[Tumor classifications].

The correct use of tumor classifications is one of the key elements of adequate oncological treatment. Tumor classifications comprise: localization, typing, grading staging and stage grouping, classification after neoadjuvant radio(chemo)therapy, TNM classification and R classification. For easier identification and better documentation it is advisable to have a summary of tumor classifications at the end of each tumor concerning pathology report. Experience in clinical use has shown that classification may be incomplete or inadequately used. Not infrequently they are reported in a way which is open for misinterpretation. Some possible mistakes and misuse of tumor classifications are discussed. Users, among which are clinicians and pathologists, have to bear in mind the limitations of tumor classifications. These are for example reflected by the difficulty to classify single tumor entities in a correct way.