Synonyms
TMN Classification
Introduction
The TNM system, also called TNM Classifications of malignant tumours, is used to classify malignant tumours. (cancer diseases). With the help of this classification, the various types of cancer can be uniformly classified worldwide according to their severity and assigned to corresponding treatment guidelines.
History
The TNM system was developed between 1943 and 1952 by the Frenchman Pierre Denoix. Since 1950 it has been further developed by the international Union internationale contre le cancer (UICC). Today, the TNM system is recognized and used by most countries in the world, and the cancer registry also uses the TNM system.
It is based on studies and statistical data on the behavior and prognosis of malignant cancers. Accordingly, it is used in most countries for the prognosis and therapy of the disease. The abbreviation TNM (TNM system) refers to the spread of the tumor in the body.
The “T” stands for the primary tumor and its size, spread and invasiveness. The letter “N” denotes the number of affected lymph nodes (engl= nodes). The letter “M” indicates the metastases.
This refers exclusively to the presence or absence of distant metastases, not to their number or which organs are affected. In principle, a number is added after each letter. Here, 0 usually stands for the absence of the corresponding tumor, while ascending numbers stand for an increasingly dangerous tumor disease.
If the tumor has been histologically examined by a pathologist, this is indicated by a “p” before the classification. If the tumor is clinically or surgically classified, a “c” is placed in front of the TNM classification (TNM system). In this way it can be distinguished whether the classification is only macroscopically or also microscopically secured. Further details are explained below under the individual components of the TNM system.
T=tumor
T0: This means that no primary tumor is visible. At first sight this makes little sense. However, this term is used if a tumor has been chemotherapied before surgery and has regressed to a point where it is no longer visible macroscopically.
Nevertheless, there are usually still tumor cells in the tissue, which have to be surgically removed. In other cases the primary tumor is unknown. This can happen if there are too many metastases and the primary tumor could not be determined exactly.
Such a clinical picture is called CUP syndrome (Cancer of unknown primary). Tis/Ta: These are tumors in a very early stage of the disease. They have not yet infiltrated the basement membrane and have therefore not yet penetrated far into the tissue.
Their prognosis is generally favorable. However, due to the very small extent to which they spread, their diagnosis is difficult. As a rule, the findings are random findings during routine examinations.
Ta tumors are only found in certain organs (urethra, renal pelvis, ureter, bladder and penis). There, Ta tumors can be associated with a better prognosis than Tis tumors. T 1,2,3 or 4: The increasing number refers to the increase in size of the primary tumor and the infestation of neighboring organs.
Since the spread paths for the individual tumor types differ, the increase in size and invasiveness will be illustrated here using breast cancer as an example:
- T1: largest tumor extension at most 2 cm
- T2: tumor extension at least 2 cm, but not more than 5 cm
- T3: largest tumor extension more than 5 cm, but no spread to neighboring organs
- T4: All tumors larger than 5 cm with spread to the chest wall or skin.
- Tx: No statement can be made about the primary tumor.
The discovery of lymph node metastases (TNM system) depends largely on the search for them. For this reason, there are guidelines for the various tumor diseases as to how many lymph nodes must be examined in order to be able to exclude an infestation with a relatively high degree of certainty. For example, in colorectal cancer, at least 12 lymph nodes must be removed and histologically examined.
As a rule, the number of lymph nodes taken is also indicated. Example N0 (0/15). For other tumor diseases, e.g. breast cancer, it is sufficient to take samples from the sentinel lymph nodes (sentinel lymph node= sn).
This is the first lymph node of an outflow area.If it is not affected, it can be assumed with high probability that the downstream lymph nodes are also free of metastases. A detailed examination is all the more important if the sentinel lymph node is affected. This is also indicated in the TNM system.
Example: pN1 (sn)= histologically confirmed infection of the sentinel lymph node.
- N0: No infestation of the regional lymph nodes with tumor tissue.
- N1,2 or 3: With increasing number, this refers to an increasing number of affected regional lymph nodes depending on the primary tumor. A further distinction is made between lymph node metastases on the tumor side (ipsilateral) and affected lymph nodes on the opposite side (contralateral) of the primary tumor. As well as their mobility and localization in relation to the primary tumor.
- Nx: No statement about the lymph node involvement is possible.
