Breast Cancer TNM Staging System
Doctors normally refer to a staging system when referring to the spread of breast cancer. The system most frequently used is known as the TNM staging system.
When your medical caregivers are describing your cancer using the TNM staging system they will refer to three characteritics:
- size (T = tumour)
- lymph node involvement (N = node)
- whether it has metastasized (M = metastasis)
The T (size) category describes the original (primary) tumour:
- TX = the cancerous tumour cannot be measured or found.
- T0 = no sign of the primary tumour.
- Tis = the tumour is "in situ" (ie it has not started to grow into the breast tissue).
- The numbers T1-T4 describe the size and/or how much the cancer has spread into the breast tissue. A low T numbers is a smaller tumour. A higher T number is a bigger tumour. It also refers to how much of the tumour may have spread into surrounding breast tissue.
The N (node involvement) category describes whether or not the cancer has reached nearby lymph nodes:
- NX = the nearby lymph nodes cannot be measured or found.
- N0 = nearby lymph nodes have no cancer.
- The numbers N1-N3 describe the size, location, and/or the number of lymph nodes involved. The higher the N number, the more the lymph nodes are involved.
The M (metastasis) category tells whether there are distant metastases (ie the extent to which the cancer has spread to other organs/ tissues in the body):
- MX = metastasis cannot be measured or found.
- M0 = no distant metastases.
- M1 = distant metastases were found.
When a pathologist is aware of your T, N, and M characteristics, they are combined to give a stage grouping. An overall stage is then able to be determined from which your overall cancer stage can be realised.
See also:
Further Information
For further information and breast cancer support, please visit Macmillan Org
