Strategies in screening for colon carcinoma

Colorectal cancer is the second most common cancer in Europe and meets the criteria for population screening. Population screening should lead to a reduction in CRC-related mortality and incidence. Several options are available for CRC screening, which can be itemised as stool-based tests and structural exams. Stool-based tests include guaiac and immunochemical faecal occult blood tests and DNA -marker tests. Structural exams comprise endoscopic techniques (flexible sigmoidoscopy, colonoscopy and capsule endoscopy) and radiological exams (double contrast barium enema, CT colonography and MR colonography). Each test has its own test performance characteristics and acceptability profile, which affect the participation and effectiveness of the associated screening programmes. Faecal occult blood tests (FOBT ) and flexible sigmoidoscopy (FS) are the only methods with a demonstrated mortality reduction during a ten-year period (FOBT 16% and FS 31%) while flexible sigmoidoscopy is the only screening test with a demonstrated reduction in CRC incidence (23%). It is likely that other screening techniques such as colonoscopy and CT colonography will also be effective in the reduction of CRC-related mortality. DNA -marker tests, capsule endoscopy and MR colonography are possible options for the future.     

The Norwegian Colorectal Cancer Prevention (NORCCAP) screening study: baseline findings and implementations for clinical work-up in age groups 50-64 years

BACKGROUND: Randomized controlled trials of sufficient power testing the long-term effect of screening for colorectal neoplasia only exist for faecal occult blood testing (FOBT). There is indirect evidence that flexible sigmoidoscopy (FS) may have a greater yield. The aim of this study was to determine the diagnostic yield of screening with FS or a combination of FS and FOBT in an average-risk population in an urban and combined urban and rural population in Norway. METHODS: 20,780 men and women (1:1), aged 50-64 years, were invited for once-only screening (FS only or a combination of FS and FOBT (1:1)) by randomization from the population registry. A positive FS was defined as a finding of any neoplasia or any polyp > or = 10 mm. A positive FS or FOBT qualified for colonoscopy. RESULTS: Overall attendance was 65%. Forty-one (0.3%) cases of CRC were detected. Any adenoma was found in 2208 (17%) participants and 545 (4.2%) had high-risk adenomas. There was no difference in diagnostic yield between the FS and the FS and FOBT group regarding CRC or high-risk adenoma. Work-up load comprised 2821 colonoscopies in 2524 (20%) screenees and 10% of screenees were recommended later colonoscopy surveillance. There were no severe complications at FS, but six perforations after therapeutic colonoscopy (1:336). CONCLUSIONS: The present study bodes well for future management of a national screening programme, provided that follow-up results reflect adequate proof of a net benefit. It is highly questionable whether the addition of once-only FOBT to FS will contribute to this effect.     

The Norwegian Colorectal Cancer Prevention (NORCCAP) Screening Study

Background: Randomized controlled trials of sufficient power testing the long-term effect of screening for colorectal neoplasia only exist for faecal occult blood testing (FOBT). There is indirect evidence that flexible sigmoidoscopy (FS) may have a greater yield. The aim of this study was to determine the diagnostic yield of screening with FS or a combination of FS and FOBT in an average-risk population in an urban and combined urban and rural population in Norway. Methods: 20,780 men and women (1:1), aged 50-64 years, were invited for once-only screening (FS only or a combination of FS and FOBT (1:1)) by randomization from the population registry. A positive FS was defined as a finding of any neoplasia or any polyp &#83 10 &#114 mm. A positive FS or FOBT qualified for colonoscopy. Results: Overall attendance was 65%. Forty-one (0.3%) cases of CRC were detected. Any adenoma was found in 2208 (17%) participants and 545 (4.2%) had high-risk adenomas. There was no difference in diagnostic yield between the FS and the FS and FOBT group regarding CRC or high-risk adenoma. Work-up load comprised 2821 colonoscopies in 2524 (20%) screenees and 10% of screenees were recommended later colonoscopy surveillance. There were no severe complications at FS, but six perforations after therapeutic colonoscopy (1:336). Conclusions: The present study bodes well for future management of a national screening programme, provided that follow-up results reflect adequate proof of a net benefit. It is highly questionable whether the addition of once-only FOBT to FS will contribute to this effect.     

Asia Pacific consensus recommendations for colorectal cancer screening

Colorectal cancer (CRC) is rapidly increasing in Asia, but screening guidelines are lacking. Through reviewing the literature and regional data, and using the modified Delphi process, the Asia Pacific Working Group on Colorectal Cancer and international experts launch consensus recommendations aiming to improve the awareness of healthcare providers of the changing epidemiology and screening tests available. The incidence, anatomical distribution and mortality of CRC among Asian populations are not different compared with Western countries. There is a trend of proximal migration of colonic polyps. Flat or depressed lesions are not uncommon. Screening for CRC should be started at the age of 50 years. Male gender, smoking, obesity and family history are risk factors for colorectal neoplasia. Faecal occult blood test (FOBT, guaiac-based and immunochemical tests), flexible sigmoidoscopy and colonoscopy are recommended for CRC screening. Double-contrast barium enema and CT colonography are not preferred. In resource-limited countries, FOBT is the first choice for CRC screening. Polyps 5-9 mm in diameter should be removed endoscopically and, following a negative colonoscopy, a repeat examination should be performed in 10 years. Screening for CRC should be a national health priority in most Asian countries. Studies on barriers to CRC screening, education for the public and engagement of primary care physicians should be undertaken. There is no consensus on whether nurses should be trained to perform endoscopic procedures for screening of colorectal neoplasia.     

Colorectal cancer screening

Colorectal cancer (CRC) is the third most common cause of cancer death worldwide and a major health problem. In this review, the different approaches for CRC screening will be outlined with emphasis on evidence-based medicine. Evidence from randomized trials on the effectiveness of CRC screening is summarized. Several screening tools for CRC are available. They can be categorized according to their mode of action: early detection tools such as the faecal occult blood test (FOBT) and cancer prevention tools such as flexible sigmoidoscopy and colonoscopy. Meta-analyses of randomized trials show that FOBT screening reduces CRC mortality by 16% (risk ratio 0.84; 95% confidence interval (CI) 0.78-0.9) compared with 30% (risk ratio 0.7; 95% CI 0.6-0.81) for flexible sigmoidoscopy screening. FOBT screening is cheap and noninvasive, but results in large numbers of false-positive tests and needs to be repeated frequently. Flexible sigmoidoscopy is more invasive, but is effective for once-only screening. Although colonoscopy screening is used in some countries, no randomized trials have been conducted to estimate its benefit, and therefore, it should not be recommended at the present time. Faecal occult blood test and flexible sigmoidoscopy are the two CRC screening tools that can be recommended as they have been proven to reduce CRC mortality. Colonoscopy has the potential to be superior to FOBT and flexible sigmoidoscopy, but needs to be evaluated in randomized trials before any recommendation can be provided.     

Screening for colorectal cancer in Chinese: comparison of fecal occult blood test,flexible sigmoidoscopy,and colonoscopy

BACKGROUND AND AIMS: Fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), and colonoscopy are the most commonly recommended screening tests for colorectal cancer. The aim of this study was to compare the accuracy and safety of these 3 screening procedures in a general population of ethnic Chinese. METHODS: Asymptomatic adults older than 50 years were recruited from the general public through health exhibitions. All enrolled subjects were offered FOBT and full colonoscopy under sedation. Advanced colonic lesions (defined as adenoma > or = 10 mm, villous adenoma, adenoma with moderate or severe dysplasia, or invasive cancer) were recorded. Lesions at the distal 40 cm in the left colon and rectum were taken as findings of FS. RESULTS: A total of 505 subjects (56% women; mean age +/- SD, 56.5 +/- 5.4 years) were enrolled, and 476 (94.3%) had a complete colonoscopy. Advanced colonic neoplasms were documented in 63 subjects (12.5%), of which 45 had lesions in the distal colon and 26 in the proximal colon. Among the 385 subjects with a normal distal colon, 14 (3.6%) had advanced lesions in the proximal colon that would be missed by FS alone. The sensitivity and specificity of FOBT for advanced colonic lesions were 14.3% and 79.2% and the sensitivity and specificity of FS were 77.8% and 83.9%, respectively. Combining FOBT with FS would not significantly improve the results of FS alone. Among these 505 subjects who underwent colonoscopy and 148 who underwent polypectomy, there was no perforation and only one occurrence of postpolypectomy bleeding recorded. CONCLUSIONS: Colonoscopy is a safe and accurate method for the screening of colorectal neoplasms in Chinese subjects.     

Screening for colorectal cancer

A review of the literature regarding the screening strategies for colorectal cancer (CRC), particularly for average risk individuals, is analysed. The advantages and disadvantages or limitations of screening modalities for CRC, such as faecal occult blood testing (FOBT) with guaiac-based tests or the new faecal deoxyribonucleic acid tests, endoscopic screening by flexible sigmoidoscopy, colonoscopy, or CT-colonography and double contrast barium enema examination, are reported. The efficacy and cost of the screening tests are evaluated, and it is found that any of the suggested tests is more cost effective than other medical intervention or treatment as compared with no screening. The reported compliance to any form of screening test was 30-40%, a rate that is low enough. The experience of our surgical department of a screening programme, based on FOBT, on 4189 individuals over 50 years old, and application of colonoscopy in positive subjects, is reported.     

Are Physicians’ Recommendations For Colorectal Cancer Screening Guideline-Consistent?

BACKGROUND  

Many older adults in the U.S. do not receive appropriate colorectal cancer (CRC) screening. Although primary care physicians’ recommendations to their patients are central to the screening process, little information is available about their recommendations in relation to guidelines for the menu of CRC screening modalities, including fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), colonoscopy, and double contrast barium enema (DCBE). The objective of this study was to explore potentially modifiable physician and practice factors associated with guideline-consistent recommendations for the menu of CRC screening modalities.     

Flexible sigmoidoscopy as a screening test for colorectal cancer

Flexible sigmoidoscopy (FS) is one of the screening modalities for colorectal cancer. The rationale for screening with flexible sigmoidoscopy is that it provides direct visualisation of the colon, and suspicious lesions can be biopsied. The most obvious disadvantage is that it examines only the lower third of the colon. The technical aspects of FS are sufficiently clear to enable us to define what FS can and cannot do. From the point of view of screening, FS clearly cannot completely exclude the presence of colon cancer in all asymptomatic people. A distinction must be made between screening the general population and testing the individual seeking screening. For the former, obtaining the greatest mortality benefit safely and at an acceptable cost to the nation is the crux of the matter. Recently published data indicate that FS is a cost-effective screening strategy, although colonoscopy and annual fecal occult blood test avert a greater number of cancer deaths. The results of randomised controlled trials of screening FS and colonoscopy, currently being conducted, will allow us to make a more accurate comparison with the established data regarding fecal occult blood test. In conclusion, flexible sigmoidoscopy every 5 years with or without FOBT is one of the screening methods recommended by major professional organizations. It identifies 50 to 70% of the advanced neoplasms, if any discovery of a distal neoplasia is followed up with a total examination of the colon by colonoscopy.     

Colon cancer prevention in Italy: Cost-effectiveness analysis with CT colonography and endoscopy

BACKGROUND: Colorectal cancer (CRC) is a major cause of mortality in Italy. Although prevention of CRC is possible, its cost-effectiveness when applied to the Italian population is unknown. Recently, computerized tomographic colonography (CTC) has been proposed for CRC screening. AIM: To compare the efficacy and cost-effectiveness of CTC screening in a simulated Italian population with those of colonoscopy and flexible sigmoidoscopy (FS). METHODS: The cost-effectiveness of different screening strategies was compared using a Markov process computer model, in which in a hypothetical population of 100,000 50 year-olds were investigated by CTC, colonoscopy or FS every decade. Outcomes were projected to the Italian national level. RESULTS: CRC incidence reduction was calculated at 40.9%, 38.2%, and 31.8% with colonoscopy, CTC and FS, respectively. As compared to no screening, all screening programs were shown to be cost-saving, allowing a saving of 11 Euro, 17 Euro, and 48 Euro per person with colonoscopy, FS and CTC, respectively. FS appeared to be less cost-effective than CTC, whilst colonoscopy appeared to be an expensive option as compared to CTC. Undiscounted national expenditure was calculated to be 1,042,489,512 Euro, 1,093,268,285 Euro, and 1,198,783,428 Euro for FS, CTC and colonoscopy, respectively, as compared to 695,818,078 Euro without screening. CONCLUSION: CRC screening is cost-saving in Italy, irrespective of the technique applied. CTC appeared to be more cost-effective than FS, and it may also become a valid alternative to colonoscopy.     

Design,organization and management of a controlled population screening study for detection of colorectal neoplasia: attendance rates in the NORCCAP study (Norwegian Colorectal Cancer Prevention)

BACKGROUND: In the past three decades, the incidence of colorectal cancer (CRC) in Norway has doubled, surpassing all other Nordic countries for both men and women to become the most frequently diagnosed cancer. A small-scale, randomized study on flexible sigmoidoscopy (FS) screening in Telemark, Norway, has shown a reduction in accumulated CRC incidence after 13 years. The aim of our study was to evaluate the effect on CRC mortality and morbidity by screen detection of CRC and removal of precursor lesions (polypectomy), and to test out the management and organization mimicking a countrywide screening service. A total of 13,823 men and women (1:1), age 55-64 years, were drawn randomly from the population registries in Oslo (urban) and the county of Telemark (mixed urban and rural) and invited to have a screening examination. The rest of the relevant age cohorts constituted the control groups. In the screening group, 535 individuals were excluded according to exclusion criteria, rendering 13,288 individuals eligible for screening examination. METHODS: A once only screening model was used. In the screening group, individuals were randomized to have a once only FS or a combination of FS and faecal occult blood test (FOBT). RESULTS: The overall attendance rate was 8,849 out of 13,288 (67%); 73% in Telemark and 60% in Oslo. Attendance for FS only was 68% and 65% for combined FS&FOBT. CONCLUSIONS: The present FSIFS&FOBT screening study obtained a high acceptance rate for both screening modalities. The attendance rate was stable throughout the trial, suggesting an acceptable model for management of future countrywide screening.     

Screening programs for sporadic colorectal carcinoma

In developed countries colorectal cancer (CRC) is the second most frequent organ malignancy of both genders. According to the world statistics Czech Republic occupies the top position in incidence of this disease. Approximately 75% of all CRC are the sporadic CRC in subjects with negative family or personal history of the disease. The low (average) risk factor in these subjects is age over 50 years, from which the incidence of CRC nearly doubles in each decade. The following options of screening are available for these subjects: 1. faecal occult blood test (FOBT), 2. flexible sigmoidoscopy, 3. combination of both previous procedures, 4. colonoscopy, 5. virtual colonography. FOBT is the mostly used programme in asymptomatic subjects over age 50 at one-year or at least two-years intervals. In FOBT-positive persons colonoscopy is considered the optimal diagnostic and in the case of polyps also therapeutic method. Prospective randomized studies proving a decrease of CRC-mortality in the range of 15-33% are available only for this type of programme. Screening of sporadic CRC was introduced on national basis in Federal Republic Germany in 1977 and in Czech Republic since the second half of the year 2000. With so many people dying of the disease, we cannot afford not to do its screening.     

Fecal DNA testing compared with conventional colorectal cancer screening methods: a decision analysis

BACKGROUND & AIMS: Fecal DNA testing is an emerging tool to detect colorectal cancer (CRC). Our aims were to estimate the clinical and economic consequences of fecal DNA testing vs. conventional CRC screening. METHODS: Using a Markov model, we estimated CRC incidence, CRC mortality, and discounted cost/life-year gained for screening by fecal DNA testing (F-DNA), fecal occult blood testing (FOBT) and/or sigmoidoscopy, or colonoscopy (COLO) in persons at average CRC risk from age 50 to 80 years. RESULTS: Compared with no screening, F-DNA at a screening interval of 5 years decreased CRC incidence by 35% and CRC mortality by 54% and gained 4560 life-years per 100,000 persons at USD $47,700/life-year gained in the base case. However, F-DNA gained fewer life-years and was more costly than conventional screening. The average number of colonoscopies per person was 3.8 with COLO and 0.8 with F-DNA. In most 1-way sensitivity analyses and Monte Carlo simulation iterations, F-DNA remained reasonably cost-effective compared with no screening, but COLO and FOBT dominated F-DNA. Assuming fecal DNA testing sensitivities of 65% for CRC and 40% for large polyp, and 95% specificity, a screening interval of 2 years and a test cost of USD $195 would be required to make F-DNA comparable with COLO. CONCLUSIONS: Fecal DNA testing every 5 years appears effective and cost-effective compared with no screening, but inferior to other strategies such as FOBT and COLO. Fecal DNA testing could decrease the national CRC burden if it could improve adherence with screening, particularly where the capacity to perform screening colonoscopy is limited.     

Predictive value of diminutive colonic adenoma trial: the PREDICT trial.

BACKGROUND & AIMS: Diminutive adenomas (1-9 mm in diameter) are frequently found during colon cancer screening with flexible sigmoidoscopy (FS). This trial assessed the predictive value of these diminutive adenomas for advanced adenomas in the proximal colon. METHODS: In a multicenter, prospective cohort trial, we matched 200 patients with normal FS and 200 patients with diminutive adenomas on FS for age and gender. All patients underwent colonoscopy. The presence of advanced adenomas (adenoma >or= 10 mm in diameter, villous adenoma, adenoma with high grade dysplasia, and colon cancer) and adenomas (any size) was recorded. Before colonoscopy, patients completed questionnaires about risk factors for adenomas. RESULTS: The prevalence of advanced adenomas in the proximal colon was similar in patients with diminutive adenomas and patients with normal FS (6% vs. 5.5%, respectively) (relative risk, 1.1; 95% confidence interval [CI], 0.5-2.6). Diminutive adenomas on FS did not accurately predict advanced adenomas in the proximal colon: sensitivity, 52% (95% CI, 32%-72%); specificity, 50% (95% CI, 49%-51%); positive predictive value, 6% (95% CI, 4%-8%); and negative predictive value, 95% (95% CI, 92%-97%). Male gender (odds ratio, 1.63; 95% CI, 1.01-2.61) was associated with an increased risk of proximal colon adenomas. CONCLUSIONS: Diminutive adenomas on sigmoidoscopy may not accurately predict advanced adenomas in the proximal colon.     

Design,Organization and Management of a Controlled Population Screening Study for Detection of Colorectal Neoplasia: Attendance Rates in the NORCCAP Study (Norwegian Colorectal Cancer Prevention)

Background: In the past three decades, the incidence of colorectal cancer (CRC) in Norway has doubled, surpassing all other Nordic countries for both men and women to become the most frequently diagnosed cancer. A small-scale, randomized study on flexible sigmoidoscopy (FS) screening in Telemark, Norway, has shown a reduction in accumulated CRC incidence after 13 years. The aim of our study was to evaluate the effect on CRC mortality and morbidity by screen detection of CRC and removal of precursor lesions (polypectomy), and to test out the management and organization mimicking a countrywide screening service. A total of 13,823 men and women (1:1), age 55-64 years, were drawn randomly from the population registries in Oslo (urban) and the county of Telemark (mixed urban and rural) and invited to have a screening examination. The rest of the relevant age cohorts constituted the control groups. In the screening group, 535 individuals were excluded according to exclusion criteria, rendering 13,288 individuals eligible for screening examination. Methods: A once only screening model was used. In the screening group, individuals were randomized to have a once only FS or a combination of FS and faecal occult blood test (FOBT). Results: The overall attendance rate was 8,849 out of 13,288 (67%); 73% in Telemark and 60% in Oslo. Attendance for FS only was 68% and 65% for combined FS&FOBT. Conclusions: The present FS/FS&FOBT screening study obtained a high acceptance rate for both screening modalities. The attendance rate was stable throughout the trial, suggesting an acceptable model for management of future countrywide screening.     

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.     

Colorectal cancer screening compliance by medicine residents: perceived and actual

OBJECTIVE: Implementation of colorectal cancer (CRC) screening with widely available techniques can result in a significant reduction in CRC-related mortality. Clinical practice paradigms are often ingrained in physicians during residency. We, therefore, investigated both compliance and perceived obstacles to CRC screening in the practices of physicians-in-training. METHODS: We conducted a retrospective analysis of medical records of patients who were receiving their primary care in the internal medicine resident clinics at the University of Nebraska Medical Center and were at average risk for CRC. In addition to demographics, data on the use of screening mammography, Pap smear, cholesterol, fecal occult blood testing (FOBT), and flexible sigmoidoscopy (FS) were collected. A questionnaire was also distributed to all internal medicine residents to assess their CRC screening knowledge and perceived screening compliance. RESULTS: One hundred eight patient charts were reviewed. The percentage of patients appropriately screened for each test was as follows: mammography 66%, Pap smear 65%, cholesterol 53%, FOBT 13%, and FS 16%. Residents dramatically overestimated their perceived FS and FOBT screening rates, 78% and 88%, respectively. Most residents identified barriers to FS screening. Although rudimentary CRC screening knowledge appeared adequate, a number of knowledge-based deficiencies were identified. CONCLUSIONS: Internal medicine residents at our institution demonstrate poor CRC screening compliance especially when compared with other health care maintenance interventions. This cannot be entirely accounted for by inadequate knowledge; discrepancy between the perceived and actual implementation of CRC screening may be important. Efforts to improve screening compliance should include a focus on physicians-in-training.     

A population-based estimate of the extent of colorectal cancer screening in Ontario

BACKGROUND/OBJECTIVE: The incidence and mortality rates for colorectal cancer (CRC) in Canada are among the highest in the world. For individuals >/=50 yr, CRC screening is effective in reducing both CRC incidence and mortality. The goal of this research was to conduct a Canadian population-based study of the use of tests and procedures to evaluate the large bowel to estimate the extent of CRC screening. METHODS: We identified an inception cohort of all residents of Ontario aged 50-59 on January 1, 1995, without a previous history of CRC or large-bowel evaluation by five tests or procedures: fecal occult blood test (FOBT), barium enema, rigid sigmoidoscopy, flexible sigmoidoscopy, and colonoscopy. We followed these individuals to December 31, 2000, identified all tests received, and determined the proportion that received one or more tests or procedures of each type. Data were obtained from three sources: the Ontario Health Insurance Plan (OHIP) database, the Canadian Institute for Health Information-Discharge Abstract Database (CIHI-DAD), and the Registered Persons Database (RPDB). RESULTS: We identified 982,443 individuals in our inception cohort without prior CRC or large bowel evaluation. The proportion that had at least one test or procedure was less than 10% for each type. The largest proportion (9.3%) had one or more FOBTs. Classified according to the initial test received, 14.5% had a non-endoscopic test (FOBT, barium enema) and 6% had an endoscopic test (rigid sigmoidoscopy, flexible sigmoidoscopy, colonoscopy). The majority (79.5%) had no test or procedure to evaluate the large bowel. CONCLUSION: An extraordinarily low proportion (<20.5%) of screen-eligible 50-59-yr-old men and women in Ontario were screened for CRC during a 6-yr follow-up. Given the high burden of CRC in Canada a major opportunity exists to improve the health of Canadians by increasing our screening efforts.     

Flexible sigmoidoscopy may be ineffective for secondary prevention of colorectal cancer in asymptomatic,average-risk men

Asymptomatic men (N=114) 50 years of age or older had screening for colorectal neoplasia with flexible sigmoidoscopy followed by colonoscopy regardless of the sigmoidoscopic result. Our study objective was to determine the prevalence of patients having isolated adenomatous polyps in a proximal colonic segment in the absence of a distal index neoplasm within reach of the sigmoidoscope. Through the combined use of sigmoidoscopy and colonoscopy, adenomatous polyps were detected in 47 of 114 individuals (41%). A total of 88 adenomas was found. Seventeen patients had isolated neoplasms in proximal colonic segments in the absence of distal adenomas. These patients represented 15% of screened subjects (17 of 114) and 20% of individuals who lacked adenomas on sigmoidoscopy (17 of 84). The majority of proximal neoplasms were small (<1.0 cm), tubular adenomas. Flexible sigmoidoscopy may be ineffective for screening asymptomatic men for neoplasia. However, it remains to be determined if a 20% miss rate (for those with a normal sigmoidoscopic examination) is significant and whether small proximal adenomas are worth finding.     

Systematic review of colorectal cancer screening guidelines for average-risk adults: Summarizing the current global recommendations

AIM To summarize and compare worldwide colorectal cancer(CRC) screening recommendations in order to identify similarities and disparities.METHODS A systematic literature search was performed using MEDLINE, EMBASE, Scopus, CENTRAL and ISI Web of knowledge identifying all average-risk CRC screening guideline publications within the last ten years and/or position statements published in the last 2 years. In addition, a hand-search of the webpages of National Gastroenterology Society websites, the National Guideline Clearinghouse, the BMJ Clinical Evidence website,Google and Google Scholar was performed. RESULTS Fifteen guidelines were identified. Six guidelines were published in North America, four in Europe, four in Asia and one from the World Gastroenterology Organization. The majority of guidelines recommend screening average-risk individuals between ages 50 and 75 using colonoscopy(every 10 years), or flexible sigmoidoscopy(FS, every 5 years) or fecal occult blood test(FOBT, mainly the Fecal Immunochemical Test, annually or biennially). Disparities throughout the different guidelines are found relating to the use of colonoscopy, rank order between test, screening intervals and optimal age ranges for screening. CONCLUSION Average risk individuals between 50 and 75 years should undergo CRC screening. Recommendations for optimal surveillance intervals, preferred tests/test cascade as well as the optimal timing when to start and stop screening differ regionally and should be considered for clinical decision making. Furthermore, local resource availability and patient preferences are important to increase CRC screening uptake, as any screening is better than none.