A prospective multicenter evaluation of new fecal occult blood tests in patients undergoing colonoscopy

University of California, San Francisco, USA.
The American Journal of Gastroenterology (Impact Factor: 10.76). 06/2000; 95(5):1331-8. DOI: 10.1111/j.1572-0241.2000.02032.x
Source: PubMed


Guaiac-based fecal occult blood (FOB) tests, in particular, Hemoccult II (HO), are commonly used to detect colorectal neoplasia. Because the sensitivity and specificity of these tests are critical to cost-effective screening programs, we aimed to investigate the improved performance characteristics of new FOB tests for known colonic lesions.
Nine centers worldwide performed FOB testing with guaiac-based tests (Hemoccult II [HO] and Hemoccult II SENSA [SENSA]) and immunochemical tests (HemeSelect [HS] and FlexSure OBT [FS]) on 554 patients referred for colonoscopy for predetermined indications. A combination testing strategy consisting of SENSA followed by HS or FS (which was considered positive only when both tests were positive) was also evaluated. Results of FOB tests were compared to findings on colonoscopy.
Cancers were identified in 2.9% of subjects, whereas adenomas > or =10 mm were found in 39 patients. Small adenomas, colitis, and other lesions were identified in 141 patients. The positivity rate of HO for adenomas > or =10 mm was less than for SENSA (20.5% vs 35.9%, p < 0.05), whereas the positivity rate of HO, SENSA, FS, HS, or the combination tests for cancers was not statistically different. The overall positivity rates were significantly greater for FS (15.9%, p = 0.0002) and significantly lower using the combination tests (SENSA/FS 6.0%, p = 0.01; SENSA/HS 6.2%, p = 0.02) compared to HO (9.4%). In this study population, the relative specificity (i.e., true-negative tests/true-negatives + false-positives in patients without adenomas > or =10 mm or cancers) of HO (93.9%; 95% CI, 91.7-96.1) was similar to that of SENSA (92.8%; 95% CI, 90.4-95.2) and HS (90.1%; 95% CI, 87.4-92.8), and greater than FS (88.0%; 95% CI, 85.1-90.9, p < 0.001). When considering adenomas > or =10 mm, cancers alone or cancers and adenomas combined, the combination test using SENSA/FS was associated with significantly fewer false-positive tests than any of the individual tests.
Compared to single tests, the combination test with the highly sensitive SENSA and an immunochemical test had slightly reduced sensitivity but significantly fewer false-positive tests than any single test. These data raise the possibility that a combination test (i.e., highly sensitive guaiac plus immunochemical) could reduce the costs of screening for colon cancer, and suggest that further study of combination test strategies is warranted.

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    • "It is essential to have a framework that compares the health benefits and resource expenditures associated with competing medical and public health interventions. Furthermore, the majority of patients who undergo cancer screening with low accuracy methods derive no benefit from the procedure, may become anxious about the result, and may actually be exposed to additional health risks as a result of screening [14] [15] [21] [22]. These risks arise from complications that can result in hospitalization and from inaccurate results that lead to unnecessary invasive followup procedures. "
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    ABSTRACT: The National Cancer Screening Program (NCSP) has since 2004 provided annual colorectal cancer screening using the fecal immunochemical test (FIT) for individuals aged 50 years or older. The aim of this study was to examine the positivity and detection rates of the FIT and to compare the detection rates of the qualitative and quantitative FITs in participants in the 2009 NCSP. We analyzed positivity and detection rates according to FIT type (qualitative and quantitative). We used a multinomial logistic regression to analyze the odds ratio of "benign" or "suspicious cancer and cancer" compared to "normal," adjusted for gender, age, health insurance type, region of residence, hospital type, and FIT type. Of the 1,181,904 participants, 72.8% received a qualitative and 27.2% a quantitative FIT. The positivity rates were 8.1% for the qualitative and 2.5% for the quantitative FIT. The detection rate was 5.2% for the qualitative and 14.4% for the quantitative FIT. The odds ratio of a "suspicious cancer and cancer" versus a "normal" result was 2.73 (95% CI = 2.22-3.35) for the quantitative compared to qualitative FIT, after adjustment. The positivity rate of the qualitative FIT was around three times higher than that of the quantitative FIT. However, the odds ratio for detection of "suspicious cancer and cancer" versus "normal" of the quantitative FIT was about three times higher than that of the qualitative FIT. These findings suggest that quality control may be important, particularly for the qualitative FIT.
    Full-text · Article · Apr 2012 · Scandinavian Journal of Gastroenterology
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    • "Also, it has been shown through prospective randomized trials that FOBT reduces CRC mortality, and consequently the evidence for its use is robust. However, FOBT presents relatively high false negative and false positive rates, and it has particularly poor sensitivity for the detection of early-stage lesions [9-11]. In an attempt to improve on the false positive rates of FOBT, a new Faecal Immunochemical testing (FIT) has been developed. "
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    ABSTRACT: Malignancies arising in the large bowel cause the second largest number of deaths from cancer in the Western World. Despite progresses made during the last decades, colorectal cancer remains one of the most frequent and deadly neoplasias in the western countries. A genomic study of human colorectal cancer has been carried out on a total of 31 tumoral samples, corresponding to different stages of the disease, and 33 non-tumoral samples. The study was carried out by hybridisation of the tumour samples against a reference pool of non-tumoral samples using Agilent Human 1A 60-mer oligo microarrays. The results obtained were validated by qRT-PCR. In the subsequent bioinformatics analysis, gene networks by means of Bayesian classifiers, variable selection and bootstrap resampling were built. The consensus among all the induced models produced a hierarchy of dependences and, thus, of variables. After an exhaustive process of pre-processing to ensure data quality--lost values imputation, probes quality, data smoothing and intraclass variability filtering--the final dataset comprised a total of 8, 104 probes. Next, a supervised classification approach and data analysis was carried out to obtain the most relevant genes. Two of them are directly involved in cancer progression and in particular in colorectal cancer. Finally, a supervised classifier was induced to classify new unseen samples. We have developed a tentative model for the diagnosis of colorectal cancer based on a biomarker panel. Our results indicate that the gene profile described herein can discriminate between non-cancerous and cancerous samples with 94.45% accuracy using different supervised classifiers (AUC values in the range of 0.997 and 0.955).
    Full-text · Article · Jan 2012 · BMC Cancer
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    • "This effect is augmented by a higher attendance rate to FIT than to gFOBT screening (van Rossum et al, 2008; Hol et al, 2008). Thus, FIT screening enables a more efficient screening with increased participation (Cole et al, 2003; van Rossum et al, 2008; Hol et al, 2008) and improved test performances (Allison et al, 1996, 2007; Greenberg et al, 2000; Zappa et al, 2001; Smith et al, 2006; Guittet et al, 2007; van Rossum et al, 2008), potentially allowing a decrease in screening intensity by lengthening the screening interval. "
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    ABSTRACT: Immunochemical faecal occult blood testing (FIT) provides quantitative test results, which allows optimisation of the cut-off value for follow-up colonoscopy. We conducted a randomised population-based trial to determine test characteristics of FIT (OC-Sensor micro, Eiken, Japan) screening at different cut-off levels and compare these with guaiac-based faecal occult blood test (gFOBT) screening in an average risk population. A representative sample of the Dutch population (n=10 011), aged 50-74 years, was 1 : 1 randomised before invitation to gFOBT and FIT screening. Colonoscopy was offered to screenees with a positive gFOBT or FIT (cut-off 50 ng haemoglobin/ml). When varying the cut-off level between 50 and 200 ng ml(-1), the positivity rate of FIT ranged between 8.1% (95% CI: 7.2-9.1%) and 3.5% (95% CI: 2.9-4.2%), the detection rate of advanced neoplasia ranged between 3.2% (95% CI: 2.6-3.9%) and 2.1% (95% CI: 1.6-2.6%), and the specificity ranged between 95.5% (95% CI: 94.5-96.3%) and 98.8% (95% CI: 98.4-99.0%). At a cut-off value of 75 ng ml(-1), the detection rate was two times higher than with gFOBT screening (gFOBT: 1.2%; FIT: 2.5%; P<0.001), whereas the number needed to scope (NNscope) to find one screenee with advanced neoplasia was similar (2.2 vs 1.9; P=0.69). Immunochemical faecal occult blood testing is considerably more effective than gFOBT screening within the range of tested cut-off values. From our experience, a cut-off value of 75 ng ml(-1) provided an adequate positivity rate and an acceptable trade-off between detection rate and NNscope.
    Full-text · Article · Apr 2009 · British Journal of Cancer
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