Colorectal Cancer Screening
Jim Cassidy, Patrick Johnston, Eric Van Cutsem in Colorectal Cancer, 2006
Using these criteria there is little doubt that colorectal cancer is a suitable candidate for screening. In the western world it is extremely common and there are well-established methods of diagnosis and treatment. Colonoscopy is the gold standard investigation for symptomatic patients and high-risk individuals, although, as will be discussed in detail, there is considerable debate as to whether it should be used as a primary screening tool in asymptomatic people. Barium enema is still widely employed, but the published evidence would indicate that this is an inferior method of investigation compared with colonoscopy (6), and most authorities would now recommend that it be supplemented by flexible sigmoidoscopy. The latest computed tomography (CT) technology and analytical software has resulted in the development of CT colography or “virtual colonoscopy,” and this is emerging as a highly sensitive and specific diagnostic modality for colorectal neoplasia, set to render barium enema obsolete and perhaps replace colonoscopy as a purely diagnostic procedure (7).
Telescopes for Inner Space: Fiber Optics and Endoscopes
Suzanne Amador Kane, Boris A. Gelman in Introduction to Physics in Modern Medicine, 2020
For example, presently colon cancer screening is mainly accomplished by regular endoscopic exams. For colon cancer prevention, persons over age 50 are recommended to undergo regular exams on a regular schedule, performed with either sigmoidoscopes, which can only access the outermost regions of the large intestine, or colonoscopes, which can see along its entire length. (Two other x-ray screening methods for colon cancer – double-contrast barium studies and computerized tomography (CT) or virtual colonoscopy – are discussed in Chapter 5.) While not a comfortable prospect, these exams are fast and can be done as an outpatient procedure using sedation only. The colonoscopy allows the physician to examine the walls of the colon for precancerous growths, and to biopsy and remove them in one step using, for example, the snares and forceps described above. The documented success of this regimen means that many cases of potential or actual colon cancer can either be prevented or cured through early detection.
Gastrointestinal system
David A Lisle in Imaging for Students, 2012
For most indications including altered bowel habit, weight loss or anaemia of unknown cause, lower GIT bleeding, and to screen for the presence of colorectal carcinoma or polyps in patients at risk, barium enema has been replaced with colonoscopy. Where colonoscopy is contraindicated or incomplete, imaging assessment of the large bowel is best performed with CT colonography, also known as virtual colonoscopy (see below). Contrast enema studies may be performed for investigation of suspected large bowel pathology in specific circumstances as outlined below, or where colonoscopy and CT colonography are unavailable. Single contrast enema studies with Gastrografin may be useful to outline and define a suspected large bowel obstruction, to define a suspected perforation or to check surgical anastomoses (Fig. 4.2). Single contrast barium enema with dilute barium may be used in children for the diagnosis of large bowel pathology, such as Hirschsprung disease. Barium enema is contraindicated in the presence of acute colitis and toxic megacolon. Complications are very rare and consist of bowel perforation and transient bacteraemia; patients with artificial heart valves should receive antibiotic cover when having a barium enema.
Implications of colonic and extra-colonic findings on CT colonography in FIT positive patients in the Dutch bowel cancer screening program
Published in Scandinavian Journal of Gastroenterology, 2021
Marieke H. A. Lammertink, Jelle F. Huisman, Marie L. E. Bernsen, Ronald A. M. Niekel, Henderik L. van Westreenen, Wouter H. de Vos tot Nederveen Cappel, Bernhard W. M. Spanier
All CTCs were reviewed by specialized CT radiologists whose experience ranges between 3 and 25 years of working with virtual colonoscopy images. All worked with Philips IntelliSpace Portal with CT-colonography software and computer-aided detection (CAD) and used 3D viewing, or ‘filet-view’, utilizing 2D views in case of relative doubt. Patients were scanned in prone and supine positions. Automatic exposure control was used in all patients. Tube voltage during scanning was 130 kV. Milliamperage values were adjusted according to contrast agent administration and patient size (around 50–95 mAs). Bowel preparation was accomplished by means of a low-residue diet and cathartic cleansing with oral administration of sodium ioxitalamate (Telebrix® Gastro) starting 24 h prior to CTC examination. Spasmolytics (Buscopan®) were administered to reduce insufflation-related discomfort and facilitate bowel evaluation. The reporting of extra-colonic findings was performed routinely.
Advances in tests for colorectal cancer screening and diagnosis
Published in Expert Review of Molecular Diagnostics, 2022
Sarah Cheuk Hei Chan, Jessie Qiaoyi Liang
Virtual colonoscopy (VC) is an imaging modality that uses computed tomography (CT) to generate two-dimensional and three-dimensional images of the colon for the detection of polyps and masses [125,126]. Its diagnostic performance is comparable to optical colonoscopy, the current gold standard for CRC detection. The sensitivities of VC in identifying adenomatous polyps of at least 10 mm, 8 mm, and 6 mm in diameter are 93.8%, 93.9%, and 88.7%, respectively, while the sensitivities of optical colonoscopy for these three categories are 87.5%, 91.5%, and 92.3%, respectively [127]. These findings are similar to that of another study, which reports a sensitivity of 70% for polyps with size between 6 and 9 mm and 85% for polyps larger than 9 mm [128].
Use of enteroscope without the overtube in incomplete colonoscopies
Published in Scandinavian Journal of Gastroenterology, 2020
Flaminia Purchiaroni, Silvia Conti, Giorgio Valerii, Guido Costamagna, Maria Elena Riccioni
The US Multi-society Task Force on CRC stated that caecal intubation rate should be above 90% for all colonoscopies and above 95% for screening colonoscopies [1]. Despite the progress in the endoscopy technology field and the improvement of training programmes for endoscopists, there still is a certain percentage of unsuccessful procedures, mostly related to either fixed and angulated colon or long and loopy colon. Incomplete procedures may lead to higher healthcare costs and possibly to increased morbidity and mortality because of missing lesions [22,23]. To overcome such issue, the use of scopes different from standard colonoscope has been suggested in literature, such as PCF [24,25], GIF [26,27], DBE and SBE [15–18,28] and PE [14]. However, there may be some disadvantages when using the aforementioned scopes to perform colonoscopy. Indeed, with respect to GIF, the main limitations are the relatively short scope length and the small suction channel, which can get easily occluded during aspiration of faecal residue. DBE and SBE are associated with higher costs and longer procedure time, because of the overtube-balloon equipment, and to patient’s X-ray exposure during fluoroscopic guidance. Moreover, they are usually available only in tertiary-care academic centres. PCF is useful in case of loopy and angulated colon because of its thinner diameter, but it is shorter than SBE and DBE and, therefore, it may not be helpful for the intubation of long colon. Other options for bowel study after an unsuccessful colonoscopy are computed tomographic virtual colonoscopy (CTVC) and capsule endoscopy (CE). However, both diagnostic techniques do not allow to perform operative endoscopy, such as polyps removal. Moreover, polyps smaller than 5 mm are not seen by CTVC, as they fall below its detection threshold [29].
Related Knowledge Centers
- Diverticulosis
- Laxative
- Polyp
- Small Intestine
- Rectum
- Large Intestine
- CT Scan
- Magnetic Resonance Imaging
- 3D Computer Graphics
- Feces