Taking Early Detection Further: Lung Cancer
CT screening for long-term smokers has only recently become available in Germany. Epidemiologist Prof. Rudolf Kaaks explains why those eligible are often unaware of the program and why it is important to undergo the screening regularly.
Prof. Kaaks, lung cancer screening for heavy smokers is the latest early cancer detection program offered by statutory health insurance providers. It was only introduced in April 2026. Unlike other cancer screening programs, the eligibility criteria are more complicated: Those who wish to participate must not only have reached a certain age but also be able to demonstrate a specific smoking history. Do those affected understand that they are eligible for the screening?
People who smoke heavily, in particular, are often not very health-conscious and not very well-informed about health services. It is to be feared that many of them are unaware of this option for early detection. Studies we conducted in the Mannheim/Ludwigshafen area have shown: In the most socioeconomically disadvantaged neighborhoods, where lung cancer incidence is often highest, participation in lung cancer early detection studies was lowest. Incidentally, female smokers are also less likely to undergo mammograms. Both factors come into play: a lack of information, but also a lack of interest.
To participate in screening, you need a referral, for example, from your primary care physician. Do doctors systematically ask their patients about their smoking habits and encourage them to participate in screening?
Perhaps some individual doctors do. But educating patients about screening is time-consuming and pays very little. Therefore, it’s to be feared that this doesn’t happen all that often.
For other types of cancer, systematic, invitation-based screening can help increase participation rates. How could this be implemented for lung cancer, which, after all, requires a very specific “smoking history”?
One possibility would be for everyone reaching the screening age to receive informational material and an invitation to fill out an online questionnaire about their smoking habits. If the smoking history meets the eligibility criteria for lung cancer screening, the person could be asked to contact their primary care physician regarding a possible screening. This would reduce the workload for the physician. The law requires that a physician be involved, and this makes sense: in addition to providing information, the physician must also assess the patient’s overall health. Some heavy smokers are already very ill—for example, they may suffer from COPD—and have a low remaining life expectancy. In such cases, screening is no longer advisable.
“Organized” and “systematic” are the magic words
Prof. Dr. Rudolf Kaaks
For lung cancer screening to be effective, the CT scan should be performed regularly, for example, once a year. Why is that?
Unfortunately, we see the risk that often only the initial examination is performed. This is particularly problematic because screening is most effective over time, when low-dose CT scans can be compared with one another and suspicious lesions can be monitored. The specificity of the test results increases with the number of examinations. And the likelihood increases that tumors will be detected at very early stages, when they are still easily treatable. Whether a CT scan is actually needed every year or whether, for many people, two-year intervals are sufficient is currently being investigated, including at the DKFZ.
How can we ensure that study participants stay on board after the initial examination?
Unfortunately, there is no legal mechanism in place to automatically re-invite participants. However, the participating radiology practices may take on this task out of their own interest. In addition, screening participants need a new referral each time. Unfortunately, this is another hurdle.
In short: What needs to be improved?
To ensure we can learn from the results and assess the effectiveness of this early detection measure after a few years, the screening should definitely be offered as an organized program, comparable to today’s mammography screening. And the few who come in spontaneously should definitely be systematically invited back on a regular basis. “Organized” and “systematic” are the magic words. But let’s be clear: a program like this costs money!
Prof. Dr. Rudolf Kaaks headed the Department of Cancer Epidemiology at the German Cancer Research Center until July 2026.
Interview: Dr. Sibylle Kohlstädt, Press Spokesperson for the DKFZ