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Stock Image. Published by 1st Book Library, Used Condition: Used: Good Hardcover. Save for Later. About this title Synopsis: Not just another diet or exercise book, but a unique reference tool that discusses a difficult subject with wisdom and wit and provides concise, expert information on how to optimize bowel function, prevent disease, and achieve great health.
I always strive to achieve best customer satisfaction and have always described book accurately. I got lot of Out of Print and Rare books in my store and still adding lot of books. More Information. Although single test performance is an important issue in the detection of colorectal cancer, the sensitivity of the test over time is more important in an ongoing screening program.ustanovka-kondicionera-deshevo.ru/libraries/2020-07-30/3772.php
Gut- Check By Jeffrey M. Aron, M.D.; Harriette Aron
However, data that permit assessment and direct comparison of screening methods to detect colorectal neoplasia in screening programs over time are limited to those from analytic modeling. The USPSTF found convincing evidence that screening for colorectal cancer in adults aged 50 to 75 years reduces colorectal cancer mortality. The USPSTF found no head-to-head studies demonstrating that any of the screening strategies it considered are more effective than others, although the tests have varying levels of evidence supporting their effectiveness, as well as different strengths and limitations Table.
About one-third of eligible adults in the United States have never been screened for colorectal cancer, 4 and offering choice in colorectal cancer screening strategies may increase screening uptake. The benefit of early detection of and intervention for colorectal cancer declines after age 75 years. Among older adults who have been previously screened for colorectal cancer, there is at best a moderate benefit to continuing screening during the ages of 76 to 85 years.
However, adults in this age group who have never been screened for colorectal cancer are more likely to benefit than those who have been previously screened. The time between detection and treatment of colorectal cancer and realization of a subsequent mortality benefit can be substantial.
As such, the benefit of early detection of and intervention for colorectal cancer in adults 86 years and older is at most small. To date, no method of screening for colorectal cancer has been shown to reduce all-cause mortality in any age group. The harms of screening for colorectal cancer in adults aged 50 to 75 years are small. The majority of harms result from the use of colonoscopy, either as the screening test or as follow-up for positive findings detected by other screening tests.
The rate of serious adverse events from colorectal cancer screening increases with age. The USPSTF concludes with high certainty that the net benefit ie, the benefit minus the harms of screening for colorectal cancer in adults aged 50 to 75 years is substantial. The USPSTF concludes with moderate certainty that the net benefit of screening for colorectal cancer in adults aged 76 to 85 years who have been previously screened is small. Adults who have never been screened for colorectal cancer are more likely to benefit.
This recommendation applies to asymptomatic adults 50 years and older who are at average risk of colorectal cancer and who do not have a family history of known genetic disorders that predispose them to a high lifetime risk of colorectal cancer such as Lynch syndrome or familial adenomatous polyposis , a personal history of inflammatory bowel disease, a previous adenomatous polyp, or previous colorectal cancer. When screening results in the diagnosis of colorectal adenomas or cancer, patients are followed up with a surveillance regimen, and recommendations for screening no longer apply.
The USPSTF did not review or consider the evidence on the effectiveness of any particular surveillance regimen after diagnosis and removal of adenomatous polyps or colorectal cancer.
For the vast majority of adults, the most important risk factor for colorectal cancer is older age. Most cases of colorectal cancer occur among adults older than 50 years; the median age at diagnosis is 68 years. Male sex and black race are also associated with higher colorectal cancer incidence and mortality. Studies have documented inequalities in screening, diagnostic follow-up, and treatment; they also suggest that equal treatment generally seems to produce equal outcomes.
The Table lists the various screening tests for colorectal cancer and notes potential frequency of use as well as additional considerations for each method. The Figure presents the estimated number of life-years gained, colorectal cancer deaths averted, lifetime colonoscopies required, and resulting complications per 1, screened adults aged 50 to 75 years for each of the screening strategies.
Final Recommendation Statement
Multiple randomized clinical trials RCTs have shown that screening with the guaiac-based fecal occult blood test gFOBT reduces colorectal cancer deaths. Multitargeted stool DNA testing has increased single-test sensitivity for detecting colorectal cancer compared with FIT alone. There are no empirical data on the appropriate longitudinal follow-up for an abnormal FIT-DNA test result followed by a negative colonoscopy; there is potential for overly intensive surveillance due to clinician and patient concerns about the implications of the genetic component of the test.
Several RCTs have shown that flexible sigmoidoscopy alone reduces deaths from colorectal cancer. Completed trials of flexible sigmoidoscopy provide indirect evidence that colonoscopy—a similar endoscopic screening method—reduces colorectal cancer mortality. A prospective cohort study also found an association between patients who self-reported being screened with colonoscopy and a lower colorectal cancer mortality rate. Harms may be caused by bowel preparation prior to the procedure eg, dehydration and electrolyte imbalances , the sedation used during the procedure eg, cardiovascular events , or the procedure itself eg, infection, colonic perforations, or bleeding.
Evidence for assessing the effectiveness of computed tomography CT colonography is limited to studies of its test characteristics.
Available RCTs of gFOBT and flexible sigmoidoscopy included patients with age ranges of 45 to 80 years and 50 to 74 years, respectively. For gFOBT, the majority of participants entered the trials at age 50 or 60 years; for flexible sigmoidoscopy, the mean age of participants was 56 to 60 years. Microsimulation analyses performed by CISNET suggest that starting colorectal cancer screening at age 45 years rather than 50 years is estimated to yield a modest increase in life-years gained and a more efficient balance between life-years gained and lifetime number of colonoscopies a proxy measure for the burden of screening.
In the case of screening colonoscopy, 2 of the 3 models found that by starting screening at age 45 years, the screening interval could be extended from 10 to 15 years. Doing so maintained the same or slightly more life-years gained as performing colonoscopy every 10 years starting at age 50 years without increasing the lifetime number of colonoscopies.
However, 1 model estimated a slight loss in life-years gained with a longer screening interval and an earlier age at which to begin screening. The USPSTF considered these findings and concluded that the evidence best supports a starting age of 50 years for the general population, noting the modest increase in life-years gained by starting screening earlier, the discordant findings across models for extending the screening interval when the age at which to begin screening is lowered, and the lack of empirical evidence in younger populations. All 3 CISNET models consistently estimate that few additional life-years are gained when screening is extended past age 75 years among average-risk adults who have previously received adequate screening.
In this age group, competing causes of mortality preclude a mortality benefit that would outweigh the harms.
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Evidence from RCTs demonstrates that annual or biennial screening with gFOBT as well as 1-time and every 3- to 5-year flexible sigmoidoscopy reduces colorectal cancer deaths. These screening strategies include 1 annual screening with FIT, 2 screening every 10 years with flexible sigmoidoscopy and annual screening with FIT, 3 screening every 10 years with colonoscopy, and 4 screening every 5 years with CT colonography.
The findings for CT colonography depend on the proxy measure used for the burden of screening number of lifetime colonoscopies or lifetime cathartic bowel preparations. Another way to conceptualize these findings is to note that CISNET modeling found that FIT-DNA screening every 3 years was estimated to provide about the same amount of benefit as screening with flexible sigmoidoscopy alone every 5 years Figure. Treatment of early-stage colorectal cancer generally consists of local excision or simple polypectomy for tumors limited to the colonic mucosa or surgical resection via laparoscopy or open approach with anastomosis for larger, localized lesions.
The USPSTF has made a recommendation on aspirin use for the primary prevention of cardiovascular disease and colorectal cancer in average-risk adults www. Colorectal cancer causes substantial morbidity and mortality, and the evidence is convincing that screening for colorectal cancer reduces that burden. Despite the availability of several effective screening options, nearly one-third of eligible adults have never been screened. For example, colonoscopy requires a relatively greater time commitment over a short period bowel preparation, procedure, and recovery but allows for much longer time between screenings compared with stool-based screening.
Stool-based screening requires persons to handle their feces, which may be difficult for some, but the test is quick and noninvasive and can be done at home the sample is mailed to the laboratory for testing. Flexible sigmoidoscopy combined with annual FIT may be an attractive option for persons who want reassurance from endoscopic screening but want to limit their exposure to colonoscopy.
For colorectal cancer screening programs to be successful in reducing mortality, they need to involve more than just the screening method in isolation. Screening is a cascade of activities that must occur in concert, cohesively, and in an organized way for benefits to be realized, from the point of the initial screening examination including related interventions or services that are required for successful administration of the screening test, such as bowel preparation or sedation with endoscopy to the timely receipt of any necessary diagnostic follow-up and treatment.
Multiple effective implementation strategies have been demonstrated to increase appropriate provision and use of colorectal cancer screening. Specifically, the Community Preventive Services Task Force recommends using clinician and patient reminder systems, using small media such as videos, letters, and brochures , reducing structural barriers to screening such as the time or distance to the screening delivery setting or offering extended or nonstandard clinic hours , and providing clinician assessment and feedback about screening rates more information is available at www.
Lastly, clinicians also need to consider how they will engage patients older than 75 years about when to stop screening. Further, because determining the ultimate worth of a screening method requires an accurate assessment of the net benefit of that intervention, randomized trials are needed to directly compare different types of colorectal cancer screening programs to more clearly define their relative benefits and harms; however, the USPSTF appreciates the challenges inherent in performing such trials, given the large sample sizes and long time horizons required.
Black and Alaska Native individuals have a higher incidence of and mortality rate from colorectal cancer compared with the general population. Empirical data about the effectiveness of different screening strategies for these at-risk populations are not available.
Although there is a growing body of evidence on the test performance characteristics of CT colonography, evidence to bound the potential harms of this technology is still lacking, particularly in regard to incidental findings. Empirical evidence is lacking on the appropriate follow-up of abnormal results from FIT-DNA screening when the initial diagnostic colonoscopy is negative.
There is a theoretical concern that FIT-DNA may generate inappropriate use of surveillance colonoscopy if clinicians and patients place increased importance on the genetic component of the test. As a condition of its approval of the test, the FDA required the manufacturer to conduct a longitudinal study examining the test characteristics of a 3-year screening interval; these data should help inform decisions. Studies on patient adherence to the various screening options, within single-method screening programs over time, as well as factors that may influence adherence across different screening methods, are needed to help better inform and improve uptake of screening across eligible populations.
The USPSTF commissioned a systematic evidence review 1 , 6 to update its recommendation on screening for colorectal cancer. The review addressed the following: 1 the effectiveness of screening with colonoscopy, flexible sigmoidoscopy, CT colonography, gFOBT, FIT, FIT-DNA, and methylated SEPT9 DNA testing in reducing incidence of and mortality from colorectal cancer or all-cause mortality; 2 the harms of these screening tests; and 3 the test performance characteristics of these tests for detecting adenomatous polyps, advanced adenomas based on size, or both, as well as colorectal cancer.
In contrast to the evidence review performed for the USPSTF in , this review expanded its approach to additionally search for and consider 1 observational evidence about the benefits of screening tests when trial evidence does not exist and 2 comparative effectiveness of screening tests on cancer incidence and mortality. Compared with the previous decision analysis performed for the USPSTF, this analysis used more narrowly defined ages at which to begin and end screening and screening intervals.
All of the available studies of the test characteristics of different screening methods evaluated 1-time application of the test. As such, it is not possible to draw meaningful inferences about the ultimate performance of these tests as intended in a real-world setting ie, in a program of repeated screening over time.
Colonoscopy is generally considered the criterion standard for test characteristic studies, although it does miss some cases of colorectal cancer. No studies have evaluated the test performance characteristics of flexible sigmoidoscopy against a colonoscopy standard in an average-risk screening population. The Hemoccult II test was the first colorectal cancer screening test to demonstrate reduction in disease-specific mortality in an RCT. Flexible sigmoidoscopy has also been assessed in multiple RCTs. However, a combined approach of flexible sigmoidoscopy repeated every 10 years with annual FIT screening was estimated to result in about to life-years gained per 1, persons screened although it would also increase the total number of diagnostic and surveillance colonoscopies required.
In addition, it is unclear based on the study design whether the benefit accrued from 1 or multiple colonoscopies or screening plus surveillance colonoscopy. Overall, the study likely overestimates the magnitude of benefit associated with colonoscopy; the observed effect size in this study also cannot be directly compared with that measured in randomized trials of other colorectal cancer screening methods.
The CISNET models commissioned for this review estimated the number of life-years gained, colorectal cancer deaths averted, lifetime colonoscopies required as a proxy measure for the burden of screening , and resulting complications ie, gastrointestinal and cardiovascular events for various screening strategies, varying the age at which to start and stop screening and the frequency of screening.
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