Best Practice & Research Clinical Gastroenterology最新文献

Prognostic model building is a process that begins much earlier than data analysis and ends later than when a model is reached. It requires careful delineation of a clinical question, methodical planning of the approach and attentive exploration of the data before attempting model building. Once following these important initial steps, the researcher may postulate a model to describe the process of interest and build such model. Once built, the model will need to be checked, validated and the exercise may take the researcher back a few steps - for instance, to adapt the model to fit a variable that displays a ‘curved’ pattern - to then return to check and validate the model again. To interpret and report the results it is vital to relate the output to the original question, to be transparent in the methodology followed and to understand the limitations of the data and the approach.

Colonoscopy is the cornerstone examination for colorectal cancer (CRC) screening and it is recommended as the first examination in the context of individuals with high risk of CRC development. Thereby, this examination is of choice in the setting of patients with hereditary CRC syndromes or in patients with long-standing inflammatory bowel disease with colon involvement. However, its role is less clear in the average risk-risk population and in patients with family history of CRC not linked to hereditary CRC syndromes. Despite this, current guidelines, include colonoscopy as alternative for CRC screening either in average risk population with the same evidence level that other screening strategies or in the familial risk population. The present manuscript reviews the clinical evidence on the role of colonoscopy in preventing CRC in different screening settings.

Even in countries with national screening programmes for colorectal cancer, most cancers are identified after the patient has developed symptoms. The patients present these symptoms usually to primary care, or in some countries to specialist care. In either healthcare setting, the clinician has to consider cancer to be a possibility, then to perform triage investigations, followed by definitive investigation, usually by colonoscopy. This apparently simple pathway is not simple: most symptoms of colorectal cancer are more likely to represent benign disease than cancer, and each of these stages represents selection of patients into a higher-risk pool. This article summarises a symptom-based approach to selection and initial investigation of such patients in primary care. Some special groups need particular attention, including the younger patient, those with an inherited predisposition to cancer, and those with co-morbidities.

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second commonest cause of cancer deaths worldwide. One of the most important prognostic factors, and thus a potential target for improving cancer care, is the stage of cancer at diagnosis. Earlier stage diagnosis is associated with better prognosis and longer survival times after treatment. At the same time, the use of targeted therapies and immunotherapy is improving CRC outcomes. Diagnostic biomarkers are key to both early detection and prediction of treatment responses. Currently faecal immunochemical testing for haemoglobin is perhaps the most widespread CRC diagnostic biomarker. However other biomarkers are approved for clinical use and others are in the validation stage of research prior to clinical use. This review focuses on these the evidence behind these biomarkers, their current and potential future use.

Faecal hemoglobin concentrations (f-Hb) can be quantitated using faecal immunochemical test for haemoglobin (FIT) analytical systems. FIT are of proven value and widely used in colorectal cancer (CRC) screening. Several factors affect f-Hb including sex, age, deprivation, geographical region, and FIT system. Thus, FIT data may not be transferable. Women are disadvantaged in programmes using a single f-Hb threshold for all participants, but risk scoring or sex stratified thresholds could be used to minimise this problem. In addition, low but detectable f-Hb, below the threshold, implies future risk of CRC. In several countries, where colonoscopy resources are constrained, FIT are now accepted as of added value in assessment of patients presenting in primary or secondary care with symptoms, although some serious colorectal disease is missed. Elevated f-Hb in the absence of any discernible colorectal lesions is common and has been found in several diseases with a systemic inflammatory component, including circulatory, respiratory, digestive, neuropsychological, blood and endocrine diseases, and others. There is growing evidence for the value of f-Hb in post-polypectomy surveillance, potentially saving costs and colonoscopy. There may be a role for FIT systems which have lower limits of detection than currently available methods. The faecal material remaining in FIT specimen collection devices could be used for further studies, including assessment of the microbiome. The estimation of f-Hb is now a mature investigative tool but further research will undoubtedly expand applications of value.

Colorectal cancer (CRC) is a major health problem and it is expected that the number of persons diagnosed with CRC and CRC-related deaths will continue to increase. However, recent years have shown reductions in CRC incidence and mortality particularly among individuals aged 50 years and older which can be attributed to screening, improvements in patients’ management, closer adherence to treatment guideline recommendations and a higher utilization of curative surgery, chemotherapy and radiotherapy. The International Agency for Research on Cancer has concluded that there has been sufficient evidence that biennially screening using a stool-test or once-only endoscopy screening reduces CRC-related mortality. In Europe, between 2008 and 2018, nine countries have successfully implemented a population-based organized program and another six are in the roll-out phase. Population-based organized programs show higher screening participation rates and lower lack of compliance to follow-up testing after a positive screen test compared to opportunistic screening. Moreover, organized programs aim to provide high quality screening thereby reducing the risk of the harms of screening, including over-screening, and complications of screening, and poor follow-up of those who test positive. We describe how population-based organized CRC screening programs are preferred, since they reflect a more appropriate utilization of available resources, reduce inequities in access, and can integrate interventions addressing barriers to screening at the individual and health system levels.

Post-polypectomy surveillance has proven to reduce colorectal cancer (CRC) incidence in patients with high-risk polyps, but it implies a major burden on colonoscopy units. Therefore, it should be targeted to individuals with a higher risk. Different societies have published guidelines on surveillance after resection of polyps, with notable discrepancies among them, and many recommendations come from low-quality evidence based on surrogate measures, such as risk of advanced adenoma, and not CRC risk. In this review, we aimed to summarize the evidence supporting post-polypectomy surveillance, compare the recently updated major guidelines, and discuss the existing discrepancies on this topic. Briefly, patients with adenomas ≥10 mm or high-grade dysplasia and patients with serrated polyps ≥10 mm or dysplasia are generally considered to have an increased risk of metachronous CRC and require surveillance, whereas the indication of surveillance is not clearly established in patients without these high-risk features.

Colorectal Cancer (CRC) is the third most commonly diagnosed form of cancer and accounts for approximately 1.9 million cancer cases each year (10% of all new cancer cases globally). Incidence strongly increases with age and has been traditionally highest in Western, affluent countries, but it is rapidly increasing in many less developed countries and in younger generations in both developed and developing countries. With demographic aging, CRC will pose a rapidly increasing challenge for many societies, which underlines the need for major efforts on primary and secondary prevention. A number of effective screening options are available, and implementation of well-organized screening programs could have a major impact on lowering the future burden of the disease.