For other uses, see TNM (disambiguation).

TNM Classification of Malignant Tumours (TNM) is the system developed and maintained by the International Union Against Cancer (UICC) to maintain consensus on one globally recognised standard for categorising 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.

Broad outline

Each tumor has its own TNM classification. Not all tumors have TNM classifications, but most do. For instance, there is no TNM classification for brain tumors.

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

• T (a,is,(0),1-4): size of the tumor
• N (0-3): spreading into lymphatic nodes
• M (0/1): spreading into other organs (metastasis)

There are other criteria which can also be taken into account:

• 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 lympatic vessels
• V (0/1) invasion into veins

Modifiers are:

• p (prefix): stage given by pathologic examination of a surgical specimen
• C (1-4): the certainty (quality) of the last mentioned parameter
• y (prefix): stage assessed after neoadjuvant therapy

For the T, N and M parameters exist subclassifications for some cancer-types (e.g. T1a, Tis, N1i).

Examples

• Small, low grade cancer, no metastasis, no spreading to lymph nodes, cancer completely removed, resection material seen by pathologist - pT1 pN0 M0 R0 G1
• Big, high grade cancer, with spread to lymph nodes and other organs, not completely removed, seen by pathologist - pT4 pN2 M1 R1 G3

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.

Reference

• Sobin LH, Wittekind Ch (eds). TNM Classification of Malignant Tumours, 6th Edition. Wiley, 2002. ISBN 0471222887.

External links

• UICC site
• TNM Cancer Staging System Database