The size of the breast cancer is usually measured in millimetres (mm) or centimetres (cm). One inch equals about 2.5cm. Although 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 report. 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 report will probably say if the cancer is localised (which means there’s only one area) or multiple foci (when there’s more than one area of cancer).
Cancers are given a grade according to how different they are to normal breast cells and how quickly they are growing. In your pathology report this may also be called differentiation.
Invasive breast cancer
There are three grades of invasive breast cancer:
- grade 1 (well differentiated) – the cancer cells look most like normal cells and are usually slow-growing
- grade 2 (moderately differentiated) – the cancer cells look less like normal cells are growing faster
- grade 3 (poorly differentiated) – the cancer cells look most changed and are usually fast-growing.
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.
Ductal carcinoma in situ (DCIS)
There are also three grades of DCIS which are usually referred to as low, intermediate and high.