Serological biomarkers in triage of FIT-positive subjects?

The carbon footprint of ambulatory gastrointestinal endoscopy

BACKGROUND

Endoscopy is considered the third highest generator of waste within healthcare. This is of public importance as approximately 18 million endoscopy procedures are performed yearly in the USA and 2 million in France. However, a precise measure of the carbon footprint of gastrointestinal endoscopy (GIE) is lacking.

METHODS

This retrospective study for 2021 was conducted in an ambulatory GIE center in France where 8524 procedures were performed on 6070 patients. The annual carbon footprint of GIE was calculated using "Bilan Carbone" of the French Environment and Energy Management Agency. This multi-criteria method accounts for direct and indirect greenhouse gas (GHG) emissions from energy consumption (gas and electricity), medical gases, medical and non-medical equipment, consumables, freight, travel, and waste.

RESULTS

GHG emissions in 2021 were estimated to be 241.4 tonnes CO2 equivalent (CO2e) at the center, giving a carbon footprint for one GIE procedure of 28.4 kg CO2e. The main GHG emission, 45 % of total emissions, was from travel by patients and center staff to and from the center. Other emission sources, in rank order, were medical and non-medical equipment (32 %), energy consumption (12 %), consumables (7 %), waste (3 %), freight (0.4 %), and medical gases (0.005 %).

CONCLUSIONS

This is the first multi-criteria analysis assessing the carbon footprint of GIE. It highlights that travel, medical equipment, and energy are major sources of impact, with waste being a minor contributor. This study provides an opportunity to raise awareness among gastroenterologists of the carbon footprint of GIE procedures.

Optimizing Screening for Colorectal Cancer: An Algorithm Combining Fecal Immunochemical Test, Blood-Based Cancer-Associated Proteins and Demographics to Reduce Colonoscopy Burden

BACKGROUND

Fecal Immunochemical Test (FIT) is widely used in population-based screening for colorectal cancer (CRC). This had led to major challenges regarding colonoscopy capacity. Methods to maintain high sensitivity without compromising the colonoscopy capacity are needed. This study investigates an algorithm that combines FIT result, blood-based biomarkers associated with CRC, and individual demographics, to triage subjects sent for colonoscopy among a FIT positive (FIT⁺) screening population and thereby reduce the colonoscopy burden.

MATERIALS AND METHODS

From the Danish National Colorectal Cancer Screening Program, 4048 FIT⁺ (≥100 ng/mL Hemoglobin) subjects were included and analyzed for a panel of 9 cancer-associated biomarkers using the ARCHITECT i2000. Two algorithms were developed: 1) a predefined algorithm based on clinically available biomarkers: FIT, age, CEA, hsCRP and Ferritin; and 2) an exploratory algorithm adding additional biomarkers: TIMP-1, Pepsinogen-2, HE4, CyFra21-1, Galectin-3, B2M and sex to the predefined algorithm. The diagnostic performances for discriminating subjects with or without CRC in the 2 models were benchmarked against the FIT alone using logistic regression modeling.

RESULTS

The discrimination of CRC showed an area under the curve (AUC) of 73.7 (70.5-76.9) for the predefined model, 75.3 (72.1-78.4) for the exploratory model, and 68.9 (65.5-72.2) for FIT alone. Both models performed significantly better (P < .001) than the FIT model. The models were benchmarked vs. FIT at cutoffs of 100, 200, 300, 400, and 500 ng/mL Hemoglobin using corresponding numbers of true positives and false positives. All performance metrics were improved at all cutoffs.

CONCLUSION

A screening algorithm including a combination of FIT result, blood-based biomarkers and demographics outperforms FIT in discriminating subjects with or without CRC in a screening population with FIT results above 100 ng/mL Hemoglobin.

Early detection of colorectal neoplasia: application of a blood-based serological protein test on subjects undergoing population-based screening

BACKGROUND

Blood-based biomarkers used for colorectal cancer screening need to be developed and validated in appropriate screening populations. We aimed to develop a cancer-associated protein biomarker test for the detection of colorectal cancer in a screening population.

METHODS

Participants from the Danish Colorectal Cancer Screening Program were recruited. Blood samples were collected prior to colonoscopy. The cohort was divided into training and validation sets. We present the results of model development using the training set. Age, sex, and the serological proteins CEA, hsCRP, TIMP-1, Pepsinogen-2, HE4, CyFra21-1, Galectin-3, ferritin and B2M were used to develop a signature test to discriminate between participants with colorectal cancer versus all other findings at colonoscopy.

RESULTS

The training set included 4048 FIT-positive participants of whom 242 had a colorectal cancer. The final model for discriminating colorectal cancer versus all other findings at colonoscopy had an AUC of 0.70 (95% CI: 0.66-0.74) and included age, sex, CEA, hsCRP, HE4 and ferritin.

CONCLUSION

The performance of the biomarker signature in this FIT-positive screening population did not reflect the positive performance of biomarker signatures seen in symptomatic populations. Additional biomarkers are needed if the serological biomarkers are to be used as a frontline screening test.

Improved risk scoring systems for colorectal cancer screening in Shanghai, China

Background

An optimal risk‐scoring system enables more targeted offers for colonoscopy in colorectal cancer (CRC) screening. This analysis aims to develop and validate scoring systems using parametric and non‐parametric methods for average‐risk populations.

Methods

Screening data of 807,695 subjects and 2806 detected cases in the first‐round CRC screening program in Shanghai were used to develop risk‐predictive models and scoring systems using logistic‐regression (LR) and artificial‐neural‐network (ANN) methods. Performance of established scoring systems was evaluated using area under the receiver operating characteristic curve (AUC), calibration, sensitivity, specificity, number of high‐risk individuals and potential detection rates of CRC.

Results

Age, sex, CRC in first‐degree relatives, chronic diarrhoea, mucus or bloody stool, history of any cancer and faecal‐immunochemical‐test (FIT) results were identified as predictors for the presence of CRC. The AUC of LR‐based system was 0.642 when using risk factors only in derivation set, and increased to 0.774 by further incorporating one‐sample FIT results, and to 0.808 by including two‐sample FIT results, while those for ANN‐based systems were 0.639, 0.763 and 0.805, respectively. Better calibrations were observed for the LR‐based systems than the ANN‐based ones. Compared with the currently used initial tests, parallel use of FIT with LR‐based systems resulted in improved specificities, less demands for colonoscopy and higher detection rates of CRC, while parallel use of FIT with ANN‐based systems had higher sensitivities; incorporating FIT in the scoring systems further increased specificities, decreased colonoscopy demands and improved detection rates of CRC.

Conclusions

Our results indicate the potentials of LR‐based scoring systems incorporating one‐ or two‐sample FIT results for CRC mass screening. External validation is warranted for scaling‐up implementation in the Chinese population.

The established scoring systems derived from the logistic regression (LR) models, incorporating one‐ or two‐sample faecal immunochemical test (FIT) results as a predictor, have the potential to triage high‐risk individuals for colonoscopy in mass screening of colorectal cancer (CRC). More importantly, the cut‐off points of the scoring systems can be adjusted flexibly, facilitating the choices of cut‐off values for populations with abundant or limited resources.

Triage May Improve Selection to Colonoscopy and Reduce the Number of Unnecessary Colonoscopies

Implementation of population screening for colorectal cancer by direct colonoscopy or follow-up colonoscopy after a positive fecal blood test has challenged the overall capacity of bowel examinations. Certain countries are facing serious colonoscopy capacity constraints, which have led to waiting lists and long time latency of follow-up examinations. Various options for improvement are considered, including increased cut-off values of the fecal blood tests. Results from major clinical studies of blood-based, cancer-associated biomarkers have, however, led to focus on a Triage concept for improved selection to colonoscopy. The Triage test may include subject age, concentration of hemoglobin in a feces test and a combination of certain blood-based cancer-associated biomarkers. Recent results have indicated that Triage may reduce the requirements for colonoscopy by around 30%. Such results may be advantageous for the capacity, the healthcare budgets and in particular, the subjects, who do not need an unnecessary, unpleasant and risk-associated bowel examination.

Older age, symptoms, or anemia: Which factors increase colorectal cancer risk with a positive fecal immunochemical test?

BACKGROUND AND AIM

Fecal immunochemical tests (FIT) are used to screen asymptomatic individuals aged 50-74 years for colorectal cancer (CRC) within the Australian screening program. Gastrointestinal symptoms or iron deficiency anemia (IDA) may also drive primary care physicians to request a FIT. This study aimed to examine factors that may increase neoplasia risk associated with a positive FIT, specifically age, gastrointestinal symptoms, or IDA.

METHODS

A retrospective audit was performed on colonoscopies performed in a single hospital in South Australia for a positive FIT (from all referral sources) between 2014 and 2017. Patients aged < 50 years, or who had a colonoscopy in the preceding 5 years, were excluded. A subgroup (n = 198) was evaluated to assess whether age ≥ 75 years, symptoms, or IDA, as well as other demographics, comorbidities, and medications, were associated with risk of neoplasia. Features found to be associated with risk for CRC or high-risk adenoma were examined in the entire cohort using multivariate analysis.

RESULTS

Colonoscopies (750/4221, 17.8%) were completed in patients ≥ 50 years for a positive FIT. Of these, 7.6% (n = 57) also had gastrointestinal symptoms, 5.5% (n = 41) IDA, and 13.1% (n = 98) were ≥ 75 years. At colonoscopy, 2.8% (n = 21) were diagnosed with CRC and 23.2% (n = 174) with high-risk adenoma. CRC was more prevalent in ≥ 75 years compared with 50-74 years (7.1% vs 2.1%, P = 0.005), and associated with symptoms (15.8% vs 1.7%, P < 0.001), and IDA (14.6% vs 2.1%, P < 0.001). Multivariate analysis showed that IDA (odds ratio 7.68, P < 0.001) and symptoms (odds ratio 10.37, P < 0.001), but not age, were independent risk factors for CRC.

CONCLUSION

The presence of gastrointestinal symptoms or IDA, independent of age, is associated with an increased risk for CRC following a positive FIT.

Can a biomarker triage test reduce colonoscopy burden in fecal immunochemical test screening?

Aim: To assess the potential of biomarker triage testing (BM-TT) in the Dutch colorectal cancer (CRC) screening program. Materials & methods: Using the Adenoma and Serrated pathway to Colorectal CAncer model, we simulated fecal immunochemical test (FIT)₄₇-screening and various FIT plus BM-TT screening scenarios in which only individuals with both a positive FIT and BM-TT are referred to colonoscopy. Results: Adding a low polyp sensitivity BM-TT to FIT-screening reduced colonoscopy burden (89-100%) while increasing CRC mortality (27-41%) compared with FIT₄₇-screening only. The FIT plus high polyp sensitivity BM-TT scenarios also decreased colonoscopy burden (71-89%) while hardly affecting CRC mortality (FIT₄₇ 0-4% increase, FIT₁₅ 2-7% decrease). Conclusion: Adding a BM-TT to FIT-screening considerably reduces colonoscopy burden, but could also decrease screening effectiveness. Combining FIT₁₅ with a high polyp sensitivity BM-TT seems most promising.

Development of blood-based biomarker tests for early detection of colorectal neoplasia: Influence of blood collection timing and handling procedures

INTRODUCTION

Blood-based, cancer-associated biomarkers are susceptible to a variety of well-known preanalytical factors. The influence of bowel preparation before a diagnostic colonoscopy on biomarker levels is, however, poorly investigated. The present study assessed the influence of bowel preparation on colorectal cancer-associated biomarkers. In addition, the effect of single versus double centrifugation of plasma biomarkers was assessed.

METHODS

Blood samples were collected pre- and post-bowel preparation from 125 subjects scheduled for first time diagnostic colonoscopy due to symptoms attributable to CRC. The samples were separated into serum and EDTA plasma, and analyzed by four independent collaborators for: 1) the proteins AFP, CA19-9, CEA, hs-CRP, CyFra21-1, Ferritin, Galectin-3 and TIMP-1, 2) the proteins BAG4, IL6ST, vWF, CD44 and EGFR, 3) the glycoprotein Galectin-3 ligand, and 4) cell-free DNA (cfDNA). Statistical analysis of biomarker data has been performed using mixed modelling, including repeated measures.

RESULTS

The biomarkers generally showed negligible variation between pre- and post-bowel preparation except for CyFra21-1, Ferritin, BAG4 and cfDNA. CyFra21-1 levels were systematically reduced with 29% (95% CI 21-36%) by bowel preparation (p ≤ 0.0001). Ferritin was not significantly different between pre- and post-bowel preparation (p = 0.07), however the estimated difference (increase) was 18%. BAG4 was systematically reduced by 12% (95% CI 1-22%, p = 0.04), while cfDNA showed a significant increase of 28% (95% CI 17-39%, p < 0.0001). Double centrifugation compared to single centrifugation showed reduced vWF (ratio 0.86, p ≤ 0.0001) and CD44 (ratio 0.85, p = 0.016), but increased IL6ST levels (ratio 1.18, p = 0.014).

CONCLUSIONS

Results of the present study demonstrated systematic, statistically significant differences between pre-bowel and post-bowel preparation levels for three independent blood-based biomarkers (BAG4, CyFra21-1, cfDNA), illustrating the importance of timing of sample collection for biomarker analyses.

Increased serological, cancer-associated protein biomarker levels at diagnosis of large bowel adenoma: Risk of subsequent primary malignancy?

BACKGROUND

Blood-based, cancer-associated biomarkers may detect subjects at risk of having neoplastic diseases. The aim of the present study was to evaluate whether elevated serological protein biomarker levels may identify adenoma patients, who are at increased risk of being diagnosed with subsequent primary malignancy.

METHODS

Levels of CEA, CA19-9, TIMP-1 and YKL-40 were determined in blood samples collected prior to diagnostic bowel endoscopy due to symptoms of colorectal neoplasia. Follow-up time was ten years, and identified adenoma patients, who were diagnosed with subsequent primary intra- or extra-colonic malignant diseases. The biomarker levels were also determined in 400 subjects, who underwent diagnostic colonoscopy, had clean colorectum and were without apparent co-morbidity; these levels were used as reference levels. In the present study, biomarkers were interpreted as elevated when levels were above the reference intervals adjusting for age and gender. The 1-year and 5-years cumulative incidences were calculated.

RESULTS

Primary malignancies were identified in 175 (19%) of the 923 subjects diagnosed with adenomas at the primary bowel endoscopy. In detail, 20 of the 175 subjects were diagnosed with colorectal cancer (CRC) and 155 subjects with extra-colonic cancers. Thirty patients were diagnosed with malignancy within the first year. Three groups were established: 0: no elevated biomarkers; 1: 1 of the 4 biomarkers elevated; and 2: ≥2 biomarkers elevated. The cumulative 5-years incidence of malignancy was: 0: 6.9%; 1: 11.8%; and 2: 17.5% (p = .0009).

CONCLUSION

Elevated blood-based, cancer-associated protein biomarker levels in subjects diagnosed with adenomas at large bowel endoscopy identifies subjects at increased risk of being diagnosed with subsequent primary malignancy.

Triage for selection to colonoscopy?

Implementation of population screening for colorectal cancer by direct colonoscopy or follow-up colonoscopy after a positive fecal blood test has challenged the overall capacity of bowel examinations. Certain countries are facing serious colonoscopy capacity constraints, which have led to waiting lists and long-time latency of follow-up examinations. Various options for improvement are considered, including increased cut-off values of the fecal blood tests. Results from major clinical studies of blood-based, cancer-associated biomarkers have led to focus, however, on a triage concept for improved selection to colonoscopy. The triage test may include subject age, concentration of hemoglobin in a feces test and a combination of certain blood-based cancer associated biomarkers. Recent results have indicated that triage may reduce the requirements for colonoscopy by around 30%. Such results may be advantageous for the capacity, the heath budgets and in particular, the subjects, who do not need an unnecessary, unpleasant and risk-associated bowel examination.