Staging is a description of the extent of spread of a cancer and is usually assessed at the time of diagnosis.
The information is important as it may influence choices about the most appropriate treatment. Staging does not imply that there is a regular or predictable progression in the growth of a cancer.
A commonly used system for the staging of many cancers is the TNM system. It is based on:
- the size and degree of invasion of the primary tumour (T)
- the number of lymph nodes containing cancer cells and their location in relation to the primary tumour (N)
- the presence or absence of distant metastases (M).
The criteria and their significance in terms of the prognosis differ with the different cancers.
There are also other systems for specific cancers. For more information on a specific cancer staging system, look at the related cancer article on this website or call 13 11 20.