Cancer cells are given a grade according to how different they are to normal breast cells and how quickly they are growing.
There are three grades of invasive breast cancer:
- grade 1 – looks most like normal breast cells and is usually slow-growing
- grade 2 – looks less like normal cells and is growing faster
- grade 3 – looks different to normal breast cells and is usually fast-growing
Grade is different to the stage of breast cancer.
Generally, people with grade 3 invasive breast cancers are more likely to be offered chemotherapy, to help destroy any cancer cells that may have spread as a result of the cancer being faster growing.
Find out more about breast cancer and prognosis.
Ductal carcinoma in situ (DCIS)
There are also three grades of ductal carcinoma in situ (DCIS), which are usually referred to as low, intermediate and high.
The size of the breast cancer is measured at its widest point, usually in millimetres (mm). One inch equals about 25mm.
If DCIS and invasive breast cancer are found together, the results will tell you their combined size (sometimes called ‘whole tumour size’) and how much there is of each. If both types are found together, only the details of the invasive breast cancer will be used by your specialist team to look at treatment and prognosis (outlook).
While in general smaller cancers may have a better outcome, size doesn’t always give the whole picture and is just one part of the overall results. A small cancer can be fast growing while a larger cancer may be slow growing, or it could be the other way around.
Sometimes there may be more than one area of breast cancer. In this case each area is measured:
- multi-centric means there’s more than one area of breast cancer in different quarters of the breast
- multi-focal means more than one area has been seen but only in one quarter of the breast
Your pathology results usually include information on whether the cancer is localised (which means there’s only one area) or multiple foci (more than one area).
Some people have chemotherapy before surgery. This is called neo-adjuvant or primary chemotherapy. For these people, pathology results after their surgery will include a summary of how much cancer remained after the chemotherapy. This is called the pathological response:
- complete pathological response means no residual cancer
- partial response means only some of the cancer remains
- no evidence of response means the cancer is the same or bigger than before the chemotherapy
The size and position of the cancer in relation to your breast size may affect what operation you’re offered. For example, with smaller cancers it’s often possible to have breast-conserving surgery (also called wide local excision or lumpectomy).
If you have a larger cancer (in relation to your breast size), your specialist team may recommend a mastectomy, or chemotherapy before surgery (called neo-adjuvant or primary chemotherapy). This is sometimes given with the aim of shrinking the cancer before surgery.
Your specialist team will make a decision about whether to recommend chemotherapy depending on the size of the breast cancer and other features, such as whether or not the lymph nodes are affected. Generally, people with larger breast cancers (greater than 2cm) are more likely to be offered chemotherapy. This is because larger cancers may have been there longer before being found and so may have had more chance to spread.
3. Breast cancer stages
The grade of a breast cancer is different to the stage. Find out more about breast cancer stages.