Active clinical trials for "Polyps"

Colon cancer is the third most common cancer in western society. To prevent colon cancer it is recommended for people to undergo a screening colonoscopy at the age of fifty. The purpose of the colonoscopy is to remove polyps, since some of these lesions are precancerous. Precancerous polyps are called adenomas. This method of prevention is effective, but the standard colonoscopy currently used does not detect all polyps. Studies have reported a polyp miss rate of about 24%. Furthermore, we are unable to distinguish precancerous polyps from benign polyps, also known as hyperplastic polyps, with standard colonoscopy. This results in all polyps being removed at time of colonoscopy, even the benign polyps. To help improve the detection of colon polyps new endoscopic technologies have been developed. These technologies include high definition white light (HDWL)and high definition narrow band imaging (HDNBI). HDWL improves the overall resolution of the images seen during colonoscopy. HDNBI can help us better classify polyps by enhancing their tissue appearance as well as seeing small blood vessels and capillaries. The goal of this study to determine if HDNBI imaging shows an increased polyp detection rate when compared to the current standard colonoscopy. In addition to develop a classification system to help better differentiate between precancerous polyps and their benign counterparts using HDWL and HDNBI.

The primary objective of the Poly Prevention Trial (PPT) is to determine whether a low fat, high fiber, high vegetable and fruit eating plan will decrease the recurrence of adenomatous polyps of the large bowel. Secondary objectives of the PPT include 1) evaluating the effectiveness of the intervention program with respect to participant achievement of dietary goals; 2) examining the relation of dietary change and biochemical markers in blood; and 3) assessing the impact of the intervention on quality of life indicators.

Colonoscopy is the gold standard for detection and removal of precancerous lesions, and has been amply shown to reduce mortality. However, the miss rate for polyps during colonoscopies is 22-28%, while 20-24% of the missed lesions are histologically confirmed precancerous adenomas. To address this shortcoming, the investigators propose a new polyp detection system based on deep learning, which can alert the operator in real-time to the presence and location of polyps during a colonoscopy. The investigators dub the system DEEP: (DEEP) DEtection of Elusive Polyps. The DEEP system was trained on 3,611 hours of colonoscopy videos derived from two sources, and was validated on a set comprising 1,393 hours of video, coming from a third, unrelated source. For the validation set, the ground truth labelling was provided by offline gastroenterologist annotators, who were able to watch the video in slow-motion and pause/rewind as required; two or three specialist annotators examined each video. This is a prospective, non-blinded, non-randomized pilot study of patients undergoing elective screening and surveillance colonoscopies using DEEP. The aim of the study is to: Assess the: Number of additional polyps detected by the DEEP system in real time colonoscopy. Safety by prospective assessment of the rate of adverse events during the study period attributed or not to the use of the DEEP system. Stability of the DEEP system by measuring the rate of false positives (False Alarms) per colonoscopies 4 And to examine its feasibility and usefulness of in clinical practice by assessing the colonoscopist user experience while using the DEEP system in a 5 point scale.

The objective of this study is to compare the polyp detection rate (PDR) of endoscopists unaware of a commercially available artificial intelligence (AI) device for polyp detection during colonoscopy and the PDR of endoscopists with the aid of such a device. Moreover, an extensive characterization of the performance of this device will be done.

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.

The aim of this study is to evaluate the efficacy of prophylactic clip application after colonoscopic removal for a large pedunculated polyp (> 1cm) in preventing immediate postpolypectomy bleeding (IPPB) and delayed postpolypectomy bleeding (DPPB).

Effectiveness of screening colonoscopy in cancer prevention relies on the detection and removal of adenomatous polyps. However, a substantial rate of adenomas is missed during a colonoscopy. It has been estimated that two thirds of missed adenomas are located on the proximal aspect of colonic folds. Attaching a transparent cap to the tip of a colonoscope may allow examination of the proximal aspect of colonic folds, and some early studies have suggested an increased polyp and adenoma detection using this technology. However, the studies have in part substantial methodological limitations (e.g. missing polyp histology, single endoscopist study, polyps not removed at the time of detection). Therefore, at this point it is unclear whether cap assisted colonoscopy may improve adenoma detection. The objective of this study is to evaluate whether cap assisted colonoscopy improves adenoma detection. The investigators propose a two-center multiple endoscopists randomized controlled trial. Patients will be randomized to cap assisted colonoscopy or standard high definition white light colonoscopy. The cap is a 4mm commercially available transparent cap that is attached to the tip of the colonoscopy. Primary outcome measure is the adenoma detection rate (mean number of adenoma per patient). The investigators will assess and adjust for possible variables that can affect adenoma detection, including withdrawal time and quality of colon preparation. As a secondary outcome of interest the investigators will evaluate a possible learning curve effect among all endoscopists (a minimum of six) new to this method. In addition the investigators will evaluate whether cap assisted endoscopy improves real time prediction of polyp histology.

To compare the adenoma miss rate with the EndoRings™ vs. the adenoma miss rate with Standard view colonoscopy. To compare the polyp miss rate with the EndoRings™ vs. the polyp miss rate with Standard view colonoscopy.In addition, time measurements including time to cecum, time for withdrawal and overall procedure time will be analyzed and reported for each group.

Extensive experimental and observational data suggest that intake of calcium and of vitamin D exert protective effects on colorectal neoplasia. Building on their previous work, the investigators will investigate the chemopreventive effect of vitamin D in the large bowel, to study whether calcium with vitamin D is more effective than calcium alone, and to confirm their positive finding regarding calcium. The goal of this study is the development of chemopreventive combinations that will reduce risk of colorectal neoplasia sufficiently to permit the lengthening of surveillance intervals in most patients and to clarify important issues regarding the mechanisms of colorectal carcinogenesis and chemoprevention.

The investigators' study is a prospective study to evaluate the enhancement pattern of contrast-enhanced endoscopic ultrasonography and suggest the criterions for differential diagnosis between gallbladder polyps by using software program of quantitative analysis.