[Approach to the Patients with Elevated CA 19-9].

With the widespread adoption of health check-ups, tumor markers are being used for screening healthy individuals without symptoms related to cancer. Although CA 19-9 is known to have diagnostic value when a patient presents with symptoms, the evidence for its clinical value as a cancer screening test in asymptomatic patients is still lacking. However, patients who experience an increase in CA 19-9 levels may feel anxious about the possibility of having cancer and may seek medical attention. If the CA 19-9 level is elevated, it may be necessary to consider initial testing for malignant tumors of the pancreas. It should be recognized that the level can also increase in malignant tumors of the gastrointestinal tract, thyroid, and reproductive organs. Since the CA 19-9 levels can also increase in various benign diseases, it is important to evaluate if there is an underlying benign disease through appropriate testing and follow-up to reduce patient anxiety and discontinue unnecessary follow-up tests.