The TNM system is one of the most widely used staging systems. This system has been accepted by the International Union Against Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Most medical facilities use the TNM system as their main method for cancer reporting. PDQ®, NCIs comprehensive cancer information database, also uses the TNM system.
The TNM system is based on the extent of the tumour (T), the extent of spread to the lymph nodes (N), and the presence of distant metastasis (M). A number is added to each letter to indicate the size or extent of the primary tumour and the extent of cancer spread.
Primary Tumour (T)
TX Primary tumour cannot be evaluated
T0 No evidence of primary tumour
Tis Carcinoma in situ (CIS; abnormal cells are present but have not spread to neighbouring tissue; although not cancer, CIS may become cancer and is sometimes called pre-invasive cancer)
T1, T2, T3, T4 Size and/or extent of the primary tumour
Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be evaluated
N0 No regional lymph node involvement
N1, N2, N3 Involvement of regional lymph nodes (number of lymph nodes and/or extent of spread)
Distant Metastasis (M)
MX Distant metastasis cannot be evaluated
M0 No distant metastasis
M1 Distant metastasis is present
For example, breast cancer classified as T3 N2 M0 refers to a large tumour that has spread outside the breast to nearby lymph nodes but not to other parts of the body. Prostate cancer T2 N0 M0 means that the tumour is located only in the prostate and has not spread to the lymph nodes or any other part of the body.
For many cancers, TNM combinations correspond to one of five stages. Criteria for stages differ for different types of cancer. For example, bladder cancer T3 N0 M0 is stage III, whereas colon cancer T3 N0 M0 is stage II.
Stage 0 Carcinoma in situ.
Stage I, Stage II, and Stage III Higher numbers indicate more extensive disease: Larger tumour size and/or spread of the cancer beyond the organ in which it first developed to nearby lymph nodes and/or organs adjacent to the location of the primary tumour.
Stage IV The cancer has spread to another organ(s).
1. TNM denotes for,
a) Tumour, nodes, and muscles
b) Tumour, Nodes and Metastasis
c) Nodes only
1. What does it mean by stage IV?
a) Carcinoma in situ
b) Large tumour size
c) Cancer has spread to another organ
1. b) Tumour, Nodes, and Metastasis
2. c) Cancer has spread to another organ