Information in the pathology report helps to determine the stage and grade of the breast cancer. [3]
Staging breast cancer
The stage of breast cancer is a way of describing how big the breast cancer is and which parts of the body are affected.
The stage is used to decide what treatment options are recommended.
Tumour-node-metastasis (TNM) system
Your doctor may use the TNM system to stage your breast cancer. It is a system used around the world, which assesses and classifies:[4]
- the extent of the primary tumour (T)
- whether and where lymph nodes have cancer cells (N)
- whether the cancer has metastasised (M).
Stages
If using the TNM system, your doctor will classify the stage of your cancer as 1 of 5 stages. The higher the numbers, the more advanced the cancer is:
- Stage 0 refers to ‘pre-invasive’ breast cancer such as ductal carcinoma in situ (DCIS) or lobular carcinoma in situ (LCIS).
- Stages I, IIA and IIB refer to early breast cancer.
- Stages IIIA, IIIB, IIIC refer to locally advanced breast cancer
- Stages IV refers to advanced or metastatic breast cancer Categories
Staging breast cancer also involves selecting a category according to whether there are cancer cells in the lymph nodes:[5]
- Category 1 is where breast cancer cells have been found in 1 to 3 lymph nodes in the armpit.
- Category 2 is where breast cancer cells have been found in either
- 4 to 9 lymph nodes in the armpit, and the lymph nodes are also enlarged and/or attached to each other or to nearby tissue
- 1 or more lymph nodes under the breastbone, but not in any lymph nodes in the armpit.
- Category 3 is where breast cancer cells have been found in either
- 10 or more lymph nodes in the armpit
- 1 or more lymph nodes above or below the collarbone
- 1 or more lymph nodes under the breastbone and 1 or more lymph nodes in the armpit.
Stages of breast cancer
| Breast cancer stage | Size of cancer | Have cancer cells been found in... | |
|---|---|---|---|
| lymph nodes? | other parts of the body? | ||
| 0 | Size not used for stage 0 | No | No |
| I | <2 cm | No | No |
| IIA | <2 cm | Yes (Category 1) |
No |
| 2–5 cm | No | No | |
| No cancer found in breast | Yes (Category 1) |
No | |
| IIB | 2–5 cm | Yes (Category 1) |
No |
| >5 cm | No | No | |
| IIIA | <2 cm | Yes (Category 2) |
No |
| 2–5 cm | Yes (Category 2) |
No | |
| >5 cm | Yes (Category 1) |
No | |
| >5 cm | Yes (Category 2) |
No | |
| No cancer found in breast | Yes (Category 2) |
No | |
| IIIB | Any size but the cancer has spread to nearby muscles and skin | Any (Can be yes or no) |
No |
| IIIC | Any size | Yes (Category 3) |
No |
| IV | Any size | Any (Can be yes or no) |
Yes |
Grade of cancer
Grades of cancer refer to how quickly the cancer is growing, and are numbered from 1 to 3:
- A low grade (Grade 1) means that the cancer is growing slowly.
- A high grade (Grade 3) means that the cancer is growing more quickly.
The higher the grade, the more active the cancer, and the more likely the cancer has spread outside the breast and armpit area.
