The size of a breast cancer tumor and if it has spread to an axillary (armpit) lymph node are important characteristics. They are used to predict how aggressive a tumor will be and which treatment is ideal.
Analyzing the type of cells and molecules in the breast cancer tumor provides specific information that allows treatment to be better targeted to an individual.
Healthy breast tissue contains estrogen and progesterone hormone receptors. All breast cancers are evaluated for these receptors. Tumors that have these receptors are more like normal breast tissue. Tumors that do not have estrogen receptors are more aggressive and are more likely to grow and spread in the body.
Breast cancer tumors are evaluated for the number of cells that are dividing, known as ki67. A lower ki67 means fewer cells are dividing, which is favorable. A tumor which has well-differentiated cells looks more like healthy breast tissue, which is also favorable. A gene, called HER2/neu is found in a small number of breast cancers and indicates that the tumor is aggressive.
Breast cancers are also evaluated to determine if they are vascular, which means blood vessels are present. The tumors are also analyzed to see if lymphatic invasion has occurred in which cancer cells have traveled outside of the tumor. No vascularity or lymphatic invasion is favorable.
This information is included in pathology, biopsy and surgical reports. Ask your surgeon or oncologist to review this information with you so you have a better understanding of your breast cancer.