[Emerging concepts in colorectal serrated polyps]

Small Intestinal Adenocarcinomas Arising in Enteritis Cystica Profunda With Metaplasia: A Report of 2 Cases

Enteritis cystica profunda (ECP) is an uncommon benign condition arising after mucosal damage. We describe 2 cases of small intestinal adenocarcinomas associated with ECP at the distal ileum, one in a background of active Crohn ileitis (case 1), the other 22 years after pelvic radiation therapy (case 2). Both patients presented with small bowel obstruction and received ileocectomy. Macroscopic examination identified an indurated/strictured area in the distal ileum. Histologically, both cases showed a low-grade tubuloglandular adenocarcinoma arising in a background of chronic ischemic stricture and ECP lined by flat cuboidal cells with mild cytologic atypia resembling pancreatobiliary-type epithelium. There was no conventional dysplasia in the surface or adjacent mucosa. Immunohistochemically, both ECP with metaplasia and invasive carcinomas were diffusely positive for CK7 and CK19, while focally positive for CDX2 or CK20. Both cases showed normal wild-type p53 expression. Case 2 was also mismatch repair protein proficient, with membranous β-catenin staining, and retained nuclear SMAD4 expression. In summary, the 2 cases uniquely exhibits "enteritis-metaplasia-carcinoma" sequence, which has not been reported before. This process appears to bypass conventional dysplasia, be slow and indolent, independent of p53, APC/β-catenin, and SMAD4/TGFβ signaling pathways.

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

Background

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

Methods

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

Results

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

Conclusions

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

Split-Dose Polyethylene Glycol Is Superior to Single Dose for Colonoscopy Preparation: Results of a Randomized Controlled Trial

Background. The efficacy of colonoscopy in detecting abnormalities within the colon is highly dependent on the adequacy of the bowel preparation. The objective of this study was to compare the efficacy, safety, and tolerability of PEG lavage and split-dose PEG lavage with specific emphasis on the cleanliness of the right colon. Methods. The study was a prospective, randomized, two-arm, controlled trial of 237 patients. Patients between the age of 50 and 75 years were referred to an outpatient university screening clinic for colonoscopy. Patients were allocated to receive either a single 4 L PEG lavage or a split-dose PEG lavage. Results. Overall, the bowel preparation was superior in the split-dose group compared with the single-dose group (mean Ottawa score 3.50 ± 2.89 versus 5.96 ± 3.53; P < 0.05) and resulted in less overall fluid in the colon. This effect was observed across all segments of the colon assessed. Conclusions. The current study supports use of a split-dose PEG lavage over a single large volume lavage for superior bowel cleanliness, which may improve polyp detection. This trial is registered with ClinicalTrials.gov identifier NCT01610856.

Expression of trefoil factor family-3 and β-catenin in different types of colorectal mucosal lesions

AIM: To analyze the expression of trefoil factor family-3 (TFF3) and β-catenin in different types of colorectal mucosal lesions and to explore their role in the development and progression of colorectal adenocarcinoma and adenoma.

METHODS: The expression of TFF3 and β-catenin was detected by immunohistochemistry in 20 normal colorectal mucosa specimens, 30 colorectal polyp specimens, 20 colorectal adenoma (CRA) specimens, 20 colorectal adenoma (with atypical hyperplasia, CRAAH) specimens, and 40 colorectal adenocarcinoma (CRCA) specimens. The differences in the expression of TFF3 and β-catenin in different types of colorectal mucosal lesions were compared.

RESULTS: The positive rate of TFF3 expression was significantly lower in CRA and CRAAH (P < 0.05), but higher in CRCA. The abnormal expression of β-catenin were gradually increasing along with the sequence of CRA→CRAAH→CRAC, the membrane expressing deletion and ectopic expression were both higher in CRAC than in CRCP and CRA (60.00% vs 0.00%, 15.00%; 75.00% vs 0.00%, 40.00%, all P < 0.05). TFF3 expression was not correlated with tumor location or differentiation in CRAC, but was related to lymph node metastasis and Duke's stage (both P < 0.05). β-catenin expression was not correlated with tumor location or lymph node metastasis, but was related to tumor differentiation. Ectopic expression of β-catenin was related to Duke's stage (P < 0.05). There were significantly positive correlations between TFF3 expression and abnormal expression and loss of membrane expression of β-catenin in CRA (r = 0.427, P = 0.006; r = 0.577, P = 0.000) but not in CRAC (r = 0.015, P = 0.951; r = 0.385, P = 0.094). There was a significantly positive correlation between loss of membrane expression and ectopic expression of β-catenin in CRAC and CRA (r = 0.638, P = 0.000; r = 0.514, P = 0.020).

CONCLUSION: The expression of TFF3 and β-catenin is closely related with the development and progression of CRAC. They may be involved in an early event in colorectal carcinogenesis. TFF3 is related to the abnormal expression of β-catenin, both of which may be involved in the development and progression of CRAC.

Diagnostic value of magnifying endoscopy in early-stage gastrointestinal tumors and their precancerous lesions

With advance in endoscopic technology and its increasing importance in clinical diagnosis, magnifying endoscopy has attracted increasing attention and has been widely used in clinics. At present the new magnifying endoscope is able to clearly demonstrate duct openings of gastrointestinal tract mucosa and microstructural changes, thus enabling discovery and diagnosis of early lesions that are difficult for common endoscope, especially early-stage malignant tumors and precancerous lesions. Recently, magnifying endoscopy in combination with staining or with narrow-band imaging technology facilitates its wider use. This paper reviewed the diagnostic value of magnifying endoscopy in early-stage gastrointestinal tumors and precancerous lesions.

Hypermethylated SFRP2 gene in fecal DNA is a high potential biomarker for colorectal cancer noninvasive screening

AIM: To investigate the feasibility of detecting hypermethylated secreted frizzled-related protein 2 (SFRP2) gene in fecal DNA as a non-invasive screening tool for colorectal cancer (CRC).

METHODS: Fluorescence-based real-time PCR assay (MethyLight) was performed to analyze SFRP2 gene promoter methylation status in a blinded fashion in tumor tissues and in stool samples taken from 69 CRC patients preoperatively and at the 9th postoperative day, 34 patients with adenoma ≥ 1 cm, 26 with hyperplastic polyp, and 30 endoscopically normal subjects. Simultaneously the relationship between hypermethylation of SFRP2 gene and clinicopathological features was analyzed.

RESULTS: SFRP2 gene was hypermethylated in 91.3% (63/69) CRC, 79.4% (27/34) and 53.8% (14/26) adenoma and hyperplastic polyp tissues, and in 87.0% (60/69), 61.8% (21/34) and 42.3% (11/26) of corresponding fecal samples, respectively. In contrast, no methylated SFRP2 gene was detected in mucosal tissues of normal controls, while two cases of matched fecal samples from normal controls were detected with hypermethylated SFRP2. A significant decrease (P < 0.001) in the rate of hypermethylated SFRP2 gene was detected in the postoperative (8.7%, 6/69) fecal samples as compared with the preoperative fecal samples (87%, 60/69) of CRC patients. Moreover, no significant associations were observed between SFRP2 hypermethylation and clinicopathological features including sex, age, tumor stage, site, lymph node status and histological grade, etc.

CONCLUSION: Hypermethylation of SFRP2 gene in fecal DNA is a novel molecular biomarker of CRC and carries a high potential for the remote detection of CRC and premalignant lesions as noninvasive screening method.