Lung cancer is the leading cause of cancer‑related deaths globally and in Belgium, where late‑stage diagnoses contribute to poor survival rates. Early detection through lung cancer screening (LCS) using low‑dose Computed Tomography (CT) (LDCT) has been shown to significantly reduce lung cancer mortality, with major trials like the National Lung Screening Trial (NLST) and the Nederlands‑Leuvens Longkanker Screenings Onderzoek (NELSON study) demonstrating mortality reductions of at least 20% and 24%, respectively. However, several challenges prevent or delay the widespread adoption of LCS, including difficulties in reaching high‑risk populations, managing incidental findings, integrating smoking cessation interventions, concerns about overdiagnosis, and false‑positive results. There is also the challenge of stigma on lung cancer. The European Council’s recent recommendations support all European countries to start implementation studies, such as ZORALCS, a feasibility study in Flanders. Continued efforts to refine LCS methods and expand access are essential to reduce the burden of lung cancer and improve outcomes for high‑risk populations.
The Scientific Evidence
Lung cancer remains the leading cause of cancer‑related deaths globally, including in Belgium, where it claims more lives than breast, colon, and prostate cancers combined [1]. According to the Belgian Cancer Registry, 9,410 new lung cancer cases were diagnosed in 2022 [2]. The 5‑year survival rate for lung cancer in Belgium stands at 26% for men and 34% for women. This poor prognosis is largely due to late‑stage diagnosis, at which point curative treatment is no longer an option. Early detection through lung cancer screening (LCS) has been shown to significantly improve survival rates, highlighting its importance in managing lung cancer [1].
Two major randomized controlled trials have provided solid evidence that LCS using low‑dose CT (LDCT) in high‑risk populations—specifically current and former smokers with significant pack‑year histories—can reduce lung cancer‑specific mortality. The National Lung Screening Trial (NLST), a landmark study published in 2011, demonstrated at least a reduction of 20% in lung cancer mortality with LDCT screening compared with chest radiography after 6.5 years of follow‑up [3]. The Nederlands‑Leuvens Longkanker Screenings Onderzoek (NELSON study) compared LDCT screening with no screening and reported a reduction of 24% in lung cancer mortality after 10 years of follow‑up [4]. Concurrently, several smaller randomized trials were conducted in Europe. A Cochrane review and meta‑analysis published in 2022, which included 11 Randomized Controlled Trials (RCTs), reported a mortality benefit of 21% with LDCT screening and a reduction of 5% in all‑cause mortality [1]. The number needed to screen (NNS) to prevent one additional lung cancer death was 303, a number that is more favorable than the NNS of the other cancer screening programs [5].
Challenges and Barriers to Screening
Despite the proven benefits, lung cancer screening faces several challenges that limit its widespread adoption and effectiveness. One major barrier is targeting the “hard to reach” population. Lung cancer screening targets high‑risk individuals: men and women aged 50/55 to 74/80 and current heavy smokers (over 20–30 pack‑years) or former heavy smokers who quit less than 10–15 years ago [1]. In Belgium, as in many countries, such data on the smoking behavior of the participants are not readily available. Additionally, this group may have less interest in health and preventive measures. Lung cancer screening is the first cancer screening program where incidental findings may be encountered during the screening process. On a LDCT scan of the chest, abnormalities in organs other than the lungs can be detected, raising ethical questions about what should or should not be reported [6]. Another challenge is integrating smoking cessation interventions into the program. Primary prevention through smoking cessation should be a key component of any lung cancer screening program, although the optimal approach for integrating it remains unclear [7]. Implementing a new screening program will also impact healthcare resources, with many specialties already under strain. Additionally, as with other cancer screening programs, overdiagnosis and false‑positive results remains a concern, as some participants may be diagnosed with cancers that might never have caused harm [1, 8]. Furthermore, the stigma on lung cancer remains a challenge and continues to bias both healthcare providers and participants [6].
From Trial to Implementation
Currently, several European countries, including Croatia, the Czech Republic, Poland, and the United Kingdom, have already implemented a national LCS program. In other countries, trials and implementation studies are ongoing. On 9 December 2022, the European Council updated its recommendations on cancer screening [9]. While the previous 2003 guideline focused on breast, cervical, and colorectal cancer, member states have now agreed to expand the scope to include lung cancer screening. They encouraged countries to explore the feasibility and effectiveness of LDCT screening, with special focus to identifying and targeting high‑risk profiles [9].
Starting in 2025, Flanders will launch an implementation study on lung cancer screening (ZORALCS‑study) (Figure 1), set to take place in the primary care zone of ZORA (Zuid‑Oost Rand Antwerpen, Belgium). Individuals aged 55–74 years will receive an invitation letter and will be asked if they have smoked more than 100 cigarettes in their life. If the answer is ‘yes’, they will be referred to a web platform to input data into a risk prediction model, which will determine the eligibility of the participant. Those who qualify will be referred for a LDCT scan.
Figure 1
Flow of the ZORALCS‑study. ICF, informed consent form; SDM, shared decision making.
Conclusions
While significant progress has been made, the field of lung cancer screening continues to evolve. Ongoing efforts to refine screening methods, expand access, and personalize approaches are vital for the future. As these advancements continue, they hold the promise of reducing the global burden of lung cancer.
Competing Interests
The authors have no competing interests to declare.