TNM
Encyclopedia
The TNM Classification of Malignant Tumours (TNM) is a cancer staging
system that describes the extent of cancer
in a patient’s body.
The TNM staging system for all solid tumors was devised by Pierre Denoix between 1943 and 1952, using the size and extension of the primary tumor, its lymphatic involvement, and the presence of metastases to classify the progression of cancer.
TNM is developed and maintained by the International Union Against Cancer
(UICC) to achieve consensus on one globally recognised standard for classifying the extent of spread of cancer
. The TNM classification is also used by the American Joint Committee on Cancer
(AJCC) and the International Federation of Gynecology and Obstetrics
(FIGO). In 1987, the UICC and AJCC staging systems were unified into a single staging system.
s.
The general outline for the TNM classification is below. The values in parentheses give a range of what can be used for all cancer types, but not all cancers use this full range.
For the T, N and M parameters exist subclassifications for some cancer-types (e.g. T1a, Tis
, N1i)
Since the number of combinations of categories is high, combinations are grouped to stages for better analysis.
As a result, a given stage may have quite a different prognosis depending on which staging edition is used, independent of any changes in diagnostic methods or treatments, an effect that has been termed "stage migration." The technologies used to assign patients to particular categories have changed also, and by intuitive consideration it can be seen that increasingly sensitive methods tend to cause individual cancers to be reassigned to higher stages, making it improper to compare that cancer's prognosis to the historical expectations for that stage. Finally, of course, a further important consideration is the effect of improving treatments over time as well.
Cancer staging
The stage of a cancer is a description of the extent the cancer has spread. The stage often takes into account the size of a tumor, how deeply it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to , and whether it has spread to distant organs...
system that describes the extent of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
in a patient’s body.
- T describes the size of the tumorTumorA tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...
and whether it has invaded nearby tissue, - N describes regional lymph nodes that are involved,
- M describes distant metastasisMetastasisMetastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
(spread of cancer from one body part to another).
The TNM staging system for all solid tumors was devised by Pierre Denoix between 1943 and 1952, using the size and extension of the primary tumor, its lymphatic involvement, and the presence of metastases to classify the progression of cancer.
TNM is developed and maintained by the International Union Against Cancer
International Union Against Cancer
The International Union Against Cancer, or UICC is the only non-governmental organization dedicated exclusively to the global control of cancer. Its vision is of a world where cancer is eliminated as a major life-threatening disease for future generations...
(UICC) to achieve consensus on one globally recognised standard for classifying the extent of spread of cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
. The TNM classification is also used by the American Joint Committee on Cancer
American Joint Committee on Cancer
The American Joint Committee on Cancer is an organization best known for defining and popularizing cancer staging standards, officially the AJCC staging system....
(AJCC) and the International Federation of Gynecology and Obstetrics
International Federation of Gynecology and Obstetrics
The International Federation of Gynaecology and Obstetrics, usually just FIGO as the acronym of its French name Fédération Internationale de Gynécologie et d'Obstétrique, is a worldwide NGO organisation representing obstetricians and gynaecologists in over one hundred territories...
(FIGO). In 1987, the UICC and AJCC staging systems were unified into a single staging system.
General outline
Most of the common tumors have their own TNM classification. Not all tumors have TNM classifications, e.g., there is no TNM classification for brain tumorBrain tumor
A brain tumor is an intracranial solid neoplasm, a tumor within the brain or the central spinal canal.Brain tumors include all tumors inside the cranium or in the central spinal canal...
s.
The general outline for the TNM classification is below. The values in parentheses give a range of what can be used for all cancer types, but not all cancers use this full range.
Mandatory parameters ("T", "N", and "M")
- T: size or direct extent of the primary tumor
- Tx: tumor cannot be evaluated
- Tis: carcinoma in situCarcinoma in situCarcinoma in situ is an early form of cancer that is defined by the absence of invasion of tumor cells into the surrounding tissue, usually before penetration through the basement membrane. In other words, the neoplastic cells proliferate in their normal habitat, hence the name "in situ"...
- T0: no signs of tumor
- T1, T2, T3, T4: size and/or extension of the primary tumor
- N: degree of spread to regional lymph nodeLymph nodeA lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
s- Nx: lymph nodes cannot be evaluated
- N0: tumor cells absent from regional lymphLymphLymph is considered a part of the interstitial fluid, the fluid which lies in the interstices of all body tissues. Interstitial fluid becomes lymph when it enters a lymph capillary...
nodesLymph nodeA lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as... - N1: regional lymph node metastasis present; (at some sites: tumor spread to closest or small number of regional lymph nodes)
- N2: tumor spread to an extent between N1 and N3 (N2 is not used at all sites)
- N3: tumor spread to more distant or numerous regional lymph nodes (N3 is not used at all sites)
- M: presence of metastasisMetastasisMetastasis, or metastatic disease , is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research...
- Mx: distant metastasis cannot be evaluated
- M0: no distant metastasis
- M1: metastasis to distant organs (beyond regional lymph nodes)
Other parameters
- G (1–4): the gradeGrading (tumors)In pathology, grading is a measure of the cell appearance in tumors and other neoplasms. Some pathology grading systems apply only to malignant neoplasms ; others apply also to benign neoplasms. The neoplastic grading is a measure of cell anaplasia in the sampled tumors arising from the...
of the cancer cells (i.e. they are "low grade" if they appear similar to normal cells, and "high grade" if they appear poorly differentiatedCellular differentiationIn developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
) - R (0/1/2): the completeness of the operation (resectionSegmental resectionSegmental resection is a surgical procedure to remove part of an organ or gland. It may also be used to remove a tumor and normal tissue around it. In lung cancer surgery, segmental resection refers to removing a section of a lobe of the lung.- External links :* entry in the public domain NCI...
-boundaries free of cancer cells or not) - L (0/1): invasion into lymphatic vesselLymphatic systemThe lymphoid system is the part of the immune system comprising a network of conduits called lymphatic vessels that carry a clear fluid called lymph unidirectionally toward the heart. Lymphoid tissue is found in many organs, particularly the lymph nodes, and in the lymphoid follicles associated...
s - V (0/1/2): invasion into veinVeinIn the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
(no, microscopic, macroscopic) - C (1–5): a modifier of the certainty (quality) of the last mentioned parameter
Prefix modifiers
- c: stage given by clinical examination of a patient. The c-prefix is implicit in absence of the p-prefix
- p: stage given by pathologicPathologyPathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
examination of a surgical specimen - y: stage assessed after neoadjuvant therapy
For the T, N and M parameters exist subclassifications for some cancer-types (e.g. T1a, Tis
Carcinoma in situ
Carcinoma in situ is an early form of cancer that is defined by the absence of invasion of tumor cells into the surrounding tissue, usually before penetration through the basement membrane. In other words, the neoplastic cells proliferate in their normal habitat, hence the name "in situ"...
, N1i)
Examples
- Small, low-grade cancer, no metastasis, no spread to regional lymph nodes, cancer completely removed, resection material seen by pathologist: pT1 pN0 M0 R0 G1; this grouping of T, N, and M would be considered StageCancer stagingThe stage of a cancer is a description of the extent the cancer has spread. The stage often takes into account the size of a tumor, how deeply it has penetrated, whether it has invaded adjacent organs, how many lymph nodes it has metastasized to , and whether it has spread to distant organs...
I. - Large, high grade cancer, with spread to regional lymph nodes and other organs, not completely removed, seen by pathologist: pT4 pN2 M1 R1 G3; this grouping of T, N, and M would be considered Stage IV. Most Stage I tumors are curable; most Stage IV tumors are inoperable.
Uses and aims
Some of the aims for adopting a global standard are to:- Aid medical staff in staging the tumour helping to plan the treatment.
- Give an indication of prognosisPrognosisPrognosis is a medical term to describe the likely outcome of an illness.When applied to large statistical populations, prognostic estimates can be very accurate: for example the statement "45% of patients with severe septic shock will die within 28 days" can be made with some confidence, because...
. - Assist in the evaluation of the results of treatment.
- Enable facilities around the world to collate information more productively.
Since the number of combinations of categories is high, combinations are grouped to stages for better analysis.
Versions
It is crucial to be aware that the criteria used in the TNM system have varied over time, sometimes fairly substantially, according to the different editions that AJCC and UICC have released. The dates of publication and adoption for use of AJCC editions is summarized here; past editions are available from AJCC for web download. [2]- Edition 1 published 1977 and went into effect 1978
- Edition 2 published 1983 and went into effect 1984
- Edition 3 published 1988 and went into effect 1989
- Edition 4 published 1992 and went into effect 1993
- Edition 5 published 1997 and went into effect 1998
- Edition 6 published 2002 and went into effect 2003
- Edition 7 published 2009 and went into effect 2010
As a result, a given stage may have quite a different prognosis depending on which staging edition is used, independent of any changes in diagnostic methods or treatments, an effect that has been termed "stage migration." The technologies used to assign patients to particular categories have changed also, and by intuitive consideration it can be seen that increasingly sensitive methods tend to cause individual cancers to be reassigned to higher stages, making it improper to compare that cancer's prognosis to the historical expectations for that stage. Finally, of course, a further important consideration is the effect of improving treatments over time as well.
External links
- UICC site
- TNM Cancer Staging System Database (information mostly outdated, from the 1997 edition of TNM)
- TNM - Explanatory Notes
- TNM Classification Help