Active clinical trials for "Adenoma"

Bowel cancer can arise from polyps, which can become cancerous. Polyps are little outgrowths within the lining of the bowel (similar to skin warts). Depending on their size and their potential to become cancerous, they can cause bleeding. However, it is not known which polyps harbour cancerous potential. Therefore, at present all patients undergo a colonoscopy (camera examination of the large bowel) in order to identify and remove any polyps. However, not all patients who undergo a colonoscopy will have polyps. Moreover, colonoscopies are invasive and disruptive to patients, as they require bowel preparation. The aim of this study is to evaluate non-invasive stool and urine tests to identify patients who are at risk of polyps and if the polyps have the potential to become cancerous. This in turn, will significantly reduce the number of 'unnecessary' polyp surveillance colonoscopies with resultant benefits to both patients and the National Health Service (NHS).

Current guidelines for initiating screening colonoscopies in patients younger than 50 years of age who have a first relative history of colorectal cancer are controversial. The aim of this study was to prospectively define the prevalence of colorectal adenoma 30- to 49-years-old asymptomatic subjects with a first relative history of colorectal cancer and to compare the data with controls. Design: Single-center prospective study

The aim of the study is to develop a computer program which is able to automatically detect colorectal polyps in endoscopic video sequences. Furthermore, the program shall be able to automatically distinguish between adenomas, serrated adenomas and hyperplastic polyps on the basis of optical features of the polyps. Video sequences of polyps will be collected during routine colonoscopy procedures. All polyps will be resected endoscopically so that histopathological diagnoses (gold standard) can be notified. In the validation phase of the study a computer program will be established which aims to distinguish between adenomas, serrated adenomas and hyperplastic polyps on the basis of optical features derived from the videos. A deep learning approach will be used for programming. Afterwards, in the testing phase of the study, videos of 100 polyps (not used in the validation phase) will be presented to the computer program. The establishment of a well- functioning computer program is the primary aim of the study.

Adenomas, serrated adenomas and hyperplastic polyps are polypoid lesion in the colorectum. At the present moment, all polyps should be resected endoscopically, although only adenomas and serrated adenomas, but not hyperplastic polyps have the potential to develop colorectal cancer. This approach enables the conduction of microscopic investigations of the lesions. By today, only the pathological diagnosis can distinguish exactly between these three polyp entities. Some studies have investigated the value of the optical characterization approach which is based on visual assessment of the polyp' surface structures. Based upon optical polyp features users are encouraged to predict histopathological polyp diagnoses solely on behalf of optical or endoscopical criteria. This method is conducted in real time during colonoscopy. If it could be shown, that endoscopist using the optical characterization approach are able to predict histopathological diagnoses of colonic polyps sufficiently this would possibly lead to simplification of diagnostic procedures. For instance, it would be conceivable to resect small polyps and discard them without further assessment by a pathologist. One problem in this context is a correct differentiation between hyperplastic polyps and serrated adenomas. These two polyp entities are known to show similar optical features. However, while serrated adenomas are premalignant lesions hyperplastic polyps have benign histology and never develop into cancer. It is therefore important to sufficiently distinguish hyperplastic polyps from serrated lesions. In this study we want to investigate whether the use of narrow-band imaging (NBI) would be capable to rise accuracy of optical polyp predictions compared to standard HD white light endoscopy. NBI is a light filter tool which can be activated by pressing a button at the endoscope. The use of NBI leads to an endoscopic picture which appears blue and enables endoscopists to better assess surface structures and vascular patterns. In a prospective randomised multicenter setting we plan to conduct colonoscopy in 370 patients. Half of the patients will be examined without the use of NBI (control arm). In these cases colonoscopists will assess optical diagnosis of polyps without turning on the NBI tool. If polyps are detected in patients belonging to the intervention arm NBI will be used and optical diagnosis will be determined using the WASP (Workgroup serrAted polypS and Polyposis) classification. All polyps will be resected and send to pathology for further microscopic assessment. After completing the trial we aim to compare accuracy of the optical diagnosis in both groups. Our hypothesis is, that by using NBI accordance between optical and histopathological diagnosis can be increased from 80% to 90%.

The aim of the study is to develop a score system in order to differentiate adenomatous polyps, hyperplastic polyps and serrated adenomas on the basis of optical features. Endoscopic images of colorectal polyps will be collected from a prospectively managed database. Histopathological diagnoses are available for all polyps. Histopathological diagnoses serve as gold standard in this study. In the first phase of the study optical features of serrated adenomas are extracted from the database. Discriminators are then defined on the basis of the extracted features. In the second phase a test set of high quality pictures are provided to both novices and experts of colorectal endoscopy. Participants are asked to use the above named discriminators in order to rate pictures and to classify polyps into three classes (adenomatous polyps, hyperplastic polyps and serrated adenomas). In the third phase of the study accuracy of optical bases diagnoses is calculated by comparing optically derived diagnoses with histopathological diagnoses (gold standard).

Sellar area tumors such as pituitary adenoma, craniopharyngioma and meningioma, etc, commonly lead to visual impairment symptoms. Patients suffer from a loss of visual acuity (VA) and visual field defects (VF) due to a local compression on the optic chiasma by the tumor. In the management of these patients, it is an important goal to evaluate their visual function throughout the treatment, so as to predict the outcome of the visual function . Since the visual pathway contains a huge complex network of both structure and function, traditional simplex evaluation of VA and VF is obviously not enough. Former studies have revealed changes in the visual network and cortex structure in neurodegenerative diseases and optic neuritis, yet the functional and structural changes caused by local tumor compression and their relation to the visual cortex activity patterns needs further research. The objective of this research is to asses the visual function in patients with sellar area tumor 1 week preoperatively (baseline),72 hours postoperatively(checking point 1) and at 3 months follow up(checkpoint 2). By using multimodal evaluation including visual resting and task state fMRI, diffusion tensor imaging (DTI), etc. The investigators aim to reveal the changes in functional connectivity (FC), amplitude of low frequency fluctuation (ALFF), regional homogeneity (REHO) ,visual cortex activity patterns and tract-based spatial statistics (TBSS).

The purpose of this study is to assess the interobserver agreement (IOV) for pancreatico-biliary Volumetric Laser Endomicroscopy (VLE) de-identified clips using the new VLE criteria. This is an Interobserver study to validate VLE criteria for indeterminate biliary and pancreatic duct strictures and evaluate impact on clinical management.

Natural killer cells (NK cells) are cytotoxic lymphocytes that play an important role in the innate immune system. In particular, it plays a very important defense function against host cells or cancer cells infected with a specific virus. Recent studies have shown that the activity of NK cells is decreased in patients with various carcinomas compared with normal controls, suggesting that the measurement of activity of NK cells in the blood may be helpful in the early diagnosis of cancer. In a recent study analyzing NK cell activity in 762 patients undergoing colonoscopy, NK cell activity showed performance in diagnosing advanced colorectal adenoma and colorectal cancer with sensitivities 42.2% and 85.7%, and specificity 58.3% and 59.5%, respectively. This finding suggests that NK cell activity may be useful as a screening method for colorectal neoplasms. However, as a single test, this diagnostic power is relatively low. On the other hands, another blood-based colorectal cancer screening test that using 29 gene panels algorithm has recently been reported. According to this study, 29 gene panel algorithms (Colox®) showed performance in diagnosing advanced colorectal adenoma and colorectal cancer with sensitivity of 55.4% and 79.5% and specificity of both 90.0%, respectively. for diagnosis of advanced adenoma and colorectal cancer, respectively. Although the Colox® test seems to be useful for the colorectal cancer screening using blood test, this diagnostic power is relatively low. In order to overcome low diagnostic performance of aforementioned tests (NK activity and Colox®) as a single use, combination of individual biomarkers can be a promising alternative. In this regards, the aim of this study was to evaluate the diagnostic value for predicting advanced colorectal neoplasms by combining Colox® and NK cell activity indicators.

Benign adenomas of the colon have the potential to degenerate and become malignant. Therefore adenomatous polyps should be detected and resected during colonoscopy. Factors like advanced age and male gender are associated with the detection of adenomas. The same epidemiological pattern can be found with regard to colon diverticula. Furthermore, western world countries report higher incidences of both colorectal carcinoma as well as diverticular disease. It is not known whether a correlation exists between both entities. Some recent data have postulated higher adenoma detection rates in patients with concomitant diverticular disease (Rondagh EJ et al. Eur J Gastroenterol Hepatol. 2011; 23:1050-5. Kieff BJ et al. Am J Gastroenterol 2004; 99: 2007-11). If a positive correlation could be found this would possibly affect recommendations regarding colonoscopy surveillance intervals for patients with and without diverticular disease. The investigators therefore plan to conduct the following trial.

This will be a retrospective chart review of 880-1000 patients who had a colonoscopy and were found to have a tubular adenoma between the years of 2004-2008. We will compare the rate and timing of completion of repeat colonoscopies pre and post establishment of a polyp registry (tracking system) in 2006. Each group will be composed of up to 500 subjects consecutively identified from all the patients who underwent colonoscopy and were found to have a tubular adenoma (Group 1-2004 to 2006, Group 2 2007-2008).