Vakil, Nimish

Objective: Colorectal cancer is the second most common cause of cancer death in Europe and North America. Alarm features are used to prioritise access to urgent investigation, but there is little information concerning their utility in the diagnosis of colorectal cancer. Methods: A systematic review and meta-analysis of the published literature was carried out to assess the diagnostic accuracy of alarm features in predicting colorectal cancer. Primary or secondary care-based studies in unselected cohorts of adult patients with lower gastrointestinal symptoms were identified by searching MEDLINE, EMBASE and CINAHL (up to October 2007). The main outcome measures were accuracy of alarm features or statistical models in predicting the presence of colorectal cancer after investigation. Data were pooled to estimate sensitivity, specificity, and positive and negative likelihood ratios. The quality of the included studies was assessed according to predefined criteria. Results: Of 11 169 studies identified, 205 were retrieved for evaluation. Fifteen studies were eligible for inclusion, evaluating 19 443 patients, with a pooled prevalence of colorectal carcinoma of 6% (95% CI 5% to 8%). Pooled sensitivity of alarm features was poor (5% to 64%) but specificity was >95% for dark red rectal bleeding and abdominal mass, suggesting that the presence of either rules the diagnosis of colorectal cancer in. Statistical models had a sensitivity of 90%, but poor specificity. Conclusions: Most alarm features had poor sensitivity and specificity for the diagnosis of colorectal carcinoma, whilst statistical models performed better in terms of sensitivity. Future studies should examine the utility of dark red rectal bleeding and abdominal mass, and concentrate on maximising specificity when validating statistical models.

Background. The ``gold-standard'' evidence of effectiveness for a clinical practice guideline is the randomized controlled trial (RCT), although RCTs have a limited ability to explore potential management strategies for a chronic disease where these interact over time. Modeling can be used to fill this gap, and models have become increasingly complex, with both dynamic sampling and representation of second-order uncertainty to provide more precise estimates. However, both simulation modeling and probabilistic sensitivity analysis are rarely used together. The objective of this study was to explore uncertainty in controversial areas of the 2005 American Gastroenterology Association position statement on the management of dyspepsia. Methods. Individual sampling model, incorporating a second-order probabilistic sensitivity analysis. Population. US adult patients presenting in primary care with dyspepsia. Interventions compared: empirical acid suppression, test and treat for Helicobacter pylori, initial endoscopy, acid suppression then endoscopy, test and treat then proton pump inhibitor (PPI) then endoscopy. Outcomes. Cost-effectiveness, quality-adjusted life years, and costs in US dollars from a societal perspective, measured over a 5-year period. Data sources: mainly Cochrane meta-analyses. Results. Endoscopy was dominated at all ages by other strategies. PPI therapy was the most cost-effective strategy in 30-year-olds with a low prevalence of H. pylori. In 60-year-olds, H. pylori test and treat was the most cost-effective option. Conclusions. Acid suppression alone was more cost-effective than either endoscopy or H. pylori test and treat in younger dyspepsia patients with a low prevalence of infection.