Serum ferritin and stool occult blood and colon cancer screening.

A group of 531 participants age 50 years or older were evaluated for colonic polyps and malignancy with stool occult blood testing, hemoglobin, hematocrit, serum ferritin, flexible fiberoptic sigmoidoscopy, and colonoscopy. Screening revealed 1 colorectal cancer, 2 malignant polyps, 30 hyperplastic polyps, 69 adenomatous polyps, 4 villous adenomas, and 2 villous components. Low serum ferritin, an indicator of iron deficiency without anemia, improved the detection of colonic malignancies and polyps when used in combination with stool occult blood testing. The program was acceptable to participants and attrition was low; the attrition rate for the screening program at 1 year was 14.5%.     

The relative value of fecal occult blood tests and flexible sigmoidoscopy in screening for large bowel neoplasia

The secondary prevention of colorectal cancer is based on the early detection of noninvasive cancer and removal of adenomatous polyps. The two commonly used screening tests are flexible sigmoidoscopy and guaiac fecal occult blood testing. Both were performed simultaneously and independently on 1176 asymptomatic volunteers followed by colonoscopic examination if either occult blood or a neoplasm was detected. Neoplasia (adenomatous polyps or cancer) were found in 48 screenees. Only ten had positive stool occult blood while 45 were detected by sigmoidoscopy. Analysis of sensitivity for neoplasia was 93.8% for sigmoidoscopy but only 20.8% for the occult blood tests, while the positive predictive values for neoplasia were 100% and 23.8% respectively. The fecal occult blood test detected only 18% of screenees with adenomas and 60% with invasive cancer. Flexible sigmoidoscopy detected 95% and 80% respectively. Analysis (kappa statistic) demonstrated little agreement between the two tests (P greater than 0.05), indicating that they are diagnosing different neoplasia. Evaluation of expected gain in diagnosing neoplasia, by combining both tests, gave 18% for the fecal blood test and 94% for the endoscopic test. These results confirm the complementary value of performing both tests, but especially the high sensitivity and predictive value positive of flexible sigmoidoscopy for adenomas, including those with severe dysplasia, and the converse for the fecal occult blood test. This latter test must be recommended and used within a screening program with caution and full understanding of its limitations.     

Dépistage organisé du cancer colorectal: état d’avancement et futur

Colorectal cancer fulfils the conditions required for mass screening. Data from controlled studies indicate that it is possible to reduce colorectal cancer mortality at a population level using faecal occult blood testing. Screening relies on biennial testing in average risk subjects aged between 50 and 74. Compliance must be over 50%. Colorectal cancer mortality decrease is between 15% and 18% in the general population; 33% and 39% among participants to screening. On the basis of available data, the European Commission recommended to organise colorectal cancer screening in the EU. Generalisation of screening has become a reality in France. Immunochemical faecal occult blood tests will probably replace guaiac faecal occult blood tests in the near future.     

Fecal occult blood testing for colorectal cancer: a perspective.

Colorectal cancer is an important health problem in western countries. Early detection of colorectal cancer reduces mortality. The best evidence for the effectiveness of screening for colorectal cancer is with annual or biennial fecal occult blood testing. While the benefit of fecal occult blood testing is small in absolute terms, the incremental cost-effectiveness of this screening strategy appears acceptable. Combining fecal occult blood testing with periodic flexible sigmoidoscopy or replacing it altogether with infrequent colonoscopy are theoretically attractive screening strategies, but the incremental costs and effectiveness of these more intensive screening strategies have not been well defined. Whether and how to implement population-based screening for colorectal cancer depends largely on available resources.     

Screening for colorectal cancer and other GI cancers.

Most of the major advances in the screening for gastrointestinal cancers this year were in the area of colorectal cancer screening. Currently, screening is recommended for the prevention of colorectal cancer in average and high-risk populations. For average risk populations, large randomized trials support the use of screening fecal occult blood testing, and case-control studies support the use of screening sigmoidoscopy. This year, several investigators have addressed issues related to the probability of identifying advanced lesions in the proximal colon following a positive screening flexible sigmoidoscopy. Similarly, two studies identified that villous histology in an index polyp was associated with an increased risk of recurrent colonic polyps. Additionally, two large trials provided new insight about the prevalence of mutations in the MLH1 or MSH2 mismatch-repair genes among patients with colorectal cancer. Lastly, a case-control study from Sweden provided the best evidence to date that surveillance colonoscopies for patients with long-standing ulcerative colitis may reduce cancer-related mortality. Although further work is needed, these studies have served to advance our knowledge of colorectal cancer screening substantially.     

Colorectal cancer screening and surveillance

Screening and surveillance substantially reduce both the incidence and mortality of colorectal cancer. Screening of normal-risk individuals may be accomplished by several methods, including fecal occult blood testing, fiberoptic sigmoidoscopy, double contrast barium enema, and colonoscopy. New technologies for screening are being developed, such as fecal immunochemical testing for blood,fecal DNA testing, and virtual colonoscopy. Patients at increased risk for colorectal cancer, such as those with a positive family history, previous adenomatous polyps or cancer, and inflammatory bowel disease, should be offered more intensive evaluation and surveillance.     

The genetics, epidemiology, and early detection of gastrointestinal cancers.

Current recommendations for screening large populations for colorectal neoplasia have been promulgated by a number of researchers and authorities who generally agree that ongoing screening is justifiable in high-risk groups but not yet in average-risk groups. Nonetheless, it is thought to be justifiable to provide screening for average-risk individuals upon request. Choice of tools for screening remains under discussion. Colonoscopy is generally agreed to be justifiable in those patients with the highest risk, ie, members of families with a clear inherited tendency to develop colorectal cancer or those with a personal history of colorectal neoplasia. There is currently no agreement concerning the recommended tools for those with a weaker family history (one or two affected relatives), but regular fecal occult blood testing with occasional limited endoscopic examination of the bowel is usually favored. The new immunochemical-based occult blood tests show great promise for improved sensitivity and specificity. The evidence of the association between Helicobacter pylori gastritis and gastric cancer has been strengthened by three studies that show that patients with gastric cancer are more likely to have had infection in the years (up to 20) prior to diagnosis. The relative risk for cancer when infected with H. pylori is 3.6 to 6, but many H. pylori-positive individuals do not develop gastric cancer and additional factors must be operative. Probably the most exciting development for gastroenterology in 1991 is the identification of the gene on chromosome 5, designated APC, which is responsible for familial adenomatous polyposis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mass screening for colorectal cancer by testing fecal occult blood

The validity of screening for colorectal cancer by testing for occult blood on 2 successive days was evaluated over a 2-year period beginning April 1980 by testing 9449 individuals without symptoms. The Shionogi slide (Shionogi Pharmaceutical Co., Osaka, Japan), a commercial guaiac-impregnated slide with moderate sensitivity, was used for screening subjects under dietary restriction. Of the 1401 persons (14.8%) who had a positive reaction for occult blood, 858 (61.2%) received further diagnostic examinations, and 265 of them proved to have one or more abnormalities of the gastrointestinal tract. Colorectal cancer was detected in 11 persons and polyps in 91 persons. Eight of the cancers were in an early stage. This screening method was found to be suitable for large-scale mass screening, and appears to have high diagnostic value.     

Advance in plasma SEPT9 gene methylation assay for colorectal cancer early detection

This review article summarizes the research advances of the plasma-based SEPT9 gene methylation assay for the clinical detection of colorectal cancer and its limitations. Colorectal cancer is a common malignancy with a poor prognosis and a high mortality, for which early detection and diagnosis are particularly crucial for the high-risk groups. Increasing evidence supported that SEPT9 gene methylation is associated with the pathogenesis of colorectal cancer and that detecting the level of methylation of SEPT9 in the peripheral blood can be used for screening of colorectal cancer in susceptible populations. In recent years, the data obtained in clinical studies demonstrated that the SEPT9 gene methylation assay has a good diagnostic performance with regard to both sensitivity and specificity with the advantage of better acceptability, convenience and compliance with serological testing compared with fecal occult blood tests and carcinoembryonic antigen for colorectal cancer (CRC). Furthermore, the combination of multiple methods or markers has become a growing trend for CRC detection and screening. Nevertheless, the clinical availability of the methylated SEPT9 assay is still limited because of the large degree of sample heterogeneity caused by demographic characteristics, pathological features, comorbidities and/or technique selection. Another factor is the cost-effectiveness of colorectal cancer screening strategies that hinders its large-scale application. In addition, improvements in its accuracy in detecting adenomas and premalignant polyps are required.     

Circulating tumour markers can define patients with normal colons, benign polyps, and cancers

Background:

Early diagnosis represents the best opportunity for cure of colorectal cancer. Current screening programmes use faecal occult blood testing for screening, which has limited sensitivity and poor specificity.

Methods:

In this study we looked at a series of previously described diagnostic markers utilising circulating free DNA (cfDNA), with a preparation method allowing small DNA fragments to be isolated. The Circulating free DNA was isolated from samples obtained from 85 patients, including 35 patients without endoscopic abnormality, a group of 26 patients with benign colorectal adenomas, and 24 patients with colorectal carcinomas. In each case, polymerase chain reaction (PCR) was performed for Line1 79 bp, Line1 300 bp, Alu 115 bp, Alu 247 bp, and mitochondrial primers. In addition, carcinoembryonic antigen (CEA) was measured by ELISA. Each marker was analysed between normal, polyp, and cancer populations, and the best performing analysed in combination by logistic regression.

Results:

The best model was able to discriminate normal from populations with adenoma or carcinoma using three DNA markers and CEA, showing an area under the receiver operator characteristic (ROC) curve of 0.855 with a positive predictive value of 81.1% for polyps and cancer diagnosis.

Conclusion:

These circulating markers in combination with other markers offer the prospect of a simple blood test as a possible secondary screen for colorectal cancers and polyps in patients with positive faecal occult blood tests.     

Emerging technologies in screening for colorectal cancer: CT colonography,immunochemical fecal occult blood tests,and stool screening using molecular markers

The American Cancer Society's (ACS) Colorectal Cancer Advisory Group held a workshop on new technologies for the early detection of colorectal cancer and adenomatous polyps as part of a regular review of ACS guidelines for colorectal cancer screening. The Advisory Group formally reviewed CT colonography, immunochemical fecal occult blood tests (FOBT), and stool screening using molecular markers, and also addressed other technologies including capsule video endoscopy. With the exception of immunochemical stool testing, the ACS has determined that at this time there is insufficient evidence to recommend these technologies for routine colorectal cancer screening. Based on recommendations of the Advisory Group, only a minor modification has been made to the ACS's Recommendations for Screening and Surveillance of the Early Detection of Adenomatous Polyps and Colorectal Cancer.     

Underuse of colorectal cancer screening in a cohort of Medicare beneficiaries

BACKGROUND: To the authors' knowledge, few population-based studies to date have considered the serial use of colorectal cancer screening tests, which are usually recommended at specific intervals. METHODS: The study included a cohort of cancer-free Medicare beneficiaries aged >or= 70 years who were identified in 1998. Inpatient, physician, and outpatient Medicare claims for colorectal screening procedures from 1991 through 1997 and 1998 through 2004 were used to categorize patients as receiving previous and subsequent complete screening, respectively. Codes were also used to identify patients at increased neoplasia risk. Cox proportional hazards models were used to measure time to receipt of complete screening in follow-up. RESULTS: The cohort consisted of 153,469 Medicare beneficiaries. Previous complete screening was performed in 29.2% of the cohort, including 76.7% of the increased risk group and 22.9% of other patients (P< .001). In the entire study cohort, the criteria for complete screening during the follow-up period were met in only 25.4% of patients, and included colonoscopy (17.6%), flexible sigmoidoscopy (2.9%), yearly fecal occult blood testing (0.8%), barium enema (0.1%), and >1 method (4.1%). Subsequent screening was strongly associated with receipt of previous screening (35.7% vs 21.2% of others; P< .001), and was also more frequent in younger and white patients. The differences were maintained in multivariate analysis. CONCLUSIONS: In a population-based cohort of Medicare beneficiaries, despite insurance reimbursement, there is significant underuse of colorectal testing. Given the ability of screening tests to reduce cancer incidence and mortality, continued efforts to promote screening are clearly warranted.     

Reduction in risk of mortality from colorectal cancer by fecal occult blood screening with immunochemical hemagglutination test. A case-control study

Fecal occult blood testing by immunochemical hemagglutination has been shown to be superior to the Hemoccult test, both in sensitivity and in specificity. The test has been widely used as a tool for population screening in Japan, but there has been no study to evaluate the efficacy of screening using this test. A case-control study to evaluate the screening was conducted in study areas where no previous and no other concomitant colorectal cancer screening had been performed. Case series in the study were 193 cases who died of colorectal cancer. Three controls were selected randomly from the list of individuals who were alive at the time of diagnosis of the corresponding case and had been living in the same area as the case, matched by gender and by age. Odds ratios (OR) of dying of colorectal cancer for those screened within 1, 2 and 3 years of case diagnosis vs. those not screened were 0.40 [95% confidence interval (CI) 0.17-0.92], 0.41 (95% CI 0.20-0.82), and 0.48 (95% CI 0.25-0.92), respectively. OR increased towards 1.0 as the duration during which screening histories were compared was extended, and showed similar tendencies when analyzed by number of years since the most recent screening history. These results suggest that colorectal cancer screening by the immunochemical fecal occult blood test would reduce mortality from colorectal cancer.     

Screening for Rectal Cancer – Will it Improve Cure Rates?

Here we give an overview of colorectal cancer screening strategies with an emphasis on the diagnosis and management of rectal cancer. We review the published studies on screening in the high-risk population, including patients with a history of colorectal cancer, inflammatory bowel disease and inherited conditions. In the average-risk population, the evidence base for a number of screening strategies is evaluated, including endoscopy, contrast studies and faecal occult blood testing. Screening guidelines in the high-risk population are predominantly based on case-control studies comparing the incidence of colorectal cancer in screened and control groups. Screening the average-risk population for colorectal cancer reduces cancer-specific mortality by 15% after biennial guaiac faecal occult blood testing and 50-80% after flexible sigmoidoscopy. All of the screening strategies outlined have a greater sensitivity for distal lesions than proximal lesions.     

Family history of colorectal adenomatous polyps as a risk factor for colorectal cancer

The aim of this study was to evaluate the risk of common colorectal cancer among first-degree relatives of patients with colorectal adenomatous polyps. In a population screening programme, 59406 subjects underwent an immunochemical faecal occult blood test. In a medical check-up-based cross-sectional study, 6139 subjects had a colonoscopic examination. They were divided into two groups, according to the results of a questionnaire on family history of colorectal adenomatous polyps, and the detection rates for colorectal cancer were compared in the groups positive or negative for a family history of colorectal adenomatous polyps. In the screening programme-based cross-sectional study, the detection rate for colorectal cancer was 0.57% (95% confidence interval (CI): 0.38-0.76) and 0.15% (95% CI: 0.12-0.18) in subjects with and without a family history of colorectal adenomatous polyps, respectively, showing a significant difference in the detection rate for colorectal cancer between the two groups (P<0.05). In the medical check-up-based cross-sectional study, the detection rate for colorectal cancer was 2.31% (95% CI: 1.15-3.47) and 0.53% (95% CI: 0. 34-0.72) in subjects with and without a family history of colorectal adenomatous polyps, respectively, indicating a significant difference between the two groups (P<0.05). These findings indicate that first-degree relatives of patients with colorectal adenomatous polyps have an elevated risk for common colorectal cancer, and that people with a family history of colorectal adenomatous polyps should be considered as a priority group for colorectal cancer screening.     

Darmkrebsfrüherkennung

Background

Colorectal cancer is the third most common neoplastic disease in men and the second most common in women in Germany. The lifetime risk for colorectal cancer is 6 % and approximately 26,000 patients die as a consequence of the disease. This article gives recommendations on the early recognition and preventive methods (described together as screening).

Conclusion

There is general agreement that screening for colorectal cancer in the asymptomatic population without familial risk should begin at the age of 50 years. There are several different screening methods available. These can be separated into methods that can be used mainly to detect cancer: fecal occult blood tests, e.g. guaiac (G-FOBT) and immunochemical (I-FOBT and FIT) procedures, feces testing for genetic alterations, blood tests and measurement of M2 pyruvate kinase (M2-PK) concentrations. Methods that can be used to detect cancers and polyps are colonoscopy, sigmoidoscopy, computed tomography (CT) magnetic resonance imaging (MRI) colonography and colon capsule endoscopy. Endoscopic methods allow preneoplastic adenomas to be detected and treated and thus make it possible to prevent cancer (primary prevention). In the current German S3 guidelines colonoscopy is recommended as the preferred screening test. For people unwilling to undergo endoscopic screening FOBTs are an alternative. Colonoscopy has been a component of the statutory German cancer screening program since 2002.

     

Is the type of test used for mass colorectal cancer screening a determinant of compliance? A cluster-randomized controlled trial comparing fecal occult blood testing with flexible sigmoidoscopy

BACKGROUND: The efficacy of colorectal cancer screening has been proved, and three different screening tests are recommended by international guidelines: the faecal occult blood test, flexible sigmoidoscopy and colonoscopy. While the effectiveness of a screening program depends on the compliance obtained, the role of the type of test on compliance has not yet been sufficiently studied. Aims: To measure the effect of the type of screening test used, i.e. faecal occult blood test or flexible sigmoidoscopy, on the compliance to colorectal cancer screening programs. SUBJECTS AND METHODS: A cluster-randomized two-arm trial was conducted. We randomly assigned 20 GP's practices that had an average of 150 patients between 50 and 74 years old. RESULTS: 1449 individuals were referred to faecal occult blood test and 1538 to flexible sigmoidoscopy. The faecal occult blood test obtained higher compliance: 17.2% (95%CI 12.5-25.7) versus 7.0% (95%CI 5.7-9.0). The socio-economic status was an effect modifier of the test type: the effect of the type of test was smaller in low socioeconomic classes. CONCLUSIONS: The type of screening test used for colorectal cancer is a determinant of participation. In a low compliance area, better compliance will result from offering the faecal occult blood test than from the flexible sigmoidoscopy.     

Colorectal cancer: screening and some notes on the prevention

At the moment cancer screening is a hot topic which is widely discussed in scientific as well as in popular press. The expected benefits, improvement of prognosis and the reduction of mortality, must be weighed against potential harms, such as the risk of over-diagnosis, false-positive findings, and complications of invasive screening examinations. Screening for breast, cervical, and colorectal cancer has proven to be effective and is therefore recommended by major medical societies and international guidelines. Different tests for colorectal cancer screening are available. Besides established strategies using fecal occult blood test and colonoscopy new and potentially less invasive techniques are on the rise. Our aim is to discuss different strategies for colorectal cancer screening and to present the available screening tests. According to the World Health Organization prevention is the most cost-effective long-term strategy for the fight against cancer. Almost half of all cancer deaths are related to preventable causes. In general, life style modification and some dietary advices can be recommended, but the role of micronutrient supplements remains unclear. There is mounting evidence that some drugs such as nonsteroidal anti-inflammatory drugs, statins, or metformin may have a chemoprotective effect, but is there enough evidence to give general recommendations?     

沈阳市苏家屯地区大肠癌筛查结果分析

[目的]通过大肠癌早诊早治项目,分析沈阳市苏家屯地区居民大肠癌发病情况。[方法]对苏家屯地区40~74岁人群采用问卷调查和粪便潜血实验免疫金标法（FIT）相结合筛出高危人群,对高危人群进行全大肠镜检查。[结果]目标人群40 157人中接受初筛人数为16 893人,顺应率为42.07%。初筛出高危人群3139人,占筛查人数18.58%。进行肠镜检查1655人,顺应率为52.72%。检出进展期腺瘤、大肠癌及类癌共83例。早诊率为95.18%,治疗率为100%。苏家屯地区居民大肠癌检出率为37.35/10万。[结论]苏家屯地区大肠癌检出率略高于我国农村地区平均水平。大肠癌筛查方案适用于城郊地区开展,可提高大肠癌的早诊率,对提高治愈率及延长生存期有重要意义。