CT colonography with minimal bowel preparation: evaluation of tagging quality, patient acceptance and diagnostic accuracy in two iodine-based preparation schemes.

PURPOSE: The 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 METHODS: One 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. RESULTS: The 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 >or=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. CONCLUSIONS: One-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.

Using CT colonography as a triage technique after a positive faecal occult blood test in colorectal cancer screening.

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 >or=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 >or=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 >or=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.

Cutoff value determines the performance of a semi-quantitative immunochemical faecal occult blood test in a colorectal cancer screening programme.

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 >or=50 ng ml(-1) were offered colonoscopy. The detection rate was the percentage of participants with CRC or advanced adenomas (>or=10 mm, >or=20% 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 >or=50 ng ml(-1) 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(-1), the detection rate was 2.7%, the NNTScope was 2.0 and the CRC miss rate compared with 50 ng ml(-1) was <5% (N=1). At 100 ng ml(-1), the detection rate was 2.4% and the NNTScope was <2. Compared with 50 ng ml(-1), up to 200 ng ml(-1) CRC miss rates remained at 16% (N=4). CONCLUSIONS: Cutoffs below the standard 100 ng ml(-1) resulted in not only higher detection rates of advanced lesions but also more colonoscopies. With sufficient capacity, 75 ng ml(-1) might be advised; if not, up to 200 ng ml(-1) CRC miss rates are acceptable compared with the decrease in performed colonoscopies.

Uptake of faecal occult blood test colorectal cancer screening by different ethnic groups in the Netherlands.

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.

Getting adequate information across to colorectal cancer screening subjects can be difficult.

OBJECTIVES: Participation in screening should be the outcome of an informed decision. We evaluated whether invitees in the first Dutch colorectal cancer (CRC) screening programme were adequately informed after having received a detailed information leaflet. METHODS: A total of 20,623 subjects aged 50-75 years were invited to the fecal occult blood test (FOBT) screening programme. All received a detailed information leaflet by mail between May 2006 and January 2007. After two weeks, a reminder letter was sent to all invitees, accompanied by a survey on CRC and screening. RESULTS: The survey was completed by 9594 invitees (47%). Almost all responders (99%) found the leaflet clear and readable. Almost all indicated that CRC can be treated better if found early (99%). Only 20% of the responders answered all knowledge-related answers correctly. Almost half of the responders (47%) believed that a negative FOBT excludes the presence of CRC. Older age and having a positive family member for CRC were correctly identified as risk factors by 80%. CONCLUSION: This study demonstrates that although an information leaflet was reported as being clear and readable, the information provided in it was not always understood well. This suggests that other educational options should be investigated in order to improve general knowledge of CRC in screening invitees.

Low priority main reason not to participate in a colorectal cancer screening program with a faecal occult blood test.

BACKGROUND: Compared with screening programs for breast and cervical cancer, reported participation rates for colorectal cancer (CRC) screening are low. The effectiveness of a screening program is strongly influenced by the participation rate. The aim of this study was to investigate the main reasons not to participate in a population-based, invitational CRC screening program. METHODS: In the Dutch study program for CRC screening, a random selection of 20 623 persons were invited received a faecal occult blood test. Of the non-participants, 500 were randomly selected and contacted for a standardized telephone interview from November 2006 to May 2007 to document the main reason not to participate. RESULTS: In total, 312 (62%) non-participants could be included for analysis. Most frequently, reported reasons for non-participation were time-related or priority-related (36%), including 'did not notice test in mailbox' (13%) and 'forgot' (8%). Other reasons were health-related issues, such as 'severe illness' (9%), or emotional reasons, such as 'family circumstances' (7%). CONCLUSIONS: 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.

[Screening the population for colorectal cancer: the background to a number of pilot studies in the Netherlands]. / Bevolkingsonderzoek op colorectaal carcinoom: achtergronden bij pilotstudies in Nederland.

Colorectal cancer is one of the most common cancers in the Netherlands, where it is now the second most commonly-occurring cancer in terms of both incidence (10,000 new cases each year) and mortality rate (4,400 each year). - In 40% of all cases the disease is diagnosed at a late stage, which is associated with a poor outcome. - Research has shown that screening of the general population for colorectal cancer by means of the faecal occult blood test (FOBT) results in a reduction in mortality of approximately 16%. Whether endoscopic screening will result in a greater reduction in the mortality rate is currently under investigation. - This year, the first pilot study on implementation of screening for colorectal cancer using two different types of FOBT will start in the Netherlands.

Involvement of previous non-participants cannot fully compensate for lower participation in a second round of FIT-screening.

INTRODUCTION: The effectiveness of colorectal cancer (CRC) screening programs depends on repeated participation. Little is known on later rounds in programs that use the fecal immunochemical test (FIT), in particular whether previous participants are likely to participate again, and if non-participants persist in declining. We compared overall participation in a second round to that in a first round, and evaluated differences in participation rates based on previous response. METHODS: Asymptomatic persons aged 50-74 years were invited to a second round of a FIT-based CRC screening pilot. We assessed the participation rate overall and within second round subgroups of previous participants, previous non-participants, and first time invitees. We also assessed whether participation rates were similar for males and females and for age groups. RESULTS: In the first screening round, 2871 of 5309 invitees returned the FIT (participation rate of 57%). This was higher than in the second in which 3187 of 5925 participated (54%; p = 0.0008). Second round participation rate was 85% (2034/2385) among previous participants, 18% (325/1826) among previous non-participants and 48% (828/1714) among first time invitees (p < .0001). Overall, males and persons aged under 55 were less likely to participate. CONCLUSIONS: Participation in a second round of FIT-screening was significantly lower than in the first round, largely due to a drop in participation in first round participants, and a relatively low response among first time invitees. This loss of uptake was partially compensated by a willingness to be screened in previous non-participants.

Earlier stages of colorectal cancer detected with immunochemical faecal occult blood tests.

BACKGROUND: The aim of colorectal cancer screening is to improve prognosis by the detection of early cancer and precursor stages. We compared the stage distribution of asymptomatic colorectal cancer patients detected by a positive immunochemical or guaiac-based faecal occult blood test (FOBT) with symptomatic colorectal cancer patients. METHODS: In a longitudinal cohort study tumour stages were assessed in 144 symptomatic (mean age 69.3 years, 56% male) and 41 asymptomatic colorectal cancer patients (mean age 64.9 years, 56% male) of which 11 were detected with guaiac FOBT s (G-FOBT, Hemoccult-II) and 30 with immunochemical FOBTs (I-FOBT, OCSensor). Stage distributions were used to calculate average stage specific predicted five-year survival rates and to analyse group differences with Wilcoxon log-rank test. RESULTS: Colorectal cancer was detected in significantly earlier stages in symptomatic compared with asymptomatic patients patients (p<0.0001). Average stage specific predicted five-year survival was 59.1% in symptomatic and 76.6% in asymptomatic patients. Compared with the symptomatic patients the stage distribution for colorectal cancer patients detected with Hemoccult-II was not significantly different(p=0.29), whereas colorectal cancer was detected at significantly earlier stages with the OCSensor (p<0.0001).Treatment could be confined to colonoscopy in 27% of the asymptomatic patients compared with 3% of the symptomatic patients (p<0.0001). Cancer distribution over the colon was comparable between symptomatic and asymptomatic patients (p=0.3). CONCLUSIONS: Compared with symptomatic patients,patients detected by FOBT and especially immunochemical FOBT , presented significantly more often at earlier stages suggesting increased survival. Additionally treatment could more often be confined to colonoscopy.