Potential role of volatile organic compound breath testing in the Australasian colorectal cancer pathway

Abstract

With colonoscopy resources under pressure and inequitable participation rates in our screening programmes, there is an urgent need to consider trialling new testing technology for the detection of colorectal cancer (CRC) in Australasia. Research has shown that volatile organic compounds (VOCs) emitted from the human body can act as biomarkers for CRC, indicating high sensitivity and specificity for early and late-stage CRC and for adenomatous polyps. Breath-based VOC testing shows promise due to acceptability and ease of sampling via simple hand-held devices. Analysis can occur via mass spectrometry, or via 'e-nose' or sensor techniques. This review summarizes the current state of knowledge in using VOCbased testing for CRC. Adoption of this technique has the potential to improve CRC survival, reduce incidence and reduce colonoscopy burden in Australasia, and positively impact on ethnic disparities in cancer outcomes. Future multicentre trials should be conducted using standardized processes and protocols. This will ensure accuracy and reproducibility under different environmental and physiological conditions, and for different ethnic groups. Studies should be explicitly targeted to various points along the CRC patient pathway. VOCs as a breath-based test for CRCIt has been theorized that VOCs are produced from oxidative stress or peroxidation of cell membranes 11,12 and can reflect changes in the microbiome, inflammation, necrosis or external factors such as diet, medication or pollution. VOCs may therefore represent a

The Detection of Colorectal Cancer through Machine Learning-Based Breath Sensor Analysis

“…Meanwhile, FIT tests are not ideal, due to their low sensitivity to detect early-stage, small-size, and proximally located neoplasms [32]. Hence, the sensor technology is currently of utmost interest [27,33].…”

Employing a honeybee olfactory neural circuit as a novel gas sensor for the detection of human lung cancer biomarkers

“…Different chemical compounds including hexanal, propanal, pentanal, acetone, pentane, 2butanone, and benzene at specific concentrations have been identified as potential lung cancer biomarkers 104 . Overall, there is growing evidence that VOCs in the breath of cancer patients are altered compared to healthy individuals [105][106][107][108] , and these unique compositions of VOCs in exhaled human breath can be used as a fingerprint for the early detection of cancer. We have shown that honeybees can detect all nine of the different lung cancer associated VOCs we tested, indicating their capacity to be a breath-based diagnostic sensor.…”

Differences in the Volatilomic Urinary Biosignature of Prostate Cancer Patients as a Feasibility Study for the Detection of Potential Biomarkers

“…Consequently, their production and release may be altered in some diseases, such as cancer [5,11]. Therefore, VOMs represent a patient's metabolic fingerprint, comprising endogenous and exogenous factors, and for these reasons, have been proposed as a promising class of disease biomarkers (Figure 1) [8,12]. VOMs have been highlighted in recent studies because of their ease of use and noninvasiveness, as they can be identified in easily accessible biofluids such as urine, saliva, and exhaled breath [13,14].…”

“…Volatilomic analysis involves sensitive analytical techniques such as mass spectrometry (MS), electronic nose (e-nose), or sensor techniques combined with multivariate statistical analysis to characterise the chemical composition of biological fluids [11,15]. MS techniques identify and quantify the levels of VOMs, whereas e-nose sensor arrays are linked to pattern recognition algorithms or chemical sensor systems [10,12]. Legend: Acc: accuracy; ANN: artificial neural networks; AUC: area under the receiver operating characteristic (ROC) curve; CART: classification and regression tree; CER: classification error rate; CNN: convolutional neural network; CV: cross-validation; GC-IMS: gas chromatography-ion migration spectroscopy; GC-MS: gas chromatography-mass spectrometry; GC-TOF-MS: gas chromatography coupled to time-of-flight mass spectrometry; HPPI-TOFMS: high-pressure photon ionization time-of-flight mass spectrometry; HS: headspace; HS-SPME: headspace solid-phase microextraction; MLR: multiple logistic regression; NA: not analyzed; PCa: prostate cancer; PCA: principal component analysis; PLS-DA: partial least-squares discriminant analysis; PTR-TOF-MS: proton-transfer-reaction time-of-flight mass spectrometry; RF: random forest; ROC: receiver operating characteristic; Sens: sensitivity; SIFT-MS: selected ion flow tube-mass spectrometry; Spec: specificity; SVM: support vector machine; TD-GC-MS: thermal desorption gas chromatography-mass spectrometry; TD-GC-TOF-MS: two-dimensional gas chromatography with time-of-flight mass spectrometer.…”

“…Owing to the enrichment of volatile compounds, ranging in polarity and complexity, urine is the preferred biological fluid for volatilomic research. In addition to its reproducibility and patient acceptability, urine has fewer interfering proteins or lipids [12,34,35]. Taverna et al [18], Filianoti et al [19], and Capelli et al [20] proposed different e-noses for PCa diagnosis through urinary volatilomic profiling (Table 1).…”