Why don't cancer cells differentiate

Cancer: What do the abbreviations in the doctor's letter mean?

There is an internationally used scheme for classifying malignant tumors in order to be able to describe cancerous tumors and to be able to compare test results. The so-called TNM classification is used by doctors, but also in research.

The abbreviation "TNM" stands for Tumor (T), Nodes (N) and (M). The English "nodes" indicates whether tumor settlements are present in the neighboring (regional) lymph nodes or not. This means that the lymph nodes belong to the drainage area of ​​the affected organ. With settlements in other body regions are meant, so-called. So the three letters denote the following:

  • T refers to the original tumor (primary tumor).
  • N describes whether regional lymph nodes are involved or not.
  • M describes whether or not it has been determined.

Numbers are added to the letters to indicate the size and spread of the tumor. The abbreviations made up of letters and numbers describe the type, size, texture and spread of a tumor. Doctors often use the classification of these tumor characteristics as a basis for assessing them and suggesting an individual treatment plan.

characteristic Abbreviation importance
Primary tumor T0 No tumor was discovered or the original tumor is no longer detectable.
  T1 to T4 The numbers 1 to 4 represent an increasing size and spread of the tumor: T1 denotes a small tumor, while T3, for example, denotes a larger one.
Lymph nodes N0 The lymph nodes are tumor-free.
  N1 to N3 The numbers 1 to 3 indicate the location and number of the affected regional lymph nodes. If there are settlements in lymph nodes that do not belong to the drainage area of ​​the affected organ, they are considered to be.
M0 No tumor settlements () were found.
  M1 There are.

Supplementary information

In addition to the TNM classification, the following information can be provided:

  • c (from English "clinical" = clinical): indicates that the classification is based on a physical examination, typical symptoms or the results of imaging procedures. Imaging methods include, for example, ultrasound examinations and the (). A clinical classification (cTNM) is usually carried out before a tissue sample is finally secured.
  • p (from English "pathological": pathological): means that the tissue removed has been examined in the laboratory and the classification has also been based on the results of this examination.
  • r (:) indicates that a tumor has reappeared.
  • R: indicates that residual cancer tissue was found after treatment.
  • Tis / Cis: means cancer precursor or early form.
  • X: indicates that the characteristic cannot be assessed. This may be because it hasn't been examined or the result is inconclusive. For example, NX means that it cannot be determined whether the tumor has spread to the lymph nodes.
  • Y: indicates that the tumor has already been treated.

Grading and staging

In contrast to healthy body cells, cancer cells are usually poorly developed (differentiated) and not specialized in certain tasks. The (English for gradation) assesses the extent to which the tumor cells differ from healthy cells. Often, the less differentiated tumor cells are, the faster they grow and the earlier they penetrate the surrounding tissue. Tumors are designated with G1 to G4: the higher the grade, the less differentiated and more malignant the tumor.

Staging means something else: Once all tumor characteristics have been examined, the results of the examination are used to determine the stage of the tumor. The term “staging” is often used for this staging. The staging can provide clues about the disease. The most common classification is based on the system of the International Association against Cancer (UICC). The combination of the information on T, N and M results in a UICC stage from I to IV, with UICC IV denoting the most advanced stage.

Classifications are not applicable to every type of tumor

The TNM system cannot be applied equally to all types of cancer, for example because the development of a particular tumor differs or because other criteria are more suitable for describing the tumor. For example, blood cancer (leukemia) does not have a primary tumor because blood cancer cells are found throughout the body at the onset of the disease. Brain tumors, on the other hand, rarely develop. In the case of leukemia, therefore, the proportion of changed blood cells, and in the case of brain tumors, the extent of the cell change () are important classification features.