Screening for colorectal cancer: possible improvements by risk assessment evaluation?

Emerging results indicate that screening improves survival of patients with colorectal cancer. Therefore, screening programs are already implemented or are being considered for implementation in Asia, Europe and North America. At present, a great variety of screening methods are available including colono- and sigmoidoscopy, CT- and MR-colonography, capsule endoscopy, DNA and occult blood in feces, and so on. The pros and cons of the various tests, including economic issues, are debated. Although a plethora of evaluated and validated tests even with high specificities and reasonable sensitivities are available, an international consensus on screening procedures is still not established. The rather limited compliance in present screening procedures is a significant drawback. Furthermore, some of the procedures are costly and, therefore, selection methods for these procedures are needed. Current research into improvements of screening for colorectal cancer includes blood-based biological markers, such as proteins, DNA and RNA in combination with various demographically and clinically parameters into a "risk assessment evaluation" (RAE) test. It is assumed that such a test may lead to higher acceptance among the screening populations, and thereby improve the compliances. Furthermore, the involvement of the media, including social media, may add even more individuals to the screening programs. Implementation of validated RAE and progressively improved screening methods may reform the cost/benefit of screening procedures for colorectal cancer. Therefore, results of present research, validating RAE tests, are awaited with interest.     

Successful colorectal cancer screening starts with primary care

Colorectal cancer screening is effective. Screening rates remain low, but that will change. All guidelines now recommend colorectal cancer screening, the value of screening is being promoted in the popular media, and insurers are beginning to pay for screening tests. For screening programs to be successful, good intentions must be backed by reminder systems, readily available patient information, and other changes in office practice. Currently recommended screening options accommodate a broad range of patient preferences and save lives, but none is ideal. Newer tests, such as virtual colonoscopy and stool-based DNA tests, will help if they offer greater sensitivity, specificity, or patient acceptability than current screening options.     

Gastrointestinal cancer screening: screening may release new research funding to improve health service also in routine clinics

Abstract

We are far from having seen the ideal method of screening for colorectal cancer (CRC) and the downsides of screening have not been fully addressed. Funding of adequately sized screening trials with a 10–15-year perspective for endpoints CRC mortality and incidence is difficult to get. Also, with such time horizons, there will always be an ongoing study to be awaited before feeling obliged to invest in the next. New, promising screening methods may, however, emerge far more often than every 10th year, and the knowledge gap may easily widen unless research is made a key responsibility for any ongoing cancer screening program. Previous lost battles on screening research may be won if accepting that scientific evidence may be obtained within the framework of screening programs – provided that they are designed as platforms for Comparative Effectiveness Research (CER). Accepting that CER-based screening programs should be preferred to non-CER programs and seriously compete for their funding sources, then CER screening programs may not be considered so much as contenders for ordinary clinical research funds. Also, CER within a screening framework may benefit patients in routine clinics as shown by screening research in Nordic countries. The Nordic countries have been early contributors to research on CRC screening, but slow in implementing screening programs.     

Survey of internal medicine residents' use of the fecal occult blood test and their understanding of colorectal cancer screening and surveillance

OBJECTIVE: Primary care physicians have imperfect understanding of current colorectal cancer screening guidelines and recommendations. Furthermore, compliance with colorectal cancer screening by internal medicine residents has been demonstrated to be poor. We sought to identify whether current trainees in internal medicine had adequate understanding of colorectal cancer screening and surveillance and test utilization. METHODS: We applied a structured questionnaire about colorectal cancer screening and the use of fecal occult blood tests to 168 internal medicine residents at four accredited programs in the U.S. They were also asked for recommendations about six hypothetical patients who may have been candidates for screening or surveillance. RESULTS: Seventy-one percent identified 50 yr as the currently recommended age to commence screening in an average-risk individual; 64.3% would begin screening with fecal occult blood testing and flexible sigmoidoscopy and 4.8% with colonoscopy. Most perform fecal occult blood testing on stool obtained at digital rectal exam and without prior dietary restrictions. Many use fecal occult blood testing for indications other than colorectal cancer screening. Only 29% recommended colonoscopy to evaluate a positive fecal occult blood test. Most residents plan to be screened for colorectal neoplasia at the appropriate age; significantly more opted for colonoscopy than recommended it for their patients. CONCLUSIONS: Internal medicine residents have many misperceptions regarding colorectal cancer screening and the utility of the fecal occult blood test. Educational efforts should be directed at internal medicine residents, many of whom plan careers in primary care, where most colorectal cancer screening is currently performed.     

Long-term effect of faecal occult blood screening on incidence and mortality from colorectal cancer

BackgroundSeveral randomized trials have shown a reduction of colorectal cancer mortality by screening using guaiac-based faecal occult blood tests. However, little is known on the long-term effect of screening at the population level in everyday practice.MethodsSmall-sized geographic areas including a total of 91,199 individuals were allocated to either biennal screening using the Hemoccult-II test or no screening. The expected mortality and incidence in the cohort invited to screening was determined using mortality and incidence in the non-screened population.ResultsColorectal cancer mortality was significantly lower in the population invited to screening than in the non-screened population after 11 screening rounds (standardized mortality ratio: 0.87; 0.80–0.94). The standardized mortality ratio remained significant whatever the duration of follow-up. This reduction in colorectal cancer mortality was more pronounced in those who participated in the first screening campaign, who were regular participants in screening rounds (standardized mortality ratio: 0.67; 0.59–0.76). In contrast, colorectal cancer incidence was not different between the screened and non-screened populations (standardized incidence ratio: 1.01; 0.96–1.06).ConclusionOur findings confirm, in the long term, that screening with Hemoccult can reduce colorectal cancer mortality. The data also highlight the benefit of regular participation in screening and the absence of effect of screening on colorectal cancer incidence.     

Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence

We have updated guidelines for screening for colorectal cancer. The original guidelines were prepared by a panel convened by the U.S. Agency for Health Care Policy and Research and published in 1997 under the sponsorship of a consortium of gastroenterology societies. Since then, much has changed, both in the research rature and in the clinical context. The present report summarizes new developments in this field and suggests how they should change practice. As with the previous version, these guidelines offer screening options and encourage the physician and patient to decide together which is the best approach for them. The guidelines also take into account not only the effectiveness of screening but also the risks, inconvenience, and cost of the various approaches. These guidelines differ from those published in 1997 in several ways: we recommend against rehydrating fecal occult blood tests; the screening interval for double contrast barium enema has been shortened to 5 years; colonoscopy is the preferred test for the diagnostic investigation of patients with findings on screening and for screening patients with a family history of hereditary nonpolyposis colorectal cancer; recommendations for people with a family history of colorectal cancer make greater use of risk stratification; and guidelines for genetic testing are included. Guidelines for surveillance are also included. Follow-up of postpolypectomy patients relies now on colonoscopy, and the first follow-up examination has been lengthened from 3 to 5 years for low-risk patients. If this were adopted nationally, surveillance resources could be shifted to screening and diagnosis. Promising new screening tests (virtual colonoscopy and tests for altered DNA in stool) are in development but are not yet ready for use outside of research studies. Despite a consensus among expert groups on the effectiveness of screening for colorectal cancer, screening rates remain low. Improvement depends on changes in patients' attitudes, physicians' behaviors, insurance coverage, and the surveillance and reminder systems necessary to support screening programs.     

Korean guidelines for colorectal cancer screening and polyp detection

Colorectal cancer is the second most common cancer in males and the fourth most common in females in Korea. Since the most of colorectal cancer occur through the prolonged transformation of adenomas into carcinomas, early detection and removal of colorectal adenomas are one of the most effective methods to prevent colorectal cancer. Considering the increasing incidence of colorectal cancer and polyps in Korea, it is very important to establish Korean guideline for colorectal cancer screening and polyp detection. Korean Multi-Society Take Force developed the guidelines with evidence-based methods. Parts of the statements drawn by systematic reviews and meta-analyses. Herein we discussed the epidemiology of colorectal cancers and adenomas in Korea, optimal screening methods for colorectal cancer, and detection for adenomas including fecal occult blood tests, radiologic tests, and endoscopic examinations.     

The Quebec Association of Gastroenterology position paper on colorectal cancer screening - 2003.

Colorectal cancer is a leading cause of death and the third most common cancer in Canada. Evidence suggests that screening can reduce mortality rates and the cost effectiveness of a program compares favourably with initiatives for breast and cervical cancer. The objectives of the Association des gastro-entérologues du Québec Task Force were to determine the need for a policy on screening for colorectal cancer in Quebec, to evaluate the testing methods available and to propose one or more of these alternatives as part of a formal screening program, if indicated. Fecal occult blood testing (FOBT), endoscopy (including sigmoidoscopy and colonoscopy), barium enema and virtual colonoscopy were considered. Although most clinical efficacy data are available for FOBT and sigmoidoscopy, there are limitations to programs based on these strategies. FOBT has a high false positive rate and a low detection yield, and even a combination of these strategies will miss 24% of cancers. Colonoscopy is the best strategy to both detect and remove polyps and to diagnose colorectal cancer, with double contrast barium enema also being a sensitive detection method. The Task Force recommended the establishment, in Quebec, of a screening program with five- to 10-yearly double contrast barium enema or 10-yearly colonoscopy for individuals aged 50 years or older at low risk. The program should include outcome monitoring, public and professional education to increase awareness and promote compliance, and central coordination with other provincial programs. The program should be evaluated; specific billing codes for screening for colorectal cancer would help facilitate this. Formal feasibility, effectiveness and cost-effectiveness studies in Quebec are now warranted.     

Ethical issues in colorectal cancer screening

In many countries, colorectal cancer screening is currently an established population screening program due to the evidence on its reduction of colorectal cancer mortality. There is general consensus that colorectal cancer screening meets the screening criteria as proposed by Wilson and Jungner. However, as for all population screening programs, colorectal cancer screening also has disadvantages and thereby entails ethical issues. There are the general issues concerning the introduction of screening programs (e.g. medicalization, overdiagnosis and overtreatment, information provision to screenees), evaluation of cancer screening programs (e.g. lead time and length bias), chosen screening method (e.g. false-positive and false-negative test results, reduction of all-cause mortality, choice between different screening methods). The different colorectal cancer screening methods and the ethical issues concerning colorectal cancer screening will be discussed in this review.     

Colorectal cancer screening 2000: The role of colonoscopy in average-risk individuals

Colorectal cancer fulfills all of the criteria of a disease process that is suitable for a screening program. Several screening tests are effective in preventing mortality from colorectal cancer and are widely recommended. Despite the lack of direct comparisons, there is compelling indirect evidence that programs using colonoscopy as the primary tool are likely to be more effective than programs using fecal occult blood testing or flexible sigmoidoscopy as initial strategies. Colonoscopy-first programs are more expensive initially, but their cost effectiveness may prove to be comparable with the currently recommended programs in certain settings.     

Positivity rates and performances of immunochemical faecal occult blood tests at different cut-off levels within a colorectal cancer screening programme

BackgroundImmunochemical faecal occult blood tests have greater sensitivity for colorectal cancer screening than guaiac-based tests; however the number of positive tests required is still under discussion.MethodsA direct comparison of Hemoccult II with two immunochemical quantitative tests (OC-Sensor and FOB-Gold) using a 2-sample strategy was performed in over 30,000 patients undergoing colorectal cancer screening in France.ResultsPositivity ratio between immunochemical tests and Hemoccult II varied between 2.2 (OC-Sensor) and 2.4 (FOB-Gold) for the lowest cut-off value and 1.5–1.4 for the highest cut-off value. The positive predictive value for colorectal cancer was similar for immunochemical tests and Hemoccult II, and significantly higher for immunochemical tests for advanced adenomas. The detection rate of both colorectal cancer and advanced adenomas was higher with immunochemical tests than with Hemoccult II. With the 2-sample strategy and the lowest cut-off value the detection rate of colorectal cancer almost doubled and for advanced adenomas quadrupled.ConclusionFor colorectal cancer screening with immunochemical faecal occult blood tests, an acceptable strategy would be 2-day sampling with at least one positive test at a cut-off between 150 and 200 ng/mL (OC-Sensor) and 176 and 234 ng/mL (FOB-Gold). Data on the ease of test interpretation and cost-effectiveness now necessary to make definitive choices.     

A New Risk-Scoring System for Colorectal Cancer and Polyp Screening by Turkish Colorectal Cancer and Polyp Study Group

Background:Colorectal cancer is one of the most commonly diagnosed types of cancer worldwide. An early diagnosis and detection of colon cancer and polyp can reduce mortality and morbidity from colorectal cancer. Even though there are a variety of options in screening tests, the question remains on which test is the most effective for the early detection of colorectal cancer. In this prospective study, we aimed to develop a simple, useful, effective, and reliable scoring system to detect colon polyp and colorectal cancer.Methods:We enrolled 6508 subjects over the age of 18 from 16 centers, with colonoscopy screening. The age, smoking status, alcohol consumption, body mass index, polyp incidence, polyp size, number and localization, and pathologic findings were recorded.Results:The age, male gender, obesity, smoking, and family history were found as independent risk factors for adenomatous polyp. We have developed a new scoring system which can be used for these factors. With a score of 4 or above, we found the following: sensitivity 81%, specificity 40%, positive predictive value 25.68%, and negative predictive value 89.84%, for adenomatous polyp detection; and sensitivity 96%, specificity 39%, positive predictive value 3.35%, negative predictive value 99.29%, for colorectal cancer detection.Conclusion:Even though the first colorectal cancer screening worldwide is generally performed for individuals over 50 years of age, we recommend that screening for colorectal cancer might begin for those under 50 years of age as well. Individuals with a score ≥ 4 must be included in the screening tests for colorectal cancer.     

Continuous quality improvement of colorectal cancer screening

Quality assurance is a key issue in colorectal cancer screening, because effective screening is able to improve primary prevention of the cancer. The quality measure may be described in terms:how well the screening test tells who truly has a disease (sensitivity) and who truly does not have a disease (specificity). This paper raises concerns about identification of the optimal screening test for colorectal cancer. Colonoscopy vs flexible sigmoidoscopy in colorectal cancer screening has been a source of ongoing debate. A multicentre randomised controlled trial comparing flexible sigmoidoscopy with usual care showed that flexible sigmoidoscopy screening is able to diminish the incidence of distal and proximal colorectal cancer, and also mortality related to the distal colorectal cancer. However, colonoscopy provides a more complete examination and remains the more sensitive exam than flexible sigmoidoscopy. Moreover, colonoscopy with polypectomy significantly reduces colorectal cancer incidence and colorectal cancer-related mortality in the general population. The article considers the relative merits of both methods and stresses an ethical aspect of patient’s involvement in decision-making. Patients should be informed not only about tests tolerability and risk of endoscopy complications, but also that different screening tests for bowel cancer have different strength to exclude colonic cancer and polyps. The authorities calculate effectiveness and costs of the screening tests, but patients may not be interested in statistics regarding flexible sigmoidoscopy screening and from an ethical point of view, they have the right to chose colonoscopy, which is able to exclude a cancer and precancerous lesions in the whole large bowel.     

Guidelines for colorectal cancer screening--a puzzle of tests and strategies

Colorectal cancer (CRC) is a leading cause of cancer death around the World. An effective way to reduce colorectal cancer mortality is to screen for it and its precursor, the adenoma. In industrialized countries the mortality related to CRC is decreasing probably due to better screening programmes in average-risk individuals as well as changes in risk factors. Screening procedures are various including faecal screening tests--which primarily detect colon cancer--and structural tests (endoscopy--flexible sigmoidoscopy or colonoscopy--, Barium enema, Computed Tomography Colonography) that may detect not only cancer but also its precursors. Video-colon capsule is a new tool for exploring the colon but needs further studies before becoming a screening test. The choice of a screening test includes several factors as cost, invasiveness, acceptability, adherence to repeat testing and acceptance referral for colonoscopy for positive tests as well as local financial resources. Every screening programme has advantages and limitations. Enhancing use and quality of CRC screening programmes is mandatory.     

Population screening for colorectal cancer: advantages and drawbacks

Screening for colorectal cancer (CRC) has been shown to reduce mortality from the disease as well as incidence. Several methods for screening are available, but none are ideal. The present short review discusses the advantages and drawbacks using fecal occult blood tests (FOBTs), fecal DNA tests, flexible sigmoidoscopy (FS), colonoscopy, double contrast barium enema, and computed tomographic colonoscopy. The use of FOBTs with following colonoscopy in persons with a positive test has been shown to reduce mortality as well as the incidence of CRC in several randomized trials. It is likely that other methods will do the same, but it is not clear how large the benefit will be. Repeated testing is necessary for FOBTs and DNA tests as well as FS, and a high degree of acceptability is crucial for the effectivity of all tests in a national program. National services may be subject to variations in enthusiasm and expertise, resulting in varying acceptability and number of complications. It is recommended to perform pilot studies in limited populations (as in the UK) before embarking on a screening program on a national level.     

国内外结直肠癌筛查的对比分析及启示

我国结直肠癌的发病率和死亡率在逐年升高,严重威胁人民群众的健康,亟待采取行之有效并且适合我国国情的结直肠癌筛查策略,从而降低结直肠癌的疾病负担。目前面临的突出问题是,我国人群结直肠癌筛查项目覆盖尚不广泛,方法并不统一,有待形成完善的国家结直肠癌筛查体系。建立筛查体系的作用在于发现癌前病变和早期病例,从而降低发病率并提高早期病例构成比,具有很重要的卫生经济学意义。本文结合国内外最新指南共识,阐述国内外结直肠癌筛查的历程和现状,比较了结直肠癌筛查常用的方法,并对我国筛查的发展提出了展望,以期未来能够建立具有我国特色的结直肠癌筛查策略。     

Screening auf Kolorektal-, Haut-, Brust- und Prostatakrebs

The major goal of cancer screening programs is the reduction of disease-specific mortality by detecting malignant tumors in an early and still curable stage. Sensitive screening tests are used in apparently healthy people and conspicuous findings are referred for further investigations. Taking the personal disease risk into account, persons considering participation in a screening program should be informed about the methods, benefits and disadvantages of the screening program. This information, together with personal preferences, is the basis for a well-informed decision for or against participation in a screening program. This article imparts essential knowledge that is needed for individual medical counseling on screening for colorectal, skin, breast and prostate cancer.     

Früherkennung des kolorektalen Karzinoms

Colorectal cancer is one of the leading causes of cancer-related morbidity and mortality. Colorectal cancer commonly develops slowly via adenomatous polyps, a process usually requiring ≥?10 years. This allows for early detection. Endoscopic polypectomy and surgery of early disease can reduce the incidence and mortality of colorectal cancer. Both hemoccult testing and colonoscopy are the most widely used tests for colorectal cancer screening; however, colonoscopy has the highest sensitivity for colorectal neoplasia. Sigmoidoscopy is not commonly used for screening in Germany. Colon contrast enema is no longer recommended for screening. As colonoscopy serves as a diagnostic and therapeutic tool and is the reference method in hemoccult and sigmoidoscopy studies, it is viewed as the gold standard for the diagnosis of colonic disease. New methods including capsule colonoscopy and virtual colonoscopy have great potential but are currently not recommended for early detection of colonic neoplasia.     

Früherkennung des kolorektalen Karzinoms

Colorectal cancer is one of the leading causes of cancer-related morbidity and mortality. Colorectal cancer commonly develops slowly via adenomatous polyps, a process usually requiring ≥?10 years. This allows for early detection. Endoscopic polypectomy and surgery of early disease can reduce the incidence and mortality of colorectal cancer. Both hemoccult testing and colonoscopy are the most widely used tests for colorectal cancer screening; however, colonoscopy has the highest sensitivity for colorectal neoplasia. Sigmoidoscopy is not commonly used for screening in Germany. Colon contrast enema is no longer recommended for screening. As colonoscopy serves as a diagnostic and therapeutic tool and is the reference method in hemoccult and sigmoidoscopy studies, it is viewed as the gold standard for the diagnosis of colonic disease. New methods including capsule colonoscopy and virtual colonoscopy have great potential but are currently not recommended for early detection of colonic neoplasia.     

The effects of promoting colorectal cancer screening on screening utilisation: evaluation of the German Campaign "Aktiv gegen Darmkrebs" (Action against Colorectal Cancer)

BACKGROUND: Although colorectal cancer is the second leading cause of cancer death in Germany, screening rates remain low. It is unknown whether local approaches to promoting colorectal cancer screening are effective. This study evaluates the effectiveness of a regional awareness campaign consisting of public information sessions and leaflet distribution, upon the use of colorectal cancer screening by faecal occult blood test (FOBT) and colonoscopy. METHODS: Data on FOBT and colonoscopy were collected by doctors for 12 months following the campaign, including reason for and result of the testing. 37 % (n = 43) of all physicians and practitioners in two administrative districts (249 632 inhabitants) that were exposed to the campaign participated in the study. It was recorded whether the individuals requesting colorectal cancer screening had been prompted by the campaign, so the number and outcome of campaign-related tests was determined. RESULTS: 3398 individuals (male: 54.6 %, female: 45.4 %, age: 64.3 +/- 8.3 years) underwent 3551 screening tests (2446 FOBT, 819 colonoscopy, 133 both). 141 additional diagnostic colonoscopies were performed because of a positive result in the FOBT. Adenomas were detected in 279 individuals, malignancies in 11 individuals. 225 FOBT (8.7 %) and 176 colonoscopies (18.5 %) were performed due to the campaign; among these individuals, 49 had adenoma(s), 1 had carcinoma. The effect could be attributed both to leaflets and to information sessions. The proportion of campaign-related screening tests declined over time. CONCLUSION: The regional information campaign could reach target individuals and motivate them to utilise colorectal cancer screening. The combination of mass media and personal communicative elements seems useful.