Bookmark this page or recommend it.

The TNM classification system classifies a tumor with reference to its spread. The letter symbols have the following meaning:

• T stands for the local spread or size of the tumor.
• N describes whether the regional lymph nodes are affected or whether they are tumor cell free.
• M describes the presence or absence of metastases in other organs, i.e. the liver in colon cancer (distant metastases)   

The letters are combined with numbers. In the letter T numbers 1 to 4 describe the tumor size and  numbers in  the letter N describe the number of cancer-affected lymph nodes. In the letter M, numbers only distinguish between the presence (M1) or absence (M0) of distant metastases.

At the time of diagnosis, the assessment of the tumor spread is important for staging because each stage requires a different therapeutic approach. During or after therapy (e.g. after surgery) it is important to determine the extent of the tumor in order to be able to evaluate the therapy’s success as well as the appropriate approach of the aftercare program. This information is unambiguously  and internationally used, thus the data can easily be communicated to every medical practitioner involved in the patient’s care.

The staging initially takes place before therapeutic measures are initiated and is referred to as  cTNM (c=clinical) which means that it is determined primarily through clinical investigations.
A staging process which includes a surgical component (e.g. histopathological tissue sampling) is called pTNM (post operative histopathological classification). 

> Back