Multi-centre discovery and validation study evaluating breath biomarkers for the diagnosis of lung cancer – the LuCID study

Background Volatile Organic Compound (VOC) research for lung cancer detection has faced study design and analytical methodology challenges limiting translation into clinical practice. We evaluated the diagnostic value of breath biomarkers in patients under investigation for suspected lung cancer.

In a multi-centre prospective case-control study involving 1844 subjects under investigation, breath samples from subjects with a conclusive diagnosis were analysed using gas-chromatography mass-spectrometry. A staged approach was adopted: an Exploratory method for targeted analysis of 63 VOCs associated with lung cancer, followed by an Optimised method for biomarker discovery and finally, evaluation of the optimised panel in a separate validation cohort. Results were compared to the Liverpool Lung Project (LLP) risk model. Findings Using breath VOCs from 677 controls and 518 cases the Exploratory method showed only 2 literature-reported compounds differed significantly between cases and controls. The Optimised method detected 102 VOCs, with ten differing between cases and controls. However, in a validation cohort the 10-VOC panel differentiated cases from controls cohort with a modest AUC: 0.54±0.14 for early-stage disease, 0.58±0.16 for advanced stage disease and 0.58±0.11 for all cases, which did not differ significantly from the LLP model. Combining VOCs with the LLP model did not significantly improve diagnostic performance (AUC 0.64±0.11). Interpretation Although some potential biomarkers were identified, their diagnostic performance did not surpass an epidemiological risk model. The study highlights the importance of careful trial design to avoid false-positive findings and indicates a need for more targeted approaches to enhance signal-to-noise ratio in breath biomarker research. Highlights Largest, to date, multi-centre prospective case-control study evaluating volatile organic compounds (VOC) for intention-to-diagnose lung cancer. Gas chromatography mass spectrometry was used to compare VOCs in lung cancer cases with co-morbidity matched controls. Although some VOCs differentiated cases from controls, diagnostic performance did not surpass an epidemiological risk model. These data explain the challenge of previous studies to validate and translate into clinical practice. A more targeted approach to enhance signal-to-noise ratio is required. Competing Interest Statement Authors affiliated to Owlstone Medical were employees and hold options on the company. RCR reports conference funding support from Owlstone Medical. Owlstone Medical Ltd supported research nurse funding at Royal Papworth Hospital, Cambridge during this work. All remaining authors have declared no conflicts of interest with regard to this work. Clinical Trial NCT02612532 Funding Statement The study was funded by Owlstone Medical Ltd and a UKRI Small Business Research Initiative (SBRI) award. RCR was funded by the NIHR Cambridge Biomedical Research Centre (NIHR203312) and Cancer Research UK Cambridge Centre (CTRQQR-2021\100012). Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study received ethical approval from the National Research Ethics Service Committee East of England; Cambridge South in October 2015 (15/EE/0298). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability Data are available through the corresponding author from the time of publication, following approval of a proposal with a signed data access agreement.