Evidence map›Paper›PMID 40731329›Full record

ArticleBMC cancer2025

Non-invasive breath testing to detect colorectal cancer: protocol for a multicentre, case-control development and validation study (COBRA2 study).

Michael G Fadel, James Murray, Georgia Woodfield, Ilaria Belluomo, Ivan Laponogov, Aaron Parker, Valerio Converso, James K Ellis, Pete Wheatstone, Julie Hepburn and 10 more

Registry-linked trialAbstract readClinical Trial Protocol
PubMed Full text at PMC Publisher
In one paragraph

Article in BMC cancer, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05844514 (The COlorectal BReath Analysis), which is not on this map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

NCT05844514 recruitingnot on this map

The COlorectal BReath Analysis (COBRA2) Study: Non-invasive Breath Testing to Detect Colorectal Cancer

TypeobservationalSponsorImperial College LondonRan2022 to 2026Enrolled720ConditionsColorectal CancerArmsBreath test
3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

20 authors.

Michael G FadelDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
James MurrayDepartment of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK.
Georgia WoodfieldDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Ilaria BelluomoDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Ivan LaponogovDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Aaron ParkerDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Valerio ConversoDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
James K EllisDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Pete WheatstonePatient and Public Involvement, Clinical Trials Research Unit, University of Leeds, Leeds, UK.
Julie HepburnPatient and Public Involvement, Health and Care Research Wales Support Centre, Cardiff, UK.
Chris GrovesDepartment of Gastroenterology, St George's Hospital, London, UK.
Kevin MonahanDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Brian P SaundersDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Patrik ŠpanělDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Kirill VeselkovDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Amanda J CrossDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Christos KontovounisiosDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK.
Linda D SharplesDepartment of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK.
George B HannaDepartment of Surgery and Cancer, Hammersmith Hospital Campus, Imperial College London, Du Cane Road, London, W12 0NN, UK. g.hanna@imperial.ac.uk.
COBRA2 Collaborators

Funding

Cancer Research UK EDDPGM-May21\10007CW+ and Westminster Medical School Research Trust JRC FS 001NIHR Doctoral Fellowship programme NIHR303043
6 · The paper itself

Abstract

backgroundColorectal cancer (CRC) is the fourth most common cancer in the United Kingdom. The five-year survival rate from CRC is only 10% when discovered at a late stage, but can exceed 90% if diagnosed early. Symptoms related to CRC can be non-specific, and therefore the decision to refer for a colonoscopy can be challenging. Breath analysis potentially offers a simple and quick method to detect CRC specific volatile organic compounds (VOCs) in breath. This protocol describes the COBRA2 study which aims to develop and validate the clinical prediction model (CPM) in the detection of CRC based on the breath test. An exploratory comparison between the breath test and faecal immunochemical test (FIT) will also be carried out to assess whether combining both tests improves diagnostic performance.

methodsThe COBRA2 study is a multicentre, case-control development and validation study. Breath samples will be collected from participants attending hospital for a planned colonoscopy (control group) or from participants with histologically confirmed colorectal adenocarcinoma (CRC group). A total of 720 participants (470 controls, 250 CRC) will be recruited. All participants will maintain a clear fluid diet for a minimum of 4-6 h prior to sampling, which will take place at outpatient clinics to avoid bowel preparation. The FIT result will be recorded where available. Breath samples will be analysed using gas chromatography-mass spectrometry to identify the VOCs present. Relationships between VOCs of interest and presence of CRC will be explored, and the CPM will be developed using statistical and machine learning methods. We will also assess whether incorporating FIT into the CPM improves diagnostic performance. The CPM will be subsequently validated in an independent sample of up to 250 participants (125 controls, 125 CRC) using the same case-control design and the potential clinical utility of decision rules for triaging will be assessed. If successful, broad validation in an unselected target population of symptomatic patients is required. DISCUSSION: The non-invasive breath test may provide direct patient benefit through earlier and accurate detection of CRC, and higher patient acceptability. It can help ensure timely secondary care referral, potentially translating to improved curative treatment and survival for patients.

trial registrationThe study is registered with ClinicalTrials.gov (NCT05844514).

Indexed as

Colorectal NeoplasmsEarly Detection of CancerVolatile Organic CompoundsBreath TestsCase-Control StudiesColonoscopyFemaleHumansMaleMiddle AgedMulticenter Studies as TopicVolatile Organic CompoundsBiomarkersBreath testColorectal cancerDetectionDiagnostic modelVolatile organic compounds

Identifiers

PMID40731329
PMCPMC12309184

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Registered trials

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.