The stakes of late detection. Lung cancer is the leading cause of cancer-related death in both men and women, killing more people than breast, colon, and prostate cancer combined. The majority of diagnoses occur at an advanced stage when treatment options are limited and survival prospects are poor. Early detection through low-dose CT (LDCT) scanning has been shown in two major clinical trials to reduce lung cancer mortality by 20-26%.
Screening works - but implementation lags. Despite strong clinical evidence, few European countries have established national lung cancer screening programmes. The NHS in England has committed to scanning over a million participants per year by 2029, but Ireland currently has no such programme. This trial is Ireland's first pilot, designed to provide the data needed to design and justify a national programme.
Who is at highest risk. Lung cancer risk is strongly linked to smoking history, age, and other demographic and clinical factors. Risk prediction algorithms - most notably PLCOM2012 and LLPv2 (Liverpool Score Version 2) - combine these factors to estimate an individual's 10-year probability of developing lung cancer. Using these scores to identify and focus screening on high-risk individuals improves the accuracy and cost-effectiveness of screening programmes.
The inequity problem. Lung cancer risk increases with socioeconomic deprivation, but attendance at screening programmes paradoxically falls in deprived communities. Fatalistic attitudes toward lung cancer, avoidance of hospital settings, and practical barriers such as travel distance all reduce participation among the people who need screening most. Addressing this inequity is a central design goal of the Irish Lung Health Check (LHC) pilot.
The primary goal: measuring feasibility. Before committing resources to a national programme, policymakers need to know whether high-risk individuals will actually participate in community-based screening in the Irish context. The primary endpoint of this trial is the proportion of eligible participants aged 55-74 who take part in a lung health check when invited through their GP - a critical first step for demonstrating the programme's viability.
Secondary goals covering the full patient journey. Beyond feasibility, the trial aims to measure how many participants are ultimately diagnosed with lung cancer, at what stage, and with what treatment outcomes. It will also evaluate uptake of smoking cessation support, detect previously undiagnosed respiratory diseases like COPD, and assess the cost-effectiveness of the overall approach.
A translational biomarker research arm. In parallel with clinical screening, the trial collects blood, exhaled breath condensate, and sputum samples from a subset of participants to investigate novel genomic, proteomic, and immunological biomarkers associated with lung cancer risk. If successful, these biomarkers could eventually be incorporated into risk models to improve early detection beyond what CT imaging alone can achieve.
Comparing and refining risk scores. The trial uses two validated risk scores (PLCOM2012 and LLPv2) to identify high-risk participants and will compare their performance against each other and against other available models. This will generate data to guide future decisions about which risk stratification tools work best in the Irish population.
A three-step invitation process. Approximately 30,000 people aged 55-74 registered with participating GP practices in North Dublin and the North East region will receive a text message alert, followed by a letter and patient information leaflet from their GP, followed by a direct phone call from the research team. This direct-calling approach is unusual in screening trials - most programmes rely on participants to self-refer - and may improve engagement among people who would otherwise not follow up on a letter alone.
Risk assessment by phone. During the phone call, potential participants are screened for eligibility using the PLCOM2012 and LLPv2 risk calculators, which incorporate age, sex, smoking history, family history of lung cancer, and other clinical factors. Those with a PLCOM2012 score of 1.51% or higher (indicating at least a 1.51% ten-year risk of developing lung cancer) or an LLPv2 score of 2.5% or higher are offered a Lung Health Check appointment.
Mobile community-based scanning units. Rather than bringing participants to a hospital, the LDCT scanners are located in mobile units placed at Gaelic Athletic Association (GAA) club grounds - familiar community venues that avoid the anxiety many people feel about hospital environments. These locations are chosen to be near GP practices and easily accessible by participants without requiring hospital visits.
What participants experience at the LHC visit. Each visit includes a respiratory assessment questionnaire, baseline spirometry (lung function testing), a consultation with a respiratory nurse, smoking cessation advice with automatic opt-out referral to the national quit programme, an LDCT scan, and - in selected cases - collection of blood, breath, and sputum samples. This comprehensive approach treats the visit as an opportunity to address the broader health needs of a high-risk population, not only to screen for cancer.
Scans read by radiologists with AI assistance. CT scans are interpreted by trained thoracic radiologists, with AI tools supporting the detection and characterization of lung nodules and abnormalities. This combination aims to improve detection accuracy while managing the workload associated with reading thousands of scans across a large-scale screening programme.
Risk-stratified follow-up for nodules. Participants with no significant findings are brought back for a second LDCT scan at 12 months. Those with lung nodules requiring surveillance are scheduled for a follow-up CT scan at 3 months. Participants whose scans show findings suspicious for lung cancer are immediately referred to the Rapid Access Lung Cancer Clinic (RALCC) for expedited diagnostic workup. Follow-up decisions are made in accordance with British Thoracic Society guidelines for pulmonary nodule management.
Managing incidental findings. LDCT scans often detect abnormalities unrelated to lung cancer - such as cardiovascular disease, emphysema, or kidney abnormalities. The trial has established protocolized pathways for managing these incidental findings, ensuring that participants are referred to appropriate clinical services rather than left without follow-up for potentially significant health issues.
Integrated COPD detection. Spirometry tests performed at the LHC visit can diagnose airway obstruction, which may represent undiagnosed COPD. The trial includes automatic referral pathways based on obstruction severity: participants with normal results or mild obstruction return to their GP, while those with severe obstruction are referred directly to a hospital respiratory service. This addresses the striking statistic that 30% of patients hospitalized with acute COPD exacerbations have no prior diagnosis of the condition.
Three types of samples collected. From a subset of approximately 400 participants, the trial collects blood (both plasma and serum), exhaled breath condensate (EBC), and sputum. Each sample type offers access to different biological information: blood contains circulating tumor DNA, proteins, and immune cells; breath contains volatile organic compounds associated with metabolic changes in cancer; and sputum contains cells shed directly from the respiratory tract.
The promise of liquid biopsy. Circulating tumor DNA (ctDNA) - fragments of cancer DNA shed into the bloodstream by tumor cells - represents a potentially transformative approach to early cancer detection. If ctDNA signatures can reliably identify lung cancer in high-risk individuals without requiring a tissue biopsy or even CT imaging, they could serve as a first-line screening test or help distinguish between benign and malignant nodules detected on CT.
Genomic, proteomic, and immunological profiling. The translational research arm will investigate whether specific patterns of gene expression, protein levels, or immune cell characteristics in blood or breath distinguish participants who develop lung cancer from those who do not. These signatures could ultimately be used to refine current risk scores, enabling more precise identification of individuals who will benefit most from CT screening.
Logistical challenges with biospecimen collection. Blood samples for ctDNA analysis must be processed within 2 hours of collection - a constraint that complicates collection in a mobile community-based setting far from hospital laboratories. The trial has rationalized collection to four participants per day, with samples transported directly to the research lab for processing, while sputum samples are stored at 4 degrees Celsius before shipping on ice for long-term storage at -80 degrees Celsius.
The combined benefit of screening and quitting. Evidence shows that combining lung cancer screening with concurrent smoking cessation support produces greater reductions in lung cancer mortality than screening alone. Including smoking cessation as an integral component of the LHC visit - not merely an afterthought - reflects this evidence and maximizes the public health value of each participant encounter.
Opt-out referral design. Rather than leaving smoking cessation as an optional extra that participants must actively seek, the trial uses an opt-out mechanism: all participants who currently smoke are automatically enrolled in a referral to the Irish HSE Quit programme unless they specifically decline. The HSE Quit programme provides a free, personalized, one-to-one smoking cessation support plan. Opt-out designs consistently achieve higher uptake than opt-in alternatives.
Measuring the impact. One of the secondary endpoints of the trial is smoking rates before and after the brief intervention and referral, which will quantify how effective this integrated approach is at motivating behavior change. The social context of a lung health check - particularly if a participant has a nodule detected - may provide a powerful moment of motivation that telephone-based cessation programmes alone cannot replicate.
Addressing COPD as a related condition. Given that approximately 50% of lifelong smokers eventually develop COPD, and that a large proportion of those who develop COPD remain undiagnosed until they present in crisis, the respiratory assessment component of the LHC offers a rare opportunity to identify and manage this condition in a high-risk population before it reaches a critical stage.
Expected numbers through the funnel. Starting from approximately 30,000 invited adults, the trial estimates that around 13,933 will be eligible based on smoking history, of whom roughly 4,179 will respond to the phone assessment (based on 30% response rate observed in UK screening trials). Of those, approximately 2,298 are expected to meet the PLCOM2012/LLPv2 risk thresholds, and 2,183 are expected to attend the LHC pilot - a carefully calculated sample that provides sufficient precision to estimate uptake rates with narrow confidence intervals.
Comparing screened to non-screened populations. A key analytical challenge in feasibility studies is assessing whether detected cancers are truly caught earlier than they would have been without screening. The trial will compare early-stage lung cancer incidence and one-year mortality in screened participants against matched historical data from the National Cancer Registry of Ireland, using Poisson regression to calculate incidence rate ratios.
The Irish healthcare structure creates unique challenges. In Ireland, GPs operate as private enterprises rather than as employees within the public health system - a fundamental difference from the UK NHS context where most lung health check pilots were developed. This means patient data cannot be automatically shared with the research team, requiring a specific consent declaration from Ireland's Health Research Consent Declaration Committee to allow Centric Health's primary care group to share age-based patient data for invitation purposes.
Patient and public involvement. The 15-person steering committee includes patient representatives from the Irish Lung Cancer Community who are co-investigators and co-authors on the study. Patient partners shaped the study design, reviewed and edited participant-facing materials (with additional review by the National Adult Literacy Agency for plain language), and designed community engagement strategies. This level of involvement is designed to ensure the programme is accessible and responsive to participant needs rather than purely driven by clinical convenience.
Lessons from the UK applied to Ireland. Ireland's LHC pilot is explicitly modelled on successful pilot programmes in Manchester and Liverpool, which demonstrated that community-based lung cancer screening is both feasible and effective at identifying early-stage cancer in deprived populations. The Irish team adapted these models to the specific structural and regulatory context of the Irish healthcare system, including the distinct role of private GPs and EU data protection regulations.
Reframing the message to reduce stigma. The programme is deliberately branded as a "lung health check" rather than a "lung cancer screening" programme. This framing - adopted from UK pilot experience - is designed to reduce the fear and fatalistic responses that the phrase "cancer screening" can provoke, particularly in communities with high smoking rates where lung cancer stigma is prevalent. Participants' own GPs serve as the trusted communication source, further reducing emotional barriers.
Broader implications for European screening policy. The trial is part of the EU4Health SOLACE consortium (Strengthening the Screening of Lung Cancer in Europe), which aims to accelerate the development of lung cancer screening programmes across multiple European countries. The Irish pilot will contribute to a growing body of evidence about how community-based implementation strategies can achieve high uptake in diverse healthcare systems and populations.
The path from pilot to national programme. If the pilot demonstrates sufficient uptake and feasibility, its findings will form the evidence base for a recommendation to establish a national lung cancer screening programme in Ireland - a step that could ultimately identify thousands of additional early-stage cancers per year, when treatment is most effective and outcomes are best. The biomarker research arm may additionally yield tools that improve screening precision beyond what current risk models and CT imaging can achieve.