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Study on Second Forward View Examination in the Right Colon

ABSTRACT: It is estimated that there are about 1.4 million patients with colorectal cancer (CRC) worldwide, with a rising trend in CRC incidence in many Asian Pacific countries. In Hong Kong, colorectal cancer ranks first in cancer incidence and second in cancer mortality based on data from 2013. CRC is one of the most preventable cancers because its development in general follows an adenoma-carcinoma sequence. Adenomas are considered precursor lesions for CRC. While early detection and removal of colorectal adenoma by screening colonoscopy with polypectomy reduce CRC incidence and mortality, interval cancers (cancers that develop after a colonoscopy and before the next scheduled colonoscopy) may still occur and were reported to account for up to 10.5% of CRC. The protective effect of colonoscopy against cancer in the right colon has not been consistently demonstrated. Interval CRC has been associated with proximal colon location, small lesion, flat lesion, missed lesion, inadequate examination, incomplete resection of lesion, tumor biology, and low adenoma detection rate (ADR). High ADR (eg, ≥ 20%) has been associated with a reduced risk of interval CRC. Methods that can improve polyp detection in the right colon such as retroflexed examination of the right colon, second forward view examination of the right colon, use of colonic fold flattening device, colonoscope with an increased field of view may potentially reduce the risk of interval CRC, but data is still limited. Performance of a second forward view (SFV) examination of the right colon may be the easiest and safest from a practical standpoint when compared to other options (eg, additional training is often needed for retroflexed examination of the right colon since there may be a potentially higher risk of perforation in endoscopists not familiar with the technique, additional equipment is needed when using a colonic fold flattening device, or a colonoscope with an increased field of view). Our current study aims to determine whether a routine SFV examination in the right colon can lead to an increase in adenoma / polyp detection when compared to conventional withdrawal examination in the right colon in both male and female patients undergoing screening and surveillance colonoscopies.

DISEASE(S): Colonic Polyps,Colorectal Cancer,Colonic Polyp,Polyps

PROVIDER: 2241947 | ecrin-mdr-crc |

REPOSITORIES: ECRIN MDR

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Project description:Alterations in glycosylation are seen in many types of cancer, including colorectal cancer (CRC). CRC is known to display glycosylation alterations. Glycans, the sugar moieties of glycoconjugates, are involved in many important functions relevant to cancer, such as cell signaling and adhesion, and may can be of value as biomarkers. In this study, we have used mass spectrometry to analyze the N-glycan profiles of 35 CRC tissue samples from patients with tumors in the right or left colon and 10 healthy tissue samples from non-CRC patients who underwent operations for other reasons. The tumor samples were divided into groups depending on tumor location (right or left colon) and stage (II or III), while the healthy samples were divided into right or left side of the colon. The levels of neutral and acidic N-glycan compositions and glycan classes were analyzed in a total of ten different groups. Surprisingly, there were no significant differences in glycan levels when all right- and left-sided CRC samples were compared, and few differences (such as in the abundance of the neutral N-glycan H3N5) were seen when the samples were divided according to both location and stage. Multiple significant differences were found in the levels of glycans and glycan classes when stage II and III samples were compared, and these glycans could be of value as candidates for new markers of cancer progression. In order to validate our findings, we analyzed healthy tissue samples from the right and left colon and found no significant differences in the levels of any of the glycans analyzed, confirming that our findings when comparing CRC samples from the right and left colon are not due to normal variations in the levels of glycans between the healthy right and left colon. Additionally, the levels of the acidic glycans H4N3F1P1, H5N4F1P1, and S1H5N4F1 were found to change in a cancer-specific but colon location-nonspecific manner, indicating that CRC affects glycan levels in similar ways, regardless of tumor location.

Project description:Background. Most colorectal cancers (CRC) arise in a progression through adenoma to carcinoma phenotypes as a consequence of altered genetic information. Clinical progression of CRC may occur in parallel with distinctive signaling alterations. We designed multidirectional analyses integrating microarray-based data with biostatistics and bioinformatics to elucidate the signaling and metabolic alterations underlying CRC development in the adenoma-carcinoma sequence. Methodology/Principal Findings. Studies were performed on normal mucosa, adenoma, and CRC samples obtained during surgery or colonoscopy. Collections of cryostat sections prepared from the tissue samples were evaluated by a pathologist to control the relative cell type content. RNA was isolated from 105 macro- and 40 microdissected specimens. The measurements were done using Affymetrix GeneChip HG-U133plus2, and probe set data were generated using two normalization algorithms: MAS5 and GCRMA with LVS. The data were evaluated using pair-wise comparisons and data decomposition into SVD modes. The method selected for the functional analysis used the Kolmogorov-Smirnov test. Based on a consensus of the results obtained by two tissue handling procedures, two normalization algorithms, and two probe set sorting criteria, we identified six KEGG signaling and metabolic pathways (cell cycle, DNA replication, p53 signaling pathway, purine metabolism, pyrimidine metabolism, and RNA polymerase) that are significantly altered in both macro- and microdissected tumor samples compared to normal colon. On the other hand, pathways altered between benign and malignant tumors were identified only in the macrodissected tissues. Conclusion/Significance. Multidirectional analyses of microarray data allow the identification of essential signaling alterations underlying CRC development. Although the proposed strategy is computationally complex and labor–intensive, it may reduce the number of false results. Gene expression profiles of 40 tissue samples representing distant full-thickness normal colon, normal colon mucosa dissected from tumor, adenoma, and carcinoma. Gene expression profiles of 105 tissue samples representing colon carcinomas, adenocarcinomas, and normal colon samples.

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Study on Second Forward View Examination in the Right Colon

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