestinal tuberculosis or histiocytosis X. Multiple finger-like polypoid lesions with the appearance of stalactites were noted on the left side of the colon, especially in the sigmoid area, at the time of colonoscopy. The polyps had a variety of sizes and shapes and were shown to have various histopathologic components among the different patients. Although filiform polyposis localized in the sigmoid colon appears not to have high oncogenic potential, periodic follow-up seems to be needed.

Clinicopathological features of colon polyps from African-Americans

BACKGROUND AND AIMS

Among the ethnic groups, the age-standardized incidence rate of colorectal cancer (CRC) is highest among African-Americans. The majority of CRC arise from preexisting adenoma. It is shown that 30% of the US adult population has adenomas. The potential risk of malignant transformation in adenomas differs by specific pathologic and clinical characteristics that we aimed to study in AAs.

MATERIALS AND METHODS

All pathologic reports (150,000) in Howard University Hospital from 1959 to 2006 were reviewed manually. Those pathology reports compatible with the colorectal polyps were carefully reviewed and selected by a GI pathologist. All cases with cancer were then excluded from the list. Data were then entered into Microsoft Excel and checked for missing data and duplications. Differences in right-side and left-side polyps for sex, histology, and clinical symptoms were assessed by Chi-2 test.

RESULTS

A total number of 5,013 colorectal polyps were diagnosed in this period that include 47% male, with mean age (SD) of 63 (12). Half of the cases were diagnosed in 2001-2006. Tubular adenoma was the most frequent pathology (73%). The highest frequency of right-sided polyps was observed in the 1990s (56%). Left-sided polyps were younger (p < 0.0001), more hyperplasic (23 vs. 5%; p < 0.0001), and more frequent in female (56 vs. 52%; p = 0.02) compared to right-sided polyps. The frequency of right-sided adenoma significantly increases from 18% in the 1960s to 51% in the period of 2001-2006 (p < 0.0001). The most frequent symptom in both sides was GI bleeding (21%).

CONCLUSION

There was a ratio of 8:1 for neoplastic to hyperplastic polyps in our study, which is more than what has been reported in Caucasians (7:1). Our data shows a shift in polyps from the left side to the right side of the colon in recent years. This data is consistent with the lack of a reduction in the incidence of colon cancer in African-Americans. Screening is thus very important in AA to reduce the incidence of colon cancer.

Sporadic and syndromic hyperplastic polyps and serrated adenomas of the colon: classification, molecular genetics, natural history, and clinical management

There is now strong evidence for an alternative pathway of colorectal carcinogenesis implicating hyperplastic polyps and serrated adenomas. This article briefly reviews the evidence for this serrated pathway, provides diagnostic criteria for clinically significant hyperplastic polyps and allied serrated polyps, and suggests how this information may be translated into safe, effective guidelines for colonoscopy-based colon cancer prevention. Consideration also is given to the definition and management of hyperplastic polyposis syndrome. The currently proposed management plan for serrated polyps is tentative because of incomplete knowledge of the nature and behavior of these polyps. This article highlights key areas warranting further research.

Colorectal serrated adenocarcinoma

Colorectal cancer (CRC) ranks among the three most common cancers in terms of both cancer incidence and cancer-related deaths in most Western countries. Serrated adenocarcinoma is a recently described, distinct variant of CRC, accounting for about 7.5% of all CRCs and up to 17.5% of most proximal CRCs. It has been postulated that about 10-15% of sporadic CRCs would have their origin in serrated polyps that harbour a significant malignant potential. These lesions include hyperplastic-type aberrant crypt foci, hyperplastic polyps, sessile serrated adenomas, admixed polyps and serrated adenomas, and constitute the so-called 'serrated pathway', which is distinct from both the conventional adenoma-carcinoma pathway and the mutator pathway of hereditary non-polyposis CRC and is characterized by early involvement of oncogenic BRAF mutations, excess CpG island methylation (CIM) and subsequent low- or high-level DNA microsatellite instability (MSI). Methylation of hMLH1 is likely to explain the increased frequency of high-level MSI (16%) and methylation of MGMT is postulated to explain the low-level MSI (29%) in serrated adenocarcinomas. Reproducible histopathological criteria for serrated adenocarcinoma have recently been established and they have been qualified by DNA expression analysis for 7928 genes, showing clustering of serrated adenocarcinomas into a molecular entity apart from conventional adenocarcinoma, and representing with distinct down-regulation of EPHB2, PTCH and up-regulation of HIF1alpha.