[Sense and nonsense of tumor markers in practice].

Tumor markers can be used for screening, diagnosis, planning and monitoring of therapy, for early detection of relapse and for psychological reasons. Unfortunately none of the currently available tumor markers can be used for all these purposes. An ever increasing number of tumor markers can be determined; however, the advantage for the individual patient's management is less obvious. We therefore critically review the routine use of some tumor markers such as CEA, AFP, beta-HCG, LDH, CA-125, CA 19-9, prostate acid phosphatase, prostate specific antigen and CA 15-3. The use of tumor markers requires a sound knowledge of the biology of the marker, the neoplastic disease and the available treatment. When tumor markers do not add new information and have no diagnostic or therapeutic consequences, their use becomes an expensive medical nonsense!