Risk stratification of symptomatic patients suspected of colorectal cancer using faecal and urinary markers

Urinary volatile organic compounds and faecal microbiome profiles in colorectal cancer

AIM

Volatile organic compounds (VOCs) are potential biomarkers for diagnosing colorectal cancer (CRC). We characterized urinary VOCs from CRC patients, their spouses/cohabitors (spouses) and first-degree relatives (relatives) to determine any differences. Correlation with stool-derived microbiomes was also undertaken.

METHODS

Urine from 56 CRC patients, 45 spouses and 37 relatives was assayed using liquid chromatography, field asymmetric ion mobility spectrometry (FAIMS), mass spectrometer technology. Analysis was performed using five-fold cross-validation and a random forest classifier. Faecal microbiome 16S rRNA was sequenced using Illumina MiSeq protocols and analysed using UPARSE and QIIME pipelines. VOC and microbiome profiles were also compared before and after cancer treatment.

RESULTS

Urinary VOC profiles of CRC patients were indistinguishable from either spouses or relatives. When spouses and relatives were grouped together to form a larger non-cancer control group (n = 82), their VOC profiles became distinguishable from those of CRC patients (n = 56) with 69% sensitivity and specificity, area under the curve 0.72 (P < 0.001). Microbiome analysis identified > 1300 operational taxonomic units across all groups. The analysis of similarity R value was 0.067 (P < 0.001), with significantly different bacterial abundances in 82 operational taxonomic units (6.2%) by Kruskal-Wallis testing. CRC patients' VOC or stool microbiome profiles were unchanged after treatment.

CONCLUSION

Although CRC patients' urinary VOC profiles cannot be differentiated from those of spouses or relatives they can be differentiated from a larger non-cancer control group. Comparison of the groups' microbiomes confirmed differences in bacterial species abundance. The current FAIMS-based assay can detect a unique, but modest, signal in CRC patients' urinary VOCs, which remains unaltered after treatment.

Diagnosing Inflammatory bowel disease using noninvasive applications of volatile organic compounds: a systematic review

Introduction: Inflammatory bowel disease (IBD) is a common disease with significant morbidity. Noninvasive diagnostic techniques are lacking in IBD. Currently, fecal calprotectin is a sensitive marker of gut inflammation however is not specific to Crohn's disease (CD) or ulcerative colitis (UC) alone. Volatile organic compounds (VOCs) were shown to have potential in IBD diagnosis.Areas covered: This systematic review aimed to examine the next-generation diagnosis of IBD in adults and children using VOCs. An in-depth literature-based search of current clinical studies of VOCs in the diagnosis of IBD was undertaken. Accuracy of IBD detection varied according to the technologies applied. Breath VOCs studies were pooled giving an overall sensitivity of 85% (95%CI: 79-89%) and specificity of 79% (95%CI 73-84%) whilst pooled fecal VOCs studies revealed a sensitivity of 87% (95%CI 77-93%) and specificity of 91% (95%CI 82-96%). Studies were limited by the variance of techniques applied in VOCs detection and the absence of well-designed longitudinal studies.Expert opinion: VOCs can be consistently and effectively detected in urine, breath, and stool in IBD patients. The sensitivity of breath VOCs in detecting IBD was comparable to feces. However, optimal VOCs detection methodology and biological sampling still need to be standardized..

Urinary Metabolomics to Identify a Unique Biomarker Panel for Detecting Colorectal Cancer: A Multicenter Study

BACKGROUND

Population-based screening programs are credited with earlier colorectal cancer diagnoses and treatment initiation, which reduce mortality rates and improve patient health outcomes. However, recommended screening methods are unsatisfactory as they are invasive, are resource intensive, suffer from low uptake, or have poor diagnostic performance. Our goal was to identify a urine metabolomic-based biomarker panel for the detection of colorectal cancer that has the potential for global population-based screening.

METHODS

Prospective urine samples were collected from study participants. Based upon colonoscopy and histopathology results, 342 participants (colorectal cancer, 171; healthy controls, 171) from two study sites (Canada, United States) were included in the analyses. Targeted liquid chromatography-mass spectrometry (LC-MS) was performed to quantify 140 highly valuable metabolites in each urine sample. Potential biomarkers for colorectal cancer were identified by comparing the metabolomic profiles from colorectal cancer versus controls. Multiple models were constructed leading to a good separation of colorectal cancer from controls.

RESULTS

A panel of 17 metabolites was identified as possible biomarkers for colorectal cancer. Using only two of the selected metabolites, namely diacetylspermine and kynurenine, a predictor for detecting colorectal cancer was developed with an AUC of 0.864, a specificity of 80.0%, and a sensitivity of 80.0%.

CONCLUSIONS

We present a potentially "universal" metabolomic biomarker panel for colorectal cancer independent of cohort clinical features based on a North American population. Further research is needed to confirm the utility of the profile in a prospective, population-based colorectal cancer screening trial.

IMPACT

A urinary metabolomic biomarker panel was identified for colorectal cancer with the potential of clinical application.

Faecal immunochemical testing (FIT) in symptomatic patients: what are we missing?

OBJECTIVE

Faecal immunochemical test (FIT) shows promise as a non-invasive triage test for colorectal cancer (CRC) in the symptomatic population. The aim of this study was to assess the use of FIT within the recent NG12 and DG30 National Institute for Health and Care Excellence (NICE) guidelines.

DESIGN

A single-centre prospective study of patients referred to University Hospitals Coventry and Warwickshire NHS Trust via the 2-week wait (TWW) pathway between January 2015 and March 2016 was conducted. 612 patients were reviewed, of which 519 were found to meet the NG12 criteria and 79 met the DG30 criteria. Data included age, sex, symptoms, colonoscopy or CT colonography, histology and FIT results.

MAIN OUTCOME MEASURES

FIT was performed in all patients and sensitivity, specificity, positive predictive value and negative predictive value, with 95% CI, for cancers and adenomas within each pathway (TWW, NG12 and DG30) was calculated.

RESULTS

CRC sensitivity in TWW pathway patients, NG12 and DG30 group was 86.84% (95% CI 71.91% to 95.59%), 84.85% (95% CI 68.1% to 94.89%) and 100% (95% CI 47.82% to 100%), respectively. Specificity was 82.23% (95% CI 78.85% to 85.27%), 81.28% (95% CI 77.52% to 84.65%) and 91.89% (95% CI 83.18% to 96.97%), respectively. Adenoma sensitivity in the groups was 30.69% (95% CI 29.9% to 40.66%), 30.77% (95% CI 21.51% to 41.32%) and 25% (95% CI 3.19% to 65.09%), respectively.

CONCLUSION

Use of FIT within the remit of the NG12 NICE guidelines shows a high sensitivity and specificity and may be an effective triage tool when considering whether to perform investigations. However, there is still a miss rate. FIT within DG30 has excellent sensitivity and improved specificity; however, DG30 targets lower risk groups and accounts for only 13% of the entire referrals for suspected cancer. Therefore, managing the larger, higher risk NG12 group may require the addition of another test or marker to ensure that CRC is not missed.