Chemoprevention began to be considered as a potential strategy for lowering the incidence of cancer and cancer‐related deaths in the 1970s. For clinical chemoprevention trials against cancer, including colorectal cancer (CRC), well‐established biomarkers are necessary for use as reliable endpoints. Difficulty in establishing validated biomarkers has delayed the start of CRC chemoprevention development. Chemoprevention trials for CRC have only recently been initiated thanks to the identification of reliable biomarkers, such as colorectal adenomas and aberrant crypt foci. Some promising agents have been developed for the prevention of CRC. The chemopreventive effect of selective cyclooxygenase 2 inhibitors has been shown, although these inhibitors are associated with cardiovascular toxicity as a crucial adverse effect. Aspirin, which is a unique agent among non‐steroidal anti‐inflammatory drugs (NSAIDs) showing minimal gastrointestinal toxicity and no cardiovascular risk, has prevented adenoma recurrence in some randomized controlled trials. More recently, metformin, which is a first‐line oral medicine for type 2 diabetes, has been shown to be safe and to prevent adenoma recurrence. A recommendation of the United States Preventive Services Task Force published in 2016 provides a Grade B recommendation for the use of aspirin for chronic prophylaxis against diseases, including CRC, in certain select populations. However, the roles of other agents have yet to be determined, and investigations to identify novel “post‐aspirin” agents are also needed. The combined use of multiple drugs, such as aspirin and metformin, is another option that may lead not only to stronger CRC prevention, but also to improvement of other obesity‐related diseases.
Visual distraction alone improves satisfaction in patients undergoing colonoscopy and decreases anxiety and pain during the procedure among patients with a high pre-procedural anxiety score.
Purpose To demonstrate the usefulness of precolonoscopy intravenous contrast material-enhanced CT for colonic diverticular bleeding (CDB). Materials and Methods A prospective, multicenter, observational study was performed. Patients with acute-onset hematochezia who were admitted to hospital were included, and those without CDB were excluded. CT was performed before colonoscopy. A Mann-Whitney U test, χ test, and multivariable logistic regression analysis were performed to determine the accuracy of CT before colonoscopy. Results A total of 442 patients (mean age, 71.2 years; 302 male patients; 68.3% men) were included between January 2014 and December 2015, and 202 patients were diagnosed as having CDB. The positive extravasation rate during CT was 50 of 202 (24.7%) among all patients and five of nine (55.6%) among patients who underwent CT within 1 hour of the last hematochezia. At multivariable analysis, the interval from the last hematochezia until CT was a predictor of extravasation (beta coefficient, -.0038 ± 0.0014 [standard deviation]). Extravasation at CT had a sensitivity of 38 of 66 (57.6%; 95% confidence interval: 44.8%, 69.7%) and a specificity of 124 of 136 (91.2%; 95% confidence interval: 85.1%, 95.4%) for the prediction of stigmata of recent hemorrhage of diverticula during colonoscopy. The sensitivity was higher in patients who underwent CT examination within 4 hours of hematochezia, compared with those examined after 4 hours (64.7% [33 of 51] vs 33.3% [five of 15]; P < .01). Conclusion Extravasation findings for CT with intravenous contrast material had high specificity for the prediction of stigmata of recent hemorrhage of diverticula during colonoscopy, regardless of the timing of the CT examination. Although the sensitivity was relatively low, it was higher when the CT examination was performed within 4 hours after the last hematochezia. Therefore, urgent precolonoscopy CT may contribute to decision making regarding whether an urgent colonoscopy should be performed.
AMPK activation as represented by metformin showed to improve disorders associated with diabetes and metabolic syndrome and became a well-established treatment strategy for these diseases. The increasing evidence suggests that AMPK is a promising target in the treatment and prevention of cancer. Further investigation including long-term clinical trials with large sample size is needed.
The use of low-dose aspirin (LDA) is well known to be associated with an increased risk of serious upper gastrointestinal complications, such as peptic ulceration and bleeding. Until recently, attention was mainly focused on aspirin-induced damage of the stomach and duodenum. However, recently, there has been growing interest among gastroenterologists on the adverse effects of aspirin on the small bowel, especially as new endoscopic techniques, such as capsule endoscopy (CE) and balloon-assisted endoscopy, have become available for the evaluation of small bowel lesions. Preliminary CE studies conducted in healthy subjects have shown that short-term administration of LDA can induce mild mucosal inflammation of the small bowel. Furthermore, chronic use of LDA results in a variety of lesions in the small bowel, including multiple petechiae, loss of villi, erosions, and round, irregular, or punched-out ulcers. Some patients develop circumferential ulcers with stricture. In addition, to reduce the incidence of gastrointestinal lesions in LDA users, it is important for clinicians to confirm the differences in the gastrointestinal toxicity between different types of aspirin formulations in clinical use. Some studies suggest that enteric-coated aspirin may be more injurious to the small bowel mucosa than buffered aspirin. The ideal treatment for small bowel injury in patients taking LDA would be withdrawal of aspirin, however, LDA is used as an antiplatelet agent in the majority of patients, and its withdrawal could increase the risk of cardiovascular/cerebrovascular morbidity and mortality. Thus, novel means for the treatment of aspirin-induced enteropathy are urgently needed.
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