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Heidelberg is a hub for cancer research and treatment. The German Cancer Research Center (DKFZ), the National Center for Tumor Diseases (NCT), the Hopp Children’s Cancer Center Heidelberg (KiTZ), the Heidelberg Institute for Radiation Oncology (HIRO) and the Heidelberg Ion Beam Therapy Center (HIT) are all located here. The Heidelberg University Hospital thorax clinic performs an important function within this network. It is the largest lung clinic in Europe and most of Germany’s lung cancer patients are treated here. For the patients there is a clear advantage in being treated in such a center of expertise. Indeed, many cancer patients who come to the clinic are already at a stage where they require treatment. 

Technically, CT is very well suited to screening. Compared to the X-ray image, the computed tomogram enables a precise visualization of smaller tumors. Since CT images are created layer by layer, physicians can also use the fine sectional images to assess the spatial extent of the tumor and obtain important information for a possible surgery.

For a long time, there was a discussion about radiation exposure from CT screening. The risk of possibly causing radiation-induced damage to health is unacceptable, especially where people undergo screening examinations repeatedly over many years. Current CT technology offers the possibility of examinations with very low radiation doses. The resulting average radiation dose is just 0.6 to 0.8 millisievert (mSv). In comparison, the cosmic radiation on a flight from Germany to Japan causes radiation exposure of up to 0.1 mSv.[2] 

“A good screening program consists of a complex package of criteria and measures,” explains the lung specialist. This includes, among other things, defining standards regarding the quality of the CT images and their evaluation. There is also a need to specify how physicians should scientifically evaluate the resulting information. The follow-up examinations must also be clearly planned: which patients will receive them and at what intervals? That is why, in Herth’s opinion, it is unlikely that every radiology practice or radiological center will be able to offer screenings; instead, he believes they should take place at certified interdisciplinary centers.

The large number of imaging examinations will also result in the discovery of many pulmonary nodules. These do not necessarily indicate cancer, but could be caused by tuberculosis or an abscess, for instance. Herth points to his computer monitor, which shows a low-dose, thin-slice CT image of a lung. It records individual layers of just 0.75 millimeters. Initially the air-filled lung tissue shows up as a black area in the cross-sectional image. Then the pulmonologist scrolls through the image layers and points out a nodule approximately 6 millimeters big.

With a nodule of this size, there is no need for immediate treatment. Nevertheless, a CT check-up is recommended after six months. Given the fact that the patient scanned in this CT is a smoker and over 50 years old, he has an increased risk of lung cancer.

In practice, a screening program is likely to reveal a large number of nodules. It is therefore essential to do a comprehensive evaluation, since not all findings automatically point to a malignant disease: The visual similarity between benign and malignant lesions in CT carries the risk of overtreatment, for example through unnecessary biopsies.

To avoid unnecessary interventions, the German Radiological Society and the German Society for Pneumology and Respiratory Medicine are calling for certified centers to conduct the screening as part of a quality-assured process, with specialists from various disciplines assessing findings.[3] The experience of other countries, e.g., the UK, shows that with this approach the risk of unnecessary interventions in the case of benign tumors is extremely low.

Looking ahead, Herth concludes that with cone-beam CT and robotics very few niches in the lungs will remain inaccessible. In addition to ‘classic’ imaging, modern diagnostics offers other methods, e.g. the visualization of individual cells with imaging techniques or bronchoscopes. Besides imaging, research is being done using liquid biopsy, for example. However, the lung expert does not believe that any one procedure will provide sufficient information to replace the biopsy, at least in the near future. So far, none have provided either the necessary sensitivity or the specificity; Herth requires that both reach a level of 95 percent. 

The Commission has formulated ten flagship initiatives for implementation, including an EU-wide network of cancer centers, cancer imaging procedures, equal access to diagnosis and treatment, and an updated early cancer detection program. The latter could in the future cover more types of cancer than is currently the case. On the basis of current scientific knowledge, consideration is being given to expanding early cancer detection to include lung, prostate and stomach cancer.[5] 

Herth regards this plan as a first step, particularly with regard to the required lung cancer screening. But various questions still have to be answered. For example, who covers the costs, which groups of people are eligible for screening, and how many cases of advanced lung cancer could be avoided as a result of screening. The decisive factor is whether and how the development of an early detection program is implemented and financed at national level. In Germany this is now a matter for the Federal Joint Committee (G-BA), after the Institute for Quality and Efficiency in Health Care (IQWIG) gave a positive assessment. In fact, successful early detection has a significant impact on cancer patients’ chances of survival for the next five years.

This gives Herth a clear idea of how the treatment pathway for lung cancer patients would change if lung cancer screening was successfully introduced. He puts it very simply: “I would be able to treat the patient early, in stage 1 of the disease, and he or she would be operated on and cured.”