Fecal Immunochemical Test Results Research Articles

Timeliness of Follow-Up to a Positive Fecal Immunochemical Test Result Among Community Health Center Patients

Timeliness of Follow-Up to a Positive Fecal Immunochemical Test Result Among Community Health Center Patients

Nonbleeding adenomas: Evidence of systematic false-negative fecal immunochemical test results and their implications for screening effectiveness-A modeling study.

If some adenomas do not bleed over several years, they will cause systematic false-negative fecal immunochemical test (FIT) results. The long-term effectiveness of FIT screening has been estimated without accounting for such systematic false-negativity. There are now data with which to evaluate this issue. The authors developed one microsimulation model (MISCAN [MIcrosimulation SCreening ANalysis]-Colon) without systematic false-negative FIT results and one model that allowed a percentage of adenomas to be systematically missed in successive FIT screening rounds. Both variants were adjusted to reproduce the first-round findings of the Dutch CORERO FIT screening trial. The authors then compared simulated detection rates in the second screening round with those observed, and adjusted the simulated percentage of systematically missed adenomas to those data. Finally, the authors calculated the impact of systematic false-negative FIT results on the effectiveness of repeated FIT screening. The model without systematic false-negativity simulated higher detection rates in the second screening round than observed. These observed rates could be reproduced when assuming that FIT systematically missed 26% of advanced and 73% of nonadvanced adenomas. To reduce the false-positive rate in the second round to the observed level, the authors also had to assume that 30% of false-positive findings were systematically false-positive. Systematic false-negative FIT testing limits the long-term reduction of biennial FIT screening in the incidence of colorectal cancer (35.6% vs 40.9%) and its mortality (55.2% vs 59.0%) in participants. The results of the current study provide convincing evidence based on the combination of real-life and modeling data that a percentage of adenomas are systematically missed by repeat FIT screening. This impairs the efficacy of FIT screening. Cancer 2016;122:1680-8. © 2016 American Cancer Society.

Sa1084 Replacing the Guaiac Fecal Occult Blood Test With the Fecal Immunochemical Test Results in Higher Colorectal Cancer Screening Completion in a Large Healthcare Setting in the United States

Sa1084 Replacing the Guaiac Fecal Occult Blood Test With the Fecal Immunochemical Test Results in Higher Colorectal Cancer Screening Completion in a Large Healthcare Setting in the United States

Su1042 Risk Factors for False Fecal Immunochemical Test Results in Colorectal Cancer Screening

Su1042 Risk Factors for False Fecal Immunochemical Test Results in Colorectal Cancer Screening

Timeliness of Colonoscopy After Abnormal Fecal Test Results in a Safety Net Practice.

Fecal testing can only reduce colorectal cancer mortality if patients with an abnormal test result receive a follow-up colonoscopy. As part of the Strategies and Opportunities to STOP Colon Cancer in Priority Populations (STOP CRC) project, we examined factors associated with adherence to follow-up colonoscopy among patients with abnormal fecal test results. As part of STOP CRC outreach, Virginia Garcia Memorial Health Center staff distributed 1753 fecal immunochemical tests (FIT), of which 677 (39%) were completed, and 56 had an abnormal result (8%). Project staff used logistic regression analyses to examine factors associated with colonoscopy referral and completion. Of the 56 patients with abnormal FIT results; 45 (80%) had evidence of a referral for colonoscopy, 32 (57%) had evidence of a completed colonoscopy within 18months, and 14 (25%) within 60days of an abnormal fecal test result. In adjusted analysis, Hispanics had lower odds of completing follow-up colonoscopy within 60days than non-Hispanic whites (adjusted OR 0.20; 95% CI 0.04, 0.92). Colonoscopy within 60days trended lower for women than for men (adjusted OR 0.25; 95% CI 0.06-1.04). Among the 24 patients lacking medical record evidence of a colonoscopy, 19 (79%) had a documented reason, including clinician did not pursue, patient refused, and colonoscopy not indicated. No reason was found for 21%. Improvements are needed to increase rates of follow-up colonoscopy completion, especially among female and Hispanic patients.

Fecal Immunochemical Test Program Performance Over 4 Rounds of Annual Screening

The fecal immunochemical test (FIT) is a common method for colorectal cancer (CRC) screening, yet its acceptability and performance over several rounds of annual testing are largely unknown. To assess FIT performance characteristics over 4 rounds of annual screening. Retrospective cohort study. Kaiser Permanente Northern and Southern California. 323349 health plan members aged 50 to 70 years on their FIT mailing date in 2007 or 2008 who completed the first round of FIT and were followed for up to 4 screening rounds. Screening participation, FIT positivity (≥20 µg of hemoglobin/g), positive predictive values for adenoma and CRC, and FIT sensitivity for detecting CRC obtained from Kaiser Permanente electronic databases and cancer registries. Of the patients invited for screening, 48.2% participated in round 1. Of those who remained eligible, 75.3% to 86.1% participated in subsequent rounds. Median follow-up was 4.0 years, and 32% of round 1 participants crossed over to endoscopy over 4 screening rounds-7.0% due to a positive FIT result. The FIT positivity rate (5.0%) and positive predictive values (adenoma, 51.5%; CRC, 3.4%) were highest in round 1. Overall, programmatic FIT screening detected 80.4% of patients with CRC diagnosed within 1 year of testing, including 84.5% in round 1 and 73.4% to 78.0% in subsequent rounds. Screening detection, rather than long-term cancer prevention, was evaluated. Annual FIT screening was associated with high sensitivity for CRC, with high adherence to annual follow-up screening among initial participants. The findings indicate that annual programmatic FIT screening is feasible and effective for population-level CRC screening. National Institutes of Health.

Ulcerative colitis patients in clinical remission demonstrate correlations between fecal immunochemical test results, mucosal healing, and risk of relapse.

To assess the risk of relapse in ulcerative colitis (UC) patients in clinical remission using mucosal status and fecal immunochemical test (FIT) results. The clinical outcomes of 194 UC patients in clinical remission who underwent colonoscopy were based on evaluations of Mayo endoscopic subscores (MESs) and FIT results. Patients with an MES of 0 (n = 94, 48%) showed a ten-fold lower risk of relapse than those with an MES of 1-3 (n = 100, 52%) (HR = 0.10, 95%CI: 0.05-0.19). A negative FIT result (fecal hemoglobin concentrations ≤ 100 ng/mL) was predictive of patients with an MES of 0, with a sensitivity of 0.94 and a specific of 0.76. Moreover, patients with a negative FIT score had a six-fold lower risk of clinical relapse than those with a positive score (HR = 0.17, 95%CI: 0.10-0.28). Inclusion of the distinguishing parameter, sustaining clinical remission > 12 mo, resulted in an even stronger correlation between negative FIT results and an MES of 0 with respect to the risk of clinical relapse (HR = 0.11, 95%CI: 0.04-0.23). Negative FIT results one year or more after remission induction correlate with complete mucosal healing (MES 0) and better prognosis. Performing FIT one year after remission induction may be useful for evaluating relapse risk.

Correlating Quantitative Fecal Immunochemical Test Results with Neoplastic Findings on Colonoscopy in a Population-Based Colorectal Cancer Screening Program: A Prospective Study.

Background and Aims. The Canadian Partnership Against Cancer (CPAC) recommends a fecal immunochemical test- (FIT-) positive predictive value (PPV) for all adenomas of ≥50%. We sought to assess FIT performance among average-risk participants of the British Columbia Colon Screening Program (BCCSP). Methods. From Nov-2013 to Dec-2014 consecutive participants of the BCCSP were assessed. Data was obtained from a prospectively collected database. A single quantitative FIT (NS-Plus, Alfresa Pharma Corporation, Japan) with a cut-off of ≥10 μg/g (≥50 ng/mL) was used. Results. 20,322 FIT-positive participants underwent CSPY. At a FIT cut-off of ≥10 μg/g (≥50 ng/mL) the PPV for all adenomas was 52.0%. Increasing the FIT cut-off to ≥20 μg/g (≥100 ng/mL) would increase the PPV for colorectal cancer (CRC) by 1.5% and for high-risk adenomas (HRAs) by 6.5% at a cost of missing 13.6% of CRCs and 32.4% of HRAs. Conclusions. As the NS-Plus FIT cut-off rises, the PPV for CRC and HRAs increases but at the cost of missed lesions. A cut-off of ≥10 μg/g (≥50 ng/mL) produces a PPV for all adenomas exceeding national recommendations. Health authorities need to take into consideration endoscopic resources when selecting a FIT positivity threshold.

A Risk-Scoring System Combined With a Fecal Immunochemical Test Is Effective in Screening High-Risk Subjects for Early Colonoscopy to Detect Advanced Colorectal Neoplasms

Age, sex, smoking, and family history are risk factors for colorectal cancer in Asia. The Asia-Pacific Colorectal Screening (APCS) scoring system was developed to identify subjects with a high risk for advanced neoplasm (AN). We tested an algorithm that combined APCS scores with fecal immunochemical test (FIT) in colorectal cancer screening. We performed a multicenter prospective study, enrolling asymptomatic individuals older than 40 years old in 12 Asia-Pacific regions from December 2011 to December 2013. APCS scores were calculated for each individual (0-1 = low risk [LR], 2-3 = medium risk [MR], and 4-7 = high risk [HR] for AN). LR and MR subjects were offered FIT and referred for early colonoscopies if FIT results were positive. HR subjects were offered colonoscopies. The proportions of subjects with ANs were determined for each group based on colonoscopy findings; odd ratios for LR and MR subjects were calculated compared to LR individuals. We calculated the sensitivity of the APCS-FIT algorithm in identifying subjects with AN. A total of 5657 subjects were recruited: 646 subjects (11.4%) were considered LR, 3243 subjects (57.3%) were considered MR, and 1768 subjects (31.3%) were considered HR for AN. The proportions of individuals with an AN in these groups were 1.5%, 5.1%, and 10.9%, respectively. Compared with LR group, MR and HR subjects had a 3.4-fold increase and a 7.8-fold increase in risk for AN, respectively. A total of 70.6% subjects with AN (95% confidence interval: 65.6%-75.1%) and 95.1% subjects with invasive cancers (95% confidence interval: 82.2%-99.2%) were correctly instructed to undergo early colonoscopy examination. The APCS scoring system, which is based on age, sex, family history, and smoking, is a useful tool for determining risk for colorectal cancer and advanced adenoma in asymptomatic subjects. Use of the APCS score-based algorithm in triaging subjects for FIT or colonoscopy can substantially reduce colonoscopy workload.

Colorectal cancer screening of immigrants to Italy. Figures from the 2013 National Survey

BackgroundColorectal cancer screening programmes in Italy invite 50–69-year-old residents for a faecal immunochemical test every two years, regardless of their citizenship. MethodsThe 2013 National Survey on Italian colorectal cancer screening programmes compared immigrants born in low- or middle-income countries with subjects who were born in Italy, by collecting aggregated data on compliance, faecal immunochemical test results, compliance with colonoscopy, detected lesions and stage at diagnosis separately for Italians and immigrants. ResultsOverall, 85 screening programmes invited 3,292,451 subjects, of whom 192,629 had been born abroad (5.9%). Compliance with invitation was lower in immigrants (34.3% vs. 51.3% in Italians), with p<0.001. Compliance was higher in females, regardless of the country of birth, in the youngest age group of immigrants but in the oldest of Italians.Immigrants showed a borderline excess of standardised faecal immunochemical test positivity rate at first screening (5.4% vs. 5.1% in Italians, p=0.05) and a significant excess at repeat screenings (4.8% vs. 4.4%, p=0.002). The detection rates for carcinoma and advanced adenomas were lower in immigrants than in Italians at first screening (respectively 1.34‰ vs. 1.62‰ and 8.41‰ vs. 9.25‰) — although the differences were not statistically significant — but not at repeat screening (respectively 1.06‰ vs. 0.98‰ and 6.90‰ vs. 6.79‰). ConclusionsMigrants showed a lower compliance with screening than Italians. The prevalence of neoplasia was lower at first screening and similar to the Italians' at repeat screenings.

Fecal immunochemical testing results and characteristics of colonic lesions

Fecal immunochemical tests (FIT) are used to detect blood in feces, which might indicate the presence of colorectal neoplasia. The aim of this study was to investigate whether FIT results vary depending on the characteristics of colonic lesions. This was a retrospective analysis of lesions detected in a cohort of asymptomatic individuals (aged 50 - 75 years) who were invited to participate in a FIT-based screening pilot in The Netherlands. The mean FIT result was compared across subgroups of individuals defined by histopathology of the most advanced lesion detected. In addition, the results were compared with data from a primary colonoscopy screening trial, in which participants also completed a FIT. In three rounds of FIT-based screening, a total of 877 FIT-positive individuals underwent colonoscopy. Higher mean FIT results (hemoglobin [Hb]/g feces) were observed in individuals with carcinomas (199 μg Hb/g) and advanced adenomas (87 μg Hb/g) compared with participants with nonadvanced adenomas (50 μg Hb/g) or those with serrated lesions (46 μg Hb/g) (P < 0.001). In the primary colonoscopy trial, 1256 participants completed a FIT test and underwent colonoscopy. The number of participants with nonadvanced adenomas as the most advanced lesion was comparable between this group and the FIT-based screening group (20 % vs. 22 %). In FIT-based screening, the mean FIT results varied depending on the characteristics of the most advanced colonic lesion. The proportion of participants with a nonadvanced adenoma as the most advanced lesion was similar in the FIT-based screening group and in the primary colonoscopy screening group, suggesting that these lesions are coincidental findings rather than FIT-detected findings. www.trialregister.nl number NTR2755.

Participation, yield, and interval carcinomas in three rounds of biennial FIT-based colorectal cancer screening

BackgroundThe effectiveness of colorectal cancer screening programs based on the fecal immunochemical test (FIT) is influenced by program adherence during consecutive screening rounds. We aimed to evaluate the participation rate, yield, and interval cancers in a third round of biennial CRC screening using FIT and to compare those with the first and the second screening round. MethodsA total of 3566 average-risk individuals aged 50–75 years were invited to participate in a third round of biennial FIT-based CRC screening. All FIT positives were recommended to undergo colonoscopy. We merged our data with the national cancer registry in the Netherlands to identify all non-screen-detected cancers in our cohort. ResultsOf the invitees, 2142 (60%) returned the FIT in this third screening round, compared to 56% in the second round and 57% in the first round. Overall, 153 of the third-round participants (7.1%) had a positive FIT result, versus 7.9% in the second round and 8.1% in the first round (P=0.05). Of all FIT positives, 123 (80%) underwent colonoscopy. Within this group, 33 persons had advanced neoplasia. The predictive value of FIT positivity for advanced neoplasia was 27% (33/123), compared to 42% in the second round and 54% in the first round – a significant decline (P<0.01). ConclusionIn an FIT-based screening program, participation rates remained stable over consecutive biennial screening rounds, while the FIT positivity rate and positive predictive value for advanced neoplasia gradually declined. Cancers in non-participants are significantly more advanced in staging than cancers in participants in the first round of screening.

1027 Ulcerative Colitis Patients in Clinical Remission Demonstrate Correlations Between Fecal Immunochemical Test Results, Mucosal Healing, and Risk of Relapse

1027 Ulcerative Colitis Patients in Clinical Remission Demonstrate Correlations Between Fecal Immunochemical Test Results, Mucosal Healing, and Risk of Relapse

A combination of clinical risk stratification and fecal immunochemical test results to prioritize colonoscopy screening in asymptomatic participants

Stool-based colonoscopy is the preferred strategy for colorectal cancer (CRC) screening. The Asia-Pacific Colorectal Screening System (APCS) score also is helpful in stratifying the risk for advanced neoplasia in the asymptomatic population. The combination of the fecal immunochemical test (FIT) result and clinical risk stratification may be more helpful in stratifying the risk. To evaluate the value of the combination of FIT and APCS scores in stratifying asymptomatic participants for colonoscopy. Cross-sectional study. University hospital. A total of 948 asymptomatic participants eligible for screening colonoscopy. FIT, APCS score evaluation, screening colonoscopy. The prevalence of colorectal neoplasia in 4 different groups of participants according to FIT and APCS score evaluations. The prevalence of non-advanced and advanced neoplasia in the 4 groups (high risk with positive FIT result, high risk with negative FIT result, moderate risk with positive FIT result, and moderate risk with negative FIT result) was 44% versus 36.9%, 30.1% versus 11.6%, 27.1% versus 12%, and 22.6% versus 6.4%, respectively (P< .001). Participants with both high-risk scores and positive FIT results had a significantly higher detection rate of advanced neoplasia (6.15-fold, 95% confidence interval, 3.72-10.17) compared with the other 3 groups. Seven cancers were discovered; 4 were in the high-risk with positive FIT result group. Hospital-based study. In countries with limited resources, participants with positive FIT results and high-risk scores by APCS should be given priority for colonoscopy because this group is most likely to have advanced neoplasia. However, this strategy needs to be confirmed for its cost-effectiveness in a large, population-based study. ( TCTR20140228001.).

Factors associated with false-positive and false-negative fecal immunochemical test results for colorectal cancer screening

Certain subgroups have higher rates of false fecal immunochemical test (FIT) results, yet few studies have addressed this topic. To identify demographic factors associated with false-positive and false-negative FIT results in colorectal cancer screening. Retrospective database review of prospectively collected data. A bowel cancer screening center in Hong Kong invited participants for colorectal cancer screening (2008-2012). Study participants who underwent both FIT and colonoscopy in the first year (n= 4482) and underwent colonoscopy after negative FIT results for 3 consecutive years (n= 857). The diagnostic accuracy and predictive values of FIT according to participant characteristics. The sensitivity, specificity, positive predictive values, and negative predictive values for advanced neoplasiawere 33.1%, 91.9%, 19.0%, and 96.0%, respectively. Participants 66 to 70 years of age had higher sensitivity, whereas older age, smoking, and use of aspirin/nonsteroidal anti-inflammatory drugs were associated with lower specificity. The rates of false-positive and false-negative results were 8.1% and 66.9%, respectively. Older age (66-70 years;adjusted odds ratio [AOR] 1.95; 95% confidence interval [CI], 1.35-2.81; P< .001), smoking (AOR 1.68; 95% CI, 1.08-2.61; P= .020), and the presence of polypoid adenoma (AOR 1.71; 95% CI, 1.14-2.57; P= .009) were associated with false-positive results. Younger participants (AOR for elderly participants 0.31) and the use ofaspirin/nonsteroidal anti-inflammatory drugs (AOR 4.44) in participants with 1 FIT with negative results and the absence of high-grade dysplasia (AOR for presence 0.41) were associated with false-negative results. Self-referred participants who received one type of qualitative FIT. These findings could be used to target screening more toward those with a higher risk of false-negative results and those with a lower risk of false-positive results for earlier colonoscopy.

Characteristics of adenomas detected by fecal immunochemical test in colorectal cancer screening.

Fecal immunochemical test (FIT) diagnostic accuracy for colorectal adenoma detection in colorectal cancer screening is limited. We analyzed 474 asymptomatic subjects with adenomas detected on colonoscopy in two blinded diagnostic tests studies designed to assess FIT diagnostic accuracy. We determined the characteristics of adenomas (number, size, histology, morphology, and location) and the risk of metachronous lesions (according to European guidelines). Finally, we performed a logistic regression to identify those variables independently associated with a positive result. Advanced adenomas were found in 145 patients (75.6% distal and 24.3% only proximal to splenic flexure). Patients were classified as low (59.5%), intermediate (30.2%), and high risk (10.3%) according to European guidelines. At a 100-ng/mL threshold, FIT was positive in 61 patients (12.8%). Patients with advanced adenomas [odds ratio (OR), 8.8; 95% confidence interval (CI), 4.76-16.25], distal advanced adenomas (OR, 6.7; 95% CI, 1.9-8.8), high risk (OR, 20.1; 95% CI, 8.8-45.8), or intermediate risk lesions (OR, 6; 95% CI, 2.9-12.4) had more probabilities to have a positive test. The characteristics of adenomas independently associated were number of adenomas (OR, 1.22; 95% CI, 1.04-1.42), distal flat adenomas (OR, 0.44; 95% CI, 0.21-0.96), pedunculated adenomas (OR, 2.28; 95% CI, 1.48-3.5), and maximum size of distal adenomas (mm; OR, 1.24; 95% CI, 1.16-1.32). European guidelines classification and adenoma location correlates with the likelihood of a positive FIT result. This information allows us to understand the FIT impact in colorectal cancer prevention. Likewise, it should be taken into account in the development of new colorectal adenomas biomarkers.

Equivalency of Fecal Immunochemical Tests and Colonoscopy in Familial Colorectal Cancer Screening

Colonoscopy is the recommended screening procedure for first-degree relatives of patients with colorectal cancer (CRC), but few studies have compared its efficacy for CRC detection with that of other screening strategies. We conducted a controlled randomized trial to compare the efficacy of repeated fecal immunochemical tests (FITs) and colonoscopy in detecting advanced neoplasia (advanced adenoma or CRC) in family members of patients with CRC. In a prospective study, 1918 first-degree relatives of patients with CRC were randomly assigned (1:1 ratio) to receive a single colonoscopy examination or 3 FITs (1/year for 3 years; OC-Sensor; cutoff ≥10 μg hemoglobin/g feces, corresponding to 50 ng hemoglobin/mL buffer). The strategies were considered to be equivalent if the 95% confidence interval of the difference for the detection of advanced neoplasia was ±3%. Follow-up analyses were performed to identify false-negative FIT results and interval CRCs. Of all eligible asymptomatic first-degree relatives, 782 were included in the colonoscopy group and 784 in the FIT group. In the intention-to-screen analysis, advanced neoplasia was detected in 33 (4.2%) and 44 (5.6%) first-degree relatives in the FIT and colonoscopy groups, respectively (odds ratio= 1.41; 95% confidence interval: 0.88-2.26; P= .14). In the per-protocol analysis, 28 first-degree relatives (3.9%) in the FIT group and 43 (5.8%) in the colonoscopy group had advanced neoplasia (odds ratio= 1.56; 95% confidence interval: 0.95-2.56; P= .08). FIT missed 16 of 41 advanced adenomas but no CRCs. The FIT strategy required endoscopic evaluation of 4-fold fewer individuals to detect 1 advanced neoplasia than the colonoscopy strategy. Repeated FIT screening (1/year for 3 years) detected all CRCs and proved equivalent to colonoscopy in detecting advanced neoplasia in first-degree relatives of patients with CRC. This strategy should be considered for populations where compliance with FITs is higher than with colonoscopy. ClinicalTrials.gov number: NCT01075633 (COLONFAM Study).

Relationship between Community Periodontal Index and Fecal Hemoglobin Concentration, an Indicator for Colorectal Neoplasm

Periodontal disease and colorectal cancer have inflammatory processes in common. It is therefore worthwhile to investigate whether there is an association between periodontal probing depth and fecal hemoglobin concentration (FHbC), an indicator of colorectal neoplasms, in 40- to 44-year-old Taiwanese. We enrolled a total of 6,214 attendees aged 40 to 44 yr who were participating in a community-based integrated screening program and who received both periodontal and FHbC examinations between 2003 and 2008. A proportional odds logistic regression model was used to estimate the odds ratios of different FHbC levels in treating an increased level of community periodontal index (CPI) measuring periodontal probing depth as ordinary data from 0 to 4. Periodontal probing depth with the order of CPI was in parallel with an increase in the mean values of FHbC: 21.3 ± 156.3, 26.0 ± 167.7, 27.2 ± 151.1, and 39.5 ± 255.7 ng/mL for CPI 0, CPI 1, CPI 2, and CPI 3/4, respectively. The log-FHbC varied across the categories of CPI (p = .0078). After adjusting for age, sex, education level, smoking, alcohol intake, exercise, body mass index, and intake of meat and vegetables, subjects with positive fecal immunochemical test results (FHbC ≥ 100 ng/mL) had a 33% higher risk of deteriorating to severe CPI than did those within the normal range of fecal immunochemical test (FHbC < 100 ng/mL) (adjusted odds ratio = 1.33, 95% confidence interval: 1.03-1.73). A positive association was demonstrated between FHbC and periodontal probing depth assessed by CPI among 6,214 Taiwanese aged 40 to 44 yr who participated in a community-based integrated health screening program. These results could have significant implications for early identification of high-risk individuals, as those with deep periodontal pockets should be advised to undergo screening for colorectal cancer at a younger age than commonly recommended.

Use of a Low Cut-Off Value for the Fecal Immunochemical Test Enables Better Detection of Proximal Neoplasia

The advantage of the quantitative fecal immunochemical test (FIT) is the flexibility to set the positivity threshold. However, the diagnostic success of the FIT has not been compared for standard and low cut-off thresholds. The purpose of this study was to compare the diagnostic success of FIT for standard and low cut-off thresholds. In 2009 and 2010 a standard cut-off threshold (20 μg Hb/g feces) was used as positivity criterion for the FIT; in 2012 a low cut-off (10 μg Hb/g feces) was used. Diagnostic success was compared between the two groups. Of the total of 14,289 participants, 195 (1.4 %) had positive FIT results. Positivity of the FIT was significantly higher in the low cut-off group than in the standard cut-off group (1.8 vs. 1.0 %, p = 0.000). Although detection of advanced neoplasia lesions was comparable, proximal neoplasia was more frequently detected in the low cut-off group (33.3 vs. 20.9 %, p = 0.016). With the low cut-off threshold, 39 (0.7 %) participants were also classified as having positive results, and 18 (46.2 %) of these had colorectal neoplasias. The number of positive results from the FIT was increased by 54.9 %, and detection of advanced neoplasia was increased by 60 % with the low cut-off threshold compared with the standard cut-off. A low cut-off threshold for the FIT resulted in better detection of proximal neoplasia in population-based screening. These results indicate the cut-off threshold for positive FIT should be properly chosen and adjusted in colorectal cancer screening.

Risk factors for false positive and for false negative test results in screening with fecal occult blood testing

Differences in the risk of a false negative or a false positive fecal immunochemical test (FIT) across subgroups may affect optimal screening strategies. We evaluate whether subgroups are at increased risk of a false positive or a false negative FIT result, whether such variability in risk is related to differences in FIT sensitivity and specificity or to differences in prior CRC risk. Randomly selected, asymptomatic individuals were invited to undergo colonoscopy. Participants were asked to undergo one sample FIT and to complete a risk questionnaire. We identified patient characteristics associated with a false negative and false positive FIT results using logistic regression. We focused on statistically significant differences as well as on variables influencing the false positive or negative risk for which the odds ratio exceeded 1.25. Of the 1,426 screening participants, 1,112 (78%) completed FIT and the questionnaire; 101 (9.1%) had advanced neoplasia. 102 Individuals were FIT positive, 65 (64%) had a false negative FIT result and 66 (65%) a false positive FIT result. Participants at higher age and smokers had a significantly higher risk of a false negative FIT result. Males were at increased risk of a false positive result, so were smokers and regular NSAID users. FIT sensitivity was lower in females. Specificity was lower for males, smokers and regular NSAID users. FIT sensitivity was lower in women. FIT specificity was lower in males, smokers and regular NSAID users. Our results can be used for further evidence based individualization of screening strategies.