An efficient strategy for evaluating new non-invasive screening tests for colorectal cancer: the guiding principles.

OBJECTIVE: New screening tests for colorectal cancer (CRC) are rapidly emerging. Conducting trials with mortality reduction as the end point supporting their adoption is challenging. We re-examined the principles underlying evaluation of new non-invasive tests in view of technological developments and identification of new biomarkers. DESIGN: A formal consensus approach involving a multidisciplinary expert panel revised eight previously established principles. RESULTS: Twelve newly stated principles emerged. Effectiveness of a new test can be evaluated by comparison with a proven comparator non-invasive test. The faecal immunochemical test is now considered the appropriate comparator, while colonoscopy remains the diagnostic standard. For a new test to be able to meet differing screening goals and regulatory requirements, flexibility to adjust its positivity threshold is desirable. A rigorous and efficient four-phased approach is proposed, commencing with small studies assessing the test's ability to discriminate between CRC and non-cancer states (phase I), followed by prospective estimation of accuracy across the continuum of neoplastic lesions in neoplasia-enriched populations (phase II). If these show promise, a provisional test positivity threshold is set before evaluation in typical screening populations. Phase III prospective studies determine single round intention-to-screen programme outcomes and confirm the test positivity threshold. Phase IV studies involve evaluation over repeated screening rounds with monitoring for missed lesions. Phases III and IV findings will provide the real-world data required to model test impact on CRC mortality and incidence. CONCLUSION: New non-invasive tests can be efficiently evaluated by a rigorous phased comparative approach, generating data from unbiased populations that inform predictions of their health impact.

Diagnostic yield of a risk model versus faecal immunochemical test only: a randomised controlled trial in a colorectal cancer screening programme.

BACKGROUND: Combining the faecal immunochemical test (FIT) result with risk factors for advanced neoplasia (AN) may increase the yield of colorectal cancer (CRC) screening without increasing the number of colonoscopies. We conducted a randomised controlled trial in the Dutch CRC screening programme to evaluate a previously developed risk model including FIT, age, sex, smoking status, and CRC family history. METHODS: A total of 22,748 individuals aged 56-75 years were pre-randomised to the risk-model group or the FIT-only group. Both groups received the FIT; those allocated to the risk-model group also received a single-page questionnaire. Study participants with a positive result (FIT ≥ 15 µg Hb/g faeces and/or risk ≥0.10) were referred for colonoscopy. The primary outcome measure was the proportion of invitees in whom AN was detected. RESULTS: In the risk-model group, 3113/11,364 invitees (27%) returned the FIT and questionnaire versus 3061/11,384 invitees (27%) in the FIT-only group (p = 0.40). The yield of AN was 3.70/1000 invitees in the risk-model group versus 3.43/1000 in the FIT-only group (absolute difference: 0.27/1000, 95%CI: -1.30 to 1.82, p = 0.82). CONCLUSIONS: Combining FIT with risk factors for CRC did not increase the yield of AN compared to FIT-only in an existing CRC screening programme. There was no difference in participation between groups. CLINICAL TRIAL REGISTRATION: NCT04490551 (ClinicalTrials.gov).

The national FIT-based colorectal cancer screening program in the Netherlands during the COVID-19 pandemic.

The COVID-19 pandemic has affected many healthcare services worldwide. Like many other nations, the Netherlands experienced large numbers of individuals affected by COVID-19 in 2020, leading to increased demands on hospitals and intensive care units. The Dutch Ministry of Health decided to suspend the Dutch biennial fecal immunochemical test (FIT) based colorectal cancer (CRC) screening program from March 16, 2020. FIT invitations were resumed on June 3. In this study, we describe the short-term effects of this suspension on a myriad of relevant screening outcomes. As a result of the suspension, a quarter of the individuals due for screening between March and November 2020 had not received their invitation for FIT screening by November 30, 2020. Furthermore, 57.8% of those who received a consecutive FIT between the restart and November 30, 2020, received it outside the upper limit of the standard screening interval (26 months). Median time between positive FIT and colonoscopy did not change as a result of the pandemic. Participation rates of FIT screening and follow-up colonoscopy in the months just before and during the suspension were significantly lower than expected, but returned to normal levels after the suspension. Based on the anticipated 2020 cohort size, we estimate that the number of individuals with advanced neoplasia currently detected up until November 2020 was 31.2% lower compared to what would have been expected without a pandemic. Future studies should monitor the impact on long-term screening outcomes as a result of the pandemic.

Stable hemoglobin concentration with fecal immunochemical test at high temperatures in a Caribbean colorectal cancer screening program.

BACKGROUND AND AIMS: High temperatures may reduce fecal immunochemical test (FIT) positivity and colorectal cancer (CRC) detection sensitivity. We investigated the effect of temperature on hemoglobin concentration [Hb], in the FOB Gold®. Additionally, we examined FIT pick-up, storage, return times and specimen collection. MATERIALS AND METHODS: In vitro experiments with buffer containing FIT devices, inoculated with Hb-spiked stool. For 7 days, 144 samples were stored in groups of 36 at 4 °C, 22 °C, 30 °C, and 50 °C. Additionally, 54 samples were stored in groups of 18 at 34 °C, 42 °C and 50 °C for 20 h. Paired t-tests and repeated measure ANOVA assessed [Hb] change. Sixty-five screening participants completed a FIT-handling questionnaire. RESULTS: After 7 days, mean [Hb] was stable at 30 °C (0.8 µg Hb/g;95 %CI: -1.5 to 3.1;p = 0.50). For 50 °C, mean [Hb] decreased within 2 days (-21.3 µg Hb/g;95 %CI: -30.2 to -12.5;p < 0.001) and after 20 h (-63.0 µg Hb/g;95 %CI: -88.7 to -37.3;p < 0.001), respectively. All other temperature categories showed significant mean [Hb] increase. Same-day FIT return was reported by 80 %. Eighty-seven percent experienced specimen collection as easy and 33 % kept the FIT refrigerated after collection. CONCLUSIONS: The FOB Gold® is suitable for CRC screening in tropical climates. Although most respondents indicated same-day sample return, we recommend avoiding FIT storage above 30 °C for longer than7 days.

Cross-sectional risk models using quantitative fecal hemoglobin in colorectal cancer screening: a systematic review.

INTRODUCTION: Fecal Immunochemical Testing (FIT) is a central tool in colorectal cancer (CRC) screening. To improve the selection of individuals for colonoscopy, risk models combining FIT with additional CRC risk factors have been developed. This systematic review aims to provide an overview of the current noninvasive FIT-based risk models for CRC screening to facilitate future implementation. METHODS: We performed a systematic literature search for risk models that combined quantitative fecal hemoglobin with clinical data or noninvasive biomarkers and that were intended for CRC screening. Risk of bias was assessed using the PROBAST tool. RESULTS: Twenty risk models reported across 29 publications were included. The overall risk of bias was high. In studies that compared risk models to FIT, 11/12 (92%) risk models had a significantly higher c-statistic than FIT only. 16/20 risk models (80%) had not been externally validated and only one model has been implemented so far. CONCLUSION: FIT-based risk models have the potential to improve the yield of CRC screening. Unfortunately, all included publications had a high risk of bias and most risk models have not yet been externally validated. The prospect of improved CRC screening with risk models should encourage more rigorous evaluation in existing screening programs.

Individualized faecal immunochemical test cut-off based on age and sex in colorectal cancer screening.

The risk of having colorectal cancer (CRC) or its precursors vary with age and sex. Yet, most CRC screening programs using the quantitative faecal immunochemical test (FIT) use a uniform FIT cut-off. We aimed to calculate individualized FIT cut-offs based on age and sex. Data from a study of 1,112 asymptomatic average-risk screening participants undergoing colonoscopy without preselection were used to build a logistic regression model to calculate the risk of having advanced neoplasia (AN) at colonoscopy using age, sex, and FIT concentration as variables. We calculated age- and sex-adjusted FIT cut-off concentrations based on a uniform risk threshold. In a total of 101 of the 1,112 participants AN was detected at colonoscopy. We selected a risk threshold that would produce a specificity of 96.9% in the study group, matching the specificity of FIT at a cut-off of 20 µg Hb/g faeces. At this threshold, age- and sex-adjusted FIT cut-off concentrations ranged from 36.9 µg Hb/g faeces for 50-year-old women to 9.5 µg Hb/g faeces for 75-year old men. At this level of specificity, the risk-based model reached a sensitivity for AN of 28.7% (95%CI: 20.8 to 38.2) versus 27.7% (95%CI: 19.9 to 37.1) for FIT only. Using a risk threshold instead of a uniform FIT-based threshold for inviting screening participants to follow-up colonoscopy ensures that everyone has a comparable risk of AN prior to colonoscopy and may improve the detection of advanced neoplasia, although the absolute magnitude of the increase is likely to be limited.

Low-FODMAP Diet Is Associated With Improved Quality of Life in IBS Patients-A Prospective Observational Study.

BACKGROUND: The low fermentable oligosaccharide, disaccharide, monosaccharide, and polyol (FODMAP) diet is effectively manages irritable bowel syndrome (IBS) symptoms. Long-term low-FODMAP studies rarely report quality of life (QoL). We aimed to determine the effect of low-FODMAP diet on long-term QoL, gastrointestinal (GI) and non-GI symptoms in IBS patients. METHODS: A prospective observational study of IBS patients referred for low-FODMAP dietary advice was performed. The primary outcome of QoL and secondary outcomes of GI symptoms, anxiety/depression, fatigue, sleep quality, and happiness were obtained at baseline, 6 weeks (T6), and 6 months (T26). RESULTS: 111 patients were recruited. 91.0%, 71.6%, and 50.5% of participants completed baseline, T6, and T26 assessments, respectively. There were significant improvements in QoL from baseline at T6 and T26 (both P < 0.001). Significant reductions were seen in GI symptoms at T6 and T26 (both P < 0.001), fatigue at T6 and T26 (both P < 0.003), and anxiety at T6 and T26 (both P < 0.007), compared with baseline. A significant reduction was seen for depression (P < 0.010) from baseline at T26, and a significant increase was seen for both happiness and vitality (both P < 0.04) from baseline at T26. There was a significant correlation between GI symptom response and change in QoL, anxiety, depression, and fatigue (all P < 0.034). CONCLUSION: Low-FODMAP diet was associated with improved long-term QoL and GI symptoms, reduced fatigue and anxiety/depression, and increased happiness and vitality. These data support a wider range of benefits for IBS patients consuming a low-FODMAP diet.

The IBD-Cope: A New Instrument for Measuring Coping in Inflammatory Bowel Disease Patients.

BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) has a major impact on psychological well-being. How an individual copes with IBD determines quality of life. We aimed to develop a brief, IBD-specific questionnaire to assess coping strategies (IBD-Cope) and to determine its test-retest reliability and validity. METHODS: Twenty IBD coping strategies were initially deemed to have face validity. Participants were recruited from an existing study, specialist outpatient clinics and via email. Distribution analyses were performed before test-retest reliability was determined. Exploratory factor analyses (EFAs) were then performed before cross-sectional validity was tested. RESULTS: The majority of participants in the study samples were female and most had Crohn's disease. All participants were aged between 18 and 65 years. EFA on the initial validation sample produced two components explaining 42% of the variance, and broadly reflected 'good' and 'bad' coping. EFA on the repeat validation sample showed three questions consistently clustering into either good or bad coping strategies. Good and bad coping strategies defined using the IBD-Cope were positively associated with adaptive (r = 0.57, p < 0.01) and maladaptive (r = 0.55, p < 0.01) coping on the Brief Coping Operations Preference Enquiry (Brief COPE), respectively. CONCLUSIONS: The IBD-Cope is a concise IBD-specific coping strategy questionnaire with demonstrated reliability and validity. The IBD-Cope subscales are moderately correlated with adaptive and maladaptive subscales of the Brief COPE. Prospective studies are required to determine whether the 6 questions represented in the IBD-Cope accurately identify IBD patients who may benefit from interventions to improve coping strategies.

Low FODMAP diet efficacy in IBS patients-what is the evidence and what else do we need to know?

Irritable Bowel Syndrome (IBS) is a common and significant health problem which may be treatable with dietary interventions. Here we aim to explain the principles of the low Fermentable Oligo-, Di-, Monosaccharides and Polyol diet, and discuss both the limitations and opportunities of the diet in those with IBS, a common cause of presentation to primary and secondary care in New Zealand.