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BACKGROUND:The cutoff of semi-quantitative immunochemical faecal occult blood tests (iFOBTs) influences colonoscopy referrals and detection rates. We studied the performance of an iFOBT (OC-Sensor) in colorectal cancer (CRC) screening at different cutoffs. METHODS: Dutch screening participants, 50 -75 years of age, with average CRC risk and an iFOBT value X50 ng ml À1 were offered colonoscopy. The detection rate was the percentage of participants with CRC or advanced adenomas (X10 mm, X20% villous, high-grade dysplasia). The number needed to scope (NNTScope) was the number of colonoscopies to be carried out to find one person with CRC or advanced adenomas. RESULTS: iFOBT values X50 ng ml À1 were detected in 526 of 6157 participants (8.5%) and 428 (81%) underwent colonoscopy. The detection rate for advanced lesions (28 CRC and 161 with advanced adenomas) was 3.1% (95% confidence interval: 2.6 -3.5%) and the NNTScope was 2.3. At 75 ng ml À1 , the detection rate was 2.7%, the NNTScope was 2.0 and the CRC miss rate compared with 50 ng ml À1 was o5% (N ¼ 1). At 100 ng ml À1 , the detection rate was 2.4% and the NNTScope was o2. Compared with 50 ng ml À1 , up to 200 ng ml À1 CRC miss rates remained at 16% (N ¼ 4). CONCLUSIONS: Cutoffs below the standard 100 ng ml À1 resulted in not only higher detection rates of advanced lesions but also more colonoscopies. With sufficient capacity, 75 ng ml À1 might be advised; if not, up to 200 ng ml À1 CRC miss rates are acceptable compared with the decrease in performed colonoscopies.

Delayed return of immunochemical fecal occult blood test (iFOBT) samples to a laboratory might cause false negatives because of hemoglobin degradation. Quantitative iFOBT's became increasingly more accepted in colorectal cancer screening. Therefore, we studied the effects of delay between sampling and laboratory delivery on iFOBT performance. IFOBT positivity ( ‡50 ng/ml hemoglobin) in colorectal cancer screening participants without delay between sampling and laboratory delivery (<5 days), was compared with positivity in participants with ‡5 and ‡7 days delay. Additionally, positive tests were stored at room temperature and retested 5 times within 10-14 days. The sampling date was reported by 61% (n 5 3,767) of the participants: in 19% delay was ‡5 days and in 5% ‡7 days. Compared with no-delay, the adenoma detection rate was already significantly decreased after ‡5 days delay (OR 0.6; 95%CI 0.4-0.9). We retested iFOBT samples of 170 positives of which 139 (82%) had a colonoscopy: 45 (32%) had advanced adenomas (not colorectal cancer) and 8 (6%) had colorectal cancer. Mean daily fecal hemoglobin decrease was 29 ng/ml (S.D. 38 and median 11 ng/ml). In patients with advanced adenomas, hemoglobin in the sample was <50 ng/ml in 5 (11%) 2-3 days after the initial test and in 16 (36%) after 10-14 days. Seven days after the initial test, 2 (25%) colorectal cancer patients became false negative. Both had stage I colorectal cancer and initial values below 100 ng/ml, where the average for stage I is 532 ng/ml. Delay in sample return increased false negative immunochemical FOBT's. Mainly precursor lesions, but also colorectal cancer, will be missed due to delayed sample return. ' 2009 UICC

Comparability of cost-effectiveness of colorectal cancer (CRC) screening strategies is limited if heterogeneous study data are combined. We analyzed prospective empirical data from a randomized-controlled trial to compare cost-effectiveness of screening with either one round of immunochemical fecal occult blood testing (I-FOBT; OC-Sensor V R ), one round of guaiac FOBT (G-FOBT; Hemoccult-II V R ) or no screening in Dutch aged 50 to 75 years, completed with cancer registry and literature data, from a third-party payer perspective in a Markov model with first-and second-order Monte Carlo simulation. Costs were measured in Euros (€), effects in life-years gained, and both were discounted with 3%. Uncertainty surrounding important parameters was analyzed. I-FOBT dominated the alternatives: after one round of I-FOBT screening, a hypothetical person would on average gain 0.003 life-years and save the health care system €27 compared with G-FOBT and 0.003 life years and €72 compared with no screening. Overall, in 4,460,265 Dutch aged 50-75 years, after one round I-FOBT screening, 13,400 life-years and €320 million would have been saved compared with no screening. I-FOBT also dominated in sensitivity analyses, varying uncertainty surrounding important effect and cost parameters. CRC screening with I-FOBT dominated G-FOBT and no screening with or without accounting for uncertainty.Cost-effectiveness studies on colorectal cancer (CRC) screening suffer from heterogeneous data based on partially ambiguous evidence.1 Usually, the effect of CRC screening is performed by exploring a single type of test or strategy. A literature search showed that, if data from studies with more than one type of test were available, they suffered from no random allocation of tests and limited comparability due to differences in inclusion criteria, follow-up periods and geographical regions. [1][2][3][4][5][6] Most studies are accompanied by extensive sensitivity analyses covering a broad range of outcomes, but authors seldom report on decreased precision and possible lack of generalizability. [2][3][4][5][6][7] Besides these forms of potential biases, several cost-effectiveness studies suffered from unrealistic assumptions. For example, participation in screening can vary between populations and screening tests. Primary endoscopy screening hardly ever exceeds 30% and is consistently lower than participation in guaiac fecal occult blood test (FOBT) screening, which hardly ever exceeds 50% participation. [8][9][10][11][12] However, in cost-effectiveness analysis, participation is often assumed to be 100%, regardless of the population, test or strategy. When imperfect participation is taken into account, it is often assumed to be only dependent on the population and not on the test or strategy. 3,5,7 In reality, participation levels related to different types of tests can vary considerably within a population, because of test-specific aspects such as the design of the test or the number of days a test has to be performed. Also, adherence to colonos...

Objective:The purpose of this study was to evaluate the effectiveness of CT colonography (CTC) as a triage technique in faecal occult blood test (FOBT)-positive screening participants.Methods:Consecutive guaiac (G-FOBT) and immunochemical (I-FOBT) FOBT-positive patients scheduled for colonoscopy underwent CTC with iodine tagging bowel preparation. Each CTC was read independently by two experienced observers. Per patient sensitivity, specificity and positive and negative predictive values (PPV and NPV) were calculated based on double reading with different CTC cut-off lesion sizes using segmental unblinded colonoscopy as the reference standard. The acceptability of the technique to patients was evaluated with questionnaires.Results:302 FOBT-positive patients were included (54 G-FOBT and 248 I-FOBT). 22 FOBT-positive patients (7%) had a colorectal carcinoma and 211 (70%) had a lesion ⩾6 mm. Participants considered colonoscopy more burdensome than CTC (p<0.05). Using a 6 mm CTC size cut-off, per patient sensitivity for CTC was 91% (95% CI 85% to 91%) and specificity was 69% (95% CI 60% to 89%) for the detection of colonoscopy lesions ⩾6 mm. The PPV of CTC was 87% (95% CI 80% to 93%) and NPV 77% (95% CI 69% to 85%). Using CTC as a triage technique in 100 FOBT-positive patients would mean that colonoscopy could be prevented in 28 patients while missing ⩾10 mm lesions in 2 patients.Conclusion:CTC with limited bowel preparation has reasonable predictive values in an FOBT-positive population and a higher acceptability to patients than colonoscopy. However, due to the high prevalence of clinically relevant lesions in FOBT-positive patients, CTC is unlikely to be an efficient triage technique in a first round FOBT population screening programme.

PurposeThe aim of this study was to compare a 1-day with a 2-day iodine bowel preparation for CT colonography in a positive faecal occult blood test (FOBT) screening population.Materials and methodsOne hundred consecutive patients underwent CT colonography and colonoscopy with segmental unblinding. The first 50 patients (group 1) ingested 7*50 ml iodinated contrast starting 2 days before CT colonography. The latter 50 patients (group 2) ingested 4*50 ml iodinated contrast starting 1 day before CT colonography. Per colonic segment measurements of residual stool attenuation and homogeneity were performed, and a subjective evaluation of tagging quality (grade 1–5) was done. Independently, two reviewers performed polyp and carcinoma detection.ResultsThe tagging density was 638 and 618 HU (p = 0.458) and homogeneity 91 and 86 HU for groups 1 and 2, respectively (p = 0.145). The tagging quality was graded 5 (excellent) in 90% of all segments in group 1 and 91% in group 2 (p = 0.749). Mean per-polyp sensitivity for lesions ≥10 mm was 86% in group 1 and 97% in group 2 (p = 0.355). Patient burden from diarrhoea significantly decreased for patients in group 2.ConclusionsOne-day preparation with meglumine ioxithalamate results in an improved patient acceptability compared with 2-day preparation and has a comparable, excellent image quality and good diagnostic performance.

We investigated the participation rates in CRC screening with a FOBT among various ethnic groups in the Netherlands. Individuals (n = 10 054) were invited by mail and grouped by country of birth. Overall participation rate was 49%. Participation among ethnic minority groups was significantly lower than among ethnic Dutch [adjusted OR for participation: Middle- or Central-East 0.25 (0.18-0.34), African 0.48 (0.34-0.67), Surinamese and Antillean 0.51 (0.43-0.61), South- or South-East Asian 0.56 (0.46-0.69) and 'other Western' 0.78 (0.63-0.96)]. Further studies are needed to explore whether ethnic minority groups are not reached or that low uptake is determined by other causes.

The majority of the reported reasons not to participate reflect low priority for screening. Adding extra instructions and information, and addressing specific concerns through additional interventions should be considered to improve individual decision-making about participation in future CRC population-based screening programs.