The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Thomas F. Imperiale - One of the best experts on this subject based on the ideXlab platform.

  • quantitative immunochemical Fecal Occult Blood tests is it time to go back to the future
    Annals of Internal Medicine, 2007
    Co-Authors: Thomas F. Imperiale
    Abstract:

    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 ...

  • Fecal dna versus Fecal Occult Blood for colorectal cancer screening in an average risk population
    The New England Journal of Medicine, 2004
    Co-Authors: Thomas F. Imperiale, David F Ransohoff, Steven H Itzkowitz, Barry A Turnbull, Michael E Ross
    Abstract:

    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...

  • Fecal dna versus Fecal Occult Blood for colorectal cancer screening in an average risk population
    The New England Journal of Medicine, 2004
    Co-Authors: Thomas F. Imperiale, David F Ransohoff, Steven H Itzkowitz, Barry A Turnbull, Michael E Ross
    Abstract:

    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.

  • 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, 2004
    Co-Authors: Charles J. Kahi, Thomas F. Imperiale
    Abstract:

    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.

Hermann Brenner - One of the best experts on this subject based on the ideXlab platform.

  • 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, 2021
    Co-Authors: Laura Fiona Gruner, Michael Hoffmeister, Efrat L Amitay, Thomas Heisser, Feng Guo, Tobias Niedermaier, Anton Gies, Hermann Brenner
    Abstract:

    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.

  • trends in colonoscopy and Fecal Occult Blood test use after the introduction of dual screening offers in germany results from a large population based study 2003 2016
    Preventive Medicine, 2019
    Co-Authors: Chen Chen, Michael Hoffmeister, Christian Stock, Lina Jansen, Jenny Changclaude, Hermann Brenner
    Abstract:

    Abstract An increasing number of countries have recently introduced colorectal cancer (CRC) screening programs. Typically, one specific screening exam, such as Fecal Occult Blood test (FOBT) or flexible sigmoidoscopy, is offered as a primary screening test. We aimed to assess trends in FOBT and colonoscopy use in Germany following the introduction of the offer of screening colonoscopy as an alternative to FOBT in 2002. We used data from 4052 control participants aged 50–79 years recruited during 2003–2016 for a population-based case-control study in Germany. Prevalence of FOBT and colonoscopy lifetime and recent use was analyzed and trends over time were examined. The percentage of all respondents who had ever undergone a colonoscopy (for either screening or diagnostic purpose) increased markedly over time from 44.6% in 2003–2005 to 57.5% in 2013–2016 (p

  • which adenomas are detected by Fecal Occult Blood testing a state wide analysis from bavaria germany
    International Journal of Cancer, 2015
    Co-Authors: Hermann Brenner, Michael Hoffmeister, Berndt Birkner, Christian Stock
    Abstract:

    Guaiac-based Fecal Occult Blood tests (gFOBTs) are the most widely used noninvasive tests for colorectal cancer screening. While it is well known that they detect only a minority of colorectal adenomas, evidence for the characteristics of adenomas associated with detection is sparse. We derived estimates of the positive likelihood ratio (LR+), a summary measure of diagnostic performance, according to adenoma characteristics by comparing findings at colonoscopy among 19,208 and 181,128 participants who underwent colonoscopy to follow-up a positive gFOBT and as a primary screening examination, respectively, in Bavaria, Germany, in 2007-2009. Age and sex-adjusted estimates of LR+ (95% confidence intervals, 95% CI) ranged from 1.09 (1.05-1.13) for adenomas 2 cm, and were much higher for pedunculated adenomas (1.96, 95% CI 1.85-2.08) than for flat or sessile adenomas (1.11, 95% CI 1.02-1.21 and 1.12, 95% CI 1.08-1.16, respectively). Villous or tubulovillous structure and dysplasia were likewise associated with a higher chance to be detected by gFOBT. Diagnostic performance was worse for proximal than for distal adenomas (age and sex adjusted LR+:1.16, 95% CI 1.09-1.23 and 1.35, 95% CI 1.29-1.41, respectively) which was explained by the lower proportions of large, pedunculated and nontubular adenomas in the proximal colon. Size, pedunculated shape, and nontubular histology are the key determinants of detection which also explain lower detection rates of adenomas located in the proximal colon.

  • diagnostic performance of guaiac based Fecal Occult Blood test in routine screening state wide analysis from bavaria germany
    The American Journal of Gastroenterology, 2014
    Co-Authors: Hermann Brenner, Michael Hoffmeister, Berndt Birkner, Christian Stock
    Abstract:

    Diagnostic Performance of Guaiac-Based Fecal Occult Blood Test in Routine Screening: State-Wide Analysis from Bavaria, Germany

  • colonoscopy and Fecal Occult Blood test use in germany results from a large insurance based cohort
    Endoscopy, 2011
    Co-Authors: Christian Stock, Peter Ihle, Ingrid Schubert, Hermann Brenner
    Abstract:

    BACKGROUND AND STUDY AIMS Colonoscopy and guaiac-based Fecal Occult Blood tests (FOBT) are recommended and offered for colorectal cancer (CRC) screening in Germany. We aimed to explore their utilization in a large insurance-based cohort. PATIENTS AND METHODS Claims data from between 2000 and 2008 were collected for 170493 individuals who were insured by a large health insurance plan in the federal state of Hesse, Germany. The percentages of individuals who had recently utilized CRC screening-related procedures were calculated. Additionally, multiple test use and identification of CRC screening providers were ascertained. RESULTS Following the inception of the current CRC screening program in 2002, colonoscopy utilization rates varied only slightly and FOBT use decreased in individuals aged ≥50 years. At the end of 2008, the age-standardized percentages of individuals who had undergone colonoscopy within ≤10 years were 23% for men and 26% for women. The proportions of individuals who had used FOBT within ≤1 year were 14% for men and 22% for women. Patient education had been utilized by 38% of eligible persons and was increasingly followed by screening colonoscopy. For women, practices that specialized in gynecology were the main providers of FOBT (93%) and patient education (61%). CONCLUSIONS This study provides new insights into the inter-related utilization of colonoscopy, FOBT, and patient education in Germany, and may be particularly informative for the design of strategies to increase CRC screening uptake. It indicates that sex differences in CRC screening test use could result to a large extent from general visits to different types of specialist physicians involved in the CRC screening process.

Yaron Niv - One of the best experts on this subject based on the ideXlab platform.

  • the compliance rate for the second diagnostic evaluation after a positive Fecal Occult Blood test a systematic review and meta analysis
    United European gastroenterology journal, 2019
    Co-Authors: Rachel Gingoldbelfer, Haim Leibovitzh, Doron Boltin, Nidal Issa, Tsachi Tsadok Perets, Ram Dickman, Yaron Niv
    Abstract:

    IntroductionOnly a minority of patients with a positive Fecal Occult Blood test (FOBT) undergo a follow-up second diagnostic procedure, thus minimizing its contribution for colorectal cancer (CRC) ...

  • a higher detection rate for colorectal cancer and advanced adenomatous polyp for screening with immunochemical Fecal Occult Blood test than guaiac Fecal Occult Blood test despite lower compliance rate a prospective controlled feasibility study
    International Journal of Cancer, 2011
    Co-Authors: Zohar Levi, Alex Vilkin, Shlomo Birkenfeld, Micha Barchana, Irena Lifshitz, Miri Chared, Eran Maoz, Yaron Niv
    Abstract:

    Immunochemical Fecal Occult Blood test (FIT) is a new colorectal cancer (CRC) screening method already recommended by the American screening guidelines. We aimed to test the feasibility of FIT as compared to guaiac Fecal Occult Blood test (G-FOBT) in a large urban population of Tel Aviv. Average-risk persons, aged 50-75 years, were offered FIT or G-FOBT after randomization according to the socioeconomic status of their clinics. Participants with positive tests underwent colonoscopy. Participants were followed through the Cancer Registry 2 years after the study. HemOccult SENSA™ and OC-MICRO™ (three samples, 70 ng/ml threshold) were used. FIT was offered to 4,657 persons (Group A) and G-FOBT to 7,880 persons (Group B). Participation rate was 25.9% and 28.8% in Group A and B, respectively (p < 0.001). Positivity rate in Group A and B was 12.7% and 3.9%, respectively (p < 0.001). Cancer found in six (0.49%) and eight (0.35%) patients of Group A and B, respectively (NS). Cancer registry follow-up found missed cancer in five (0.22%) cases of Group B and none in Group A (NS). The sensitivity, specificity, negative and positive predictive value for cancer in Group A and B were 100%, 85.9%, 100%, 3.9% and 61.5%, 96.4%, 99.8%, 9.1%, respectively. There was increased detection of advanced adenomatous polyp (AAP) by FIT, irrespective of age, gender, and socioeconomic status (Per Protocol: odds ratio 2.69, 95% confidence interval 1.6-4.5; Intention to Screen: odds ratio 3.16, 95% confidence interval 1.8-5.4). FIT is feasible in urban, average-risk population, which significantly improved performance for detection of AAP and CRC, despite reduced participation.

  • sensitivity but not specificity of a quantitative immunochemical Fecal Occult Blood test for neoplasia is slightly increased by the use of low dose aspirin nsaids and anticoagulants
    The American Journal of Gastroenterology, 2009
    Co-Authors: Zohar Levi, Alex Vilkin, Shlomo Birkenfeld, Eran Maoz, Paul Rozen, Rachel Hazazi, Amal Waked, Nicky Lieberman, S Klang, Yaron Niv
    Abstract:

    Sensitivity, but Not Specificity, of a Quantitative Immunochemical Fecal Occult Blood Test for Neoplasia Is Slightly Increased by the Use of Low-Dose Aspirin, NSAIDS, and Anticoagulants

  • evaluation of a desk top instrument for the automated development and immunochemical quantification of Fecal Occult Blood
    Medical Science Monitor, 2006
    Co-Authors: Paul Rozen, Zohar Levi, Alex Vilkin, Amal Waked, Yaron Niv
    Abstract:

    BACKGROUND The guaiac Fecal Occult Blood test (FOBT) for colorectal cancer (CRC) screening is user dependent and not specific for human hemoglobin (Hb). The automated-developed, quantitative, immunochemical human Hb FOBT (I-FOBT) is specific, allows for quality control and selection of a suitable Hb level, with optimal sensitivity and specificity, for colonoscopy. MATERIAL/METHODS We evaluated a desktop instrument, OC-MICRO (Eiken, Japan), which automatically develops and quantifies 50 Fecal tests/hr for Hb; for ease of use, test reproducibility and stability and intra-patient daily I-FOBT variation; clinical evaluation included sensitivity and specificity for neoplasia in patients undergoing colonoscopy. RESULTS Five hundred patients prepared 3 Fecal tests which were quantified for Hb, I-FOBT samples were: (1) repeatedly re-examined; (2) stored at 4 degrees C or 20 degrees C or 28 degrees C and re-examined; (3) I-FOBT levels correlated with colonoscopic findings. Five I-FOBTs re-examined 6 times had no significant changes; 30 tests stored > or = 21 days had a decay/day of: 0.3%+/-0.4 at 4 degrees C (NS), 2.2%+/-1.7 at 20 degrees C (NS) and 3.7%+/-1.8 at 28 degrees C (P<0.05). Receiver operator characteristic curve analysis showed that at the 100 ng Hb/mL I-FOBT level 76.5% of CRCs and advanced adenomas were detected with a specificity of 95.3%. CONCLUSIONS The instrument provided reproducible results and refrigerated I-FOBT samples were stable 21 days. An I-FOBT level can be chosen to provide optimal sensitivity and specificity for significant neoplasia.

  • performance characteristics and evaluation of an automated developed and quantitative immunochemical Fecal Occult Blood screening test
    The American Journal of Gastroenterology, 2005
    Co-Authors: Alex Vilkin, Zohar Levi, Shlomo Birkenfeld, Eran Maoz, Paul Rozen, Amal Waked, Yaron Niv
    Abstract:

    OBJECTIVES: Guaiac Fecal Occult Blood colorectal cancer (CRC) screening tests (FOBT) are faulted for low sensitivity and nonspecificity for human hemoglobin (Hb). Automated-developed, immunochemical, human Hb FOBT (I-FOBT) is specific, eliminates diet restrictions, and Hb quantification allows selection of a threshold for colonoscopy. Aims were to determine 1) test reproducibility; 2) test stability; 3) intrapatient daily I-FOBT variation; 4) test sensitivity and specificity for neoplasia in 500 symptomatic/high-risk patients undergoing colonoscopy; and 5) to correlate Fecal Hb measurements with findings. METHODS: The desktop instrument OC-Sensor (Eiken, Japan) automatically develops and quantitates 50 tests/h for Hb. Patients prepared three tests, which were quantified and then 1) repeatedly re-examined; 2) stored at 4 ◦ Co r 20 ◦ Co r 28 ◦ C and repeatedly examined; and 3) Fecal Hb levels were correlated with colonoscopic findings. RESULTS: Five I-FOBTs re-examined five times in 1 day had no significant measurement changes. Thirty tests stored for 21 or more days had a decay/day of 0.3% ± 0.4 at 4 ◦ C (NS), 2.2% ± 1.7 at 20 ◦ C (NS), and 3.7% ± 1.8 at 28 ◦ C( p < 0.05). There were intrapatient variations between the three daily I-FOBTs (NS). At the recommended 100 ng Hb/mL threshold, all six cases of CRCs and 20 out of 28 cases of advanced adenomas were detected; evaluated together their sensitivity and specificity were 76.5% and 95.3%. CONCLUSIONS: Desktop, automated-developed, quantitative I-FOBT is now available. Refrigerated OC-Sensor samples are stable for 21 days, easy to prepare and develop and, at the 100 ng Hb/mL threshold, have high sensitivity, specificity, and negative predictive values for significant neoplasia. Suitability for population CRC screening awaits further evaluation. (Am J Gastroenterol 2005;100:2519‐2525)

John H. Bond - One of the best experts on this subject based on the ideXlab platform.

  • Fecal Occult Blood test in patients on low dose aspirin warfarin clopidogrel or non steroidal anti inflammatory drugs
    Digestive Diseases and Sciences, 2010
    Co-Authors: John H. Bond, Mandeep S Sawhney, Heather Mcdougall, Douglas B Nelson
    Abstract:

    Aim To determine the effect of anticoagulants and antiplatelet medications on the positive-predictive-value of Fecal Occult Blood test (FOBT).

  • the effect of Fecal Occult Blood screening on the incidence of colorectal cancer
    The New England Journal of Medicine, 2000
    Co-Authors: Jack S Mandel, Fred Ederer, Mindy S Geisser, Steven J Mongin, John H. Bond, Dale C Snover, Timothy R Church, Leonard M Schuman
    Abstract:

    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...

  • colorectal cancer mortality effectiveness of biennial screening for Fecal Occult Blood
    Journal of the National Cancer Institute, 1999
    Co-Authors: Jack S Mandel, Fred Ederer, Timothy R Church, John H. Bond
    Abstract:

    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.

  • reducing mortality from colorectal cancer by screening for Fecal Occult Blood
    The New England Journal of Medicine, 1993
    Co-Authors: Jack S Mandel, Mary G Bradley, Leonard M Schuman, John H. Bond, Dale C Snover, Timothy R Church, Fred Ederer
    Abstract:

    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...

Ulrike Haug - One of the best experts on this subject based on the ideXlab platform.

  • how should individuals with a false positive Fecal Occult Blood test for colorectal cancer be managed a decision analysis
    International Journal of Cancer, 2012
    Co-Authors: Ulrike Haug, Amy B Knudsen, Karen M Kuntz
    Abstract:

    Several industrialized nations recommend Fecal Occult Blood testing (FOBT) to screen for colorectal cancer (CRC), but corresponding screening guidelines do not specify how individuals with a prior false-positive FOBT result (fpFOBT) should be managed in terms of subsequent CRC screening. Accordingly, we conducted a decision analysis to compare different strategies for managing such individuals. We used a previously developed CRC microsimulation model, SimCRC, to calculate life-years and the lifetime number of colonoscopies (as a measure of required resources) for a cohort of 50-year-olds to whom FOBT-based CRC screening is offered annually from 50 to 75 years. We compared three management strategies for individuals with a prior fpFOBT: (i) resume screening in 10 years with 10-yearly colonoscopy (SwitchCol_long); (ii) resume screening in 1 year with annual FOBT (ContinueFOBT_Short) and (iii) resume screening in 10 years (i.e., the recommended interval following a negative colonoscopy) with annual FOBT (ContinueFOBT_long). We performed sensitivity analyses on various parameters and assumptions. When using different management strategies for individuals with a prior fpFOBT, the variation in the number of life-years gained relative to no screening was <2%, whereas the variation in the lifetime number of colonoscopies was 23% (percentages are calculated as the maximum difference across strategies divided by the lowest number across strategies). The ContinueFOBT_long strategy showed the lowest lifetime number of colonoscopies per life-year gained even when key assumptions were varied. In conclusion, the ContinueFOBT_long strategy was advantageous regarding both clinical benefit and required resources. Specifying an appropriate management strategy for individuals with a prior fpFOBT may substantially reduce required resources within a FOBT-based CRC screening program without limiting its effectiveness.

  • is Fecal Occult Blood testing more sensitive for left versus right sided colorectal neoplasia a systematic literature review
    Expert Review of Molecular Diagnostics, 2011
    Co-Authors: Ulrike Haug, Hermann Brenner, Amy B Knudsen, Karen M Kuntz
    Abstract:

    Owing to its slow development from removable precursor lesions and early cancer stages with good prognosis, screening for colorectal cancer holds potential to reduce both the incidence and mortality of the disease. While sigmoidoscopy only detects left-sided neoplasia, there is accumulating evidence that colonoscopy is also more effective in protecting from neoplasia in the left versus the right colon and rectum. In this context, it is an important question whether the sensitivity of the most common noninvasive screening tool for colorectal cancer, Fecal Occult Blood testing (FOBT), also differs for left- versus right-sided neoplasia. Therefore, we systematically searched the literature for prospective screening studies conducted in average-risk adults that performed FOBT (immunochemical and/or guaiac-based) and colonoscopy among all participants, and reported site-specific sensitivities of FOBT for advanced colorectal neoplasia. Most of the seven included studies showed a higher sensitivity of FOBT for advanced neoplasia in the left versus right colon, but this finding needs to be confirmed since the available literature is scarce and not entirely consistent.

  • sex differences in performance of Fecal Occult Blood testing
    The American Journal of Gastroenterology, 2010
    Co-Authors: Hermann Brenner, Ulrike Haug, Sabrina Hundt
    Abstract:

    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

  • inter test agreement and quantitative cross validation of immunochromatographical Fecal Occult Blood tests
    International Journal of Cancer, 2010
    Co-Authors: Hermann Brenner, Ulrike Haug, Sabrina Hundt
    Abstract:

    Immunochromatographical Fecal Occult Blood tests were shown to have higher sensitivity for detecting colorectal neoplasms than the commonly used guaiac-based test. However, positivity rates, sensitivity and specificity vary widely. We aimed to assess the reasons for this heterogeneity. Six dichotomous (qualitative) immunochromatographical tests were used in the same stool samples, taken before cathartic bowel preparation, from 1,330 participants of the German colonoscopy screening program. Positivity rates were determined, and inter-test agreement beyond chance was quantified by kappa coefficients (kappa). In addition, kappa coefficients were expressed in relation to their maximum possible values given differences in test positivity rates (kappa/kappa(max)). Furthermore, the distribution of Fecal hemoglobin concentration was assessed by an additional quantitative test in participants classified as clearly positive, borderline positive or clearly negative according to the qualitative tests. Positivity rates strongly varied from 6.4 to 46.8%. As a result, overall agreement between tests was only poor to moderate, with kappa ranging from 0.14 to 0.61. However, apart from the different positivity rates, agreement was mostly very high, with kappa/kappa(max) ranging from 0.53 to 1.00, and exceeding 0.70 in 12 of 15 cases. Distribution of Fecal hemoglobin concentrations in the various categories strongly varied across tests. The observed patterns suggest that the strongly different positivity rates essentially reflect different cutoff levels of tests with otherwise very high inter-test agreement. Definition of cutoffs is a critical issue in the application of immunochromatographical tests and should be redefined for several of these tests.

  • 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, 2010
    Co-Authors: Ulrike Haug, Sabrina Hundt, Hermann Brenner
    Abstract:

    Quantitative Immunochemical Fecal Occult Blood Testing for Colorectal Adenoma Detection: Evaluation in the Target Population of Screening and Comparison With Qualitative Tests