TNM staging system
The TNM classification (also: TNM system; engl. TNM Classification of Malignant Tumours TNM staging system or short ) is a faceted classification of the medicine that is used for staging of malignant tumors ( cancer).
It was developed by the Frenchman Pierre Denoix in the years 1943-1952 and will be continued since 1950 by the International Union contre le cancer (UICC ). The classification has prevailed in many countries and is used, among other cancer registries. It is based on statistical studies that allow statements about the expected behavior of tumors (eg, that the disease prognosis deteriorates beyond a certain size of a tumor ). Therefore, the classification of a tumor disease in the individual categories of the TNM system allows a prognosis and often determines the further therapy.
TNM is an abbreviation for
- T = tumor, description of extent and behavior of the primary tumor
- N = nodes = lymph nodes, absence or presence of regional lymph node metastases
- M = metastases, absence or presence of distant metastases
T, N and M are the most important category of the so-called TNM system.
T ( tumor)
T denotes the size of the primary tumor.
- T0: no evidence of a primary tumor ( this appears to make little sense at first, but it is possible if the tumor was treated with neoadjuvant chemotherapy, eg before surgery)
- Or the primary tumor is unknown ( CUP syndrome, cancer of unknown primary ).
- T1: greatest extent of the tumor more than 2 cm
- T2: greatest extent of the tumor more than 2 cm but not more than 5 cm
- T3: greatest extent of the tumor more than 5 cm
- T4: tumor of any size with direct extension to the chest wall or skin
Ta is only available on certain organs ( renal pelvis and ureter, bladder, urethra ). Where Ta tumors with a better prognosis may be connected as Tis tumors.
N ( nodes / lymph nodes / lymph nodes)
N describes the presence or absence of regional lymph node metastases.
- N0: No evidence of lymph node involvement.
- N1, 2 or 3: increasing lymph node involvement depending on the localization of the primary tumor. Divisions can be used by ipsi- or contralateral involvement and mobility, and localization in relation to the primary tumor.
- NX: no statements about possible lymph node involvement.
Since the discovery of lymph node involvement depends on it, it looks as intense after infection, a minimum number of lymph nodes must usually depending on the organ system have been investigated (eg, 12 in colon cancer ) to be able to say with reasonable certainty can no infestation in the corresponding region is present. Frequently specifying how many lymph nodes as much lymph nodes examined were infested, the N category is added back, such as N0 ( 0 /13).
Increasingly, there are tumors (eg breast cancer), where it is considered sufficient to examine only the so-called sentinel lymph node ( sentinel lymph node). This is the first lymph node ( sometimes more than one) which receives the lymph from the area of the tumor. Can be found in him no metastases, then the probability to find in the " downstream " lymph node metastases is very low. Conversely, the downstream lymph nodes must be examined closely if the sentinel lymph node is infected. If this method is used, the pN category is characterized by ( sn ), so for example, pN0 ( sn ) = no lymph node metastasis histologically, pN1 ( sn ) = infestation of ( the ) sentinel lymph nodes.
M ( metastases)
M denotes the presence or absence of blood-borne metastases. Generally, the classification is only possible after a staging.
- M0: No evidence of distant metastases
- M1: Distant metastasis present.
The earlier allowed classification MX ( no statement about possible distant metastases ) of the TNM classification was deleted in the current version. If the pathologist does not explicitly get a metastasis to study, so may find pM1, they can not make a statement to distant metastasis and provide example only the statement pT1pN0.
A pM0 is not common in general, because you can exclude metastases only in the context of an autopsy performed by pathological- anatomical examination. A M0 is usually adopted after examination of the most commonly affected organs of metastases when doing nothing is found striking. These studies are different depending on the type of cancer.
In addition, the location of the metastases can be specified and thus the location of the tumor metastasis can be specified. The derived from English abbreviations PUL for lung, OSS for bones, HEP for liver, BRA stand for brain LYM for lymph nodes, MAR for bone marrow, PLE for pleura, PER for the peritoneum ( ), ADR for adrenal gland, SKI for skin and OTH for other locations. May be cited here as examples:
- M1OSS: Bone Metastases
- M1PUL: lung metastases
The reliability of investigations and analysis, in addition to the descriptor "C" (English: certainty ) are given behind the respective TNM category. It indicates the reliability of the diagnosis:
- C1: General methods of investigation, such as clinical examination findings, standard x-ray etc.
- C2: Special methods of investigation, such as ERCP, computed tomography, etc.
- C3: results of surgical exploration, cytology or biopsy.
- C4: findings after surgery and histopathological examination. Synonymous with the pTNM classification.
- C5: findings after autopsy including histopathological examination.
Clinical and pathological classification
If the staging determined by clinical examination and minor procedures ( approximately corresponding to C1 - C3, see above), then one speaks of a clinical TNM (also cTNM for c = clinical ). TNM is determined as this as a rule, before the therapy, it is also referred to as at baseline.
A staging, in which incorporate the knowledge gained from surgery and from histopathology is called pTNM (pathological classification, postoperative histopathological classification). It essentially corresponds to the C- factor of 4 in the TNM formula of each category is preceded by a p.
Example: pT1pN0M0 features a small primary tumor without lymph node involvement and without distant metastases, studied pathological in the primary tumor and lymph nodes, but distant metastases were only sought clinically.
It is important that the extent of the investigation would actually make it possible (eg T4 so ) determine the highest category. Exceptionally, a major surgical procedure to determine the pTNM not required. Example: if, can be determined by a little investigation, such as a biopsy of the stomach during a gastroscopy that a large colon cancer has broken through into the stomach, then the category pT4 is certainly determined without the colon was removed.
Sometimes it is common to specify ( for ultrasound u) is a uTNM when the Tumoreindringtiefe was determined in the wall of the esophagus, stomach or the rectum and possibly spread to nearby lymph nodes by means of endoscopic ultrasonography, eg uT2uN0. This corresponds to the reliability class C2. This notation is not described by the current body and is at best a special form of clinical classification.
If a tumor is classified only at autopsy, the TNM formula is preceded by an a- symbol, such as aT1N1M0 the stomach means that the tumor has not yet grasped the muscle layers of the stomach, 1-6 regional lymph nodes has infested but no distant metastases exist.
When a tumor is clinically relatively large, for example, breast cancer ( breast cancer ), the size of T2 (2-5 cm ), sometimes the actual operation is preceded by a so-called neo-adjuvant chemotherapy or radiotherapy to allow the body, in this case the chest can be largely preserved. When actually pathological examination after surgery then see if any no or only small residual tumor. It would be wrong, such pTNM findings statistically equal to treat as cases in which no pre-treatment has taken place. That is why such classifications are preceded by a y- symbol, such as ypT0N0M0 ( no tumor found at surgery ).
If a tumor after initial successful treatment occurs, it is called a recurrence, which in turn can be classified clinically or pathologically. Even such classifications should not be confused with the primary clinical or pathological classification and therefore get an r- symbol prefixed, eg rpT2pN1M0.
More categories and additional information
There are other categories and additional data which are of vital importance in some cases, the tumor classification. This applies particularly to the disclosure of Residualgrenzen because is classified only with her, whether a tumor is only part of the tumor has been removed "in the healthy " or.
- L0 / 1: invasion into the lymphatic vessels ( lymphatic vessels or Tumorzellemboli in a contact with the vessel wall is not required for the diagnosis)
- V0/1/2: invasion of veins ( no, microscopic, macroscopic )
- Pn0 / 1: Perineural invasion (none, any), new additional specification in the TNM Supplement (page 115) is mentioned ( not to be confused with, for example, pN0 = pathological N category, see above)
- SX/0-3: Serum tumor markers. Be detected only in malignant testicular tumors. (X = not available / analyzed, 0 = normal, 1-3 = at least one marker increased)
- R0/1/2: Indicates whether tumor remaining after treatment (local, regionär or distant metastases). R0 = No tumor left in the organism detectable, R1 = Microscopic residual tumor at the cut edges, R2 = Macroscopic tumor or metastases.
- G1 -4: Grading, an indication of how differentiated the tumor tissue. G1 = well differentiated, that is, that the tumor tissue the tissue of origin is still relatively similar, G4 = undifferentiated, the tissue of origin is only on ultrastructural and immunohistochemical study methods differentiable.
Since there are theoretically very many combinations of T, N and M ( sometimes also exist subcategories, such as T1a ), which are then no longer statistically meaningful recyclable, combinations are dependent on the type of tumor combined into so-called UICC stages.