Factors associated with false‐positive fecal immunochemical tests in a large German colorectal cancer screening study

The effect of antiplatelet therapy and oral anticoagulants on the accuracy of faecal immunochemical testing

INTRODUCTION

Faecal immunochemical testing (FIT) has been adopted to identify patients requiring further investigations on the colorectal cancer (CRC) referral pathway. We aimed to investigate the effect of antiplatelet and anticoagulant drugs on the accuracy of FIT results.

METHODS

This observational study categorised patients with suspected CRC symptoms, who completed both FIT and colonic investigations, into two groups (control and exposed) based on their use of antiplatelet and anticoagulant drugs. Two-by-two tables and receiver operating characteristic (ROC) curve analysis were used to determine accuracy.

RESULTS

A total of 928 patients were divided into a control (n=683) and an exposed group (n=245). A nonsignificant higher proportion of patients tested positive in the exposed group (24.1% vs 18.4%, p=0.063). For detection of CRC, improved sensitivity of 87% vs 81.2%, specificity of 84.8% vs 79.9% and negative predictive value of 99.2% vs 98.3% was calculated in the control vs exposed groups, respectively. The positive predictive value was comparable between the two groups (21.4% vs 22% in the control and exposed groups, respectively). In ROC analysis, there was no difference between the groups (AUC 90% vs 87%, p=0.56). The use of antiplatelet and anticoagulant drugs did not increase the risk of positive FIT results on multivariate logistic regression analysis.

CONCLUSIONS

FIT accuracy for CRC detection remained unaffected despite more patients testing positive in the exposed group. FIT should be considered a supplementary tool for triage. Antiplatelet and anticoagulant drugs do not need to be discontinued before collection of FIT.

Effect of aspirin, warfarin, and proton-pump inhibitors on performance of fecal immunochemical test in colorectal cancer screening: a systematic review and meta-analysis

This study aims to investigate the impact of antithrombotic agents and proton-pump inhibitors (PPIs) on fecal immunochemical test (FIT). PubMed, EMBASE, Web of Science, Cochrane Central, and Google Scholar were searched from inception until September 3, 2023. Studies comparing the diagnostic performance of FIT between medicine users and non-users in average-risk colorectal cancer screening populations were included. Pooled sensitivity, specificity, and positive predictive values (PPVs) for advanced neoplasia (AN) of FIT were compared by reporting pooled odds ratios (ORs) with 95% confidence intervals (CIs) using a random-effects model. Twenty-two studies enrolling 5,572,367 individuals were included. For aspirin, pooled sensitivity and specificity for AN were 57.2% and 88.4% in users versus 60.2% and 93.2% in non-users; while pooled ORs were 1.49 (95% CI 0.89-2.48, P = 0.13) and 0.72 (95% CI 0.62-0.83, P < 0.001), respectively. In subgroup analysis, there was no difference in sensitivity and specificity between the two groups at the cutoff of 20 μg Hb/g (P = 0.57 and 0.29, respectively) but a significantly lower specificity in users compared with non-users at lower cutoffs (P < 0.001). Moreover, a significantly lower PPVAN in users compared with non-users was observed after matching age and sex confounders (P = 0.001). Warfarin had no significant influence on PPVAN of FIT (P = 0.43). PPIs were associated with a significantly lower PPVAN in users (P < 0.001). Aspirin use was associated with lower specificity and PPV of FIT. Aspirin discontinuation before FIT to reduce false-positive results should be interpreted with caution given concerns about cardiovascular events. Increasing cutoff values of FIT in aspirin users may be another possible approach. Additionally, warfarin withdrawal before FIT is unnecessary but PPIs withdrawal before FIT is recommended to reduce false-positive results.

Positive Results from the Fecal Immunochemical Test Can Be Related to Dementia: A Nationwide Population-Based Study in South Korea

BACKGROUND

The fecal immunochemical test (FIT) is widely used in screening for colorectal cancer (CRC), but FIT results can be positive for diseases other than CRC.

OBJECTIVE

We investigated the association between positive results of FIT and the incidence of dementia using a nationwide database.

METHODS

FIT-positive participants were collected from a database provided by the Korean National Health Insurance Service.

RESULTS

The incidence of all kinds of dementia was higher in FIT-positive than FIT-negative subjects (p < 0.0001). FIT-positive participants had a higher risk of Alzheimer's disease (AD) (p < 0.0001) and vascular dementia (p = 0.0002), compared to participants with FIT negativity. The risk of all kinds of dementia or AD in FIT-positive participants was higher in younger (age < 65 years) than older participants (p < 0.0001 for all kinds of dementia; p = 0.0002 for AD).

CONCLUSION

FIT positivity was correlated with an increased risk of dementia, especially in participants under 65 years of age. The study suggests that clinicians can consider dementia when FIT-positive participants fail to show any malignancies.

Faecal haemoglobin concentrations are associated with all-cause mortality and cause of death in colorectal cancer screening

BACKGROUND

Colorectal cancer (CRC) screening reduces all-cause and CRC-related mortality. New research demonstrates that the faecal haemoglobin concentration (f-Hb) may indicate the presence of other serious diseases not related to CRC. We investigated the association between f-Hb, measured by a faecal immunochemical test (FIT), and both all-cause mortality and cause of death in a population-wide cohort of screening participants.

METHODS

Between 2014 and 2018, 1,262,165 participants submitted a FIT for the Danish CRC screening programme. We followed these participants, using the Danish CRC Screening Database and several other national registers on health and population, until December 31, 2018. We stratified participants by f-Hb and compared them using a Cox proportional hazards regression on all-cause mortality and cause of death reported as adjusted hazard ratios (aHRs). We adjusted for several covariates, including comorbidity, socioeconomic factors, demography and prescription medication.

RESULTS

We observed 21,847 deaths in the study period. Our multivariate analyses indicated an association relationship between increasing f-Hb and the risk of dying in the study period. This risk increased steadily from aHR 1.38 (95% CI: 1.32, 1.44) in those with a f-Hb of 7.1-11.9 μg Hb/g faeces to 2.20 (95% CI: 2.10, 2.30) in those with a f-Hb ≥60.0 μg Hb/g faeces, when compared to those with a f-Hb ≤7.0 μg Hb/g faeces. The pattern remained when excluding CRC from the analysis. Similar patterns were observed between incrementally increasing f-Hb and the risk of dying from respiratory disease, cardiovascular disease and cancers other than CRC. Furthermore, we observed an increased risk of dying from CRC with increasing f-Hb.

CONCLUSIONS

Our findings support the hypothesis that f-Hb may indicate an elevated risk of having chronic conditions if causes for the bleeding have not been identified. The mechanisms still need to be established, but f-Hb may be a potential biomarker for several non-CRC diseases.

Strategies to minimise the current disadvantages experienced by women in faecal immunochemical test-based colorectal cancer screening

Currently, women are disadvantaged compared to men in colorectal cancer (CRC) screening, particularly in programmes that use faecal immunochemical tests for haemoglobin (FIT) followed by colonoscopy. Although there is no single cause for all the known disadvantages, many can be attributed to the ubiquitous finding that women have lower faecal haemoglobin concentrations (f-Hb) than men; there are many plausible reasons for this. Generally, a single f-Hb threshold is used in CRC screening programmes, leading to lower positivity for women than men, which causes poorer outcomes for women, including lower CRC detection rate, higher interval cancer (IC) proportion, and higher CRC mortality. Many of the now widely advocated risk scoring strategies do include factors taking account of sex, but these have not been extensively piloted or introduced. Using different f-Hb thresholds for the sexes seems advantageous, but there are difficulties, including deciding which characteristic should be selected to achieve equivalency, for example, positivity, IC proportions, or specificity. Moreover, additional colonoscopy resources, often constrained, would be required. Governments and their agencies should be encouraged to prioritise the allocation of resources to put simple strategies into practice, such as different f-Hb thresholds to create equal positivity in both sexes.

Colorectal cancer screening participation among citizens not recommended to be screened: a cohort study

BACKGROUND

Guidelines on colorectal cancer (CRC) screening recommend screening of average-risk adults only. In addition, screening of individuals with active inflammatory bowel disease (IBD) might result in too many false-positive cases. However, the organisers of CRC screening programmes are often uninformed of whom to exclude due to an elevated CRC risk or active IBD. It is therefore unknown how often high-risk individuals (i.e. individuals with a previous diagnosis of CRC or polyps associated with hereditary CRC syndromes and certain patient groups with a diagnosis of inflammatory bowel disease (IBD) or multiple polyps) and individuals with active IBD participate in CRC screening following invitation.

MATERIALS AND METHODS

We used data from the first two years of the Danish CRC screening programme (2014-2015). Information on invitations, participations and FIT test results were obtained from the national screening database, while information on previous CRC, hereditary CRC syndromes, IBD or multiple polyps diagnoses were obtained from the Danish Cancer Registry and the Danish Patient Register. Screening participation rates and FIT-positive rates were calculated and compared for high-risk invitees, invitees having IBD and an average risk group of remaining invitees not diagnosed with colorectal polyps in 10 years preceding the invitation.

RESULTS

When invited to CRC screening, 28-48% of high-risk residents (N: 29; 316; 5584) and 55% of residents with IBD (N: 2217; 6927) chose to participate. The participation rate was significantly higher (67%) among residents without previous colorectal disease, i.e. the average risk group (N = 585,624). In this average group 6.7% of the participants had a positive FIT test. The proportion of positive FIT results was higher among all disease groups (7.7-14.8%), though not statistically significant for participants with prior CRC diagnosis and participants with high-risk IBD.

CONCLUSION

When high-risk residents and residents with IBD receive an invitation to CRC screening, many participate despite being recommended not to. The screening program was not intended for these groups and further research is needed as several of these groups have a higher rate of positive screening result than the average risk population.

Alternative diagnoses and demographics associated with a raised quantitative faecal immunochemical test in symptomatic patients

Background

The faecal immunochemical test (FIT) has proven utility for colorectal cancer detection in symptomatic patients. However, most patients with a raised faecal haemoglobin (f-Hb) do not have colorectal cancer. We investigated alternative diagnoses and demographics associated with a raised f-Hb in symptomatic patients.

Methods

A retrospective, observational study was performed of patients with FIT submitted between August 2018 to January 2019 in NHS Greater Glasgow and Clyde followed by colonoscopy. Colonoscopy/pathology reports were searched for alternative diagnoses. Covariables were compared using the χ² test. Multivariate binary logistic regression identified independent predictors of a raised f-Hb.

Results

1272 patients were included. In addition to colorectal cancer (odds ratio (OR), 9.27 (95% confidence interval (CI): 3.61–23.83; p < 0.001)), older age (OR, 1.52 (95% CI: 1.00–2.32; p = 0.05)), deprivation (OR, 1.54 (95% CI: 1.21–1.94; p < 0.001)), oral anticoagulants (OR, 1.78 (95% CI: 1.01–3.15; p = 0.046)), rectal bleeding (OR, 1.47 (95% CI: 1.15–1.88; p = 0.002)), advanced adenoma (OR, 7.52 (95% CI: 3.90–14.49; p < 0.001)), non-advanced polyps (OR, 1.78 (95% CI: 1.33–2.38; p < 0.001)) and inflammatory bowel disease (IBD) (OR, 4.19 (95% CI: 2.17–8.07; p < 0.001)) independently predicted raised f-Hb. Deprivation (Scottish Index of Multiple Deprivation (SIMD) 1-2: OR, 2.13 (95% CI: 1.38–3.29; p = 0.001)) independently predicted a raised f-Hb in patients with no pathology found at colonoscopy.

Conclusions

An elevated f-Hb is independently associated with older age, deprivation, anticoagulants, rectal bleeding, advanced adenoma, non-advanced polyps and IBD in symptomatic patients. Deprivation is associated with a raised f-Hb in the absence of pathology. This must be considered when utilising FIT in symptomatic patients.

Variation of Positive Predictive Values of Fecal Immunochemical Tests by Polygenic Risk Score in a Large Screening Cohort

INTRODUCTION

Prevalence of colorectal neoplasms varies by polygenic risk scores (PRS). We aimed to assess to what extent a PRS might be relevant for defining personalized cutoff values for fecal immunochemical tests (FITs) in colorectal cancer screening.

METHODS

Among 5,306 participants of screening colonoscopy who provided a stool sample for a quantitative FIT (Ridascreen Hemoglobin or FOB Gold) before colonoscopy, a PRS was determined, based on the number of risk alleles in 140 single nucleotide polymorphisms. Subjects were classified into low, medium, and high genetic risk of colorectal neoplasms according to PRS tertiles. We calculated positive predictive values (PPVs) and numbers needed to scope (NNS) to detect 1 advanced neoplasm (AN) by the risk group, and cutoff variation needed to achieve comparable PPVs across risk groups in the samples tested with Ridascreen (N = 1,271) and FOB Gold (N = 4,035) independently, using cutoffs yielding 85%, 90%, or 95% specificity.

RESULTS

Performance of both FITs was very similar within each PRS group. For a given cutoff, PPVs were consistently higher by 11%-15% units in the high-risk PRS group compared with the low-risk group (all P values < 0.05). Correspondingly, NNS to detect 1 advanced neoplasm varied from 2 (high PRS, high cutoff) to 5 (low PRS, low cutoff). Conversely, very different FIT cutoffs would be needed to ensure comparable PPVs across PRS groups.

DISCUSSION

PPVs and NNS of FITs varied widely across people with high and low genetic risk score. Further research should evaluate the relevance of these differences for personalized colorectal cancer screening.

Predictive Modeling of Colonoscopic Findings in a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program

BACKGROUND

The fecal immunochemical test (FIT) is the primary modality used by the Los Angeles County Department of Health Services (LADHS) for colorectal cancer (CRC) screening in average-risk patients. Some patients referred for FIT-positive diagnostic colonoscopy have neither adenomas nor more advanced pathology. We aimed to identify predictors of false-positive FIT (FP-FIT) results in our largely disenfranchised, low socioeconomic status population.

METHODS

We conducted a retrospective study of 596 patients who underwent diagnostic colonoscopy following a positive screening FIT. Colonoscopies showing adenomas (or more advanced pathology) were considered positive. We employed multiple logistic and linear regression as well as machine learning models (MLMs) to identify clinical predictors of FP-FIT (primary outcome) and the presence of advanced adenomas (secondary outcome).

RESULTS

Overall, 268 patients (45.0%) had a FP-FIT. Female sex and hemorrhoids (odds ratios [ORs] 1.59 and 1.89, respectively) were associated with increased odds of FP-FIT and fewer advanced adenomas (β = - 0.658 and  - 0.516, respectively). Conversely, increasing age and BMI (ORs 0.94 and 0.96, respectively) were associated with decreased odds of FP-FIT and a greater number of advanced adenomas (β = 0.073 and 0.041, respectively). MLMs predicted FP-FIT with high specificity (93.8%) and presence of advanced adenoma with high sensitivity (94.4%).

CONCLUSION

Increasing age and BMI are associated with lower odds of FP-FIT and greater number of advanced adenomas, while female sex and hemorrhoids are associated with higher odds of FP-FIT and fewer advanced adenomas. The presence of the aforementioned predictors may inform the decision to proceed with diagnostic colonoscopy in FIT-positive patients.

A user-friendly objective prediction model in predicting colorectal cancer based on 234 044 Asian adults in a prospective cohort

BACKGROUND

Prediction models of colorectal cancer (CRC) had limited application for not being user-friendly. Whether fecal immunochemical tests (FITs) can help predict CRC has been overlooked.

PATIENTS AND METHODS

With 1972 CRCs identified, 234 044 adults aged ≥40 years were successively enrolled between 1994 and 2008. Prediction models were developed by questionnaire/medical screening and quantitative FIT. NNS (number needed to scope to find one cancer) is time dependent, spanning entire study period. Significant 'risk factors' were family history, body mass index, smoking, drinking, inactivity, hypertension, diabetes, carcinoembryonic antigen, and C-reactive protein.

RESULTS

Positive FIT (≥20 μg/g hemoglobin/feces) had cancer risk 10-fold larger than negative FIT, and within each age group, another 10-fold difference. The C statistic of FIT (0.81) with age and sex alone was superior to the 'common risk-factors' model (0.73). NNS, stratified by age and by FIT values, demonstrated a scorecard of cancer risks, like 1/15 or 1/25, in 5 years. When FIT was negative, cancer risk was small (1/750-1/3000 annually). The larger the FIT, the sooner the appearance of CRC. For every 80-μg/g increase of FIT, there were 1.5-year earlier development of CRC incidence and 1-year earlier development of CRC mortality, respectively. Given the same FIT value, CRC events appeared in the proximal colon sooner than the distal colon.

CONCLUSIONS

A simple user-friendly model based on a single FIT value to predict CRC risk was developed. When positive, NNS offered a simple quantitative value, with a better precision than most risk factors, even combined. When FIT is negative, risk is very small, but requiring a repeat every other year to rule out false negative. FIT values correlated well with CRC prognosis, with worst for proximal CRC.

A fecal-based test for the detection of advanced adenoma and colorectal cancer: a case-control and screening cohort study

BACKGROUND

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. Screening is a confirmed way to reduce the incidence and mortality rates of CRC. This study aimed to identify a fecal-based, noninvasive, and accurate method for detection of colorectal cancer (CRC) and advanced adenoma (AA).

METHODS

Through detection in tissue (n = 96) and fecal samples (n = 88) and tested in an independent group of fecal samples (n = 294), the methylated DNA marker ITGA4 and bacterial markers Fusobacterium nucleatum (Fn) and Pepetostreptococcusanaerobius (Pa) were identified from the candidate biomarkers for CRC and AA detection. A prediction score (pd-score) was constructed using the selected markers and fecal immunochemical test (FIT) for distinguishing AA and CRC from healthy subjects by logistic regression method. The diagnostic performance of the pd-score was compared with FIT and validated in the external validation cohort (n = 117) and in a large CRC screening cohort.

RESULTS

The pd-score accurately identified AA and CRC from healthy subjects with an area under the curve (AUC) of 0.958, at a specificity of 91.37%; the pd-score showed sensitivities of 95.38% for CRC and 70.83% for AA, respectively. In the external validation cohort, the sensitivities of the pd-score for CRC and AA detection were 94.03% and 80.00%, respectively. When applied in screening, the pd-score identified 100% (11/11) of CRC and 70.83% (17/24) of AA in participants with both colonoscopy results and qualified fecal samples, showing an improvement by 41.19% compared to FIT.

CONCLUSIONS

The current study developed a noninvasive and well-validated approach for AA and CRC detection, which could be applied widely as a diagnostic and screening test.

Inflammatory bowel disease in a colorectal cancer screening population: Diagnosis and follow-up

BACKGROUND

Inflammatory bowel disease (IBD) is usually diagnosed in subjects with gastrointestinal symptoms, but may also be asymptomatic and diagnosed incidentally.

AIMS

to determine the prevalence of IBD in asymptomatic adults.

METHODS

we identified subjects who underwent colonoscopy between 1 September 2013 and 31 August 2019 in a regional colorectal cancer screening program with endoscopic findings suggestive of IBD, and retrieved their clinical, histological and therapeutic information.

RESULTS

5116 subjects underwent colonoscopy, and 4640 persons were considered assessable. Of these, 54 (1.16%) had endoscopic findings suggestive of IBD, including 40 of Crohn's disease (CD) and 14 of ulcerative colitis (UC). A definite diagnosis of IBD was made in 19 patients, for an overall IBD prevalence of 0.41%, with 13 cases of CD (0.28%) and 6 of UC (0.13%). The mean follow-up was 26.8 months after the first colonoscopy. Therapy was started in 5 of 13 CD patients and all UC patients.

CONCLUSION

Endoscopic findings suggestive of IBD are not infrequent in an asymptomatic colorectal cancer screening population. Visualization of the terminal ileum is recommended in this setting. A definite diagnosis of IBD was made in about 1 out of 3 subjects with endoscopic lesions. Most IBD patients had a mild form of disease, but some needed biologic therapy.

Selection of patients for large mailed fecal immunochemical test colorectal cancer screening outreach programs: A systematic review

OBJECTIVE

Digital health care offers an opportunity to scale and personalize cancer screening programs, such as mailed outreach for colorectal cancer (CRC) screening. However, studies that describe the patient selection strategy and process for CRC screening are limited. Our objective was to evaluate implementation strategies for selecting patients for CRC screening programs in large health care systems.

METHODS

We conducted a systematic review of 30 studies along with key informant surveys and interviews to describe programmatic implementation strategies for selecting patients for CRC screening. PubMed and Embase were searched since inception through December 2018, and hand searches were performed of the retrieved reference lists but none were incorporated (n = 0). No language exclusions were applied.

RESULTS

Common criteria for outreach exclusion included: being up-to-date with routine CRC screening (n = 22), comorbidities (n = 20), and personal history (n = 22) or family history of cancer (n = 9). Key informant surveys and interviews were performed (n = 28) to understand data sources and practices for patient outreach selection, and found that 13 studies leveraged electronic medical care records, 10 studies leveraged a population registry (national, municipal, community, health), 4 studies required patient opt-in, and 1 study required primary care provider referral. Broad ranges in fecal immunochemical test completion were observed in community clinic (n = 8, 31.0-59.6%), integrated health system (n = 5, 21.2-82.7%), and national regional CRC screening programs (n = 17, 23.0-64.7%). Six studies used technical codes, and four studies required patient self-reporting from a questionnaire to participate.

CONCLUSION

This systematic review provides health systems with the diverse outreach practices and technical tools to support efforts to automate patient selection for CRC screening outreach.

The Roadmap of Colorectal Cancer Screening

Colorectal cancer (CRC) is the third most common form of cancer in terms of incidence and the second in terms of mortality worldwide. CRC develops over several years, thus highlighting the importance of early diagnosis. National screening programs based on fecal occult blood tests and subsequent colonoscopy have reduced the incidence and mortality, however improvements are needed since the participation rate remains low and the tests present a high number of false positive results. This review provides an overview of the CRC screening globally and the state of the art in approaches aimed at improving accuracy and participation in CRC screening, also considering the need for gender and age differentiation. New fecal tests and biomarkers such as DNA methylation, mutation or integrity, proteins and microRNAs are explored, including recent investigations into fecal microbiota. Liquid biopsy approaches, involving novel biomarkers and panels, such as circulating mRNA, micro- and long-non-coding RNA, DNA, proteins and extracellular vesicles are discussed. The approaches reported are based on quantitative PCR methods that could be easily applied to routine screening, or arrays and sequencing assays that should be better exploited to describe and identify candidate biomarkers in blood samples.

Risk-Adapted Cutoffs in Colorectal Cancer Screening by Fecal Immunochemical Tests

INTRODUCTION

Fecal immunochemical tests (FITs) for hemoglobin are increasingly used in colorectal cancer (CRC) screening. The use of uniform positivity thresholds (cutoffs) within screening populations is expected to imply lower positive predictive values (PPVs) and higher numbers of colonoscopies needed (numbers needed to scope [NNSs]) to detect advanced neoplasms among screening participants at lower risk compared with those at higher risk. We aimed to assess such variation and its potential implications in a large screening cohort.

METHODS

A quantitative FIT (FOB Gold; Sentinel Diagnostics, Milan, Italy) was conducted in fecal samples collected by 4,332 participants of screening colonoscopy before bowel preparation. Participants were classified into 3 risk groups (low, medium, and high) by tertiles of a previously derived risk-factor-based risk score. We determined the variation of PPVs and NNSs for detecting advanced neoplasms (i.e., CRC or advanced adenoma) when using the same FIT cutoffs and variation of FIT cutoffs that would yield uniform PPVs across risk groups.

RESULTS

When a fixed FIT cutoff of 10 μg/g was used, the PPV increased from 23.3% to 41.8% from the low- to the high-risk group, with NNS decreasing from 4.3 to 2.4 (P < 0.001). Similar variations of PPVs and NNSs across risk groups were observed at higher FIT cutoffs. When risk group-specific cutoffs were defined to achieve fixed PPVs of 25%, 30%, and 35% across all risk groups, cutoffs varied from 5.3 to 11.4, 6.5 to 18.7, and 7.5 to 31.0 μg hemoglobin/g feces, respectively, between high- and low-risk groups (P < 0.05 for all differences).

DISCUSSION

Using risk-adapted cutoffs may help to achieve target levels of PPV and NNS and might be an option to consider for personalized FIT-based CRC screening.

Colorectal cancer screening: Assessment of CEACAM6, LGALS4, TSPAN8 and COL1A2 as blood markers in faecal immunochemical test negative subjects

Prevention is essential to reduce Colorectal Cancer (CRC) mortality. We previously reported a panel of four genes: CEACAM6, LGALS4, TSPAN8, COL1A2 (CELTiC) able to discriminate patients with CRC. Here, we assessed the CELTiC panel by quantitative polymerase chain reaction, in the blood of 174 healthy subjects, who resulted negative to the faecal immunochemical test (FITN). Using non-parametric statistic and multinomial logistic models, the FITN were compared to previously analysed subjects: 36 false positive FIT (NFIT), who were negative at colonoscopy, 36 patients with low risk lesions (LR) and 92 patients with high risk lesions or CRC (HR/CRC). FITN showed a significantly lower expression of the four genes when compared to HR/CRC. Moreover, FITN showed a significantly lower expression of TSPAN8 and COL1A2 compared to NFIT and LR patients.

The multinomial logistic model confirmed that TSPAN8 alone specifically discriminated FITN from NFIT, LR and HR/CRC, while LGALS4 was able to differentiate FITN from false positive FIT. Finally, ROC curves analysis of the comparisons between FITN and HR/CRC, LR or NFIT reported AUC greater than 0.87, with a sensitivity and specificity of 83% and 76%, respectively. The CELTiC panel was confirmed a useful tool to identify CRC patients and to discriminate false FIT positive subjects.

Stage-Specific Sensitivity of Fecal Immunochemical Tests for Detecting Colorectal Cancer: Systematic Review and Meta-Analysis

OBJECTIVE

Fecal immunochemical tests (FITs) detect the majority of colorectal cancers (CRCs), but evidence for variation in sensitivity according to the CRC stage is sparse and has not yet been systematically synthesized. Thus, our objective was to systematically review and summarize evidence on the stage-specific sensitivity of FITs.

METHODS

We screened PubMed, Web of Science, Embase, and the Cochrane Library from inception to June 14, 2019, for English-language articles reporting on the stage-specific sensitivity of FIT for CRC detection using colonoscopy as a reference standard. Studies reporting stage-specific sensitivities and the specificity of FIT for CRC detection were included. Summary estimates of sensitivity according to the CRC stage and study setting (screening cohorts, symptomatic/diagnostic cohorts, and case-control studies) were derived from bivariate meta-analysis.

RESULTS

Forty-four studies (92,447 participants including 3,034 CRC cases) were included. Pooled stage-specific sensitivities were overall very similar but suffered from high levels of imprecision because of small case numbers when calculated separately for screening cohorts, symptomatic/diagnostic cohorts, and case-control studies. Pooled sensitivities (95% confidence intervals) for all studies combined were 73% (65%-79%) for stage-I-CRCs and 80% (74%-84%), 82% (77%-87%), and 79% (70%-86%) for the detection of CRC stages II, III, and IV, respectively. Even substantially larger variation was seen in sensitivity by T-stage, with summary estimates ranging from 40% (21%-64%) for T1 to 83% (68%-91%) for T3-CRC.

DISCUSSION

Although FITs detect 4 of 5 CRCs at stages II-IV, the substantially lower sensitivity for stage-I-CRC and, in particular, T1 CRC indicates both need and potential for further improvement in performance for the early detection of CRC.

Circulating lncRNA SNHG11 as a novel biomarker for early diagnosis and prognosis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer mortality worldwide. Emerging evidence indicates that tumour cells release substantial amounts of RNA into the bloodstream, in which RNA strongly resists RNases and is present at sufficient levels for quantitative analyses. Our study aimed to discover blood-based markers for the early detection of CRC and to ascertain their efficiency in discriminating healthy controls, patients with polyps and adenomas and cancer patients. We first analysed and screened ZFAS1, SNHG11, LINC00909 and LINC00654 in a bioinformatics database and then collected clinical plasma samples for preliminary small-scale analysis and further large-scale verification. We then explored the mechanism of dominant lncRNA SNHG11 expression in CRC by in vitro and in vivo assays. The combination of ZFAS1, SNHG11, LINC00909 and LINC00654 showed high diagnostic performance for CRC (AUC: 0.937), especially early-stage disease (AUC: 0.935). Plasma levels of the four candidate lncRNAs were significantly reduced in postoperative samples compared to preoperative samples. A panel including these four lncRNAs performed well in distinguishing patient groups with different stages of colon disease, and SNHG11 exhibited the greatest diagnostic ability to identify precancerous lesions and early-stage tumour formation. Mechanistically, high SNHG11 expression promotes proliferation and metastasis by targeting the Hippo pathway. Taken together, the data indicate that SNHG11 may be a novel therapeutic target for the treatment of CRC and a potential biomarker for the early detection of CRC.