Early cancer detection

a laboratory employee examines contents of a test tube

Source: © Volker Wiciok, Lichtblick

The early detection of occupational diseases, including cancers, is an important part of secondary prevention.

Occupational cancers are one of the greatest challenges in the field of occupational medical care. As a result of the long latency periods that are associated with these diseases, cases continue to occur despite enormous improvements in the field of occupational safety and health (OSH). Exposure to carcinogenic substances often occurred a number of decades ago at a time when there was insufficient knowledge about many hazardous substances.

Many cancers are no longer at an early stage when diagnosed and symptoms already appeared. Therefore, the aim of early cancer detection (cancer screening) is to maximise the chance of successfully treating a tumour by making a correct diagnosis at the earliest possible stage.

Traditional methods of early diagnosis that are available today often do not provide sufficient early evidence of new cancerous growth. Although computed tomography (CT) scans of the lungs can detect even small levels of the most common occupational cancer (lung carcinoma), CT scans involve additional exposure to radiation. Thus, careful consideration should be given to its regular use and it must be justified in each individual case by a medical indication. The importance of CT in the diagnosis of mesothelioma is currently being investigated by the Institute for Occupational, Social and Environmental Medicine (IASA) at Uniklinik RWTH Aachen in cooperation with the German Social Accident Insurance.

However, there is justifiable hope that current advances in the field of biomedical research will lead to new early detection methods in the future. Molecular markers represent both an alternative and supplement to conventional methods. Molecular markers are endogenous substances which tumours produce on an increased or modified basis before releasing them into the body (for example, into the bloodstream). They can be extracted non-invasively from blood samples or, depending on the location of the tumour, from urine, sputum or other bodily fluid samples and identified using modern, molecular-biological procedures in the laboratory. From the patient’s perspective, this type of method represents a far less stressful approach to cancer detection.

There are already some potential new molecular markers, including those for bladder cancer and mesotheliomas. However, these still have to be validated as part of larger-scale, prospective studies. This is to ensure that they are also suitable and effective for use under practical conditions. There are currently two studies being conducted to investigate the use of various markers individually and in combination for the early detection of cancers. These studies involve numerous cooperation partners in Germany and abroad, under the auspices of the Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA) at the Ruhr University Bochum.

Promising initial results from one of the IPA studies are now available. The MoMar study (‘Molecular Markers for Cancer Screening’) validated two molecular markers for the early detection of mesotheliomas using samples from a group of individuals who were previously exposed to asbestos. Around 2,800 insured persons formally diagnosed with asbestosis or other non-malignant asbestos-related pleural diseases (german occupational disease no. 4103) were invited to attend a yearly check-up (including blood sampling) over a period of ten years. The more than 12,500 blood samples were stored in a biobank and used to quantify the tumour markers mesothelin and calretinin. Over the course of the study, more than 30 mesotheliomas occurred in the group, from which blood samples had been collected prior to clinical diagnosis. It was thus possible to test the markers for their ability to detect mesotheliomas at an earlier stage. The combination of the markers calretinin and mesothelin was able to correctly detect 46% of mesothelioma cases up to 15 months prior to clinical diagnosis. The proportion of false-positives was only 2%. It appears that early detection of mesotheliomas is possible for the first time. The extent to which the marker combination can be used in follow-up preventive health care is currently being investigated.


Contact

Dr. rer. nat. Georg Johnen
Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA)
Center of Molecular Medicine
Tel.: +49 30 13001-4350

 Prof. Dr. Thomas Behrens
Institute for Prevention and Occupational Medicine of the German Social Accident Insurance (IPA)
Tel.: +49 30 13001-4210