Point-of-care testing in the diagnosis of gastrointestinal cancers: Current technology and future directions

Size-exclusion chromatography-based extracellular vesicle size subtyping and multiplex membrane protein profiling for differentiating gastrointestinal cancer prognosis

Extracellular vesicles (EVs), as a type of subcellular structure, have been extensively researched for their potential for developing advanced diagnostic technologies for various diseases. However, the biomolecular and biophysical heterogeneity of EVs has restricted their application in clinical settings. In this article, we developed a size-exclusion chromatography-based technique for simultaneous EV size subtyping and protein profiling. By eluting fluorescent aptamer-treated patient plasma through a size-exclusion column, the mixture can be classified into 50 nm aptamer-bound EVs, 100 nm aptamer-bound EVs and free-floating aptamers, which could further enable multiplex EV membrane protein profiling by analyzing the fluorescence intensities of EV-bound aptamers. Using this technique, we successfully identified EV size subtypes for differentiating gastrointestinal cancer prognosis states. Overall, we developed a rapid, user-friendly and low-cost EV size subtyping and protein profiling technique, which holds great potential for identifying crucial EV size subtypes for disease diagnosis in the clinic.

Comparison of the QuikRead go® point-of-care faecal immunochemical test for haemoglobin with the FOB Gold Wide® laboratory analyser to diagnose colorectal cancer in symptomatic patients

OBJECTIVES

Faecal immunochemical testing for haemoglobin (FIT) is used to triage patients for colonic investigations. Point-of-care (POC) FIT devices on the market have limited data for their diagnostic accuracy for colorectal cancer (CRC). Here, a POC FIT device is compared with a laboratory-based FIT system using patient collected samples from the urgent referral pathway for suspected CRC.

METHODS

A prospective, observational cohort study. Patients collected two samples from the same stool. These were measured by POC QuikRead go^® (Aidian Oy, Espoo, Finland) and laboratory-based FOB Gold Wide^® (Sentinel Diagnostics, Italy). Faecal haemoglobin <10 μg haemoglobin/g of faeces was considered as negative. At this threshold, comparisons between the two systems were made by calculating percentage agreement and Cohen's kappa coefficient. Proportion of negative results were compared with Chi squared testing. Sensitivities for CRC were calculated.

RESULTS

A total of 629 included patients provided paired samples for FIT to compare the QuikRead go^® and FOB Gold Wide^®. The agreement around the negative threshold was 83.0% and Cohen's kappa coefficient was 0.54. The QuikRead go^® reported 440/629 (70.0% of samples) as negative compared to 523/629 (83.1%) for the FOB Gold Wide^®, this difference was significant (p-value<0.001). Sensitivities for CRC detection by the QuikRead go^® and FOB Gold Wide^® were 92.9% (95% confidence interval (CI): 68.5-98.7%) and 100% (CI: 78.5-100%) respectively.

CONCLUSIONS

Both systems were accurate in their ability to detect CRC. Whilst good agreement around the negative threshold was identified, more patients would be triaged to further colonic investigation if using the QuikRead go^®.

Noninvasive fecal testing for colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is the third most common malignancy worldwide, with the second highest mortality rate among all malignancies. In this review, we describe the current utility of stool diagnostic biomarkers for CRC.

METHODS

We reviewed stool-related tests and biomarker candidates for the diagnosis of CRC. The guaiac-based fecal occult blood test (gFOBT), fecal immunochemical test (FIT), and multitarget stool DNA test (MT-sDNA) have been used as clinical CRC screening tools. Although microRNAs, protein biomarkers, and microbiota have not yet been used in clinical CRC screening, there is growing evidence that they have the potential to function as CRC screening tools.

RESULTS

According to the literature, the sensitivity of MT-sDNA for detecting CRC was 87.0-100%, 32.7-82.0% for advanced adenomas, and the specificity was 86.1-95.2%. The sensitivity of individual biomarkers of fecal microRNAs for detecting CRC was 34.2-88.2%, 73.0% for advanced adenomas, and the specificity was 68-100%. The sensitivity of fecal protein markers for detecting CRC was 63.6-93.0%, 47.7-69.4% for advanced adenomas, and the specificity was 38.3-97.5%. The sensitivity of fecal microbiota for detecting CRC was 54.0-100.0%, 32.0-48.3% for advanced adenomas, and the specificity was 61.3-90.0%.

CONCLUSION

MT-sDNA is the most sensitive CRC screening test, and its sensitivity is the highest for advanced adenomas; however, its detection cost is high. MT-sDNA was more sensitive to CRC and advanced precancerous lesions than FIT, but compared to three years of MT-sDNA, annual FIT as the first non-invasive screening test for CRC seemed to be more effective.

Diagnostic accuracy of point of care faecal immunochemical testing using a portable high-speed quantitative analyser for diagnosis in 2-week wait patients

AIM

Laboratory-based faecal immunochemical testing (FIT) is the gold standard for detecting the presence of blood in the stool. The aim was to perform a diagnostic accuracy study to confirm if a point of care (POC) analyser for FIT could be safely used as an adjunct in the triage and management of 2-week wait (TWW) colorectal patients.

METHODS

The Point of Care Faecal Immunochemical Testing (POC FIT) prospective observational cohort study was designed for TWW patients at a regional referral centre. Between July 2019 and March 2020, patients were invited to perform and bring a FIT sample to clinic. FIT was completed within the clinic appointment using a POC quantitative analyser that has a 2-min processing time (QuikRead go®). Patients and clinicians were blinded to results within the clinic appointment. The results were compared with subsequent diagnostic outcomes. Faecal haemoglobin of <10 µg haemoglobin/g of faeces was considered a negative result. Sensitivities for colorectal cancer (CRC) and combined serious bowel disease (SBD) were calculated using this pre-determined cut-off.

RESULTS

A total of 553 patients were included for analytical comparison with diagnostic outcomes. There were 14 (2.5%) patients with CRC and 52 (9.4%) with SBD. The sensitivities for CRC and SBD were 92.9% (95% CI 68.5%-98.7%) and 76.9% (95% CI 63.9%-86.3%) respectively. 379 (68.5%) patients had a negative FIT result (negative predictive value for CRC was 99.7%).

CONCLUSIONS

This POC FIT device is a useful adjunct to better manage TWW patients. The high observed sensitivity for CRC offers opportunities, within a single consultation, for improved triage and rationalization of investigation for those with bowel symptoms.

Qualitative analysis of stakeholder interviews to identify the barriers and facilitators to the adoption of point-of-care diagnostic tests in the UK

OBJECTIVES

This study investigated the barriers and facilitators to the adoption of point-of-care tests (POCTs).

DESIGN

Qualitative study incorporating a constant comparative analysis of stakeholder responses to a series of interviews undertaken to design the Point-of-Care Key Evidence Tool.

SETTING

The study was conducted in relation to POCTs used in all aspects of healthcare.

PARTICIPANTS

Forty-three stakeholders were interviewed including clinicians (incorporating laboratory staff and members of trust POCT committees), commissioners, industry, regulators and patients.

RESULTS

Thematic analysis highlighted 32 barriers in six themes and 28 facilitators in eight themes to the adoption of POCTs. Six themes were common to both barriers and facilitators (clinical, cultural, evidence, design and quality assurance, financial and organisational) and two themes contained facilitators alone (patient factors and other (non-financial) resource use).

CONCLUSIONS

Findings from this study demonstrate the complex motivations of stakeholders in the adoption of POCT. Most themes were common to both barriers and facilitators suggesting that good device design, stakeholder engagement and appropriate evidence provision can increase the likelihood of a POCT device adoption. However, it is important to realise that while the majority of identified barriers may be perceived or mitigated some may be absolute and if identified early in device development further investment should be carefully considered.

Can Coupling Multiple Complementary Methods Improve the Spectroscopic Based Diagnosis of Gastrointestinal Illnesses? A Proof of Principle Ex Vivo Study Using Celiac Disease as the Model Illness

Spectroscopic methods are a promising approach for providing a point-of-care diagnostic method for gastrointestinal mucosa associated illnesses. Such a tool is desired to aid immediate decision making and to provide a faster pathway to appropriate treatment. In this pilot study, Raman, near-infrared, low frequency Raman, and autofluoresence spectroscopic methods were explored alone and in combination for the diagnosis of celiac disease. Duodenal biopsies (n = 72) from 24 participants were measured ex vivo using the full suite of studied spectroscopic methods. Exploratory principal component analysis (PCA) highlighted the origin of spectral differences between celiac and normal tissue with celiac biopsies tending to have higher protein relative to lipid signals and lower carotenoid spectral signals than the samples with normal histology. Classification of the samples based on the histology and overall diagnosis was carried out for all combinations of spectroscopic methods. Diagnosis based classification (majority rule of class per participant) yielded sensitivities of 0.31 to 0.77 for individual techniques, which was increased up to 0.85 when coupling multiple techniques together. Likewise, specificities of 0.50 to 0.67 were obtained for individual techniques, which was increased up to 0.78 when coupling multiple techniques together. It was noted that the use of antidepressants contributed to false positives, which is believed to be associated with increased serotonin levels observed in the gut mucosa in both celiac disease and the use of selective serotonin reuptake inhibitors (SSRIs); however, future work with greater numbers is required to confirm this observation. Inclusion of two additional spectroscopic methods could improve the accuracy of diagnosis (0.78) by 7% over Raman alone (0.73). This demonstrates the potential for further exploration and development of a multispectroscopic system for disease diagnosis.

Assessment of the analytical performance of point-of-care faecal immunochemical tests for haemoglobin

BACKGROUND

The faecal immunochemical test (FIT) detects the presence of haemoglobin (Hb) in faeces. It is used as a screening tool for colorectal cancer (CRC) and increasingly to triage patients presenting with symptoms of CRC. A number of quantitative point-of-care (POC) FIT systems marketed for professional use and intended for use in a clinical setting are available. Here we reviewed the POC FIT systems available; three (Eurolyser Cube, OC-Sensor iO and QuikRead go) were evaluated to assess their performance against manufacturers' claims and suitability for use in a clinical setting.

METHODS

The analytical evaluation of the POC FIT systems was undertaken using Hb lysates, patient samples and an external quality assessment sample. The evaluation focused on linearity, recovery, imprecision, prozone effect, Hb variant detection and suitability for use in a clinical setting.

RESULTS

All three POC FIT systems performed to their manufacturer's claims and demonstrated good analytical performance with acceptable linearity, recovery, within- and between-run imprecision. The QuikRead go and OC-Sensor iO were able to accurately detect samples with results above their measuring range. However, because of a prozone effect the Eurolyser Cube gave falsely low results when using high concentrations of Hb. The QuikRead go performed best in the usability assessment due to portability and timeliness of result.

CONCLUSION

Each system performed according to their manufacturers' claims. The QuikRead go and OC-Sensor iO are suitable for use. The Eurolyser Cube is not recommended because of the risk of falsely low results.

Biomarkers for detecting colorectal cancer non-invasively: DNA, RNA or proteins?

Colorectal cancer (CRC) is a global problem affecting millions of people worldwide. This disease is unique because of its slow progress that makes it preventable and often curable. CRC symptoms usually emerge only at advanced stages of the disease, consequently its early detection can be achieved only through active population screening, which markedly reduces mortality due to this cancer. CRC screening tests that employ non-invasively detectable biomarkers are currently being actively developed and, in most cases, samples of either stool or blood are used. However, alternative biological substances that can be collected non-invasively (colorectal mucus, urine, saliva, exhaled air) have now emerged as new sources of diagnostic biomarkers. The main categories of currently explored CRC biomarkers are: (1) Proteins (comprising widely used haemoglobin); (2) DNA (including mutations and methylation markers); (3) RNA (in particular microRNAs); (4) Low molecular weight metabolites (comprising volatile organic compounds) detectable by metabolomic techniques; and (5) Shifts in gut microbiome composition. Numerous tests for early CRC detection employing such non-invasive biomarkers have been proposed and clinically studied. While some of these studies generated promising early results, very few of the proposed tests have been transformed into clinically validated diagnostic/screening techniques. Such DNA-based tests as Food and Drug Administration-approved multitarget stool test (marketed as Cologuard®) or blood test for methylated septin 9 (marketed as Epi proColon® 2.0 CE) show good diagnostic performance but remain too expensive and technically complex to become effective CRC screening tools. It can be concluded that, despite its deficiencies, the protein (haemoglobin) detection-based faecal immunochemical test (FIT) today presents the most cost-effective option for non-invasive CRC screening. The combination of non-invasive FIT and confirmatory invasive colonoscopy is the current strategy of choice for CRC screening. However, continuing intense research in the area promises the emergence of new superior non-invasive CRC screening tests that will allow the development of improved disease prevention strategies.

Emerging Designs of Electronic Devices in Biomedicine

A long-standing goal of nanoelectronics is the development of integrated systems to be used in medicine as sensor, therapeutic, or theranostic devices. In this review, we examine the phenomena of transport and the interaction between electro-active charges and the material at the nanoscale. We then demonstrate how these mechanisms can be exploited to design and fabricate devices for applications in biomedicine and bioengineering. Specifically, we present and discuss electrochemical devices based on the interaction between ions and conductive polymers, such as organic electrochemical transistors (OFETs), electrolyte gated field-effect transistors (FETs), fin field-effect transistor (FinFETs), tunnelling field-effect transistors (TFETs), electrochemical lab-on-chips (LOCs). For these systems, we comment on their use in medicine.

Faecal Occult Blood Point-of-Care Tests

Background

Early detection of colorectal cancer decreases the risk of mortality. Faecal occult blood tests (FOBT) are recognised as a useful tool for colorectal cancer screening. These non-invasive, rapid, and easy-to-carry assays are very often used as a point-of-care test and for self-testing. On the market, there are various types of FOB tests available, including chemical and immunochromatographic tests, which are based on different detection methods and differ in their sensitivity and specificity.

Conclusions

Clinicians should be aware of the causes of false-negative and false-positive test results, which can vary depending on the test. Additionally, stool sampling bias may be a source of error and must be considered by the clinician. The current FOBT methods are subject to various interfering factors; items such as proper preparation of the patient prior to testing or the clinician’s knowledge of testing limitations are key in correct interpreting results. Novel technologies such as FOBT DNA tests, micro RNA tests, and biochips equipped with bacteria can indicate bleeding from the gastrointestinal tract and improve diagnostics process.

Development of the Point-of-Care Key Evidence Tool (POCKET): a checklist for multi-dimensional evidence generation in point-of-care tests

Background

This study aimed to develop the Point-of-Care Key Evidence Tool (POCKET); a multi-dimensional checklist to guide the evaluation of point-of-care tests (POCTs) incorporating validity, utility, usability, cost-effectiveness and patient experience. The motivation for this was to improve the efficiency of evidence generation in POCTs and reduce the lead-time for the adoption of novel POCTs.

Methods

A mixed qualitative and quantitative approach was applied. Following a literature search, a three round Delphi process was undertaken incorporating a semi-structured interview study and two questionnaire rounds. Participants included clinicians, laboratory personnel, commissioners, regulators (including members of National Institute for Health and Care Excellence [NICE] committees), patients, industry representatives and methodologists. Qualitative data were analysed based on grounded theory. The final tool was revised at an expert stakeholder workshop.

Results

Forty-three participants were interviewed within the semi-structured interview study, 32 participated in the questionnaire rounds and nine stakeholders attended the expert workshop. The final version of the POCKET checklist contains 65 different evidence requirements grouped into seven themes. Face validity, content validity and usability has been demonstrated. There exists a shortfall in the evidence that industry and research methodologists believe should be generated regarding POCTs and what is actually required by policy and decision makers to promote implementation into current healthcare pathways.

Conclusions

This study has led to the development of POCKET, a checklist for evidence generation and synthesis in POCTs. This aims to guide industry and researchers to the evidence that is required by decision makers to facilitate POCT adoption so that the benefits they can bring to patients can be effectively realised.

Treatment for unresectable or metastatic oesophageal cancer: current evidence and trends

Approximately half of the patients diagnosed with oesophageal cancer present with unresectable or metastatic disease. Treatment for these patients aims to control dysphagia and other cancer-related symptoms, improve quality of life and prolong survival. In the past 25 years, modestly improved outcomes have been achieved in the treatment of patients with inoperable non-metastatic cancer who are medically not fit for surgery or have unresectable, locally advanced disease. Concurrent chemoradiotherapy offers the best outcomes in these patients. In distant metastatic oesophageal cancer, several double-agent or triple-agent chemotherapy regimens have been established as first-line treatment options. In addition, long-term results of multiple large randomized phase III trials using additional targeted therapies have been published in the past few years, affecting contemporary clinical practice and future research directions. For the local treatment of malignant dysphagia, various treatment options have emerged, and self-expandable metal stent (SEMS) placement is currently the most widely applied method. Besides the continuous search for improved SEMS designs to minimize the risk of associated complications, efforts have been made to develop and evaluate the efficacy of antireflux stents and irradiation stents. This Review outlines the current evidence and ongoing trends in the different modern-day, multidisciplinary interventions for patients with unresectable or metastatic oesophageal cancer with an emphasis on key randomized trials.

Omics-based molecular techniques in oral pathology centred cancer: prospect and challenges in Africa

BACKGROUND

The completion of the human genome project and the accomplished milestones in the human proteome project; as well as the progress made so far in computational bioinformatics and "big data" processing have contributed immensely to individualized/personalized medicine in the developed world.

MAIN BODY

At the dawn of precision medicine, various omics-based therapies and bioengineering can now be applied accurately for the diagnosis, prognosis, treatment, and risk stratification of cancer in a manner that was hitherto not thought possible. The widespread introduction of genomics and other omics-based approaches into the postgraduate training curriculum of diverse medical and dental specialties, including pathology has improved the proficiency of practitioners in the use of novel molecular signatures in patient management. In addition, intricate details about disease disparity among different human populations are beginning to emerge. This would facilitate the use of tailor-made novel theranostic methods based on emerging molecular evidences.

CONCLUSION

In this review, we examined the challenges and prospects of using currently available omics-based technologies vis-à-vis oral pathology as well as prompt cancer diagnosis and treatment in a resource limited setting.

Available technologies and clinical applications of targeted chemotherapy in pancreatic cancer

The incidence of pancreatic cancer, the fourth leading cause of cancer death in United States, is increasing worldwide. Even though the cure rate has doubled in 40 years, it is abysmally poor at 6-7%. As surgical resection remains the only curative treatment and less than 20% of the newly diagnosed cancers are resectable, the major burden of disease management lies in early diagnosis, good prognostication, and proper neo-adjuvant and/or adjuvant therapy. With advancing technologies and their ease of availability, researchers have better tools to understand pancreatic cancer. In the post-genetic era, proteomic, phosphoproteomic, metabolomic, and more have brought us to a multi-omics era. These newer avenues bring promises of better screening modalities, less invasive diagnostics and monitoring, subtyping of pancreatic cancer, and fine tuning the treatment modalities not only to the right stage of tumor but also to the right tumor biology. As the multitudes of technologies are generating extensive amounts of incongruous data, they are giving clinicians a lot of non-actionable information. In this paper, we wish to encompass the newer technologies, sub-classifications, and future treatment modalities in personalized care of patients with pancreatic cancer.

VOCC: a database of volatile organic compounds in cancer

Volatile organic compounds in cancer database (VOCC) has been developed, which provides comprehensive information of VOCs distinctly observed in cancer vs. normal from various malignancies and different sources.

Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

AIM: To evaluate ATP-binding cassette (ABC) transporters in colonic pathophysiology as they had recently been related to colorectal cancer (CRC) development.

METHODS: Literature search was conducted on PubMed using combinations of the following terms: ABC transporters, ATP binding cassette transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1/Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function.

RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in relation to colitis was suggested by the animal studies. The finding that colitis was preceded by altered gut bacterial composition suggests that deletion of Abcb1 leads to fundamental changes of host-microbiota interaction. Also, high fat diet increases the frequency and severity of colitis in specific pathogen-free Abcb1 KO mice. The Abcb1 KO mice might thus serve as a model in which diet/environmental factors and microbes may be controlled and investigated in relation to intestinal inflammation. Potential molecular mechanisms include defective transport of inflammatory mediators and/or phospholipid translocation from one side to the other of the cell membrane lipid bilayer by ABC transporters affecting inflammatory response and/or function of tight junctions, phagocytosis and vesicle trafficking. Also, diet and microbes give rise to molecules which are potential substrates for the ABC transporters and which may additionally affect ABC transporter function through nuclear receptors and transcriptional regulation. Another critical role of ABCB1 was suggested by the finding that ABCB1 expression identifies a subpopulation of pro-inflammatory Th17 cells which were resistant to treatment with glucocorticoids. The evidence for the involvement of ABCC2 and ABCG2 in colonic pathophysiology was weak.

CONCLUSION: ABCB1, diet, and gut microbes mutually interact in colonic inflammation, a well-known risk factor for CRC. Further insight may be translated into preventive and treatment strategies.

Fecal DNA testing for colorectal cancer screening: Molecular targets and perspectives

The early detection of colorectal cancer with effective screening is essential for reduction of cancer-specific mortality. The addition of fecal DNA testing in the armamentarium of screening methods already in clinical use launches a new era in the noninvasive part of colorectal cancer screening and emanates from a large number of previous and ongoing clinical investigations and technological advancements. In this review, we discuss the molecular rational and most important genetic alterations hallmarking the early colorectal carcinogenesis process. Also, representative DNA targets-markers and key aspects of their testing at the clinical level in comparison or/and association with other screening methods are described. Finally, a critical view of the strengths and limitations of fecal DNA tests is provided, along with anticipated barriers and suggestions for further exploitation of their use.