Lung cancer is a leading cause of cancer mortality in Croatia, with more than 3300 new diagnoses and over 2800 deaths recorded in 2021. To address late-stage diagnosis and high mortality, the Ministry of Health initiated a national, fully reimbursed screening programme built into existing services. The design combines low-dose computed tomography (LDCT), artificial intelligence for volumetric analysis, modified I-ELCAP criteria for nodule management, comprehensive digital infrastructure and a general practitioner (GP)-centred recruitment model. The approach aims to achieve equitable access across the country while streamlining referral, reporting and follow-up within a single electronic pathway. It represents the first government-funded national lung cancer screening programme in the European Union.
From Trial Evidence to National Deployment
The programme rests on evidence from large randomised trials. In the United States, the National Lung Screening Trial enrolled 53,454 high-risk adults and showed a 20% reduction in lung cancer mortality with three annual LDCT rounds compared with chest radiography after a median follow-up exceeding six years. Eligibility included ages 55–74 years with a 30 pack-year smoking history and either ongoing smoking or cessation within the previous 15 years. In Europe, the NELSON trial randomised high-risk participants to LDCT or no screening with scheduled scans at baseline, 1, 3 and 5.5 years, reporting a 24% reduction in lung cancer mortality overall over ten years and a 33% reduction among females, alongside low rates of follow-up procedures. Together, these studies signposted LDCT as the preferred modality for identifying individuals at higher risk.
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Despite these data and a European position statement encouraging implementation, no EU country had operationalised a national programme when Croatia moved ahead in 2020. The decision reflected a high smoking prevalence, an unfavourable mortality-to-incidence ratio and the frequency of advanced-stage presentation that precludes surgical treatment for many patients. The Croatian model prioritises early detection within a structured pathway and nationwide availability, positioning it as a practical route from trial-level efficacy to real-world delivery.
GP-Centred Recruitment and Digital Infrastructure
A defining feature is the central role of GPs. Approximately 2300 GP clinics provide routine care nationally and about 90% of the population attends at least once each year. The programme leverages these touchpoints for proactive identification, eligibility checks and motivational interviewing without reliance on mailed invitations. GPs enrol consenting individuals, deliver smoking cessation counselling, describe potential harms and benefits and select LDCT appointment slots across 24 radiology sites in 17 cities according to geography and availability. This design intends to counter historically low uptake seen elsewhere by harnessing established doctor-patient relationships to improve participation and adherence to follow-up.
Digitalisation underpins the workflow. A purpose-built application embedded in the national health IT platform enables paperless referrals, structured reporting and secure data sharing. Each participant is tracked via a unique insurance identifier that links screening events to the personal electronic health record. Radiologists issue structured reports that include nodule characteristics plus ancillary findings such as emphysema and coronary artery calcification, with staging on visual scales. The GP receives clear, protocol-driven next steps, whether routine follow-up, early recall or referral to a lung nodule clinic. Multidisciplinary nodule clinics in five cities provide diagnostic work-up, staging and treatment planning, with a final report due at six months covering histology, TNM stage and applied therapy.
Early Activity and Safety Outcomes
Eligibility spans ages 50–75 years with a 30 pack-year smoking history, including current smokers and those who quit within 15 years, with exclusions for recent chest CT, prior lung cancer treatment within five years, symptoms suggesting malignancy and factors precluding consent or imaging. After reviewing available protocols, Croatia adopted a modified I-ELCAP pathway that integrates volume-based assessment and volume-doubling-time categories, while retaining a stepwise focus on early detection at baseline and growth assessment on repeat LDCT. Biennial screening is advised for participants with negative baseline and stable follow-up scans, thereby limiting unnecessary exposure and resource use. Comparative work indicates differing positive screen rates across protocols, and the chosen approach was selected for efficiency in immediate work-up and overall management.
Imaging standards target an effective dose below 1.5 mSv per scan and specify CTDIvol, detector configuration and acquisition parameters appropriate for LDCT. Licensed radiologists, each with a high annual thoracic CT workload, complete dedicated training that combines lectures and hands-on case review with a volume measurement tool. Quality control includes routine physicist oversight, phantom-based external checks and mandatory recording of per-scan and cumulative dose in structured reports. Operationally, screening is offered after hours to avoid disrupting routine lists, and participating radiologists and GPs are compensated for additional work. Across October 2020 to August 2025, more than 50,000 people underwent screening with over 70,000 LDCT scans. The cohort was 54% male and 46% female with a mean age of 62 years. Positive results occurred in 4.5% of participants. Among those with a positive result, 2% of cancers were identified, including 1.7% lung cancer. Mean effective dose was 0.89 mSv, well below the preset maximum.
Croatia has translated evidence from large LDCT trials into a nationwide pathway that is fully integrated, reimbursed and digitally managed, with GPs driving equitable access and adherence. Modified I-ELCAP criteria, AI-supported volumetry, robust training and quality assurance, and multidisciplinary nodule clinics collectively support consistent decision-making and timely care. Early activity shows substantial throughput with low radiation exposure and defined routes for follow-up and treatment. For healthcare leaders considering scale-up within public systems, the model demonstrates that national lung cancer screening can be organised around primary care engagement, structured protocols and a single digital spine to enable safe, accountable delivery.
Source: European Radiology
Image Credit: iStock
