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Hermann Brenner - One of the best experts on this subject based on the ideXlab platform.
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the effects of different invitation schemes on the use of fecal Occult Blood tests for colorectal cancer screening systematic review of randomized controlled trials
Cancers, 2021Co-Authors: Laura Fiona Gruner, Michael Hoffmeister, Efrat L Amitay, Thomas Heisser, Feng Guo, Tobias Niedermaier, Anton Gies, Hermann BrennerAbstract:Personal invitations for fecal Occult Blood tests (nowadays mostly fecal immunochemical tests) are increasingly used to raise their usage for colorectal cancer screening. However, there is a large heterogeneity in applied invitation schemes. We aimed to review evidence for the effectiveness of various invitation schemes. The main outcome was the fecal Occult Blood test usage rate. A systematic search was performed in Medline and Web of Science (up to 9 July 2020). Randomized controlled trials or cluster-randomized controlled trials were eligible, which reported on general invitations for fecal Occult Blood test-based colorectal cancer screening sent to the general population at average colorectal cancer risk. (PROSPERO 2020 CRD42020169409). Overall, 34 studies were included. Invitations with an attached, i.e., mailed fecal Occult Blood test consistently increased test usage by 4-19.7% points, compared to other methods of test provision. Likewise, the introduction of advance notification consistently led to a higher usage rate, with an increase of 3.3-10.8% points. Reminders showed positive but varying effects by method. With an increase of 8.5-15.8% points, letter or email reminders were more effective than reminders by phone call or text message (0.6-6.5% points). Inconsistent results were found for financial incentives ((-8.4)-20% points) and for added or changed invitation material ((-3.5)-11.8% points). With 3.5-24.7% points, the strongest increases in use were achieved by multifaceted invitation, implementing multiple components. Any invitation scheme was superior over no invitation. Advance notification, mailing of fecal Occult Blood test, and reminders were consistently shown to have major, complementary potential to increase participation in fecal Occult Blood test-based colorectal cancer screening settings.
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diagnostic performance of guaiac based fecal Occult Blood test in routine screening state wide analysis from bavaria germany
The American Journal of Gastroenterology, 2014Co-Authors: Hermann Brenner, Michael Hoffmeister, Berndt Birkner, Christian StockAbstract:Diagnostic Performance of Guaiac-Based Fecal Occult Blood Test in Routine Screening: State-Wide Analysis from Bavaria, Germany
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sensitivity of immunochemical faecal Occult Blood testing for detecting left vs right sided colorectal neoplasia
British Journal of Cancer, 2011Co-Authors: Ulrike Haug, Sabrina Hundt, Karen M Kuntz, Amy B Knudsen, Hermann BrennerAbstract:Faecal Occult Blood tests (FOBTs) are used for colorectal cancer (CRC) screening. We aimed to assess the sensitivity of an immunochemical FOBT for detecting advanced colorectal neoplasia in the left vs the right colon and to explore reasons for potential differences in site-specific test performance. We prospectively measured faecal Occult Blood levels by a quantitative immunochemical FOBT (RIDASCREEN) in 2310 average-risk subjects undergoing screening colonoscopy. We compared diagnostic performance for subjects with left- vs right-sided advanced neoplasia, as well as patient characteristics and adenoma characteristics that have been suggested to impact faecal haemoglobin levels. Sensitivities for subjects with left- vs right-sided advanced neoplasia were 33% (95% confidence interval (CI), 26–41%) and 20% (CI, 11–31%) (P=0.04) at a specificity of 95% (overall sensitivity: 29%) and the areas under the receiver-operating characteristics curve were 0.71 (CI, 0.69–0.72) and 0.60 (CI, 0.58–0.63), respectively. Pedunculated shape was strikingly more common in participants with left- vs right-sided advanced neoplasia (47% vs 14%). In logistic regression analyses adjusted for site, pedunculated shape was statistically significantly associated with test sensitivity (P=0.04). The immunochemical FOBT in our study was more sensitive for detecting subjects with left- vs right-sided advanced colorectal neoplasia. Our findings may stimulate further diagnostic research in the field as well as modelling analyses to estimate the potential effect of site-specific test performance on the effectiveness of annual or biennial FOBT-based screening programmes, in particular with respect to protection from right-sided CRC.
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sex differences in performance of fecal Occult Blood testing
The American Journal of Gastroenterology, 2010Co-Authors: Hermann Brenner, Ulrike Haug, Sabrina HundtAbstract:OBJECTIVES:Immunological and guaiac-based fecal Occult Blood tests (iFOBTs and gFOBTs) are widely used for early detection of colorectal cancer (CRC). We aimed to assess potential sex differences in performance of iFOBTs and gFOBT in the screening setting.METHODS:The sensitivity, specificity, and po
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quantitative immunochemical fecal Occult Blood testing for colorectal adenoma detection evaluation in the target population of screening and comparison with qualitative tests
The American Journal of Gastroenterology, 2010Co-Authors: Ulrike Haug, Sabrina Hundt, Hermann BrennerAbstract:Quantitative Immunochemical Fecal Occult Blood Testing for Colorectal Adenoma Detection: Evaluation in the Target Population of Screening and Comparison With Qualitative Tests
Thomas F. Imperiale - One of the best experts on this subject based on the ideXlab platform.
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quantitative immunochemical fecal Occult Blood tests is it time to go back to the future
Annals of Internal Medicine, 2007Co-Authors: Thomas F. ImperialeAbstract:Immunochemical fecal Occult Blood tests (I-FOBTs) provide a superior alternative to the standard guaiac-based tests. Levi and coworkers show that the I-FOBT is more sensitive and specific than the ...
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fecal dna versus fecal Occult Blood for colorectal cancer screening in an average risk population
The New England Journal of Medicine, 2004Co-Authors: Thomas F. Imperiale, David F Ransohoff, Steven H Itzkowitz, Barry A Turnbull, Michael E RossAbstract:Background Although fecal Occult-Blood testing is the only available noninvasive screening method that reduces the risk of death from colorectal cancer, it has limited sensitivity. We compared an approach that identifies abnormal DNA in stool samples with the HemOccult II fecal Occult-Blood test in average-risk, asymptomatic persons 50 years of age or older. Methods Eligible subjects submitted one stool specimen for DNA analysis, underwent standard HemOccult II testing, and then underwent colonoscopy. Of 5486 subjects enrolled, 4404 completed all aspects of the study. A subgroup of 2507 subjects was analyzed, including all those with a diagnosis of invasive adenocarcinoma or advanced adenoma plus randomly chosen subjects with no polyps or minor polyps. The fecal DNA panel consisted of 21 mutations. Results The fecal DNA panel detected 16 of 31 invasive cancers, whereas HemOccult II identified 4 of 31 (51.6 percent vs. 12.9 percent, P=0.003). The DNA panel detected 29 of 71 invasive cancers plus adenomas w...
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fecal dna versus fecal Occult Blood for colorectal cancer screening in an average risk population
The New England Journal of Medicine, 2004Co-Authors: Thomas F. Imperiale, David F Ransohoff, Steven H Itzkowitz, Barry A Turnbull, Michael E RossAbstract:BACKGROUND: Although fecal Occult-Blood testing is the only available noninvasive screening method that reduces the risk of death from colorectal cancer, it has limited sensitivity. We compared an approach that identifies abnormal DNA in stool samples with the HemOccult II fecal Occult-Blood test in average-risk, asymptomatic persons 50 years of age or older. METHODS: Eligible subjects submitted one stool specimen for DNA analysis, underwent standard HemOccult II testing, and then underwent colonoscopy. Of 5486 subjects enrolled, 4404 completed all aspects of the study. A subgroup of 2507 subjects was analyzed, including all those with a diagnosis of invasive adenocarcinoma or advanced adenoma plus randomly chosen subjects with no polyps or minor polyps. The fecal DNA panel consisted of 21 mutations. RESULTS: The fecal DNA panel detected 16 of 31 invasive cancers, whereas HemOccult II identified 4 of 31 (51.6 percent vs. 12.9 percent, P=0.003). The DNA panel detected 29 of 71 invasive cancers plus adenomas with high-grade dysplasia, whereas HemOccult II identified 10 of 71 (40.8 percent vs. 14.1 percent, P<0.001). Among 418 subjects with advanced neoplasia (defined as a tubular adenoma at least 1 cm in diameter, a polyp with a villous histologic appearance, a polyp with high-grade dysplasia, or cancer), the DNA panel was positive in 76 (18.2 percent), whereas HemOccult II was positive in 45 (10.8 percent). Specificity in subjects with negative findings on colonoscopy was 94.4 percent for the fecal DNA panel and 95.2 percent for HemOccult II. CONCLUSIONS: Although the majority of neoplastic lesions identified by colonoscopy were not detected by either noninvasive test, the multitarget analysis of fecal DNA detected a greater proportion of important colorectal neoplasia than did HemOccult II without compromising specificity.
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Do aspirin and nonsteroidal anti-inflammatory drugs cause false-positive fecal Occult Blood test results? A prospective study in a cohort of veterans.
The American journal of medicine, 2004Co-Authors: Charles J. Kahi, Thomas F. ImperialeAbstract:Purpose To determine whether use of regular aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) is a risk factor for a false-positive fecal Occult Blood test result. Methods Consecutive patients referred for colonoscopy for a positive fecal Occult Blood test result at a Veterans Affairs hospital were eligible. Patients with hematochezia, peptic ulcer disease, or unevaluated dyspepsia requiring antacids, or who used warfarin, were excluded. Regular aspirin and NSAID use was defined as at least one daily dose for at least 3 days per week. Colonoscopic findings unlikely to explain a positive test result alone were defined a priori as diverticulosis, hemorrhoids, or polyps Results The sample comprised 193 veterans with a mean (± SD) age of 66 ± 10 years; 98% were male and 86% were white. No colonoscopic findings explained the positive fecal Occult Blood test result in 153 patients (79%). One hundred and thirty-five patients (70%) were regular aspirin or NSAID users, of whom 21% (n = 29) had findings to explain the positive test results, compared with 19% (11/58) of nonusers ( P = 0.7). There was no relation between aspirin dose and colonoscopic findings unlikely to explain a positive test result. Multivariate analysis found no association between regular aspirin or NSAID use and a false-positive test result (odds ratio=0.85; 95% confidence interval: 0.39 to 1.84). Conclusion Aspirin and NSAID use were not risk factors for a false-positive fecal Occult Blood test result in this study.
M Zappa - One of the best experts on this subject based on the ideXlab platform.
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european guidelines for quality assurance in colorectal cancer screening and diagnosis first edition faecal Occult Blood testing
Endoscopy, 2012Co-Authors: Stephen P. Halloran, Guy Launoy, M ZappaAbstract:Multidisciplinary, evidence-based guidelines for quality assurance in colorectal cancer screening and diagnosis have been developed by experts in a project coordinated by the International Agency for Research on Cancer. The full guideline document covers the entire process of population-based screening. It consists of 10 chapters and over 250 recommendations, graded according to the strength of the recommendation and the supporting evidence. The 450-page guidelines and the extensive evidence base have been published by the European Commission. The chapter on faecal Occult Blood testing includes 21 graded recommendations. The content of the chapter is presented here to promote international discussion and collaboration by making the principles and standards recommended in the new EU Guidelines known to a wider professional and scientific community. Following these recommendations has the potential to enhance the control of colorectal cancer through improvement in the quality and effectiveness of screening programmes and services.
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cost evaluation in a colorectal cancer screening programme by faecal Occult Blood test in the district of florence
Journal of Medical Screening, 2008Co-Authors: G Grazzini, Guido Castiglione, S Ciatto, Paola Mantellini, Cesare Cislaghi, Manuele Falcone, M ZappaAbstract:ObjectivesTo evaluate the direct costs of first and repeat colorectal cancer screening by immunochemical faecal Occult Blood testing (I-FOBT).MethodsFlorence district residents aged 50–70 were invited to undergo one-time I-FOBT every two years. Full colonoscopy was recommended for FOBT-positive subjects. Direct cost analysis was carried out separately for the first and repeat screening. All relevant resources consumed by the programme were calculated.ResultsAmong 25,428 or 62,369 subjects invited to the first or repeat screening, respectively, the corresponding participation rate was 47.8% or 52.3%, and the positivity rate was 4.4% and 3.3%. Corresponding detection rates and positive predictive values for cancer and advanced adenoma were 11.3% or 8.9% and 32.4% or 32.8%, respectively. The assessment phase accounted for the major cost, as compared with recruitment and screening. All cost indicators were slightly higher in the first screening compared with repeat screening. Cost per cancer and advanced aden...
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sensitivity of latex agglutination faecal Occult Blood test in the florence district population based colorectal cancer screening programme
British Journal of Cancer, 2007Co-Authors: Guido Castiglione, Carmen Beatriz Visioli, S Ciatto, G Grazzini, A G Bonanomi, Tiziana Rubeca, Paola Mantellini, M ZappaAbstract:We evaluated the sensitivity for colorectal cancer (CRC) of the latex agglutination test (LAT), an immunochemical test routinely used in the Florence District screening programme since 2000. Sensitivity was calculated by the proportional interval cancer incidence method in a population of 27 503 consecutive subjects screened in 2000–2002, interval cancers being identified by linkage to the Tuscany Cancer Registry files. Sensitivity was calculated overall and by gender, age, time since last negative LAT, CRC site, and rank of screening. Overall 1- and 2-year sensitivity estimates were 80.7 and 71.5%, respectively, suggesting that faecal Occult Blood testing screening sensitivity may be suboptimal due to testing or programme quality problems. Increasing screening sensitivity might be achieved if the detection rate of advanced adenomas could be increased without unacceptable loss in specificity.
James E Allison - One of the best experts on this subject based on the ideXlab platform.
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faecal immunochemical tests versus guaiac faecal Occult Blood tests what clinicians and colorectal cancer screening programme organisers need to know
Gut, 2015Co-Authors: Jill Tinmouth, Iris Lansdorpvogelaar, James E AllisonAbstract:Although colorectal cancer (CRC) is a common cause of cancer-related death, it is fortunately amenable to screening with faecal tests for Occult Blood and endoscopic tests. Despite the evidence for the efficacy of guaiac-based faecal Occult Blood tests (gFOBT), they have not been popular with primary care providers in many jurisdictions, in part because of poor sensitivity for advanced colorectal neoplasms (advanced adenomas and CRC). In order to address this issue, high sensitivity gFOBT have been recommended, however, these tests are limited by a reduction in specificity compared with the traditional gFOBT. Where colonoscopy is available, some providers have opted to recommend screening colonoscopy to their patients instead of faecal testing, as they believe it to be a better test. Newer methods for detecting Occult human Blood in faeces have been developed. These tests, called faecal immunochemical tests (FIT), are immunoassays specific for human haemoglobin. FIT hold considerable promise over the traditional guaiac methods including improved analytical and clinical sensitivity for CRC, better detection of advanced adenomas, and greater screenee participation. In addition, the quantitative FIT are more flexible than gFOBT as a numerical result is reported, allowing customisation of the positivity threshold. When compared with endoscopy, FIT are less sensitive for the detection of advanced colorectal neoplasms when only one time testing is applied to a screening population; however, this is offset by improved participation in a programme of annual or biennial screens and a better safety profile. This review will describe how gFOBT and FIT work and will present the evidence that supports the use of FIT over gFOBT, including the cost-effectiveness of FIT relative to gFOBT. Finally, specific issues related to FIT implementation will be discussed, particularly with respect to organised CRC screening programmes.
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Advances in Fecal Occult Blood Tests: The FIT Revolution
Digestive Diseases and Sciences, 2015Co-Authors: Graeme P Young, James E Allison, Erin L. Symonds, Stephen R. Cole, Callum G. Fraser, Stephen P. Halloran, Ernst J. Kuipers, Helen E. SeamanAbstract:There is a wide choice of fecal Occult Blood tests (FOBTs) for colorectal cancer screening. Goal : To highlight the issues applicable when choosing a FOBT, in particular which FOBT is best suited to the range of screening scenarios. Four scenarios characterize the constraints and expectations of screening programs: (1) limited colonoscopy resource with a need to constrain test positivity rate; (2) a priority for maximum colorectal neoplasia detection with little need to constrain colonoscopy workload; (3) an “adequate” endoscopy resource that allows balancing the benefits of detection with the burden of service provision; and (4) a need to maximize participation in screening. Guaiac-based FOBTs (gFOBTs) have significant deficiencies, and fecal immunochemical tests (FITs) for hemoglobin have emerged as better tests. gFOBTs are not sensitive to small bleeds, specificity can be affected by diet or drugs, participant acceptance can be low, laboratory quality control opportunities are limited, and they have a fixed hemoglobin concentration cutoff determining positivity. FITs are analytically more specific, capable of quantitation and hence provide flexibility to adjust cutoff concentration for positivity and the balance between sensitivity and specificity. FITs are clinically more sensitive for cancers and advanced adenomas, and because they are easier to use, acceptance rates are high. Conclusions : FOBT must be chosen carefully to meet the needs of the applicable screening scenario. Quantitative FIT can be adjusted to suit Scenarios 1, 2 and 3, and for each, they are the test of choice. FITs are superior to gFOBT for Scenario 4 and gFOBT is only suitable for Scenario 1.
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screening for colorectal neoplasms with new fecal Occult Blood tests update on performance characteristics
Journal of the National Cancer Institute, 2007Co-Authors: James E Allison, Irene S Tekawa, Lori C Sakoda, Theodore R Levin, Jo P Tucker, Thomas Cuff, Mary Pat Pauly, Lyle Shlager, Albert Palitz, Wei K ZhaoAbstract:Background One type of fecal Occult Blood test (FOBT), the unrehydrated guaiac fecal Occult Blood test (GT), is recommended by the United States Preventive Services Task Force and the Institute of Medicine for use in screening programs, but it has relatively low sensitivity as a single test for detecting advanced colonic neoplasms (cancer and adenomatous polyps ≥ 1 cm in diameter). Thus, improving the sensitivity of FOBT should make colon cancer screening programs that use these tests more effective. Methods We assessed prospectively the performance characteristics of two newer FOBTs in 5841 subjects at average risk for colorectal cancer in a large group – model managed care organization. The tests evaluated included a sensitive GT, a fecal immunochemical test (FIT), and the combination of both tests. Patients with positive and negative test results were advised to have colonoscopy and sigmoidoscopy, respectively. Sensitivity and specificity for detecting advanced neoplasms in the left colon within 2 years after the FOBT screening were evaluated for the two tests administered separately and in combination. Results A total of 139 patients were diagnosed with advanced colorectal neoplasms (n = 14 cancers, n = 128 adenomas) within the 2 years following their initial FOBT screening. Sensitivity for detecting cancer was 81.8% (95% confidence interval [CI] = 47.8% to 96.8%) for the FIT alone and 64.3% (95% CI = 35.6% to 86.0%) for the sensitive GT and the combination test. Sensitivity for detecting advanced colorectal adenomas was 41.3% (95% CI = 32.7% to 50.4%) for the sensitive GT, 29.5% (95% CI = 21.4% to 38.9%) for the FIT, and 22.8% (95% CI =16.1% to 31.3%) for the combination test. Specificity for detecting cancer and adenomas was 98.1% (95% CI = 97.7% to 98.4%) and 98.4% (95% CI = 98.0% to 98.7%), respectively, for the combination test; 96.9% (95% CI = 96.4% to 97.4%) and 97.3% (95% CI = 96.8% to 97.7%), respectively, for the FIT; and 90.1% (95% CI = 89.3% to 90.8%) and 90.6% (95% CI = 89.8% to 91.4%), respectively, for the sensitive GT. Conclusions The FIT has high sensitivity and specificity for detecting left-sided colorectal cancer, and it may be a useful
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a comparison of fecal Occult Blood tests for colorectal cancer screening
The New England Journal of Medicine, 1996Co-Authors: James E Allison, Irene S Tekawa, Laura J Ransom, Alyn L AdrainAbstract:Background HemOccult II, a widely used guaiac test for fecal Occult Blood, has a low sensitivity for detecting colorectal neoplasms in asymptomatic patients at average risk. In such patients, the performance characteristics of screening tests developed to improve on HemOccult II are not known. Methods A set of three fecal Occult-Blood tests — HemOccult II; HemOccult II Sensa, a more sensitive guaiac test; and HemeSelect, an immunochemical test for human hemoglobin — was mailed to all patients 50 years of age or older who were scheduled for personal health appraisals at the Kaiser Permanente Medical Center in Oakland, California. The performance of each test and of a combination test (HemeSelect to confirm positive HemOccult II Sensa results) was evaluated by identifying screened patients who had colorectal neoplasms (carcinoma or a polyp >1 cm in diameter) in the two years after screening. Results Of the 10,702 eligible patients, 8104 (75.7 percent) had at least one interpretable sample and were screened ...
John H. Bond - One of the best experts on this subject based on the ideXlab platform.
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fecal Occult Blood test in patients on low dose aspirin warfarin clopidogrel or non steroidal anti inflammatory drugs
Digestive Diseases and Sciences, 2010Co-Authors: John H. Bond, Mandeep S Sawhney, Heather Mcdougall, Douglas B NelsonAbstract:Aim To determine the effect of anticoagulants and antiplatelet medications on the positive-predictive-value of fecal Occult Blood test (FOBT).
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the effect of fecal Occult Blood screening on the incidence of colorectal cancer
The New England Journal of Medicine, 2000Co-Authors: Jack S Mandel, Fred Ederer, Mindy S Geisser, Steven J Mongin, John H. Bond, Dale C Snover, Timothy R Church, Leonard M SchumanAbstract:Background Both annual testing for fecal Occult Blood and biennial testing significantly reduce mortality from colorectal cancer. However, the effect of screening on the incidence of colorectal cancer remains uncertain, despite the diagnosis and removal of precancerous lesions in many persons who undergo screening. Methods We have followed the participants in the Minnesota Colon Cancer Control Study for 18 years. A total of 46,551 people, most of whom were 50 to 80 years old, were enrolled between 1975 and 1978 and randomly assigned to annual screening, biennial screening, or usual care (the control group). Those assigned to the screening groups were asked to prepare and submit two samples from each of three consecutive stools for guaiac-based testing. Those with at least one positive slide in the set of six were offered a diagnostic examination that included colonoscopy. Screening was conducted between 1976 and 1982 and again between 1986 and 1992. Study participants have been followed with respect to ne...
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colorectal cancer mortality effectiveness of biennial screening for fecal Occult Blood
Journal of the National Cancer Institute, 1999Co-Authors: Jack S Mandel, Fred Ederer, Timothy R Church, John H. BondAbstract:BACKGROUND: In 1993, a randomized controlled trial in Minnesota showed, after 13 years of follow-up, that annual fecal Occult Blood testing was effective in reducing colorectal cancer mortality by at least 33%. Biennial screening (i.e., every 2 years) resulted in only a 6% mortality reduction. Two European trials (in England and in Denmark) subsequently showed statistically significant 15% and 18% mortality reductions with biennial screening. Herein, we provide updated results-through 18 years of follow-up--from the Minnesota trial that address the apparent inconsistent findings among the trials regarding biennial screening. METHODS: From 1976 through 1977, a total of 46551 study subjects, aged 50-80 years, were recruited and randomly assigned to an annual screen, a biennial screen, or a control group. A screen consisted of six guaiac-impregnated fecal Occult Blood tests (HemOccult) prepared in pairs from each of three consecutive fecal samples. Participants with at least one of the six tests that were positive were invited for a diagnostic examination that included colonoscopy. All participants were followed annually to ascertain incident colorectal cancers and deaths. RESULTS: The numbers of deaths from all causes were similar among the three study groups. Cumulative 18-year colorectal cancer mortality was 33% lower in the annual group than in the control group (rate ratio, 0.67; 95% confidence interval [CI] = 0.51-0.83). The biennial group had a 21% lower colorectal cancer mortality rate than the control group (rate ratio, 0.79; 95% CI = 0.62-0.97). A marked reduction was also noted in the incidence of Dukes' stage D cancers in both screened groups in comparison with the control group. CONCLUSION: The results from this study, together with the other two published randomized trials of fecal Occult Blood screening, are consistent in demonstrating a substantial, statistically significant reduction in colorectal cancer mortality from biennial screening.
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reducing mortality from colorectal cancer by screening for fecal Occult Blood
The New England Journal of Medicine, 1993Co-Authors: Jack S Mandel, Mary G Bradley, Leonard M Schuman, John H. Bond, Dale C Snover, Timothy R Church, Fred EdererAbstract:Background Although tests for Occult Blood in the feces are widely used to screen for colorectal cancers, there is no conclusive evidence that they reduce mortality from this cause. We evaluated a fecal Occult-Blood test in a randomized trial and documented its effectiveness. Methods We randomly assigned 46,551 participants 50 to 80 years of age to screening for colorectal cancer once a year, to screening every two years, or to a control group. Participants who were screened submitted six guaiac-impregnated paper slides with two smears from each of three consecutive stools. About 83 percent of the slides were rehydrated. Participants who tested positive underwent a diagnostic evaluation that included colonoscopy. Vital status was ascertained for all participants over 13 years of follow-up. A committee determined causes of death. A single pathologist determined the stage of cancer for each tissue specimen. Differences in mortality from colorectal cancer, the primary study end point, were monitored with the...
