58 research outputs found
Screening Relevance of Sessile Serrated Polyps
Conventional adenomas have historically been considered to be the only screening-relevant colorectal cancer (CRC) precursor lesion. The prevailing paradigm was that most CRCs arise along the chromosomal instability pathway, where adenomas accumulate incremental genetic alterations over time, leading eventually to malignancy. However, it is now recognized that this "conventional" pathway accounts for only about two-thirds of CRCs. The serrated pathway is responsible for most of the remainder, and is a disproportionate contributor to postcolonoscopy CRC. Hallmarks of the serrated pathway are mutations in the BRAF gene, high levels of methylation of promoter CpG islands, and the sessile serrated polyp (SSP). Accumulating evidence shows that SSPs can be considered adenoma-equivalent from the standpoint of CRC screening. SSPs have a higher prevalence than previously thought, and appear to have a relatively long dwell time similar to that of conventional adenomas. In addition, SSPs, whether sporadic or as part of the serrated polyposis syndrome, are associated with increased risk of synchronous and metachronous neoplasia. These features collectively support that SSPs are highly relevant to CRC prevention
Reviewing the Evidence That Polypectomy Prevents Cancer
Colonoscopic polypectomy is fundamental to effective prevention of colorectal cancer. Polypectomy reduces colorectal cancer incidence and mortality by altering the natural history and progression of precancerous precursor polyps. Epidemiologic data from the United States, where colorectal cancer rates have been steadily declining in parallel with screening efforts, provide indisputable evidence about the effectiveness of polypectomy. Randomized controlled trials of fecal occult blood tests and flexible sigmoidoscopy, and observational colonoscopy studies, provide additional support. Longitudinal studies have shown variable levels of protection after polypectomy, highlighting the central importance of high quality and adequate surveillance of higher-risk patients
Advanced Colonoscopy Techniques and Technologies
Colonoscopy is the most frequently performed endoscopic procedure in the United States. It is the mainstay of diagnostic and therapeutic options for the practicing gastroenterologist. It plays a fundamental role in colorectal cancer (CRC) prevention, with a dominant position among the screening options for CRC and precancerous lesions. Over the past decade, there have been significant advances in the field of CRC and colonoscopy, including a better understanding of the importance of right-sided lesions, the sessile serrated pathway, and recognition of the significance of operator dependence in colonoscopy. This has been paralleled by an array of technological and technical advances that has transformed the field of colonoscopy and improved patient care. This article addresses the diverse and expanding field of advanced colonoscopy techniques and technologies. It is intended to be a primer on recent and effective developments in advanced technologies for screening or imaging, mucosal resection techniques, and endoscopic management of CRC
Does Increased Adenoma Detection Reduce the Risk of Colorectal Cancer, and How Good Do We Need to Be?
Purpose of Review
Colorectal cancer (CRC) is largely preventable with colonoscopy and other screening modalities. However, the effectiveness of screening and surveillance depends on the quality of the colonoscopy exam. Adenoma detection rate (ADR) is the best-validated metric by which we measure individual physicians’ performance.
Recent Findings
Recent evidence suggests that ADR benchmarks may be inappropriately low. There is proof that improving ADR leads to significant reductions in post-colonoscopy CRC (PCCRC). Two studies have demonstrated that when a colonoscopy is performed by physicians with higher ADRs, patients are less likely to have advanced adenomas on surveillance and less likely to develop or die from PCCRC. Finally, there is at least some evidence that higher ADRs do not lead to more cumulative surveillance exams.
Summary
The ADR is a useful outcome measure that can provide individual endoscopists and their patients with information about the likelihood of developing PCCRC. To achieve the lowest possible PCCRC rate, we should be striving for higher ADRs. While strategies and innovations may help a bit in improving ADRs, our efforts should focus on ensuring a complete mucosal exam for each patient. Behavioral psychology theories may provide useful frameworks for studying motivating factors that drive a careful exam
Colonoscopy Quality Assessment
Colonoscopy is the cornerstone of colorectal cancer screening programs. There is significant variability in the quality of colonoscopy between endoscopists. Colonoscopy quality assessment tracks various metrics in order to improve the effectiveness of colonoscopy, aiming at reducing the incidence and mortality from colorectal cancer. Adenoma detection rate is the prime metric, as it is associated with the risk of interval cancers. Implementing processes to measure and improve the adenoma detection rate is essential to improve the quality of colonoscopy
Adenoma Detection Rate in Asymptomatic Patients with Positive Fecal Immunochemical Tests
Background and Aims
The adenoma detection rate (ADR) is a powerful measure of screening colonoscopy quality. Patients who undergo colonoscopy for the evaluation of a positive fecal immunochemical test (FIT) have increased prevalence of colorectal neoplasia, but it is not known whether separate quality benchmarks are required. The aim of this study was to compare the conventional ADR to the ADR of colonoscopies performed for the evaluation of positive FIT, in asymptomatic average-risk patients.
Methods
Patients ≥ 50 years old who underwent colonoscopy for the evaluation of a positive FIT between January 1, 2013, and July 31, 2014, at a tertiary Veterans Affairs Medical Center were identified. FIT performed for any indication other than average-risk screening was excluded. The comparison group included average-risk patients ≥ 50 years old undergoing screening colonoscopy during the same time frame. The two groups were compared for ADR, advanced neoplasm [adenoma ≥ 10 mm, tubulovillous, high-grade dysplasia, CRC, sessile serrated polyp (SSP) ≥ 10 mm], CRC, and SSP detection after propensity score adjustment using a logistic regression model adjusted for endoscopist.
Results
There were 207 patients in the FIT group and 601 in the screening colonoscopy comparison group. After propensity score adjustment, ADR (72.9 vs. 50.0%, p = 0.003), number of adenomas per colonoscopy (3.3 ± 3.6 vs. 1.4 ± 2.3, p = 0.033), and advanced neoplasm detection rate (32.4 vs. 11.0%, p < 0.0001) were significantly higher in the FIT group. There were no significant differences in the number of CRC and the SSP detection rate.
Conclusions
In this cohort of average-risk Veterans, the ADR of colonoscopies performed for the evaluation of a positive FIT was higher than the ADR of screening colonoscopies. Patients with a positive FIT also had significantly more adenomas per colonoscopy and advanced neoplasms. These findings suggest that the quality of colonoscopies performed for a positive FIT is insufficiently assessed by the conventional ADR and requires additional quality metrics
Who Is at Risk for Early-Onset Colorectal Cancer?
Modern medical decision making, whether preventive, diagnostic, or therapeutic, emphasizes the risk stratification of patients, and is heavily informed and influenced by evidence-based guidelines. Such guidelines for colorectal cancer (CRC) screening were first published in 1997,1 and subsequently by multiple professional organizations. Although there have been disagreements regarding choice of screening modality, the start age of 50 years for most average-risk individuals (with the notable exception of African Americans) has been mostly unchallenged
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