Working out how to minimize harm and maximize benefits from CT lung cancer screening reporting is a major objective and urgent priority, expert speakers told ECR 2025 attendees at a special focus session on 1 March.
Radiologists need to assiduously evaluate modules, assess their risk for future malignancy, and determine follow-up intervals, while patient management should focus on the growth rate and prognosis in the context of age and comorbidities, said Prof. Mathias Prokop, chair of radiology at Radboud University Medical Center (UMC) in Nijmegen, the Netherlands.
Prof. Mathias Prokop. All images courtesy of ESR and Sebastian Kreuzberger.
"Current screening recommendations are based on the Brock model, but this model does not factor in age as a risk factor. We don't think this is the right approach," he said, adding that he is also concerned about both solid and subsolid nodules. Details about new European Society of Thoracic Imaging (ESTI) guidelines will be published soon in European Radiology. These guidelines are based on the rate of growth of indeterminate lung nodules, to avoid the risk of a major stage shift while minimizing overtreatment of indolent lesions.
Prokop expressed reservations too about the subsolid nodule 2022 guidelines of Lung-RADS (Lung Imaging Reporting and Data System) because they may lead to overdiagnosis. After removing a subsolid nodule, it is difficult to remove future lung cancers, and he advocates more conservative patient management. New nodules need to be watched carefully, with a 12-month follow-up, he said.
Overdiagnosis risk
Dr. Mario Silva, a chest radiologist at the University of Parma in Italy, echoed similar concerns about nodule assessment, level of surveillance and timing of screening follow-up, and the risk of a major stage shift. He defined the three pillars of lung cancer stratification of nodules as density, size, and morphology, noting that a minority of lung nodules represent cancer.
Silva advised that after a baseline screening, the active surveillance of low-to-intermediate risk nodules should be based on the balance of the risk of stage shift. He cautioned that subsolid nodules are prototype examples of overdiagnosed findings. They are indicative of lung cancer, but they are also considered a biomarker of having a comorbidity from something else that causes death.
"Avoid overinvestigation," he added. "It takes six to 12 months to see measurable accurate changes. We typically wait one to two years to see the clinical changes."
Incidental findings
Incidental findings are another dilemma, and what to do about them in a lung cancer screening exam is still debatable, said Prof. Annemiek Snoeckx, head of radiology at Antwerp University Hospital in Belgium. "There is no consensus, no standardization, and no guidelines relating to definition, reporting, or management about what to do with incidental findings."
She categorizes them as either incidental lesions, which may represent future malignancies if not treated, or as opportunistic findings. Radiologists need to make ethical decisions based on their clinical knowledge about whether to report them or not.
Prof. Annemiek Snoeckx.
Low-dose CT identifies incidental findings in about a third of screenings. "I want to put things in perspective. If radiologists route one-third of lung cancer screened patients for additional medical care because they have found a nodule or something else, it may overwhelm the lung cancer screening program," Snoeckx noted. "Most countries are not enthusiastic about lung cancer screening because they don't have the resources to see all these participants."
Additionally, the long-term outcomes of referral versus no referral are as yet unknown. There is a void of knowledge, and she encouraged radiologists to combat this by gathering data and conducting research.
Snoeckx emphasized that lung cancer screening is a population health issue to reduce the burden of disease of high-risk individuals in the community, and it does not guarantee that lung cancer will not occur. It also must be viewed in the context of providing maximum cost-effective benefit for a population. This supersedes the benefit of a single individual who requires significant health resources to determine that an incidental finding during screening is a malignancy.
Optimum use of AI
It's essential for radiologists to optimize lung cancer screening with AI, Dr. Colin Jacobs, associate professor in AI in thoracic oncology and research group leader at the Department of Medical Imaging of Radboud UMC, told the same ECR session.
To do this successfully requires learning about the different types of AI systems that can benefit lung cancer screening programs, understanding novel AI developments that assess the probability of malignancy of nodules and lung cancer risk of participants, and understanding how AI can be integrated to optimise workflow in lung cancer screening, he said.
The broader picture
Overall, lung cancer is the leading cause of cancer deaths in Europe, representing an estimated 19.5% of the total number, according to the European Commission, session moderator Prof. Marie-Pierre Revel, PhD, head of radiology at Hôpital Cochin in Paris and ex-president of ESTI, told ECR 2025 delegates.
A useful initiative is Strengthening the Screening of Lung Cancer in Europe (SOLACE), launched in April 2023 as an EU4Health project, she noted. SOLACE is intended to break down barriers to screening to ensure people across all social and economic groups can access it (go to europeanlung.org/solace for more details).
To date, 20 EU member states, Norway, and the U.K. have ongoing or planned lung cancer screening implementation projects. However, questions remain about reporting and patient management, and optimization of program guidelines, especially relating to the risk of overdiagnosis are still in development, she explained.
Revel has also participated in the European School of Radiology (ESOR) Special Focus Series on Lung Cancer Screening (see connect.myesr.org/course/lung-cancer-screening). In this series, she gives a 40-minute lecture on "How to conduct lung cancer screening: Technical requirements and quality assurance."
