The TNM Classification of Malignant Tumours (TNM) is a cancer staging system that describes the extent of cancer in a patient’s body. T describes the size of the tumor and whether it has invaded nearby tissue, N describes regional lymph nodes that are involved, and M describes distant metastasis (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.^[1]

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.

Contents 1 General outline 1.1 Mandatory parameters ("T", "N", and "M") 1.2 Other parameters 1.3 Prefix modifiers 2 Examples 3 Uses and aims 4 Versions 5 See also 6 References 7 External links

[edit] 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 tumors.

The general outline for the TNM classification is below. The values in parenthesis give a range of what can be used for all cancer types, but not all cancers use this full range.

[edit] Mandatory parameters ("T", "N", and "M")

• T (a,is,(0),1–4): size or direct extent of the primary tumor
• N (0–3): degree of spread to regional lymph nodes
  • N0: tumor cells absent from regional lymph nodes
  • N1: tumor cells spread to closest or small number of regional lymph nodes
  • N2: tumor cells spread to an extent between N1 and N3.
  • N3: tumor cells spread to most distant or numerous regional lymph nodes
• M (0/1): presence of metastasis
  • M0: no distant metastasis
  • M1: metastasis to distant organs (beyond regional lymph nodes)

Use of an "X" instead of a number or other suffix means that the parameter was not assessed.

[edit] Other parameters

• G (1–4): the grade of the cancer cells (i.e. they are "low grade" if they appear similar to normal cells, and "high grade" if they appear poorly differentiated)
• R (0/1/2): the completeness of the operation (resection-boundaries free of cancer cells or not)
• L (0/1): invasion into lymphatic vessels
• V (0/1): invasion into vein
• C (1–4): a modifier of the certainty (quality) of the last mentioned parameter

[edit] 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 pathologic 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, N1i)

[edit] 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 Stage 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.

[edit] 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 prognosis.
• 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.

[edit] Versions

The latest version of TNM is TNM7, published in october 2009 and set to take effect in january 2010.

[edit] See also

• Cancer staging
• Ann Arbor staging, used in lymphomas

[edit] References

1. ^ Denoix PF. Enquete permanent dans les centres anticancereaux. Bull Inst Nat Hyg 1946;1:70–5.

• Wittekind, Ch; Sobin, L. H. (2002). TNM classification of malignant tumours. New York: Wiley-Liss. ISBN 0-471-22288-7. 

[edit] External links

• UICC site
• TNM Cancer Staging System Database (information mostly outdated, from the 1997 edition of TNM)
• TNM - Explanatory Notes
• TNM Classification Help