[Principles of the TNM system]

The principle of the TNM system consists of the exclusive description of the anatomical spreading of cancerous diseases. We distinguish between clinical and postsurgical classification. Clinical classification is applied in principle before the decision for therapy. This pretherapeutical status is the foundation for the interdisciplinary treatment planning, prognosis and recording of results. The postsurgical classification is mainly used in visceral localizations. According to the most important stages of the disease, further classifications may be used, like the surgical-evaluative and the autopsy classification. Such different classifications are necessary because the preciseness of the prognosis depends upon the accuracy of the description of tumor extension. It is therefore important to supplement the tumor formula by a factor C (C for Certainty). This factor indicates by what diagnostic means the TNM categories of the mentioned formula were determined. The C-factor categories are defined and described in their principal use. Finally there are some fundamental observations to the problem of the revision of the TNM classification.