Effect of aspirin on the diagnostic accuracy of the faecal immunochemical test for colorectal advanced neoplasia

Role of demographics in noninvasive testing for colorectal cancer screening: do targeted cut-off values improve detection?

BACKGROUND

Fecal immunochemical test (FIT) is a yearly alternative colorectal screening modality for average risk individuals unwilling or unable to undergo invasive colorectal cancer (CRC) screening due to cost and accessibility. This study aimed to determine whether FIT should be interpreted within the context of patient demographics and medical history.

METHODS

Patients >50 years old who had a FIT followed by colonoscopy within 1 year were analyzed based on age, race, BMI, social and medical comorbidities. False positive (FP) and false negative (FN) FIT results within each patient demographic and medical history variable were determined by comparing with the gold standard of colonoscopy using χ2 analysis.

RESULTS

One thousand twenty-five patients were reviewed. 21.8% of FIT results were positive. Factors which differed in positive FIT rates were age (P=0.003), smoking (P<0.001), alcohol (P=0.001), and hypertension (P<0.001). The difference in rates of FP and FN FIT outcomes among each variable underwent further subanalysis. The FP was 66.8% and the FN rate was 12.8%. Higher FN outcomes were noted in those above 70, males and smokers, though the result was only statistically significant for males (P=0.009). Females were observed to have higher FP rates (P=0.019).

CONCLUSIONS

Females had higher FP FIT rates compared to males, indicating that sex may influence FIT outcomes and should be accounted for when interpreting FIT results. This information can be utilized to identify populations at higher risk of FP or FN FIT results to target CRC screening. Additionally, recalculating the FP and FN rates for each variable may help determine new FIT targets.

Impact of antithrombotic drugs on the accuracy of fecal occult blood testing for advanced colorectal neoplasia screening: a meta-analysis and systematic review

BACKGROUND

The current meta-analysis was conducted to determine whether antithrombotic drug use would affect the diagnostic accuracy of fecal occult blood testing for advanced colorectal neoplasia.

METHODS

Articles published between 2000 and 2019 were systematically retrieved and screened according to the inclusion and exclusion criteria by two reviewers independently. Pooled analyses were conducted with a fixed-effect model if no apparent heterogeneity (I² ≥ 50%) was found between studies; otherwise, the random effects model would be used. Sensitivity analysis and subgroup analysis were also conducted using Review Manager 5.3.

RESULTS

Pooled analysis revealed that aspirin and nonsteroidal anti-inflammatory drugs were associated with a decrease in the positive predictive value of fecal occult blood testing for advanced colorectal neoplasia screening, with a RR of 0.89 (95% CI: 0.84-0.94) and 0.88 (95% CI: 0.84-0.93, p<0.001) respectively. Subgroup analysis based on data limited to high-quality studies, fecal immunochemical testing, or in Caucasians also showed that the use of aspirin/NSAID drugs decreased the accuracy for advanced colorectal neoplasia screening.

CONCLUSION

Aspirin/NSAIDs and direct oral anticoagulants rather than warfarin may decrease the diagnostic accuracy of fecal occult blood testing for advanced colorectal neoplasia screening.

Faecal immunochemical testing (FIT) in patients with signs or symptoms of suspected colorectal cancer (CRC): a joint guideline from the Association of Coloproctology of Great Britain and Ireland (ACPGBI) and the British Society of Gastroenterology (BSG)

Faecal immunochemical testing (FIT) has a high sensitivity for the detection of colorectal cancer (CRC). In a symptomatic population FIT may identify those patients who require colorectal investigation with the highest priority. FIT offers considerable advantages over the use of symptoms alone, as an objective measure of risk with a vastly superior positive predictive value for CRC, while conversely identifying a truly low risk cohort of patients. The aim of this guideline was to provide a clear strategy for the use of FIT in the diagnostic pathway of people with signs or symptoms of a suspected diagnosis of CRC. The guideline was jointly developed by the Association of Coloproctology of Great Britain and Ireland/British Society of Gastroenterology, specifically by a 21-member multidisciplinary guideline development group (GDG). A systematic review of 13 535 publications was undertaken to develop 23 evidence and expert opinion-based recommendations for the triage of people with symptoms of a suspected CRC diagnosis in primary care. In order to achieve consensus among a broad group of key stakeholders, we completed an extended Delphi of the GDG, and also 61 other individuals across the UK and Ireland, including by members of the public, charities and primary and secondary care. Seventeen research recommendations were also prioritised to inform clinical management.

Impact of antiplatelet agents and anticoagulants on the performance of fecal immunochemical tests: a systematic review and meta-analysis

BACKGROUND

Antithrombotic agents may increase the bleeding tendency and affect the performance of fecal immunochemical test (FIT). We aimed to evaluate the impact of antithrombotic agents on the performance of FIT through a systematic review and meta-analysis.

METHODS

All relevant studies published between January 1980 and September 2020 that examined the diagnostic performance of FIT were searched through MEDLINE, EMBASE, and Cochrane Library databases. We performed a meta-analysis for the positive predictive value (PPV) of FIT for detecting advanced colorectal neoplasia (ACRN) or colorectal cancer (CRC) according to the administration of antithrombotic agents including aspirin, antiplatelet agents, and oral anticoagulants (OACs).

RESULTS

Thirteen studies with 27,518 patients were included. Of these, 11 studies with data required for the calculation of pooled PPV were included in the meta-analysis. The pooled PPV of FIT for detecting ACRN was significantly lower in antithrombotic agent users than in non-users (odds ratio [OR] [95% confidence interval [CI]]: aspirin, 0.82 [0.68-0.99]; antiplatelet agents, 0.82 [0.69-0.96]; OACs, 0.66 [0.52-0.84]). For detecting CRC, antithrombotic agent use tended to be associated with a reduced PPV (aspirin, 0.76 [0.51-1.14]; antiplatelet agents, 0.73 [0.52-1.02]; OACs, 0.60 [0.25-1.44]). In the subgroup analysis, a FIT cutoff value of 15 μg Hb/g feces tended to be associated with lower PPVs compared to a value of 20 μg Hb/g feces in antithrombotic agent users.

CONCLUSIONS

Aspirin, antiplatelet agents, and OACs significantly lowered the PPV of FIT for detecting ACRN. These drugs may increase the false-positive of FIT.

Faecal immunochemical test to triage patients with possible colorectal cancer symptoms: meta-analysis

BACKGROUND

This review evaluated the utility of single quantitative faecal immunochemical test (FIT) as a triaging tool for patients with symptoms of possible colorectal cancer, the effect of symptoms on FIT accuracy, and the impact of triaging incorporating FIT on service provision.

METHODS

Five databases were searched. Meta-analyses of the extracted FIT sensitivities and specificities for detection of colorectal cancer at reported f-Hb thresholds were performed. Secondary outcomes included sensitivity and specificity of FIT for advanced colorectal neoplasia and serious bowel disease. Subgroup analysis by FIT brand and symptoms was undertaken.

RESULTS

Fifteen prospective cohort studies, including 28 832 symptomatic patients were included. At the most commonly reported f-Hb positivity threshold of ≥ 10 µg Hb/g faeces (n=13), the summary sensitivity was 88.7% (95% c.i. 85.2 to 91.4) and the specificity was 80.5% (95% c.i. 75.3 to 84.8) for colorectal cancer. At lower limits of detection of ≥ 2 µg Hb/g faeces, the summary sensitivity was 96.8% (95% c.i. 91.0 to 98.9) and the specificity was 65.6% (95% c.i. 59.0 to 71.6). At the upper f-Hb positivity thresholds of ≥ 100 µg Hb/g faeces and ≥ 150 µg Hb/g faeces, summary sensitivities were 68.1% (95% c.i. 59.2 to 75.9) and 66.3% (95% c.i. 52.2 to 78.0), with specificities of 93.4% (95% c.i. 91.3 to 95.1) and 95.1% (95% c.i. 93.6 to 96.3) respectively. FIT sensitivity was comparable between different assay brands. FIT sensitivity may be higher in patients reporting rectal bleeding.

CONCLUSION

Single quantitative FIT at lower f-Hb positivity thresholds can adequately exclude colorectal cancer in symptomatic patients and provides a data-based approach to prioritization of colonoscopy resources.

Use of Antiplatelet Agents Decreases the Positive Predictive Value of Fecal Immunochemical Tests for Colorectal Cancer but Does Not Affect Their Sensitivity

Previous studies have evaluated the effects of antithrombotic agents on the performance of fecal immunochemical tests (FITs) for the detection of colorectal cancer (CRC), but the results were inconsistent and based on small sample sizes. We studied this topic using a large-scale population-based database. Using the Korean National Cancer Screening Program Database, we compared the performance of FITs for CRC detection between users and non-users of antiplatelet agents and warfarin. Non-users were matched according to age and sex. Among 5,426,469 eligible participants, 768,733 used antiplatelet agents (mono/dual/triple therapy, n = 701,683/63,211/3839), and 19,569 used warfarin, while 4,638,167 were non-users. Among antiplatelet agents, aspirin, clopidogrel, and cilostazol ranked first, second, and third, respectively, in terms of prescription rates. Users of antiplatelet agents (3.62% vs. 4.45%; relative risk (RR): 0.83; 95% confidence interval (CI): 0.78–0.88), aspirin (3.66% vs. 4.13%; RR: 0.90; 95% CI: 0.83–0.97), and clopidogrel (3.48% vs. 4.88%; RR: 0.72; 95% CI: 0.61–0.86) had lower positive predictive values (PPVs) for CRC detection than non-users. However, there were no significant differences in PPV between cilostazol vs. non-users and warfarin users vs. non-users. For PPV, the RR (users vs. non-users) for antiplatelet monotherapy was 0.86, while the RRs for dual and triple antiplatelet therapies (excluding cilostazol) were 0.67 and 0.22, respectively. For all antithrombotic agents, the sensitivity for CRC detection was not different between users and non-users. Use of antiplatelet agents, except cilostazol, may increase the false positives without improving the sensitivity of FITs for CRC detection.

Development and user-testing of a brief decision aid for aspirin as a preventive approach alongside colorectal cancer screening

BACKGROUND

Several epidemiological and cohort studies suggest that regular low-dose aspirin use independently reduces the long-term incidence and risk of colorectal cancer deaths by approximately 20%. However, there are also risks to aspirin use, mainly gastrointestinal bleeding and haemorrhagic stroke. Making informed decisions depends on the ability to understand and weigh up benefits and risks of available options. A decision aid to support people to consider aspirin therapy alongside participation in the NHS bowel cancer screening programme may have an additional impact on colorectal cancer prevention. This study aims to develop and user-test a brief decision aid about aspirin to enable informed decision-making for colorectal screening-eligible members of the public.

METHODS

We undertook a qualitative study to develop an aspirin decision aid leaflet to support bowel screening responders in deciding whether to take aspirin to reduce their risk of colorectal cancer. The iterative development process involved two focus groups with public members aged 60-74 years (n = 14) and interviews with clinicians (n = 10). Interviews (n = 11) were used to evaluate its utility for decision-making. Analysis was conducted using a framework approach.

RESULTS

Overall, participants found the decision aid acceptable and useful to facilitate decision-making. They expressed a need for individualised risk information, more detail about the potential risks of aspirin, and preferred risk information presented in pictograms when offered different options. Implementation pathways were discussed, including the possibility of involving different clinicians in the process such as GPs and/or community pharmacists. A range of potentially effective timepoints for sending out the decision aid were identified.

CONCLUSION

An acceptable and usable decision aid was developed to support decisions about aspirin use to prevent colorectal cancer.

Occult blood in faeces is associated with all-cause and non-colorectal cancer mortality

OBJECTIVE

An association between detectable faecal haemoglobin (f-Hb) and both the risk of death from colorectal cancer (CRC) and all-cause mortality has been reported. We set out to confirm or refute this observation in a UK population and to explore the association between f-Hb, as indicated by a positive guaiac faecal occult blood test (gFOBT) result, and different causes of death.

DESIGN

All individuals (134 192) who participated in gFOBT screening in Tayside, Scotland between 29/03/2000 and 29/03/2016 were studied by linking their test result (positive or negative) with mortality data from the National Records of Scotland database and following to 30/03/2016.

RESULTS

Those with a positive test result (n=2714) had a higher risk of dying than those with a negative result, from CRC: HR 7.79 (95% CI 6.13 to 9.89), p<0.0001, (adjusted for, gender, age, deprivation quintile and medication that can cause bleeding) and all non-CRC causes: HR 1.58 (95% CI 1.45 to 1.73), p<0·0001.· In addition, f-Hb detectable by gFOBT was significantly associated with increased risk of dying from circulatory disease, respiratory disease, digestive diseases (excluding CRC), neuropsychological disease, blood and endocrine disease and non-CRC.

CONCLUSION

The presence of detectable f-Hb is associated with increased risk of death from a wide range of causes.