Tumor marker

Tumor marker

So-called tumor markers are only conditionally part of preventive medicine. They are mainly an instrument of tertiary diagnostics, occasionally of secondary prevention, and are primarily used for monitoring and follow-up care of already existing or suspected cancers. In certain cases, however, they can also be used for early detection, such as close monitoring of people with a high familial risk. Tumor markers are specific substances (usually proteins) that are found in increased amounts in blood, urine, or other body fluids either produced by the tumor cells themselves or as a reaction of the body to a tumor. An increasing focus of clinical research is the so-called liquid biopsy for searching for novel tumor markers, where circulating tumor cells or nucleic acids from tumors are sought in the blood. But why are they not routinely queried in preventive medicine for healthy individuals? Many tumor markers lack sufficient specificity or sensitivity, meaning they can also be elevated in benign diseases or remain inconspicuous despite existing tumors. This can lead to false alarms, unnecessary anxiety, or overdiagnosis. However, an exception is PSA screening, used as part of prostate cancer prevention for people at increased risk (e.g., men over 45 years with a family history), but it continues to be controversially discussed regarding the risk-benefit ratio. Here, too, informed decision-making is highly valued in preventive medicine.