At a glance
- What the study gets you
- Health checks and monitoring — no treatment given
- Type of study
- Observational (no treatment given)
- Time in hospital
- In-person visits at study sites — visit count not specified by the sponsor
- Drug or intervention
- Breath test (diagnostic test)
- How long the study runs
- Study runs about 51 months (dates as stated)
- About the drug or intervention
- Breath test — diagnostic test: Patients must be fasted for a minimum of 4-6 hours prior to breath sample collection.
- Patient visit burden
- Not specified by the sponsor
In plain English
This study, run by Imperial College London, is looking at breath analysis in people with suspected or confirmed colorectal cancer (CRC). It aims to involve adults referred from their GP with symptoms, and those with confirmed colorectal cancer.
Who can take part
- Adults aged 18 or over referred from their GP with symptoms of suspected colorectal cancer
- People with confirmed colorectal adenocarcinoma (a type of bowel cancer), stages I to IV, who have not yet had treatment
Who may not be able to
- Previous surgery that changed the shape of the lower bowel, such as removing part of the colon or bowel
- Previous treatment for colorectal cancer, such as chemotherapy, radiotherapy or immunotherapy before surgery
- Having received bowel preparation for a colonoscopy procedure
- Any other cancer within the past three years
- Unable or unwilling to give written informed consent
What taking part involves
- • Not stated — ask the trial team
Time commitment: Not stated — ask the trial team
Plain-English summary (AI-generated) from registry data. Not eligibility advice — only the trial team can confirm whether you can take part. Use the eligibility checker to see how your health profile matches this trial.
- Type of study
- Observing health over time
- Ages
- 18 Years and over
- Who
- All
- Number of participants
- 720
- Started
- 2022-09-23
- Last checked
- 2025-06
Plain English Summary
What is this study?
- • Testing a new treatment for colorectal cancer
- • Clinical study - 720 participants
- • Colorectal cancer (CRC) is the second most common cause of cancer death in the United Kingdom, with approximately 17,000 deaths per year
Who can take part?
- • Ages 18 Years and over
- • Diagnosed with colorectal cancer
Where?
- • London - Chelsea and Westminster Hospital
- • London - Royal Marsden Hospital
- • London - St Mark's Hospital
- • London - St Mary's Hospital
- • +1 more UK sites
This is a simplified summary. Always discuss with your doctor before making any decisions.
About This Trial
Colorectal cancer (CRC) is the second most common cause of cancer death in the United Kingdom, with approximately 17,000 deaths per year. The five-year survival rate from CRC is only 10% when discovered at a late stage, but exceeds 90% if diagnosed early. Symptoms related to CRC can be non-specific, therefore the decision to refer for a colonoscopy can be challenging. There is a clear need to improve earlier detection of CRC so that patients with CRC can be identified earlier and faster, enabling them to start treatment more quickly. The study team is developing a non-invasive breath test that detects small molecules called volatile organic compounds (VOCs) that are specific to CRC. For patients with non-specific symptoms, this test would help GPs to identify those patients that may have underlying CRC, who would benefit from referral for specialised CRC tests.
More detail
The COBRA1 study initially assessed VOCs in CRC and identified a list of 14 VOC biomarkers for CRC and provided a detection model with an area under the receiver operating characteristic curve of 0.91, sensitivity of 83% and specificity of 88% in symptomatic patients. COBRA2 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. Methods: COBRA2 is be a prospective, multicentre validation study. The study team are recruiting the following patients: The following groups of patients are being recruited: i) Control group: symptomatic patients who are attending a planned colonoscopy referred under the suspected lower GI cancer pathway. Any patient who is found to have histologically-proven CRC on colonoscopy will be analysed as part of the CRC group. ii) CRC group: patients who either have a confirmed diagnosis of colorectal adenocarcinoma according to a biopsy, or who are due to undergo surgical resection for suspected CRC (with histological confirmation to follow within three months). Target recruitment is 720 patients (470 controls, 250 CRC), aiming for 576 patients (376 controls, 200 CRC) with reliable and complete data. Participants are required to maintain a clear fluid diet for a minimum of 4-6 hours prior to sampling and should not have received bowel preparation. Participants will be asked to provide breath samples by exhaling into single-use breath collection bags and breath will be transferred using a precision pump onto thermal desorption (TD) tubes. Breath samples will be analysed with gas chromatography-mass spectrometry in accordance with existing quality control processes.
How this trial compares with your answers
Answer 2 more questions to improve match
What we know so far
Still need:
- • Tell us your age for better matching
- • Tell us your sex for better matching
Preliminary match based on your answers. Full eligibility requires on-site assessment including medical history, physical exam, and lab tests. This does not guarantee enrolment.
Eligibility at a Glance
Key info
- Age: 18 Years and over
- Who can join: All genders
Treatment history
Treatments you must have had:
- ✓ (neoadjuvant chemotherapy
What the study is looking for
- ✓Patients aged ≥ 18 years referred from primary care with symptoms of suspected CRC.
- ✓Patients with confirmed by a biopsy colorectal adenocarcinoma (stages I-IV) who are treatment naïve (CRC group).
- ✓Exclusion Criteria - patients with any of the following will not be eligible for inclusion:
- ✓Previous surgery altering the anatomy of the lower GI tract (e.g., hemicolectomy, anterior resection).
- ✓Previous treatment (before surgery drug treatment or radiotherapy or treatment that helps your immune system fight cancer) for CRC.
See the full criteria
Where Is This Study? (5 UK sites)
Chelsea and Westminster Hospital
London, United Kingdom
Royal Marsden Hospital
London, United Kingdom
St Mark's Hospital
London, United Kingdom
St Mary's Hospital
London, United Kingdom
West Middlesex University Hospital
London, United Kingdom
How to Get in Touch
Mr Michael G Fadel, BSc MBBS MRCS
Sponsor contactCONTACT