Eline H. Schreuders

Colorectal cancer screening: a global overview of existing programmes

Colorectal cancer (CRC) ranks third among the most commonly diagnosed cancers worldwide, with wide geographical variation in incidence and mortality across the world. Despite proof that screening can decrease CRC incidence and mortality, CRC screening is only offered to a small proportion of the target population worldwide. Throughout the world there are widespread differences in CRC screening implementation status and strategy. Differences can be attributed to geographical variation in CRC incidence, economic resources, healthcare structure and infrastructure to support screening such as the ability to identify the target population at risk and cancer registry availability. This review highlights issues to consider when implementing a CRC screening programme and gives a worldwide overview of CRC burden and the current status of screening programmes, with focus on international differences.

The Appropriateness of Surveillance Colonoscopy Intervals after Polypectomy

BACKGROUND Adherence to surveillance colonoscopy guidelines is important to prevent colorectal cancer (CRC) and unnecessary workload. OBJECTIVE To evaluate how well Canadian gastroenterologists adhere to colonoscopy surveillance guidelines after adenoma removal or treatment for CRC. METHODS Patients with a history of adenomas or CRC who had surveillance performed between October 2008 and October 2010 were retrospectively included. Time intervals between index colonoscopy and surveillance were compared with the 2008 guideline recommendations of the American Gastroenterological Association and regarded as appropriate when the surveillance interval was within six months of the recommended time interval. RESULTS A total of 265 patients were included (52% men; mean age 58 years). Among patients with a normal index colonoscopy (n=110), 42% received surveillance on time, 38% too early (median difference = 1.2 years too early) and 20% too late (median difference = 1.0 year too late). Among patients with nonadvanced adenomas at index (n=96), 25% underwent surveillance on time, 61% too early (median difference = 1.85) and 14% too late (median difference = 1.1). Among patients with advanced neoplasia at index (n=59), 29% underwent surveillance on time, 34% too early (median difference = 1.86) and 37% later than recommended (median difference = 1.61). No significant difference in adenoma detection rates was observed when too early surveillance versus appropriate surveillance (34% versus 33%; P=0.92) and too late surveillance versus appropriate surveillance (21% versus 33%; P=0.11) were compared. CONCLUSION Only a minority of surveillance colonoscopies were performed according to guideline recommendations. Deviation from the guidelines did not improve the adenoma detection rate. Interventions aimed at improving adherence to surveillance guidelines are needed.

Awareness of Postpolypectomy Surveillance Guidelines: A Nationwide Survey of Colonoscopists in Canada

INTRODUCTION Due to the increasing demand for colonoscopy, adherence to postpolypectomy surveillance guidelines is important. Suboptimal compliance can lead to unnecessary risks and ineffective use of resources. OBJECTIVE To determine the awareness of and adherence to postpolypectomy surveillance guidelines among members of the Canadian Association of Gastroenterology (CAG). METHODS A survey describing 14 clinical cases was mailed to all physician members (n=411) of the CAG. Respondents were required to recommend a surveillance interval and a reason for his or her choice. RESULTS A total of 150 colonoscopists (37%) completed the survey. Adherence to the guidelines varied from 23% to 96% per clinical scenario (median 63%). Recommended surveillance intervals were too short in 0% to 60% of the different cases (median 8%). The recommended interval was most often (60%) too short for a patient with one tubular adenoma with high-grade dysplasia. Surveillance intervals were too long in 4% to 75% of the cases (median 9%). The recommended interval was most often too long in a patient with a villous adenoma 15 mm in size and removed piecemeal (75%). Most often, recommendations were reported to be based on guidelines (median 74%; range 31% to 94%). However, in nine of 14 cases, more than 10% (median 18%; range 12% to 38%) of the respondents stated that their recommendation was based on guidelines, but did not provide the appropriate surveillance interval. CONCLUSIONS Compliance to colonoscopy surveillance guidelines is suboptimal and reflects both overuse and underuse. The results show that awareness about the content of guidelines needs to be raised and strategies implemented to increase adherence.

Advances in Fecal Tests for Colorectal Cancer Screening

Opinion statementColorectal cancer (CRC) forms an important public health problem, especially in developed countries. CRC screening tests can be used to identify asymptomatic individuals with CRC precursors and (early) cancer. Removal of these lesions reduces CRC incidence and prevents CRC-related mortality. There are a range of screening tests available, each with advantages and disadvantages. Stool screening tests can broadly be divided into fecal occult blood tests (FOBTs) and molecular biomarker test, such as DNA/RNA marker tests, protein markers, and fecal microbiome marker tests. Guaiac fecal occult blood tests (gFOBT) have been demonstrated in large randomized screening trials to reduce CRC mortality. Fecal immunochemical tests (FIT) have superior adherence, usability, and accuracy as compared to gFOBT. Advantage of the use of quantitative FITs in CRC screening programs is the cut-off level that can be adjusted. Molecular biomarker DNA tests have shown to detect significantly more cancers than FIT. By combining biomarker DNA tests with FIT, sensitivity for advanced adenomas can be increased significantly. However, it has lower specificity thus demands more colonoscopy resources, is more cumbersome, and costly. The adherence has not been assessed in population screening trials. For these reasons, FIT is therefore at present regarded as the preferred method of non-invasive CRC screening. This chapter will review the current status of fecal test-based CRC screening.

Variable Quality and Readability of Patient-oriented Websites on Colorectal Cancer Screening

BACKGROUND & AIMS: The efficacy of colorectal cancer (CRC) screening is dependent on participation and subsequent adherence to surveillance. The internet increasingly is used for health information and is important to support decision making. We evaluated the accuracy, quality, and readability of online information on CRC screening and surveillance. METHODS: A Website Accuracy Score and Polyp Score were developed, which awarded points for various aspects of CRC screening and surveillance. Websites also were evaluated using validated internet quality instruments (Global Quality Score, LIDA, and DISCERN), and reading scores. Two raters independently assessed the top 30 websites appearing on Google.com. Portals, duplicates, and news articles were excluded. RESULTS: Twenty websites were included. The mean website accuracy score was 26 of 44 (range, 9–41). Websites with the highest scores were www.cancer.org, www.bowelcanceraustralia.org, and www.uptodate.com. The median polyp score was 3 of 10. The median global quality score was 3 of 5 (range, 2–5). The median overall LIDA score was 74% and the median DISCERN score was 45, both indicating moderate quality. The mean Flesch–Kincaid grade level was 11th grade, rating the websites as difficult to read, 30% had a reading level acceptable for the general public (Flesch Reading Ease > 60). There was no correlation between the Google rank and the website accuracy score (rs = ‐0.31; P = .18). CONCLUSIONS: There is marked variation in quality and readability of websites on CRC screening. Most websites do not address polyp surveillance. The poor correlation between quality and Google ranking suggests that screenees will miss out on high‐quality websites using standard search strategies.

Effects of Increasing Screening Age and Fecal Hemoglobin Cutoff Concentrations in a Colorectal Cancer Screening Program.

BACKGROUND & AIMS Several countries have implemented programs to screen for colorectal cancer (CRC) by using the fecal immunochemical test (FIT). These programs vary considerably in age of the population screened and the cutoff concentration of fecal hemoglobin (Hb) used to identify candidates for further evaluation; these variations are usually based on a countrys colonoscopy resources. We calculated how increasing the Hb cutoff concentration and screening age affects colonoscopy yield, missed lesions, and demand. METHODS We collected data from 10,008 average-risk individuals in The Netherlands, 50-74 years old, who were invited for an FIT in the first round of a population-based CRC screening program from November 2006 through December 2008. Fecal samples were collected, and levels of Hb were measured by using the OC-sensor Micro analyzer; concentrations ≥10 μg Hb/g feces were considered positive. Subjects with a positive FIT were scheduled for colonoscopy within 4 weeks. Logistic regression analysis was performed to evaluate the association between age and detection of advanced neoplasia. RESULTS In total, 5986 individuals (62%) participated in the study; 503 (8.4%) had a positive test result. Attendance, positive test results, detection of advanced neoplasia, and the FITs positive predictive value all increased significantly with age (P < .001). Detection of advanced neoplasia ranged from 1.3% in the youngest age group to 6.2% in the oldest group; the positive predictive value of the FIT was 26% in the youngest group and 47% in the oldest group. Increasing the starting age of invitees from 50-74 years to 55-74 years reduced the proportion of subjects who underwent colonoscopy evaluation by 14% and resulted in 9% more subjects with advanced neoplasia being missed. Increasing the cutoff concentration from 10 to 15 μg Hb/g feces reduced the proportion of subjects who underwent colonoscopy evaluation by 11% and resulted in 6% of advanced neoplasia being missed. CONCLUSIONS In an analysis of an average-risk screening population in The Netherlands, we found that detection of advanced neoplasia by FIT increases significantly with age and fecal Hb cutoff concentration. Increasing the cutoff concentration or screening age reduces the numbers of patients who undergo colonoscopy evaluation in FIT-based CRC screening programs. Our findings provide insight in these effects per age category and cutoff concentration and the consequences in terms of missed lesions.

Incidence of faecal occult blood test interval cancers in population-based colorectal cancer screening: a systematic review and meta-analysis

Objective Faecal immunochemical tests (FITs) are replacing guaiac faecal occult blood tests (gFOBTs) for colorectal cancer (CRC) screening. Incidence of interval colorectal cancer (iCRC) following a negative stool test result is not yet known. We aimed to compare incidence of iCRC following a negative FIT or gFOBT. Design We searched Ovid Medline, Embase, Cochrane Library, Science Citation Index, PubMed and Google Scholar from inception to 12 December 2017 for citations related to CRC screening based on stool tests. We included studies on FIT or gFOBT iCRC in average-risk screening populations. Main outcome was pooled incidence rate of iCRCs per 100 000 person-years (p-y). Pooled incidence rates were obtained by fitting random-effect Poisson regression models. Results We identified 7 426 records and included 29 studies. Meta-analyses comprised data of 6 987 825 subjects with a negative test result, in whom 11 932 screen-detected CRCs and 5 548 gFOBT or FIT iCRCs were documented. Median faecal haemoglobin (Hb) positivity cut-off used was 20 (range 10–200) µg Hb/g faeces in the 17 studies that provided FIT results. Pooled incidence rates of iCRC following FIT and gFOBT were 20 (95% CI 14 to 29; I2=99%) and 34 (95% CI 20 to 57; I2=99%) per 100 000 p-y, respectively. Pooled incidence rate ratio of FIT versus gFOBT iCRC was 0.58 (95% CI 0.32 to 1.07; I2=99%) and 0.36 (95% CI 0.17 to 0.75; I2=10%) in sensitivity analysis. For every FIT iCRC, 2.6 screen-detected CRCs were found (ratio 1:2.6); for gFOBT, the ratio between iCRC and screen-detected CRC was 1:1.2. Age below 60 years and the third screening round were significantly associated with a lower iCRC rate. Conclusion A negative gFOBT result is associated with a higher iCRC incidence than a negative FIT. This supports the use of FIT over gFOBT as CRC screening tool.

Optimizing Fecal Immunochemical Testing for Colorectal Cancer Screening

Colorectal cancer (CRC) screening aims to detect CRC and its precursors in an early phase, thereby reducing disease burden. This field is evolving rapidly, with an emphasis on population coverage, quality assurance, new screening methods, and individualized screening. There are various screening modalities available, each with their advantages and disadvantages. Guaiac fecal occult blood test (gFOBT) and sigmoidoscopy are the only strategies supported by evidence from prospective randomized controlled trials with CRC-related mortality as the end point. Fecal immunochemical testing (FIT) has been introduced as an alternative to gFOBT. FIT is easier to use, leads to higher population participation, and has higher accuracy for advanced neoplasia and CRC than gFOBT. FIT thus is expected to outperform gFOBT screening significantly in reducing CRC incidence and mortality. Consequently, most national screening programs in Europe and Asia-Pacific use FIT as the primary method for population-based screening. [...]