Question: What is the difference between the stage and grade of my breast cancer?
Answer: The stage -- as we define by the extent of the tumor, lymph node involvement, and spread of the disease -- is a basic measure of the risk of spread of cancer.
There are a number of other factors that may impact the risk of spread and help doctors define treatment. One of those is what we call the grade of cancer.
The grade refers to the appearance of the cancer cells under the microscope. Some cancer cells, while they are clearly cancer cells, look very bland under the microscope, and they are called 'low-grade,' or grade 1.
Other cancer cells look very large, different sizes and shapes, and what we might call 'angry' or 'aggressive.' And those are what we call grade 3.
A grade 3 cancer of the same size and lymph node status has a substantially higher chance of being able to spread than a grade 1 cancer.