A pathologist will determine the stage of your cancer and other critical data by examining your cancer cells under a microscope. He will give you a pathology report that details all the findings, which will include:
Grade. Your cancer will be assigned a grade from I to III. The higher the grade, the faster the cells are growing. The pathologist assigns the grade by examining the cancer cells’ appearance and determining how many cells are dividing and at what speed.
TNM level. Your pathologist will determine how extensive the disease is by using the TNM system, which stands for tumor (size), nodes (cancer present or not) and metastasis (cancer spread to distant organs). A number is assigned to each category. Once the TNM categories are determined, this info is combined with the grade to create an overall stage, from 0 for noninvasive to IV for the most invasive (see below).
Stages of breast cancer
0—Non-invasive: Cancer cells contained within the breast ducts only
I—Invasive: Early stage, tumor less than 2 centimeters (cm), with no or microscopic involvement of lymph nodes
II—Invasive: Early stage, tumor greater than 2 cm or with spread to underarm lymph nodes
III—Invasive: Tumor greater than 5 cm or tumor involves skin, or more extensive involvement of lymph node
IV—Invasive: Metastatic (has spread to other parts of the body)
Review your pathology report with your oncologist to make sure you have a thorough understanding of your cancer. That will help you make the best treatment decisions and learn how to be a proactive member of your health team.