Pathology of colorectal adenomas: a colonoscopic survey

Expression of adipokine ghrelin and ghrelin receptor in human colorectal adenoma and correlation with the grade of dysplasia

BACKGROUND

Ghrelin is an adipokine that plays an important role in energy balance. Expression of ghrelin and ghrelin receptor has been investigated in different tissues and tumors. Studies regarding expression of ghrelin and ghrelin receptor in colorectal tumors are scarce and no data on expression of ghrelin and its receptor in colorectal adenomas has been published. Ghrelin and ghrelin receptor were highly expressed in colon carcinoma cells while expression was decreased in less differentiated tumors, presuming that ghrelin might be important in early phases of tumorigenesis.

AIM

To investigate the expression of ghrelin and ghrelin receptor in human colorectal adenomas and adjacent colorectal tissue.

METHODS

In this prospective study (conducted from June 2015 until May 2019) we included 92 patients (64 male and 28 female) who underwent polypectomy for colorectal adenomas in the Department of Gastroenterology and Hepatology, “Sestre milosrdnice” Clinical Hospital Center in Zagreb, Croatia. After endoscopic removal of colorectal adenoma, an additional sample of colon mucosa in the proximity of the adenoma was collected for pathohistological analysis. Adenomas were graded according to the stage of dysplasia, and ghrelin and ghrelin receptor expression were determined immunohistochemically in both adenoma and adjacent colon tissue using the polyclonal antibody for ghrelin (ab150514, ABCAM Inc, Cambridge, United States) and ghrelin receptor (ab48285, ABCAM Inc, Cambridge, United States). Categorical and nominal variables were described through frequencies and proportions and the difference between specific groups were analyzed with Fisher’s and Fisher-Freeman-Halton’s method respectively. Spearman's rank correlation coefficient was determined for correlation of expression of ghrelin and ghrelin receptor in adenoma and adjacent colon tissue with the grade of adenoma dysplasia.

RESULTS

Among 92 patients with colorectal adenoma 43 had adenomas with high-grade dysplasia (46.7%). High expression of ghrelin was 7 times more common in high-grade adenoma compared to low-grade adenomas (13.95% to 2.04%, P = 0.048), while the expression of ghrelin in adjacent colon tissue was low. We found no correlation between ghrelin receptor expression in adenoma and adjacent colon tissue and the grade of colorectal adenoma dysplasia. The most significant correlation was found between ghrelin and ghrelin receptor expression in adenomas with high-grade dysplasia (rho = 0.519, P < 0.001).

CONCLUSION

Ghrelin and ghrelin receptor are expressed in colorectal adenoma and adjacent tissue with ghrelin expression being more pronounced in high grade dysplasia as a possible consequence of increased local synthesis.

Adenoma Characteristics and the Influence of Alcohol and Cigarette Consumption on the Development of Advanced Colorectal Adenomas

Background: Colorectal cancer (CRC), one of the leading public health problems worldwide, is a disease that can be prevented when it is detected in time. The objectives of this cross-sectional study were to investigate the characteristics of colorectal adenomas and whether alcohol consumption and cigarette smoking correlated with the development of advanced adenomas in participants in The National Programme for Early Detection of Colorectal Cancer (NP) in Osijek-Baranja County (OBC), Croatia. Methods: The screening methods were the guaiac Faecal Occult Blood Test (gFOBT), colonoscopy, histological analysis, and risk factor questionnaire. Results: The results showed the presence of adenomas in 136 men (57.4%) and 101 women (42.6%), p < 0.001. There was one adenoma in 147 (62%) most commonly located in sigmorect, in 86 (59%) participants, and 44 (18.6%) participants had multiple adenomas, most commonly found in multi loc, p < 0.001. According to size, 118 (49.8%) of all adenomas were between 0.1 and 0.9 cm, while adenomas of 3 cm 19 (8%) were the fewest, p < 0.001. There were 142 (59.9%) advanced adenomas. Conclusions: Adenoma development in the OBC population was correlated with predictors: adenoma size, high-grade dysplasia, smoking and alcohol consumption of 20 g per day. Non-smoking was found to be a health protective behaviour.

Probiotic Lactobacillus salivarius Ren prevent dimethylhydrazine-induced colorectal cancer through protein kinase B inhibition

Probiotics are known to be a potential agent for colorectal cancer (CRC) inhibition, but the precise mechanisms by which probiotic exert anti-tumorigenic effects remain to be explored. Lactobacillus salivarius (LS) Ren was isolated from centenarians living in Bama of China, which showed an anticancer potent in animal model of oral cancer. Here, we investigated the effect of LS on colorectal carcinogenesis and its putative mechanism. Oral administration of LS effectively suppressed the formation of dimethylhydrazine (DMH)-induced CRC in both initial and post-initial stages. Significant antiproliferation and proapoptotic effects were observed with inhibition of tumor formation by dietary intake of LS. Besides, LS metabolites inhibited growth, arrested cell cycle, and induced apoptosis of HT-29 cells. Furthermore, upon the treatment of LS, protein kinase B (AKT) phosphorylation and the downstream proteins of cyclinD1 and cyclooxygenase-2 (COX-2) were significantly downregulated in both in vivo and in vitro tests. These results showed that LS inhibited the colorectal carcinogenesis through suppressing AKT signaling pathway, resulting in suppressing cell proliferation and inducing cell apoptosis. Our findings suggest that this probiotic may act as a prophylactic agent for CRC prevention. Key points • LS effectively prevented rat colorectal carcinogenesis induced by DMH. • LS modulated the proliferation and apoptosis in both in vivo and in vitro. • LS inhibited AKT phosphorylation and expressions of downstream cyclinD1 and COX-2.

Increased Risk of Colorectal Cancer Tied to Advanced Colorectal Polyps: An Untapped Opportunity to Screen First-Degree Relatives and Decrease Cancer Burden

Advanced adenomas represent a subset of colorectal polyps that are known to confer an increased risk of colorectal neoplasia to the affected individual and their first-degree relatives (FDRs). Accordingly, professional guidelines suggest earlier and more intensive screening for FDRs of those with advanced adenomas similar to FDRs of those with colorectal cancer (CRC). Although the risk to family members is less clear among patients with advanced serrated polyps, they are often considered in the same category. Unfortunately, there is a growing concern that patients, endoscopists, and primary care providers are unaware of the familial risk associated with these polyps, leaving a wide gap in screening these high-risk individuals. Herein, we propose a standardized language around advanced colorectal polyps and present a detailed review of the literature on associated familial risk. We outline the challenges to implementing the current screening recommendations and suggest approaches to overcome these limitations, including a proposed new colonoscopy quality metric to capture communication of familial CRC risk. Improving screening in these high-risk groups has the potential to substantially reduce the burden of CRC.

Vitamin D supplementation reduces the occurrence of colorectal polyps in high-latitude locations

There is suggestive evidence for the role of vitamin D in the development of colorectal cancer (CRC). Due to high latitudes in Canada, many Canadians are vitamin D deficient throughout winter. In this analysis, we examined the association between vitamin D supplement use and high-risk adenomatous polyps (HRAPs). The study population was drawn from the biorepository at the Forzani & MacPhail Colon Cancer Screening Centre (CCSC) in Calgary. Individuals enrolled between 2013 and 2016 between the age of 50 and 74 years (n = 1409) were included. When examining the association between any supplemental vitamin D use and HRAPs, a protective effect is observed with an OR_adj of 0.57 (95% CI: 0.33-0.96). Similarly, meeting the recommended daily intake (RDI) of vitamin D (600 IU) is protective against HRAPs with an OR_adj of 0.78 (95% CI: 0.62-0.99). This study suggests that adequate vitamin D supplementation reduces the occurrence of colorectal polyps in high-latitude locations.

Prophylactic clip application for large pedunculated polyps before snare polypectomy may decrease immediate postpolypectomy bleeding

BACKGROUND

Although prophylactic clip application before polypectomy may prevent postpolypectomy bleeding (PPB), the usefulness of prophylactic clipping in the treatment of large pedunculated polyps is controversial in some prospective randomized studies. This study was conducted to evaluate the efficacy of prophylactic clip application and to investigate the predictors of PPB in large pedunculated colorectal polyps.

METHODS

A total of 137 pedunculated polyps (size ≥1 cm) in 116 patients were prospectively included and randomized into group A (with clipping) and group B (without clipping), and resected. The occurrences of immediate PPB (graded 1-4) and delayed PPB were compared.

RESULTS

Sixty-seven polyps were allocated in group A and 70 polyps in group B. In both groups, the median polyp diameter was 15 mm (P = 0.173) and the median stalk diameter was 3 mm (P = 0.362). Twenty-eight (20.4%) immediate PPB episodes in 137 polyps occurred, 6 (9.0%) in group A and 22 (31.4%) in group B (P = 0.001). However, the occurrence of delayed PPB was not different between the groups (P = 0.943). Prophylactic clip application decreased the occurrence of immediate PPB (odds ratio 0.215, 95% confidence interval 0.081-0.571). Moreover, polyp size ≥20 mm and stalk diameter ≥ 4 mm increased the risk of immediate PPB.

CONCLUSIONS

Clip application before polypectomy of ≥1 cm pedunculated polyps is effective in decreasing the occurrence of immediate PPB. Thus, clip application should be considered before performing snare polypectomy, especially for large polyps with a thick stalk.

TRIAL REGISTRATION

This research was studied a prospective maneuver and enrolled in a registry of clinical trials run by United States National Library of Medicine at the National Institutes of Health (ClinicalTrials.gov Protocol Registration and Results system ID: NCT01437631). This study was registered on September 19, 2011.

Underwater versus conventional endoscopic resection of nondiminutive nonpedunculated colorectal lesions: a prospective randomized controlled trial (with video)

BACKGROUND AND AIMS

Incomplete resection of colorectal neoplasia decreases the efficacy of colonoscopy. Conventional resection (CR) of polyps, performed in a gas-distended colon, is the current standard, but incomplete resection rates of approximately 2% to 30% for nondiminutive (>5 mm), nonpedunculated lesions are reported. Underwater resection (UR) is a novel technique. The aim of this study was to determine the incomplete resection rates of colorectal lesions removed by UR versus CR.

METHODS

In a randomized controlled trial, patients with small (6-9 mm) and large (≥10 mm) nonpedunculated lesions were assigned to CR (gas-distended lumen) or UR (water-filled, gas-excluded lumen). Small lesions in both arms were removed with a dedicated cold snare. For CR, large lesions were removed with a hot snare after submucosal injection. For UR, large lesions were removed with a hot snare without submucosal injection. Four-quadrant biopsy samples around the resection sites were used to evaluate for incomplete resection.

RESULTS

Four hundred sixty-two eligible polyps (248 UR vs 214 CR) from 255 patients were removed. Incomplete resection rates for UR and CR were low and did not differ (2% vs 1.9%, P = .91). UR was performed significantly faster for lesions ≥10 mm in size (10-19 mm, 2.9 minutes vs 5.6 minutes, P < .0001); ≥20 mm, 7.3 minutes vs 9.5 minutes, P = .015).

CONCLUSIONS

Low incomplete resection rates are achievable with UR and CR. UR is effective and safe with the advantage of faster resection and potential cost savings for removal of larger (≥10 mm) lesions by avoiding submucosal injection. As an added approach, UR has potential to improve the cost-effectiveness of colonoscopy by increasing efficiency and reducing cost while maintaining quality. (Clinical trial registration number: NCT02889679.).

Retrospective study on melanosis coli as risk factor of colorectal neoplasm: a 3-year colonoscopic finding in Zhuhai Hospital, China

BACKGROUND

Melanosis coli (MC) is a colonoscopic finding in which the colonic mucosa appears darkly pigmented than usual and generally caused by extended anthranoid laxative use.

METHODS

We performed a retrospective study at Zhuhai Hospital to investigate the risk of MC for CR neoplasm development. A total of 12,776 patients who underwent colonoscopy from 2013 to 2016 including 250 diagnosed with MC and 500 controls were included in this study. Odds ratios (OR) and 95% confidence intervals (95%CI) for associations of MC with CR neoplasm detection were estimated using univariate and multivariable multinomial logistic analyses for known risk factors.

RESULTS

The presence of MC was associated with a significant increase in the CR neoplasm detection rate compared with controls (OR = 1.701, 95% CI = 1.252-2.31; P = 0.001). The effect was also observed in different tumor sites, age group, gender, and lifestyle. Using univariate multinomial analysis, patients with MC were significantly associated with both hyperplastic polyp (OR = 2.069, 95% CI = 1.253-3.415; P = 0.005) and low-grade (LG) adenoma (OR = 1.585, 95% CI = 1.115-2.254; P = 0.010). However, there was no significant difference with adenocarcinoma (OR = 1.701, 95% CI = 0.990-2.924; P = 0.055). Using multivariate multinomial analysis, MC patients remained associated with increased hyperplastic polyp (OR = 1.870, 95% CI = 1.119-3.125; P = 0.017) and LG adenoma (OR = 1.474, 95% CI = 1.027-2.114; P = 0.035), but not adenocarcinoma (OR = 1.620, 95% CI = 0.914-2.871; P = 0.098). A significant increase in CR neoplasm rate was observed with drinker, smoker, and elderly patients but not with gender.

CONCLUSION

Patients with MC were more likely to have both hyperplastic polyp and LG adenoma. If confirmed, such findings could suggest the discontinuation of anthranoid laxative use particularly in the elderly.

Capability of four sigmoidoscopy-based screening strategies to predict proximal neoplasia in an asymptomatic Chinese population

BACKGROUND AND AIM

A proper colonoscopy referral criterion is essential for flexible sigmoidoscopy-based colorectal cancer screening. We aimed to compare the predictive capability of four existing criteria to detect proximal neoplasia (PN) and advanced proximal neoplasia (APN) in a Chinese population.

METHODS

Asymptomatic Chinese participants aged 50-75 years, who received screening colonoscopy, were consecutively recruited. The four criteria included (i) UK flexible sigmoidoscopy; (ii) Italian Screening for COlon REctum; (iii) NORwegian Colorectal Cancer Prevention trial; and (iv) US clinical index. The sensitivity, specificity, positive/negative predictive value, and the number of subjects needed to screen (NNS)/refer (NNR) to detect one APN/PN were examined. The area under receiver operating characteristic curve was evaluated.

RESULTS

Among 5833 subjects, 749 (12.8%) and 151 (2.6%) cases were found to have PN and APN, respectively. US criteria achieved the highest sensitivity for PN (49%) and APN (66%), while UK criteria attained the highest specificity (93%) for PN/APN. The lowest NNS was required by US criteria for PN (16 vs 19-38) and APN (58 vs 69-86), while the lowest NNR was required by UK criteria for PN (3.2 vs 4.0-4.8) and APN (7 vs 10-16). The receiver operating characteristic of all four criteria was 0.57-0.61 for PN and 0.68-0.70 for APN.

CONCLUSIONS

Among all the four criteria, US criteria had the highest sensitivity and lowest NNS, while UK criteria achieved the highest specificity and lowest NNR. Their limited discriminatory capability highlighted the need for a new score to predict PN/APN in Chinese populations.

Villous Gastrointestinal Tumors: Multimodality Imaging with Histopathologic Correlation

Villous lesions are advanced adenomas that manifest most commonly in the colon; however, they can develop throughout the gastrointestinal tract. The duodenum is the most common small-bowel site of these lesions. Although in most cases these are isolated lesions that occur sporadically, patients with certain specific colorectal cancer syndromes, including familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer, may develop multiple advanced adenomas. Villous lesions are important because although they are histologically benign, they may harbor dysplasia and have potential for malignancy. These characteristics make them a primary target for colorectal cancer screening with optical and virtual colonoscopy. However, these lesions can also be symptomatic and detected at diagnostic imaging when patients present for examination. They have characteristic features at a variety of imaging examinations, including barium fluoroscopy, CT, MRI, and endoscopic US. It is important for radiologists to be aware of these lesions, their potential morphologies, and their typical appearances at multimodality imaging. Although villous tumors can be detected at imaging and confirmed with biopsy, owing to limitations in identifying dysplasia and foci of malignancy with the above modalities alone and the potential for malignancy, referral for surgical resection of these lesions ultimately is required. ^©RSNA, 2018.

The Double Contrast Barium Enema in the Identification of Proximal Colonic Adenomas and Carcinomas beyond the Limits of Fiberoptic Sigmoidoscopy

Eight hundred and twenty patients were examined by fiberoptic sigmoidoscopy (SIG) and double contrast barium enema (DCBE) to detect colonic cancers or adenomas. Cancer or adenoma in the bowel tract proximal to the upper limit of SIG insertion was detected in 4-patients and in 12 on DCBE. The DCBE detection rate of proximal colonic lesions varied according to the hemoccult (HO) outcome. This was 1.16 % for cancer and 2.03 % for adenoma in HO+ patients and null for cancer and 1.23 % for adenoma in HO–- patients. The detection rate of proximal adenomas was higher in patients who presented adenomas on endoscopy in the distal bowel (SIG+), 2.46 % as compared to 0.48 % in SIG- patients,. independent of the HO reports. Routine DCBE is practically useless in HO-SIG- patients and questionable in HO-SIG+ patients since improvement of the detection rate is null for cancer and moderate for adenoma. It is recommended for HO+ patients because it increases the colonic cancer detection rate (10.5 % in this study).

An algorithm to predict advanced proximal colorectal neoplasia in Chinese asymptomatic population

This study aims to develop and validate a new algorithm that incorporates distal colonoscopic findings to predict advanced proximal neoplasia (APN) in a Chinese asymptomatic population. We collected age, gender, and colonoscopic findings from a prospectively performed colonoscopy study between 2013 and 2015 in a large hospital-based endoscopy unit in Shanghai, China. Eligible subjects were allocated to a derivation group (n = 3,889) and validation group (n = 1,944) by random sampling. A new index for APN and its cut-off level were evaluated from the derivation cohort by binary logistic regression. The model performance was tested in the validation cohort using area under the curve (AUC). Age, gender, and distal finding were found to be independent predictors of APN in the derivation cohort (p < 0.001). Subjects were categorized into Average Risk (AR) and High Risk (HR) based on a cut-off score of 2. The AUC of the derivation and validation cohorts were 0.801 (0.754-0.847) and 0.722 (0.649-0.794), respectively. In the validation cohort, those in the HR group had a 3.57 fold higher risk of APN when compared with the AR group (P < 0.001), requiring 18 (95% CI = 12-28) follow-up colonoscopies to detect 1 APN. This new clinical index is useful to stratify APN risk in Chinese population.

The association between location, age and advanced colorectal adenoma characteristics: a propensity-matched analysis

PURPOSE

Evidence supports an association between certain colorectal adenoma characteristics and predisposition to cancer. The association between anatomical location of colorectal adenoma, age and advanced adenomas needs attention. The objective of this study was to evaluate the possible association between occurrence of sporadic advanced adenomas with location and age.

MATERIALS AND METHODS

A cross-sectional study using baseline data from index colonoscopy from a randomized controlled trial evaluating chemopreventive treatment against recurrence of colorectal adenomas was performed. Inclusion criteria for patients were one adenoma of >1 cm in diameter or multiple adenomas of any size, or an adenoma of any size and familial disposition for colorectal cancer. Multivariate regression and propensity score-matched analyses were used to correlate location of adenomas and age with advanced adenoma features.

RESULTS

In this study, 2149 adenomas were removed in 1215 patients. Advanced colorectal adenomas primarily occurred in the anal part of the colon. Older age was associated with more adenomas and more oral occurrence of adenomas, as well as a higher risk of advanced adenomas. Surprisingly, specifically for the oral adenomas the risk of advanced adenoma seems to be lower for older patients compared with younger.

CONCLUSIONS

This study presents new results with regard to association between age, location of adenomas and risk of advanced adenomas. The results indicate that sigmoidoscopy for screening purposes may be obsolete, and add to the existing literature on which future guidelines for screening may be based.

Comparison of biomarker expression between proximal and distal colorectal adenomas: The Tennessee-Indiana Adenoma Recurrence Study

It is unclear if proximal and distal traditional adenomas present with differences in molecular events which contribute to cancer heterogeneity by tumor anatomical subsite. Participants from a colonoscopy-based study (n = 380) were divided into subgroups based on the location of their most advanced adenoma: proximal, distal, or "equivalent both sides." Eight biomarkers in the most advanced adenomas were evaluated by immunohistochemistry (Ki-67, COX-2, TGFβRII, EGFR, β-catenin, cyclin D1, c-Myc) or TUNEL (apoptosis). After an adjustment for pathological features, there were no significant differences between proximal and distal adenomas for any biomarker. Conversely, expression levels did vary by other features, such as their size, villous component, and synchronousness. Large adenomas had higher expression levels of Ki-67(P < 0.001), TGFβRII (P < 0.0001), c-Myc (P < 0.001), and cyclin D1 (P < 0.001) in comparison to small adenomas, and tubulovillous/villous adenomas also were more likely to have similar higher expression levels in comparison to tubular adenomas. Adenoma location is not a major determinant of the expression of these biomarkers outside of other pathological features. This study suggests similarly important roles of Wnt/β-catenin and TGF-β pathways in carcinogenesis in both the proximal and distal colorectum. © 2016 Wiley Periodicals, Inc.

Correlation of Ki-67 proliferation index and 18-fluorodeoxyglucose uptake in colorectal incidental lesions detected by positron emission tomography-computed tomography

BACKGROUND/AIM

To investigate whether focal high maximum standardized uptake value (SUVmax) determined by 18-fluorodeoxyglucose (FDG) positron emission tomography (PET)-computed tomography (CT) imaging is correlated with proliferation index in the colorectal region.

MATERIALS AND METHODS

SUVmax values of 31 colorectal neoplasms that were incidentally detected during PET-CT examination were compared to dysplasia degree, histopathologic diagnosis, and immunohistochemical expression of the Ki-67 proliferation marker.

RESULTS

Statistically significant correlations were found between SUVmax and Ki-67 proliferation index, dysplasia degree, and histopathologic diagnosis. Median SUVmax value was found to be significantly higher in high-risk lesions than low-risk lesions.

CONCLUSION

The Ki-67 proliferation index is an indicator of SUVmax in colorectal tract. SUVmax values can predict malignancy and prognosis in this region. Colonoscopy and biopsy should always be performed whenever a focal high FDG uptake is determined incidentally in a patient.

A new functional role uncovered for RASGRF2 in control of nuclear migration in cone photoreceptors during postnatal retinal development

Despite their homologous structure and central nervous system(CNS) expression patterns, the GRF1 and GRF2 guanine nucleotide exchange factors(GEF) appear to play distinct, non-overlapping functions in cellular excitability, synaptic plasticity or neuromodulation. We recently uncovered a new functional role of GRF2 controlling nuclear migration in cone photoreceptors during postnatal neuroepithelial differentiation of the mouse retina. Analyzing GRF2-KO mice, we detected the specific accumulation of abnormally located, "ectopic" cone photoreceptor nuclei in the photoreceptor segment(PS) layer of their retinas. This alteration was accompanied by defective electroretinograms(ERG) indicative of impaired cone-mediated visual function, and accumulation around the "ectopic" nuclei of signaling molecules known to be functionally relevant for intracellular organelle migration, cytoskeletal reorganization or cell polarity establishment including PAR3, PAR6, and the phosphorylated proteins pPAK, pMLC2 and pVASP. We propose a mechanism whereby the absence of a productive functional interaction between GRF2 and its downstream target CDC42 leads to altered formation/structure of PAR-containing, polarity-related macromolecular complexes and abnormal activation of downstream signaling mediated by activated, phosphorylated forms of PAK, VASP and MLC2. As cone photoreceptors are responsible for color vision and visual acuity, these observations are potentially relevant for degenerative diseases of the human retina, harboring almost double number of cones than mice.

McKittrick-Wheelock syndrome: a rare case report of acute renal failure

Giant tubular-villous adenoma of the rectum can determine secretory diarrhea, associated with a depleting syndrome of prerenal acute renal failure, hyponatremia, hypokalemia and hypoproteinemia. These symptoms are known as the McKittrick-Wheelock syndrome, and there are about 50 cases reported in literature. We present the case of a 59-year-old woman presented to our emergency department with abdominal pain, prerenal azotemia, and electrolyte disturbances with a background of chronic diarrhea, caused by a giant rectal tumor. Conservative therapy initially improved and normalized renal function, and made surgical resection of the tumor possible.

Surveillance of colonic polyps: Are we getting it right?

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. The identification of colonic polyps can reduce CRC mortality through earlier diagnosis of cancers and the removal of polyps: the precursor lesion of CRC. Following the finding and removal of colonic polyps at an initial colonoscopy, some patients are at an increased risk of developing CRC in the future. This is the rationale for post-polypectomy surveillance colonoscopy. However, not all individuals found to have colonic adenomas have a risk of CRC higher than that of the general population. This review examines the literature on post-polypectomy surveillance including current international clinical guidelines. The potential benefits of surveillance procedures must be weighed against the burden of colonoscopy: resource use, the potential for patient discomfort, and the risk of complications. Therefore surveillance colonoscopy is best utilised in a selected group of individuals at a high risk of developing cancer. Further study is needed into the specific factors conferring higher risk as well as the efficacy of surveillance in mitigating this risk. Such evidence will better inform clinicians and patients of the relative benefits of colonoscopic surveillance for the individual. In addition, the decision to continue with surveillance must be informed by the changing profile of risks and benefits of further procedures with the patient’s advancing age.

Histological Spectrum of Large Intestinal Lesions with Clinicopathological Correlation

INTRODUCTION

Large intestine is affected by various types of lesions, both non-neoplastic and neoplastic. Due to vague symptoms, the clinical diagnosis is usually delayed. A battery of laboratory tests including biopsy is essential to arrive at a specific diagnosis for appropriate management.

MATERIALS AND METHODS

This five years study was done during the period of 2005 to 2010 in a tertiary care centre which included 124 biopsies and resected specimens of large intestine and 64 from Anal canal. All tissues were fixed in formalin, stained with H&E and special stains like Periodic Acid Schiff (PAS), Reticulin, Zeihl Neelsen (ZN) along with Immunohistochemistry (IHC) were done as and when required.

RESULTS

Out of the 124 cases of large intestine 38 were non-neoplastic, 77 were neoplastic and 9 were inadequate biopsies. Sixty four cases from Anal canal included 55 non-neoplastic and 9 neoplastic lesions. The non-neoplastic conditions included congenital anomalies, infective and ischaemic lesions while neoplastic included benign and malignant lesions. Most of the cases presented with symptoms like abdominal pain, vomiting and constipation.

CONCLUSION

We observed that neoplastic lesions were more common in large intestine while non-neoplastic lesions were frequently seen in Anal canal. Present study emphasizes the need for early histopathological diagnosis for appropriate treatment.

Expression profile of mucin-associated sialyl-Tn antigen in Chinese patients with different colorectal lesions (adenomas, carcinomas)

BACKGROUND

The sialyl-Tn (sTn) antigen is a mucin-associated carbohydrate antigen expressed by numerous human carcinomas, and is also claimed to be a prognostic factor in colorectal cancer. But the associations between sTn and colorectal cancer remain elusive and controversial. Here, we investigated the expression profile of sTn antigen in a series of human colorectal tissue samples including normal colon, colorectal adenomas, and colorectal carcinomas (CRCs), with an aim to analyzing whether sTn plays a role in the progression and development of Chinese patients with CRCs.

METHODS

Immunohistochemical staining of sTn antigen was performed in formalin-fixed, paraffin-embedded colonic sections from 4 healthy controls, 44 patients with colorectal adenomas, and 186 patients with primary CRCs.

RESULTS

No sTn antigen was detected in normal colonic tissues. There were 41 of 44 patients with colorectal adenomas (93.2%), and 141 of 186 patients with CRCs (75.8%) found to express sTn antigen. The patterns of sTn localization were different in adenomas and carcinomas of colonic tissues. Colorectal adenomas showed predominant supranuclear distribution of sTn antigen, while carcinomas revealed apical membrane, mucin droplet and diffuse cytoplasmic localization. Notably, sTn was significantly associated with the degree of differentiation (P = 0.006) and perineural invasion (P = 0.041) of the tumors, but was independent of age, gender, tumor location, depth of penetration, status of lymph nodes, lymphovascular invasion and TNM stage.

CONCLUSIONS

These results indicate that sTn may play a role in initiating colorectal carcinogenesis and promoting tumor progression. Determination of sTn expression and localization may assist in evaluating malignant status of colorectal lesions.

A Risk Prediction Index for Advanced Colorectal Neoplasia at Screening Colonoscopy

OBJECTIVES

Eliciting patient preferences within the context of shared decision making has been advocated for colorectal cancer screening. Risk stratification for advanced colorectal neoplasia (ACN) might facilitate more effective shared decision making when selecting an appropriate screening option. Our objective was to develop and validate a clinical index for estimating the probability of ACN at screening colonoscopy.

METHODS

We conducted a cross-sectional analysis of 3,543 asymptomatic, mostly average-risk patients 50-79 years of age undergoing screening colonoscopy at two urban safety net hospitals. Predictors of ACN were identified using multiple logistic regression. Model performance was internally validated using bootstrapping methods.

RESULTS

The final index consisted of five independent predictors of risk (age, smoking, alcohol intake, height, and a combined sex/race/ethnicity variable). Smoking was the strongest predictor (net reclassification improvement (NRI), 8.4%) and height the weakest (NRI, 1.5%). Using a simplified weighted scoring system based on 0.5 increments of the adjusted odds ratio, the risk of ACN ranged from 3.2% (95% confidence interval (CI), 2.6-3.9) for the low-risk group (score ≤2) to 8.6% (95% CI, 7.4-9.7) for the intermediate/high-risk group (score 3-11). The model had moderate to good overall discrimination (C-statistic, 0.69; 95% CI, 0.66-0.72) and good calibration (P=0.73-0.93).

CONCLUSIONS

A simple 5-item risk index based on readily available clinical data accurately stratifies average-risk patients into low- and intermediate/high-risk categories for ACN at screening colonoscopy. Uptake into clinical practice could facilitate more effective shared decision-making for CRC screening, particularly in situations where patient and provider test preferences differ.

Advanced colorectal adenoma related gene expression signature may predict prognostic for colorectal cancer patients with adenoma-carcinoma sequence

BACKGROUND

There are still no absolute parameters predicting progression of adenoma into cancer. The present study aimed to characterize functional differences on the multistep carcinogenetic process from the adenoma-carcinoma sequence.

METHODS

All samples were collected and mRNA expression profiling was performed by using Agilent Microarray high-throughput gene-chip technology. Then, the characteristics of mRNA expression profiles of adenoma-carcinoma sequence were described with bioinformatics software, and we analyzed the relationship between gene expression profiles of adenoma-adenocarcinoma sequence and clinical prognosis of colorectal cancer.

RESULTS

The mRNA expressions of adenoma-carcinoma sequence were significantly different between high-grade intraepithelial neoplasia group and adenocarcinoma group. The biological process of gene ontology function enrichment analysis on differentially expressed genes between high-grade intraepithelial neoplasia group and adenocarcinoma group showed that genes enriched in the extracellular structure organization, skeletal system development, biological adhesion and itself regulated growth regulation, with the P value after FDR correction of less than 0.05. In addition, IPR-related protein mainly focused on the insulin-like growth factor binding proteins.

CONCLUSION

The variable trends of gene expression profiles for adenoma-carcinoma sequence were mainly concentrated in high-grade intraepithelial neoplasia and adenocarcinoma. The differentially expressed genes are significantly correlated between high-grade intraepithelial neoplasia group and adenocarcinoma group. Bioinformatics analysis is an effective way to study the gene expression profiles in the adenoma-carcinoma sequence, and may provide an effective tool to involve colorectal cancer research strategy into colorectal adenoma or advanced adenoma.

Use of a double-channel gastroscope reduces procedural time in large left-sided colonic endoscopic mucosal resections

Background/Aims

Endoscopic mucosal resection (EMR) of large colorectal lesions is associated with increased procedural time. The objective of this study was to evaluate the effect of double-channel gastroscope (DCG) use on the procedural time of EMRs in the rectosigmoid area.

Methods

All EMRs for sessile or flat rectosigmoid lesions ≥2 cm performed between July 2011 and September 2012 were retrospectively analyzed.

Results

There were 55 lesions ≥2 cm in the rectosigmoid area in 55 patients, of which 26 were removed by EMR using a DCG (DC group) and 29 by using an ordinary colonoscope or gastroscope (OS group). The mean size of the removed polyps, morphology, adverse effects, and other parameters were similar between the two groups. The mean procedural time was significantly lower in the DC group than in the OS group (24.4±18.3 minutes vs. 36.3±24.4 minutes, p=0.015). Moreover, in a subgroup of patients with polyps >40 mm, the statistical difference in the mean procedural time between the DC and OS groups was even more pronounced (33±21 minutes vs. 58.7±20.6 minutes, p=0.004).

Conclusions

Our data suggest that the use of a DCG in the resection of large nonpedunculated rectosigmoid lesions significantly reduces the procedural time.

Colorectal adenomas contain multiple somatic mutations that do not coincide with synchronous adenocarcinoma specimens

We have performed a comparative ultrasequencing study of multiple colorectal lesions obtained simultaneously from four patients. Our data show that benign lesions (adenomatous or hyperplastic polyps) contain a high mutational load. Additionally multiple synchronous colorectal lesions show non overlapping mutational signatures highlighting the degree of heterogeneity between multiple specimens in the same patient. Observations in these cases imply that considering not only the number of mutations but an effective oncogenic combination of mutations can determine the malignant progression of colorectal lesions.

Chronic subordinate colony housing paradigm: a mouse model to characterize the consequences of insufficient glucocorticoid signaling

Chronic, in particular chronic psychosocial, stress is a burden of modern societies and known to be a risk factor for numerous somatic and affective disorders (in detail referenced below). However, based on the limited existence of appropriate, and clinically relevant, animal models for studying the effects of chronic stress, the detailed behavioral, physiological, neuronal, and immunological mechanisms linking stress and such disorders are insufficiently understood. To date, most chronic stress studies in animals employ intermittent exposure to the same (homotypic) or to different (heterotypic) stressors of varying duration and intensity. Such models are only of limited value, since they do not adequately reflect the chronic and continuous situation that humans typically experience. Furthermore, application of different physical or psychological stimuli renders comparisons to the mainly psychosocial stressors faced by humans, as well as between the different stress studies almost impossible. In contrast, rodent models of chronic psychosocial stress represent situations more akin to those faced by humans and consequently seem to hold more clinical relevance. Our laboratory has developed a model in which mice are exposed to social stress for 19 continuous days, namely the chronic subordinate colony housing (CSC) paradigm, to help bridge this gap. The main aim of the current review article is to provide a detailed summary of the behavioral, physiological, neuronal, and immunological consequences of the CSC paradigm, and wherever possible relate the findings to other stress models and to the human situation.

Colorectal serrated pathway cancers and precursors

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

Predictive gene signatures: molecular markers distinguishing colon adenomatous polyp and carcinoma

Cancers exhibit abnormal molecular signatures associated with disease initiation and progression. Molecular signatures could improve cancer screening, detection, drug development and selection of appropriate drug therapies for individual patients. Typically only very small amounts of tissue are available from patients for analysis and biopsy samples exhibit broad heterogeneity that cannot be captured using a single marker. This report details application of an in-house custom designed GenomeLab System multiplex gene expression assay, the hCellMarkerPlex, to assess predictive gene signatures of normal, adenomatous polyp and carcinoma colon tissue using archived tissue bank material. The hCellMarkerPlex incorporates twenty-one gene markers: epithelial (EZR, KRT18, NOX1, SLC9A2), proliferation (PCNA, CCND1, MS4A12), differentiation (B4GANLT2, CDX1, CDX2), apoptotic (CASP3, NOX1, NTN1), fibroblast (FSP1, COL1A1), structural (ACTG2, CNN1, DES), gene transcription (HDAC1), stem cell (LGR5), endothelial (VWF) and mucin production (MUC2). Gene signatures distinguished normal, adenomatous polyp and carcinoma. Individual gene targets significantly contributing to molecular tissue types, classifier genes, were further characterised using real-time PCR, in-situ hybridisation and immunohistochemistry revealing aberrant epithelial expression of MS4A12, LGR5 CDX2, NOX1 and SLC9A2 prior to development of carcinoma. Identified gene signatures identify aberrant epithelial expression of genes prior to cancer development using in-house custom designed gene expression multiplex assays. This approach may be used to assist in objective classification of disease initiation, staging, progression and therapeutic responses using biopsy material.

Whites and blacks have similar risk of metachronous advanced colorectal neoplasia

BACKGROUND

Current guidelines for surveillance of colonic neoplasia are based on data from predominantly white populations, yet whether these recommendations are applicable to blacks is unknown.

AIM

To define the prevalence of advanced colorectal neoplasia (ACN) among whites and blacks undergoing surveillance colonoscopy.

METHODS

This was a retrospective, cross-sectional analysis of asymptomatic, average-risk non-Hispanic white (N = 246) and non-Hispanic black (N = 203) patients with colorectal neoplasia who underwent baseline screening colonoscopy between January 1, 2000, and December 31, 2007, and a surveillance colonoscopy before December 31, 2010, at an academic safety-net hospital. The main outcome measure was the prevalence of ACN, defined as a tubular adenoma or sessile serrated adenoma (SSA) ≥ 10 mm, any adenoma with villous histology or high-grade dysplasia, any serrated lesion with dysplasia, or invasive cancer at surveillance.

RESULTS

During a median follow-up of 4.3 years, the overall prevalence of ACN at surveillance was similar among blacks and whites (11.3 vs. 9.8 %; P = 0.59) with an odds ratio of 1.18 (95 % CI 0.65-2.16) [corrected]. Blacks and whites with non-advanced neoplasia had similar rates of ACN at the 1-3, 4-5, and >5 year follow-up intervals. Blacks with ACN or multiplicity at baseline had higher rates of ACN at the 1- to 3-year interval compared with whites, but the difference was non-significant (26.7 vs. 12.5 %; P = 0.32). No interval cancers were observed for either group.

CONCLUSIONS

The overall prevalence of ACN was similar between non-Hispanic blacks and non-Hispanic whites undergoing surveillance in a safety-net healthcare setting suggesting that current surveillance guidelines are appropriate for both blacks and whites.

Predictive factors of proximal advanced neoplasia in the large bowel

INTRODUCTION

The aim of the study was to evaluate the impact of sex, age, family history and distal findings on the risk of proximal advanced neoplasia (cancer or advanced adenoma) in the large bowel.

MATERIAL AND METHODS

Records for 10 111 asymptomatic participants of the Colonoscopy Screening Program (CSP), recruited from the Warsaw region between 2000 and 2004, were analyzed. A multivariate logistic regression model was used to estimate the impact of sex, age, family history and most advanced distal lesions on the occurrence of proximal advanced neoplasia. To enhance comparability of the study two definitions of the proximal colon were applied - either the splenic flexure (1(st)) or the bend between the descending and sigmoid colon (2(nd) definition) represented the boundary.

RESULTS

One hundred and thirty-three (1(st)) and 167 patients (2(nd) definition) were found to have at least one advanced neoplastic lesion in the proximal part, respectively. Eleven and 14 patients were found to have carcinoma, while in 130 and 163 patients at least one proximal advanced adenoma appeared. Men were at twice as high risk of having advanced neoplasia in the proximal colon than women (OR = 1.94, 95% CI: 1.31-2.87, p = 0.001 or OR = 1.69, 95% CI: 1.20-2.40, p = 0.003, respectively). The presence of distal advanced neoplastic lesions was associated with 3.5 times higher risk of proximal advanced neoplasia (OR = 3.58, 95% CI: 2.00-6.43, p < 0.0001 or OR = 3.41, 95% CI: 1.95-5.96, p < 0.0001), respectively.

CONCLUSIONS

The results may confirm some limitation of flexible sigmoidoscopy in the screening settings in comparison with colonoscopy, at least in men and people with distal advanced neoplasia.

The CIMP Phenotype in BRAF Mutant Serrated Polyps from a Prospective Colonoscopy Patient Cohort

Colorectal cancers arising via the serrated pathway are often associated with BRAF V600E mutation, CpG island methylator phenotype (CIMP), and microsatellite instability. Previous studies have shown a strong association between BRAF V600E mutation and serrated polyps. This study aims to evaluate CIMP status of all the serrated polyp subtypes and its association with functionally important genes such as MLH1, p16, and IGFBP7. CIMP status and methylation were evaluated using the real-time based MethyLight assay in 154 serrated polyps and 63 conventional adenomas. Results showed that CIMP-high serrated polyps were strongly associated with BRAF mutation and proximal colon. CIMP-high was uncommon in conventional adenomas (1.59%), occurred in 8.25% of hyperplastic polyps (HPs), and became common in sessile serrated adenomas (SSAs) (51.43%). MLH1 methylation was mainly observed in the proximal colon and was significantly associated with BRAF mutation and CIMP-high. The number of samples methylated for p16 and IGFBP7 was the highest in SSAs. The methylation panel we used to detect CIMP is highly specific for CIMP-high cancers. With this panel, we demonstrate that CIMP-high is much more common in SSAs than HPs. This suggests that CIMP-high correlates with increased risk of malignant transformation which was also observed in methylation of functionally important genes.

The relationship between proximal and distal colonic adenomas: is screening sigmoidoscopy enough in the presence of a changing epidemiology?

BACKGROUND AND STUDY AIMS

Because the relationship between distal and proximal colonic findings remains uncertain, controversy exists over whether proctosigmoidoscopy or colonoscopy is more suitable for colorectal cancer (CRC) screening. We aim to describe the distribution and characteristics of polyps removed in colonoscopy screening.

PATIENTS AND METHODS

A prospective registry of a colonoscopy-based CRC screening program was developed on asymptomatic individuals over 50 years. All polyps were removed and characterized. Polyp size and histology were noted. Adenomas were considered advanced if they measured greater than 10 mm or were tubulovillous, villous, or malignant. The prevalence of advanced proximal polyps was determined and patients were categorized according to their family history of CRC.

RESULTS

A total of 696 individuals (418 women), aged 57.7 ± 10.3 years, were examined; 45.8% presented a colonic lesion, being adenomatous polyps in 32.7% individuals. Among these, 24.7% were advanced adenomas. Three patients (0.6%) presented invasive CRC. There were no significant differences with respect to sex and family history of CRC between patients with or without adenomas. Adenomas were more prevalent in individuals aged at least 65, irrespective of location (P<0.001). In 65.1% of individuals with adenomatous polyps in the right colon, there were no synchronous adenomas in the left colon (P<0.001). More adenomas were also present in the right colon of patients with no family history of CRC (P<0.001).

CONCLUSION

Most patients with adenomatous polyps in the right colon showed no synchronic adenomas on the left side. Lesions on the right side would have gone undetected if the individuals undergoing CRC screening had been explored with proctosigmoidoscopy.

Tailoring colorectal cancer screening by considering risk of advanced proximal neoplasia

BACKGROUND

Quantifying the risk of advanced proximal colorectal neoplasia might allow tailoring of colorectal cancer screening, with colonoscopy for those at high risk and less invasive screening for very low-risk persons.

METHODS

We analyzed findings from 10,124 consecutive adults aged≥50 years who underwent screening colonoscopy to the cecum. We quantified the risk of advanced neoplasia (tubular adenoma≥1 cm, a polyp with villous histology or high-grade dysplasia, or adenocarcinoma) both proximally (cecum to splenic flexure) and distally (descending colon to anus). The prevalence of advanced proximal neoplasia was quantified by age, gender, and distal findings.

RESULTS

The mean (standard deviation) age was 57.5 (6.0) years; 44% were women; 7835 (77%) had no neoplasia, and 1856 (18%) had 1 or more nonadvanced adenomas. Overall, 433 subjects (4.3%) had advanced neoplasia (267 distally, 196 proximally, 30 both), 33 (0.33%) of which were adenocarcinoma (18 distal, 15 proximal). The risk of advanced proximal neoplasia increased with age decade (1.13%, 2.00%, and 5.26%, respectively; P=.001) and was higher in men (relative risk [RR], 1.91; confidence interval [CI], 1.32-2.77). In women aged less than 70 years, the risk was 1.1% overall (vs 2.2% in men; RR, 1.98; CI, 1.42-2.76) and 0.86% in those with no distal neoplasia (vs 1.54% in men; RR, 1.81; CI, 1.20-2.74).

CONCLUSIONS

Risk of advanced proximal neoplasia is a function of age and gender. Women aged less than 60 to 70 years have a very low risk, particularly those with no distal adenoma. Sigmoidoscopy with or without occult blood testing may be sufficient and even preferable for screening these subgroups.

The frequency of advanced adenoma in consulting patients: a nationwide survey in Iceland (2003-2006)

AIM

To assess the frequency of advanced colorectal adenomas in consulting patients in Iceland.

METHOD

The histological configuration of colorectal adenomas (CRA) found in 3603 patients was classified into tubular (TA), villous (VA) and serrated (SA) and the degree of neoplastic severity into low-grade dysplasia (LGD), high-grade dysplasia (HGD), carcinoma in situ (CIS), intramucosal carcinoma (IMC) and submucosal carcinoma (SMC). Advanced CRA were those showing HGD, CIS, IMC and/or SMCs. In patients with two or more adenomas, the adenoma with the highest degree of epithelial neoplasia was selected to record cases.

RESULTS

Between 2003 and 2006 a total of 19424 endoscopic examinations (13572 colonoscopies and 5852 sigmoidoscopies) were performed in Iceland (mean, 4856 endoscopies per year). At histology a mean of 759.3 CRA per year were found. Thus, CRA were found in 15.6% of the colorectal endoscopies performed per year. Out of the 3037 CRA studied, 67% were TA, 29% VA and the remaining 4% SA. LGD was present in 79%, HGD in 15%, CIS in 2.4%, IMC in 1.9% and SMC in 1.9%. Consequently, out of 3037 CRA investigated, 652 (21.5%) were advanced CRA; 71% of these showed HGD, 11% CIS, 9% IMC and 9% SMC. Two-thirds of the 652 advanced CRA were advanced VA, and more than three-quarters of 58 advanced CRA with SMC, were advanced VA.

CONCLUSION

Advanced VA displaying intraepithelial neoplasia (HGD and CIS) showed a propensity to evolve into invasive carcinoma. Accordingly, VA displaying HGD and CIS might be regarded as biological markers for predicting colorectal cancer risk. This is the first study in which the frequency of CRA and advanced CRA detected in consulting patients is reported on a nationwide basis.

Chronic psychosocial stress increases the risk for inflammation-related colon carcinogenesis in male mice

Patients with inflammatory bowel diseases (IBDs) have a higher risk of developing colorectal cancer (CRC) than the general population. Furthermore, chronic psychosocial stress increases the likelihood of developing IBD and multiple types of malignant neoplasms, including CRC. Here, for the first time, we investigate the effects of chronic psychosocial stress in male mice on an artificially induced CRC, by employing the chronic subordinate colony (CSC) housing paradigm in combination with the reliable azoxymethane (AOM)/dextran sodium sulfate (DSS) CRC model. Colonoscopy revealed that CSC mice showed accelerated macroscopic suspect lesions. In addition, more CSC mice developed low-grade dysplasia (LGD) and/or high-grade dysplasia (HGD) in the colonic tissue compared to the single-housed control mice (SHC). CSC mice showed an increased number of Ki67+ and a decreased number of terminal deoxynucleotidyl transferase dUTP nick end labeling epithelial cells in colonic tissue. Colonic liver receptor homolog-1 (LRH-1), cyclooxygenase II (COXII), tumor necrosis factor, forkhead box P3 (FoxP3) mRNA as well as colonic ß-catenin, COXII, and LRH-1 protein expression were also increased in CSC compared with SHC mice. Although the number of CD4+ Th cells was increased, a tendency toward a decreased colonic interferon-γ (IFN-γ) mRNA expression was observed. Furthermore, despite an increased percentage of CD3+ cells and CD3+/FoxP3+ double-positive cells within mesenteric lymph node cells of CSC mice, IFN-γ secretion from these cells was unaffected. Altogether, our results suggest that chronic psychosocial stress increases the risk for AOM/DSS-induced and, thus, inflammation-related CRC. Finally, assessment of additional time points may test whether the shift from tumor-protective Th1 cell to regulatory T-cell immunity represents a consequence of increased carcinogenesis or a causal factor involved in its development.

The Your Disease Risk Index for colorectal cancer is an inaccurate risk stratification tool for advanced colorectal neoplasia at screening colonoscopy

Tailoring the use of screening colonoscopy based on the risk of advanced colorectal neoplasia (ACN) could optimize the cost-effectiveness of colorectal cancer (CRC) screening. Our goal was to assess the accuracy of the Your Disease Risk (YDR) CRC risk index for stratifying average risk patients into low- versus intermediate/high-risk categories for ACN. The YDR risk assessment tool was administered to 3,317 asymptomatic average risk patients 50 to 79 years of age just before their screening colonoscopy. Associations between YDR-derived relative risk (RR) scores and ACN prevalence were examined using logistic regression and χ(2) analyses. ACN was defined as a tubular adenoma ≥1 cm, tubulovillous or villous adenoma of any size, and the presence of high-grade dysplasia or cancer. The overall prevalence of ACN was 5.6%. Although YDR-derived RR scores were linearly associated with ACN after adjusting for age and gender (P = 0.033), the index was unable to discriminate "below average" from "above/average" risk patients [OR, 1.01; 95% confidence interval (CI), 0.75-1.37]. Considerable overlap in rates of ACN was also observed between the different YDR risk categories in our age- and gender-stratified analyses. The YDR index lacks accuracy for stratifying average risk patients into low- versus intermediate/high-risk categories for ACN.

Meta-analysis of observational studies on cholecystectomy and the risk of colorectal adenoma

AIM

Cholecystectomy has been suggested as a risk factor for colorectal cancer. However, the association of cholecystectomy and the risk of colorectal adenoma (CRA) remains unclear. We conducted a meta-analysis of observational studies to explore this relationship.

METHODS

We identified studies by a literature search of MEDLINE and EMBASE through 30 September 2011, and by searching the reference lists of pertinent articles. Summary relative risks (SRRs) with their 95% confidence intervals (CIs) were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and the I2.

RESULTS

A total of 10 studies (including 4061 CRA cases) were included in this meta-analysis. Analysis of these 10 studies found that no effect of cholecystectomy on the risk of CRAs was shown (SRR, 1.17; 95% CI: 0.93-1.48), with no significant heterogeneity among these studies (P heterogeneity=0.106, I2=37.9%). This null association was seen in both men and women (men: SRR=1.00, 95% CI: 0.58-1.73; women: SRR=1.39, 95% CI: 0.95-2.04).

CONCLUSION

The results of this meta-analysis suggest that there is no positive association between previous cholecystectomy and the risk of CRA development in both men and women.

Body mass index increases risk for colorectal adenomas based on meta-analysis

BACKGROUND & AIMS

There have been inconsistent results published about the relationship between excess body weight, expressed as increased body mass index (BMI), and risk of colorectal adenoma (CRA). We conducted a meta-analysis to explore this relationship. We focused on whether the relationship varied based on the sex of the study subjects, study design, features of the polyps, or potential confounders, including alcohol use, nonsteroidal anti-inflammatory drug use, smoking, and exercise.

METHODS

We identified studies by performing a literature search of Medline, EMBASE, and ISI Web of Science through July 31, 2011, and by searching the reference lists of pertinent articles. We analyzed 36 independent studies, which included 29,860 incident cases of CRA. Summary relative risks with their 95% confidence intervals (CIs) were calculated with a random-effects model. Between-study heterogeneity was assessed using Cochran's Q statistic and I(2) analyses.

RESULTS

Overall, a 5-unit increase in BMI (calculated as kg/m(2)) increased the risk for CRA (summary relative risk = 1.19; 95% CI: 1.13-1.26), although there was a high level of heterogeneity among studies (P(heterogeneity) < .001; I(2) = 76.8%). Subgroup analyses revealed that the increased risk of CRA in obese individuals was independent of race, geographic location, study design, sex, adenoma progression, and confounders. The association between increased BMI and risk for CRA was stronger for colon than rectal adenoma.

CONCLUSIONS

Based on a meta-analysis, increased BMI increases the risk for colon but not rectal adenoma. Unlike colorectal cancer, there is no sex difference in the relationship between increased BMI and risk of CRA.

Derivation and validation of a prediction rule for estimating advanced colorectal neoplasm risk in average-risk Chinese

No prediction rule is currently available for advanced colorectal neoplasms, defined as invasive cancer, an adenoma of 10 mm or more, a villous adenoma, or an adenoma with high-grade dysplasia, in average-risk Chinese. In this study between 2006 and 2008, a total of 7,541 average-risk Chinese persons aged 40 years or older who had complete colonoscopy were included. The derivation and validation cohorts consisted of 5,229 and 2,312 persons, respectively. A prediction rule was developed from a logistic regression model and then internally and externally validated. The prediction rule comprised 8 variables (age, sex, smoking, diabetes mellitus, green vegetables, pickled food, fried food, and white meat), with scores ranging from 0 to 14. Among the participants with low-risk (≤3) or high-risk (>3) scores in the validation cohort, the risks of advanced neoplasms were 2.6% and 10.0% (P < 0.001), respectively. If colonoscopy was used only for persons with high risk, 80.3% of persons with advanced neoplasms would be detected while the number of colonoscopies would be reduced by 49.2%. The prediction rule had good discrimination (area under the receiver operating characteristic curve = 0.74, 95% confidence interval: 0.70, 0.78) and calibration (P = 0.77) and, thus, provides accurate risk stratification for advanced neoplasms in average-risk Chinese.

Smoking and the association of advanced colorectal neoplasia in an asymptomatic average risk population: analysis of exposure and anatomical location in men and women

BACKGROUND

Identifying risk factors for advanced colorectal adenomas may aid in colorectal cancer (CRC) screening, especially in light of the American College of Gastroenterology's recent guidelines, emphasizing cancer prevention through identification and removal of advanced adenomas. Smoking is an important risk factor for advanced adenomas but there is little data regarding levels of exposure for genders.

METHODS

The aim of this study was to use an existing database to examine the genders separately with respect to exposure level and anatomic location of advanced adenomas. Our database was designed to study smoking in an asymptomatic, screening population. Data included demographics, family history of CRC, smoking exposure (pack-years and years smoked), alcohol, diabetes, medications, exercise and dietary history. We excluded patients with a first degree relative with CRC.

RESULTS

Compared to non-smokers, female smokers had an increased risk for advanced adenomas with an exposure of 10-30 pack-years (adjusted odds ratio [AOR] = 4.11; 95% confidence interval [CI], 1.88-9.01) as well as for ≥30 pack-years (AOR = 2.54; 95% CI, 1.08-5.96) while men had an increased risk with smoking ≥30 pack-years (AOR = 3.10; 95% CI, 1.71-5.65). An increased association with smoking was observed for proximal advanced adenomas (AOR = 4.06; 95% CI, 1.62-10.19) and large hyperplastic polyps in women.

CONCLUSIONS

Women smokers had an increased risk for advanced adenomas at a lower exposure level and had a greater risk for proximal lesions. These findings may have an impact on CRC screening for women.

Nuclear positioning: mechanisms and functions

The nucleus is the largest organelle in the cell and its position is dynamically controlled in space and time, although the functional significance of this dynamic regulation is not always clear. Nuclear movements are mediated by the cytoskeleton which transmits pushing or pulling forces onto the nuclear envelope. Recent studies have shed light on the mechanisms regulating nuclear positioning inside the cell. While microtubules have been known for a long time to be key players in nuclear positioning, the actin and cytoplasmic intermediate filament cytoskeletons have been implicated in this function more recently and various molecular links between the nuclear envelope and cytoplasmic elements have been identified. In this review, we summarize the recent advances in our understanding of the molecular mechanisms involved in the regulation of nuclear localization in various animal cells and give an overview of the evidence suggesting a crucial role of nuclear positioning in cell polarity and physiology and the consequences of nuclear mispositioning in human pathologies.

Colorectal carcinogenesis: Review of human and experimental animal studies

This review gives a comprehensive overview of cancer development and links it to the current understanding of tumorigenesis and malignant progression in colorectal cancer. The focus is on human and murine colorectal carcinogenesis and the histogenesis of this malignant disorder. A summary of a model of colitis-associated colon tumorigenesis (an AOM/DSS model) will also be presented. The earliest phases of colorectal oncogenesis occur in the normal mucosa, with a disorder of cell replication. The large majority of colorectal malignancies develop from an adenomatous polyp (adenoma). These can be defined as well-demarcated masses of epithelial dysplasia, with uncontrolled crypt cell proliferation. When neoplastic cells pass through the muscularis mucosa and infiltrate the submucosa, they are malignant. Carcinomas usually originate from pre-existing adenomas, but this does not imply that all polyps undergo malignant changes and does not exclude de novo oncogenesis. Besides adenomas, there are other types of pre-neoplasia, which include hyperplastic polyps, serrated adenomas, flat adenomas and dysplasia that occurs in the inflamed colon in associated with inflammatory bowel disease. Colorectal neoplasms cover a wide range of pre-malignant and malignant lesions, many of which can easily be removed during endoscopy if they are small. Colorectal neoplasms and/or pre-neoplasms can be prevented by interfering with the various steps of oncogenesis, which begins with uncontrolled epithelial cell replication, continues with the formation of adenomas and eventually evolves into malignancy. The knowledge described herein will help to reduce and prevent this malignancy, which is one of the most frequent neoplasms in some Western and developed countries.