Fraser CG, Mathew CM, Mowat NA, Wilson JA, Carey FA, Steele RJEvaluation of a card collection-based faecal immunochemical test in screening for colorectal cancer using a two-tier reflex approach. Gut 56: 1415-1418

Scottish Bowel Screening Centre Laboratory, Kings Cross, Dundee DD3 8EA, UK.
Gut (Impact Factor: 13.32). 11/2007; 56(10):1415-8. DOI: 10.1136/gut.2007.119651
Source: PubMed

ABSTRACT The guaiac faecal occult blood test (gFOBT) has been proved as a screening investigation for colorectal cancer, but has disadvantages. Newer faecal immunochemical tests (FITs) have many advantages, but yield higher positivity rates and are expensive. A two-tier reflex follow-up of gFOBT-positive individuals with a FIT before colonoscopy has been advocated as an efficient and effective approach.
A new simple and stable card collection FIT was evaluated.
1124 individuals who were gFOBT positive were asked to provide samples. 558 individuals participated, 320 refused and 246 did not return samples. No evidence of sampling bias was found. 302 individuals tested FIT negative and 256 tested positive. In the 302 FIT-negative individuals, 2 (0.7%) had cancer and 12 (4.0%) had large or multiple (high-risk) adenomatous polyps. In contrast, of 254 positive individuals, 47 (18.5%) had cancer and 54 (21.3%) had high-risk polyps. 93 (30.8%) of the FIT-negative individuals had a normal colonoscopy, but only 34 (13.4%) of the FIT-positive individuals had no pathology. Sensitivity, specificity, and positive and negative likelihood ratios (and 95% CIs) for cancer were 95.9% (84.8 to 99.3), 59.2% (54.7 to 63.5), 2.35 (2.08 to 2.65) and 0.07 (0.02 to 0.27), and for cancer and high-risk polyps were 87.8% (80.1 to 92.9), 65.3% (60.6 to 69.7), 2.53 (2.19 to 2.93) and 0.19 (0.11 to 0.31), respectively.
A two-tier reflex screening algorithm, in which gFOBT-positive participants are tested with a FIT, is effective in identifying individuals at high risk of significant colorectal neoplasia. This strategy is transferable across different FIT formats. This approach has been adopted for the Scottish Bowel Screening Programme.

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Available from: Robert Steele, Apr 24, 2014
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    • "A different way of managing the challenge of colonoscopy referrals has been adopted in the screening programme in Scotland, where FIT is used for reflex testing following a positive gFOBT. This has reduced the proportion of screened individuals referred for colonoscopy compared with using second-line gFOBT (Fraser et al, 2006, 2007). However, the potential impact of gFOBT with reflex FIT on cancer incidence and mortality does not appear to have been evaluated. "
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    ABSTRACT: Several colorectal cancer-screening tests are available, but it is uncertain which provides the best balance of risks and benefits within a screening programme. We evaluated cost-effectiveness of a population-based screening programme in Ireland based on (i) biennial guaiac-based faecal occult blood testing (gFOBT) at ages 55-74, with reflex faecal immunochemical testing (FIT); (ii) biennial FIT at ages 55-74; and (iii) once-only flexible sigmoidoscopy (FSIG) at age 60. A state-transition model was used to estimate costs and outcomes for each screening scenario vs no screening. A third party payer perspective was adopted. Probabilistic sensitivity analyses were undertaken. All scenarios would be considered highly cost-effective compared with no screening. The lowest incremental cost-effectiveness ratio (ICER vs no screening euro 589 per quality-adjusted life-year (QALY) gained) was found for FSIG, followed by FIT euro 1696) and gFOBT (euro 4428); gFOBT was dominated. Compared with FSIG, FIT was associated with greater gains in QALYs and reductions in lifetime cancer incidence and mortality, but was more costly, required considerably more colonoscopies and resulted in more complications. Results were robust to variations in parameter estimates. Population-based screening based on FIT is expected to result in greater health gains than a policy of gFOBT (with reflex FIT) or once-only FSIG, but would require significantly more colonoscopy resources and result in more individuals experiencing adverse effects. Weighing these advantages and disadvantages presents a considerable challenge to policy makers.
    British Journal of Cancer 02/2012; 106(5):805-16. DOI:10.1038/bjc.2011.580 · 4.82 Impact Factor
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    • "It is known that a large fraction of high grade adenomas actually progress into carcinomas. In fact, the sensitivity in detecting these lesions ranges from 20 to 45%, using noninvasive diagnostic tests based on fecal occult blood [2] [9] [17], and only few data are available on molecular tests [3] [6]. The development of a qualitative analysis of long DNA fragments from stool to identify high-risk adenomas would therefore constitute an important step forward in the area of early diagnosis [3] [7] [27]. "
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    ABSTRACT: A variety of molecular markers have been evaluated for the development of a non-invasive approach to the diagnosis of colorectal cancer. We aimed to validate the diagnostic accuracy, using the same threshold as in the previous pilot study, of fluorescent long DNA test as a relatively simple and inexpensive tool for colorectal cancer detection. A case-control study was conducted on 100 healthy subjects and 100 patients at first diagnosis of colorectal cancer. Human long-fragment DNA in stool was quantified by fluorescence primers and a standard curve and expressed in DNA nanograms. We validated the 25-ng value, which emerged as the most accurate cut-off in the pilot study, obtaining 79% (95% CI, 71-87%) sensitivity and 89% (95% CI, 83-95%) specificity. Specificity was very high for all cut-off values (15-40 ng) analyzed, ranging from 78 to 96%. Sensitivity was only slightly lower, reaching 84% at the lowest cut-off and maintaining a good level at the higher values. Diagnostic potential was independent of gender, age and tumor site. Fecal DNA analysis is a non-invasive and fairly simple test showing high diagnostic potential. These characteristics, together with the small amount of stool required, make it potentially suitable to be used alongside or as an alternative to current non-invasive screening approaches. Our next step will be to validate these results in a large-scale cohort study of a screening population, which is needed prior to implementation into clinical practice.
    Cellular oncology: the official journal of the International Society for Cellular Oncology 02/2009; 31(1):11-7. · 4.17 Impact Factor
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    • "Other countries that have evaluated immunochemical tests, such as Korea, China, Israel, Australia, and Italy, have generally concluded that these tests perform better than guaiac tests [22,36–42]. The Scottish Bowel Screening Program adopted a two-tiered screening program using an immunochemical test on guaiac-positive patients that seemed to reduce the number of colonoscopies and the overall cost of screening [43]. The Multisociety Task Force on Colorectal Cancer recommends annual screening using a guaiac test with dietary restrictions or an immunochemical test without dietary restrictions [44]. "
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    ABSTRACT: Although there are several methods available for colon cancer screening, none is optimal. This article reviews methods for screening, including fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, CT colonography, capsule endoscopy, and double contrast barium enema. A simple, inexpensive, noninvasive, and relatively sensitive screening test is needed to identify people at risk for developing advanced adenomas or colorectal cancer who would benefit from colonoscopy. It is hoped that new markers will be identified that perform better. Until then we fortunately have a variety of screening strategies that do work.
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