Active clinical trials for "Polyps"

The study purpose is to assess the accuracy of experienced endoscopists at a community hospital in predicting histological types of polyps resected at colonoscopy using white light. Patients 50 years or older undergoing first-time screening colonoscopy will be included in this observational study.

Chromoendoscopy (that involves spraying of dyes over the colonic mucosa) combined with magnification has been utilized for polyp histology identification. Pit patterns on the surface of polyps described by Kudo et al have been shown to have a high diagnostic accuracy in differentiating the polyp types (18, 19). NBI, that is also referred to as "electronic chromoendoscopy" is another technique that has been evaluated for polyp histology identification by highlighting the superficial mucosal and vascular architecture (15, 20, 21). pCLE is another novel addition to the technologies aiming to accomplish in vivo histologic diagnosis with a high degree of accuracy. The pCLE system has three major components (Mauna Kea Technologies, Paris, France). The first is the confocal miniprobe made of approximately thirty thousand optical fibers bundled together and terminated by a distal microsystem. The images obtained have a lateral resolution of 1µm, an axial resolution of 10 µm and a maximum field of view of 240 µm. The depth of observation is from 55 to 65 µm. The miniprobe tip diameter is 2.5 mm and can be passed through the accessory channel of any standard endoscope. The second is the laser scanning unit (excitation wavelength - 488 nm) that combines the functions of laser light illumination and rapid laser scanning, enabling a frame rate up to 12 images per second and signal detection. The third is the control and acquisition software for real time image reconstruction, immediate sequences display and post-procedure analysis and editing tools. Once an area of interest (e.g. a polyp) is identified, 5 ml of 10% fluorescein sodium is injected intravenously; the confocal probe is passed through the accessory channel of the endoscope and placed against the lesion to obtain several high-quality images and video sequences. In a study by Buchner et al from the Mayo Clinic, Jacksonville, (22) this system was used to evaluate confocal images of 37 polyps from 25 patients in a blinded fashion without the knowledge of their histologic diagnosis or endoscopic appearance. The investigators developed the following criteria that were suggestive of neoplastic polyps: villiform pattern, nuclear characteristics - oval/irregular nuclear shape and increased number of nuclei. These features had a sensitivity of 82.6%, specificity of 92.9% and accuracy of 86.5% for the characterization of neoplastic polyps. Similarly, Meining et al (23) have also evaluated criteria for differentiating neoplastic from benign lesions in the colon with encouraging results. The investigators hypothesize that pCLE will have a high rate for accurate characterization of polyp histology real time during colonoscopy

The aim of this study is to develop a blood test to determine which patients are at risk for pre-cancerous colon polyps (ACPs: Advanced Colon Polyps). The telomere length of peripheral blood lymphocytes (PBLs) can be measured from a blood sample. Mechanistic pathways and the investigator's preliminary data support PBL telomere length as a biomarker for ACPs. The long-term goal of this project is to decrease deaths from colon cancer by using a blood test to target colonoscopy for those patients who are at high risk for pre-cancerous polyps.

The investigators hypothesize that NBI will have a high accuracy in predicting polyp histology real time during a colonoscopy by visualization of the surface mucosal and vascular patterns. Aim#1: To determine the sensitivity, specificity and accuracy of NBI and standard white light colonoscopy for predicting polyp histology by evaluating the surface mucosal and vascular patterns during colonoscopy. Aim#2: To determine the inter-observer agreement between investigators for the recognition of various polyp patterns.

Our group, prior to the present study, developed a handcrafted predictive model based on the extraction of surface patterns (textons) with a diagnostic accuracy of over 90%24. This method was validated in a small dataset containing only high-quality images. Artificial intelligence is expected to improve the accuracy of colorectal polyp optical diagnosis. We propose a hybrid approach combining a Deep learning (DL) system with polyp features indicated by clinicians (HybridAI). A pilot in vivo experiment will carried out.

The colorectal cancer is the first incidence and ranks the third cancer-death cause in Taiwan. Based on the Taiwan-national colon cancer screening program, early colorectal cancer detection rate and the survival are markedly improved. Besides to disclose the early cancer, there are vast populations to be disclosed with colon adenoma. Some of colon adenoma really presents as advanced colon adenoma (ACA) to carry higher risk of recurrence and even cancer progression. The current clinical guidelines raise strategy for colonoscopy surveillance based on the results of the index colonoscopy to categorize the patients into different risks of colon polyp recurrence and early detection of colorectal cancer. It is worthy to validate whether the real scenario of Taiwan colonoscopy surveillance can fulfill the guidelines worldwide. Furthermore, it shall be of clinical importance to elucidate out the high risky group who may be commonly disclosed during intense colonoscopy surveillance and to disclose with advanced adenoma. Accordingly, the domestic amending to the worldwide guideline shall be in need and need a more reliable biomarker to predict the recurrence of colon adenoma during surveillance colonoscopy. Concerning, cyclooxygenase-2 (COX-2) and DNA methyltransferases (DNMT) are involved during colorectal carcinogenesis via chronic inflammatory process and early tumorigenesis. This study proposes COX-2 and DNMT shall be potential biomarkers correlating to the recurrence of colon adenoma disclosed during surveillance colonoscopy in Taiwan. We thus conduct a prospective study, containing at least 1,400 cases, who will undergo surveillance colonoscopy in National Cheng Kung University Hospital in the next year. The study shall be a large-case study to answer whether the surveillance interval of the surveillance colonoscopy can be fulfilled to the suggestion of the 2012 United States Multi-society Task Force (USMTF) on colorectal cancer guideline. Factors that affect the detection of polyps in the surveillance will be explored. Based on the invitation of the patients to receive surveillance colonoscopy, the study also test whether COX-2 or DNMT over-expression are markers to predict polyps recurrence and to identify the risky patient deserve for earlier colonoscopy.

Recent studies have shown that narrow-band imaging (NBI) is a powerful diagnostic tool for the differentiation between neoplastic and non-neoplastic colorectal polyps. The aim of the present study is to develop and evaluate a computer-based method for automated classification of small colorectal polyps on the basis of vascularization features.In a prospective study 207 polyps with a size of 10mm or smaller should be detected by a zoom NBI colonoscopy. These polyps were imaged and subsequently removed for histological analysis. the polyp images were analyzed by a computer algorithm. The proposed computer-based method consists of several steps: preprocessing, vessel segmentation, feature extraction and classification. The results of the automatic classification (sensitivity, specificity, negative predictive value, positive predictive value and accuracy)were compared to those of human observers, who were blinded to the histological gold standard.

Colorectal cancer is the second most common cause of cancer death in the US. Colonoscopy is considered the best test colorectal cancer screening. It allows resection of adenomatous polyps (a known cancer precursor) and thus, interrupt the adenoma-carcinoma sequence. Despite the potential benefit of screening colonoscopy recent studies have reported cases of colorectal cancers in a short interval after prior screening or surveillance colonoscopies. One possible cause of such interval cancers may be incomplete resection of adenomatous polyps and hence ongoing growth and cancer development in such lesions. Complete resection may be particularly important for polyps of at least 5mm in size as up 10% of such polyps higher risk lesions as villous adenoma, tubulovillous adenoma, high grade dysplasia, or early carcinoma. Although adenoma resection of sessile and flat adenomatous polyps between 5 and 20mm is believed to be well standardized data on complete resection of adenomatous tissue are sparse. This may be related to the assumption that using a snare with electro-cautery will successfully remove the polyp and cauterize remaining marginal adenomatous tissue and hence completely remove and or destroy the lesion. The investigators are interested in examining how often sessile adenomatous polyps between 5 and 20mm are completely removed using standard polypectomy snare. The investigation was also directed at a comparison between complete resection of polyps between 5 and 9mm and 10 and 20mm.

Prospective study of accuracy of colonic polyp characterisation in vivo using high resolution white light endoscopy, narrow band imaging and chromoendoscopy.

Resect and discard (RD) is a new paradigm for management of diminutive colorectal polyps wherein histology is determined by real-time endoscopic imaging; polyps are then resected and discarded rather than sent for histopathological review. The aims of this study were to compare the surveillance recommendations between RD and the standard of care where polyps are sent for histopathological review in a mixed setting of academic and community gastroenterologists and to evaluate the diagnostic performance of an RD program for management of diminutive polyps.