Population-based Colorectal Screening Program Research Articles

Interval Cancer in Population-Based Colorectal Screening Programmes: Incidence and Characteristics of Tumours.

The objective of this study is to evaluate interval cancer (IC) in colorectal cancer (CRC) screening, which is CRC diagnosed in an individual after having received a negative faecal occult blood test and before the next invitation to participate in screening. A follow-up study was conducted on a cohort of participants in the first three screening rounds of four colorectal cancer screening programmes in Spain, n = 664,993. A total of 321 ICs and 2120 screen-detected cancers (SCs) were found. The IC and SC rates were calculated for each guaiac (gFOBT) or immunochemical (FIT) test. A Cox regression model was used to estimate the hazard ratios (HR) of IC risk factors. A nested case-control study was carried out to compare IC and SC tumour characteristics. The IC rate was 1.16‱ with the gFOBT and 0.35‱ with the FIT. Men and people aged 60-69 showed an increased probability of IC (HR = 1.81 and HR = 1.95, respectively). There was a decreased probability of IC in individuals who regularly participated in screening, HR = 0.62 (0.47-0.82). IC risk gradually rose as the amount of Hb detected in the FIT increased. IC tumours were in more advanced stages and of a larger size than SC tumours, and they were mostly located in the cecum. These results may play a key role in future strategies for screening programmes, reducing IC incidence.

Intervening factors for participation and non-participation in colorectal cancer screening in Spain.

e22552 Background: The Spanish Ministry of Health introduced a population-based colorectal screening program within its common services portfolio in 2014. The program targeted adults from 50 to 69 years. They receive a personal invitation letter asking them to perform the fecal occult blood test (FOBT). To achieve public health benefits on incidence, mortality and cost-effectiveness from this screening program a 65% participation in the program is needed1.Although participation rates have been improved since 2014, there is still room from improvement as only 56% of the Spanish regions reach the participacion threshold2. In this study we examined attitudinal and social factors impacting on participation in the target population. Methods: A CAWI survey was conducted among the target population of the screening program using a nation-wide citizen panel. A representative sample of the Spanish population, with size of 5131 valid responses, was obtained. The fieldwork was conducted in June 22nd. The data was analyzed using a descriptive analysis for the entire sample as well as the logistic regression technique using the maximum likelihood estimation. This technique allows us to determine the variables that have the greatest predictive capacity with respect to the participation (or non-participation) on the (FOBT). Results: We found that 97.6% of people have heard of colon cancer, 86.8% are aware of the test, 72.5% have received the program information letter and 62.5% have performed the test (FOBT). Furthermore, logistic regression demonstrates that the reception of a program information letter (OR=7,381, p<0.01), and the prior knowledge of the screening test (FOBT) (OR=6,768, p<0,01) significantly predicted the participation. Other variables with a high contribution were age between 62-69 (OR= 1,470, p<0.01), the frequency of routine medical check-ups (OR= 1,717, p<0.01), a positive perception of routine medical checkups (OR= 1,659, p<0.01), and personal risk of colon cancer perception (OR= 1,404, p<0.01). Conclusions: The effective participation in the program is influenced by factors that are unrelated to the implementation process (including the reception of the invitation letter). Most influential factors on actual participation on the program are the prior knowledge of the program and the importance attributed to routine heath checkups. Specific interventions on these variables should be done concurrently with expanding coverage in order to achieve the goals of higher effective participation.

Perforation and post-polypectomy bleeding complicating colonoscopy in a population-based screening program.

Background and study aims We aimed to estimate the rate of hospital admissions for perforation and for post-polypectomy bleeding, after outpatient colonoscopy following a first positive fecal occult blood test screen through the population-based ColonCancerCheck program in Ontario, Canada. Patients and methods We identified all individuals aged 50 to 74 years with a first positive CCC gFOBT screening result from 2008 to 2017 who underwent outpatient colonoscopy ≤ 6 months later and who did not receive a diagnosis of CRC ≤ 24 months later. We identified inpatient hospital admissions for colonic perforation ≤ 7 days after and for post-polypectomy bleeding ≤ 14 days following colonoscopy. Results Among 121,626 individuals who underwent colonoscopy, the rate of perforation was 0.6 per 1000 from 2008 to 2012 and 0.4 per 1000 from 2013 to 2017. The rate was elevated among those aged 70 to 74 years; those with comorbidities; when colonoscopy was performed by endoscopists other than gastroenterologists or endoscopists with low prior year volume; and when polypectomy was performed during colonoscopy. The rate of bleeding was 4.3 per 1000 and was elevated among those aged 70 to 74 years, those with comorbidity, and with complex polypectomy. Both outcomes were more common among those aged 70 to 74 years, those with a 5-year cumulative Charlson score ≥ 1, those with prior hospitalization for ischemic heart disease, and those with endoscopists whose prior year colonoscopy volume was in the three lower quartiles. Conclusions Colonic perforation and post-polypectomy bleeding, among participants of population-based colorectal screening programs who test positive in the absence of colorectal cancer, are infrequent but serious complications, which increase with participant age and comorbidity, and with endoscopist characteristics.

Morbidity and mortality after major large bowel resection of non-malignant polyp among participants in a population-based screening program.

Background and aimsColonoscopy following positive fecal occult blood screening may detect non-malignant polyps deemed to require major large bowel resection. We aimed to estimate the major inpatient morbidity and mortality associated with major resection of non-malignant polyps detected at colonoscopy following positive guaiac fecal occult blood screening in Ontario's population-based colorectal screening program.MethodsWe identified those without a diagnosis of colorectal cancer in the Ontario Cancer Registry ≤24 months following the date of colonoscopy prompted by positive fecal occult blood screening between 2008 and 2017, who underwent a major large bowel resection ≤24 months after the colonoscopy, with a diagnosis code for non-malignant polyp, in the absence of a code for any other large bowel diagnosis. We extracted records of major inpatient complications and readmissions ≤30 days following resection. We computed mortality within 90 days following resection.ResultsFor those undergoing colonoscopy ≤6 months following positive guaiac fecal occult blood screening, 420/127,872 (0.03%) underwent major large bowel resection for a non-malignant polyp. In 50/420 (11.9%), the resection included one or more rectosigmoid or rectal polyps, with or without a colonic polyp. There were one or more major inpatient complications or readmissions within 30 days in 117/420 (27.9%). Death occurred within 90 days in 6/420 (1.4%).ConclusionsSerious inpatient complications and readmissions following major large bowel resection for non-malignant colorectal polyps are common, but mortality ≤90 days following resection is low. These outcomes should be considered as unintended adverse consequences of population-based colorectal screening programs.

Morbidity and mortality following major large bowel resection for colorectal cancer detected by a population-based screening program

In 2008, Ontario initiated a population-based colorectal screening program using guaiac fecal occult blood testing. This work was undertaken to fill a major gap in knowledge by estimating serious post-operative complications and mortality following major large bowel resection of colorectal cancer detected by a population-based screening program. We identified persons with a first positive fecal occult blood result between 2008 and 2016, at the age of 50-74 years, who underwent a colonoscopy within 6 months, and proceeded to major large bowel resection for colon cancer within 6 months or rectosigmoid/rectal cancer within 12 months, and identified an unscreened cohort of resected cases diagnosed during the same years at the age of 50-74 years. We identified serious postoperative complications and readmissions ≤30 days following resection, and postoperative mortality ≤30 days, and between 31 and 90 days among the screen-detected and the unscreened cohorts. Serious post-operative complications or readmissions within 30 days were observed among 1476/4999 (29.5%) cases in the screen-detected cohort, and among 3060/8848 (34.6%) unscreened cases. Mortality within 30 days was 43/4999 (0.9%) among the screen-detected cohort, and 208/8848 (2.4%) among the unscreened cohort. Among 30 day survivors, mortality between 31 and 90 days was 28/4956 (0.6%) and 111/8640 (1.3%), respectively. Serious post-operative complications, readmissions, and mortality may be more common following major large bowel resection for colorectal cancer between the ages of 50 and 74 among unscreened compared to screen-detected cases.

False-Positive Results in a Population-Based Colorectal Screening Program: Cumulative Risk from 2000 to 2017 with Biennial Screening.

The aim of this study was to estimate the cumulative risk of a false-positive (FP) result in a fecal occult blood test (FOBT) through 7 screening rounds and to identify its associated factors in a population-based colorectal cancer screening program. Retrospective cohort study, which included participants ages 50 to 69 years of a colorectal cancer screening program in Catalonia, Spain. During this period, 2 FOBTs were used (guaiac and immunochemical). A discrete-time survival model was performed to identify risk factors of receiving a positive FOBT with no high-risk adenoma or colorectal cancer in the follow-up colonoscopy. We estimated the probability of having at least 1 FP over 7 screening rounds. During the period of 2000 to 2017, the cumulative FP risk was 16.3% (IC95%: 14.6%-18.3%), adjusted by age, sex, and type of test. The median number of screens was 2. Participants who began screening at age 50 years had a 7.3% [95% confidence interval (CI), 6.35-8.51] and a 12.4% (95% CI, 11.00-13.94) probability of an FP with 4 screening rounds of guaiac-based test and immunochemical test, respectively. Age, the fecal immunochemical test, first screening, and number of personal screens were factors associated with an FP result among screenees. The cumulative risk of an FP in colorectal screening using FOBT seems acceptable as the colonoscopy, with its high accuracy, lengthens the time until additional colorectal screening is required, while complication rates remain low. It is useful to determine the cumulative FP risk in cancer screening for both advising individuals and for health resources planning.

Comparison of prognostic models to predict the occurrence of colorectal cancer in asymptomatic individuals: a systematic literature review and external validation in the EPIC and UK Biobank prospective cohort studies

ObjectiveTo systematically identify and validate published colorectal cancer risk prediction models that do not require invasive testing in two large population-based prospective cohorts.DesignModels were identified through an update of a...

Assessment of a Colonoscopy Triage Sheet for Use in a Province-Wide Population-Based Colorectal Screening Program

Background and Aims. A colonoscopy triage sheet (CTS) integrating 6 hierarchical scheduling priorities based on indications for screening, surveillance, or symptoms was designed for colonoscopy referral. We compared CTS priority ratings by referring physicians and endoscopists, assessing yields. Methods. Retrospective study of consecutive patients. Data were collected on demographics, CTS and endoscopist priority ratings, and endoscopic findings. Weighted kappa values measured interrater agreement on priority assignment. Predictors of agreement and lesions were identified using multivariable analysis. Results. Among 1230 patients (60.3 years, 52.5% female), clinically significant lesions included tumors (1.1%), polyps per patient ≥ 10 mm (7.6%), and ileocolitis (4.6%). Moderate agreement was found between referring physician and endoscopist on all 6 priorities (weighted kappa 0.55 (0.51; 0.59)). P4 and P5 ratings predicted increased agreement (range of OR for P4: 2.47–4.57; P5: 1.58–2.93). Predictors of clinically significant findings were male gender (OR 1.44, 1.03–2.03) and P1/P2 priorities that were significantly superior to P3 (OR = 2.14; 1.04–4.43), P4 (OR = 2.90; 1.35–6.23), and P5 (OR = 4.30; 2.08–8.88). Conclusion. Priority-assignment agreement is moderate and highest for less urgent ratings. Predictors of clinically significant findings validate the hierarchal priority scheme. Broader validation and physician education are needed.

Mo1083 Assessment of a Colonoscopy Triage Sheet for Use in a Province-Wide Population-Based Colorectal Screening Program

Mo1083 Assessment of a Colonoscopy Triage Sheet for Use in a Province-Wide Population-Based Colorectal Screening Program

Effect of oral anticoagulants on the outcome of faecal immunochemical test

Background:We aimed to evaluate whether oral anticoagulants (OACs) alter faecal immunochemical test (FIT) performance in average-risk colorectal cancer (CRC) screening.Methods:Individuals aged 50–69 years were invited to receive one FIT sample (cutoff 75 ng ml–1) between November 2008 and June 2011.Results:Faecal immunochemical test was positive in 9.3% (21 out of 224) of users of OAC and 6.2% (365 out of 5821) of non-users (P-trend=0.07). The positive predictive value (PPV) for advanced neoplasia (AN) in non-users was 50.4% vs 47.6% in users (odds ratio, 0.70; 95% CI, 0.3–1.8; P=0.5). The PPV for AN in OAC more antiplatelets (aspirin or clopidogrel) was 75% (odds ratio, 2; 95% CI, 0.4–10.8; P=0.4).Conclusions:Oral anticoagulant did not significantly modify the PPV for AN in this population-based colorectal screening program. The detection rate of advanced adenoma was higher in the combination OAC more antiplatelets.

Effect of Aspirin and Antiplatelet Drugs on the Outcome of the Fecal Immunochemical Test

ObjectiveTo evaluate the effect of aspirin and nonaspirin antiplatelet agents (NAAAs) on the performance of the fecal immunochemical test (FIT). Participants and MethodsWe performed a post hoc analysis of results from a clinical trial that involved 28,696 asymptomatic average-risk men and women aged 50 to 69 years invited to participate in a colorectal cancer screening program with FIT between November 1, 2008, and June 31, 2011. ResultsThe test was returned by 6390 individuals (22.3%), of whom 5821 (91.1%) reported not using antiplatelet drugs (nonusers group) and 569 (8.9%) reported using these drugs at the time of testing (users group). The FIT result was positive in 48 of 569 users (8.4%) and 365 of 5821 nonusers (6.3%) (P=.05). A positive FIT result was found in 7.3% (28/384) of aspirin users, 7.1% (10/140) of NAAA users, and 22.2% (10/45) of those undergoing dual antiplatelet therapy (DAPT) (aspirin plus an NAAA). The DAPT subgroup had a significantly higher positive FIT rate than the nonuser group (odds ratio, 3.5; 95% CI, 1.7-7.3; P<.05). The positive predictive value (PPV) for advanced neoplasia (AN) in nonusers was 50.4% vs 50.0% in users (P = .40). The PPV for AN was 57.0% in aspirin users, 30.0% in NAAA users, and 50.0% in DAPT users, without statistically significant differences between the user and nonuser groups. ConclusionThe use of DAPT increased the rate of positive FIT results. Use of aspirin, NAAAs, or both did not modify the PPV for AN in this population-based colorectal screening program. Trial Registrationclinicaltrials.gov Identifier: NCT00906997

Adherence to colorectal polyp surveillance guidelines

Colorectal polyps are usually asymptomatic and are found opportunistically. Individuals with adenomata are at increased risk for cancer and therefore guidelines exist for surveillance of these lesions including those of the British Society of Gastroenterology (BSG). Deviation from these guidelines is common and increases the workload of endoscopy. We examined those individuals waiting for endoscopy for polyp surveillance to see whether strict adherence to BSG guidelines could facilitate opportunities for screening. A total of 413 patients with earlier colonic polyps were examined, of whom 50 patients were excluded based on having alternative indications for surveillance, 179 (49.3%) were appropriately scheduled for surveillance and 184 patients (55.9%) were scheduled incorrectly. Seventy-nine patients (30%) could have been discharged; of these, 59 had hyperplastic polyps. Of the remaining 105 inappropriate triages under surveillance at the wrong interval, seven patients were scheduled for too infrequent surveillance and 98 were too frequent. A total of 284 patients with adenomatous polyps were under surveillance of whom 11 patients (3.8%) were in the high-risk category and all were appropriately scheduled, and 75 patients (26.4%) were in the intermediate-risk category, of whom 48 were appropriately scheduled, 20 were incorrectly triaged as high risk and seven were triaged as low risk. A total of 198 (69.7%) patients were in the low-risk category, 117 of these were correctly triaged, 15 were incorrectly triaged as high risk and 66 were classified as intermediate risk. Over a five-year period, 318 unnecessary colonoscopies are being performed. On the basis of the data obtained from a population-based colorectal screening programme using immunohistochemical-faecal occult blood testing in our department another 1516 patients could be screened annually without requiring any additional endoscopy resources, if strict adherence to guidelines was assured.

Effect of Gender, Age and Deprivation on Key Performance Indicators in a Fobt-based Colorectal Screening Programme

To assess the effect of gender, age and deprivation on key performance indicators in a colorectal cancer screening programme. Between March 2000 and May 2006 a demonstration pilot of biennial guaiac faecal occult blood test (gFOBT) colorectal screening was carried out in North-East Scotland for all individuals aged 50-69 years. The relevant populations were subdivided, by gender, into four age groups and into five deprivation categories according to the Scottish Index of Multiple Deprivation (SIMD), and key performance indicators analysed within these groups. In all rounds, uptake of the gFOBT increased with age (P < 0.001), decreased with increasing deprivation in both genders (P < 0.001), and was consistently higher in women than in men in all age and all SIMD groups. In addition, increasing deprivation was negatively associated with uptake of colonoscopy in men with a positive gFOBT (P < 0.001) although this effect was not observed in women. Positivity rates increased with age (P < 0.001) and increasing deprivation (P < 0.001) in both genders in all rounds, although they were higher in men than in women for all age and SIMD categories. Cancer detection rates increased with age (P < 0.001), were higher in men than in women in all age and SIMD categories, but were not consistently related to deprivation. In both genders, the positive predictive value (PPV) for cancer increased with age (P < 0.001) and decreased with increasing deprivation (P < 0.001) in all rounds and was consistently higher in men than in women in all age and SIMD categories. In this population-based colorectal screening programme gender, age, and deprivation had marked effects on key performance indicators, and this has implications both for the evaluation of screening programmes and for strategies designed to reduce inequalities.