When your cancer is evaluated by a pathologist after the biopsy, he or she will classify the cancerís stage, a numerical number that indicates how far the cancer has progressed, and its histological grade, which describes how fast or slow the cancer, if left untreated, is likely to progress from the current stage to the next stage. Although a cancerís grade is not as important as its stage in order to determine the best course of treatment, the grade is one of the many factors your doctor needs to consider in recommending treatment options.
Three features of cells inside a tumor determine the grade of the cancer:
Frequency (rate) of cell mitosis (i.e.: cell division)
Percentage of cancer cells containing tubules (tubular structures)
Change in size and shape of nuclei within cells
Each of these features is assigned a score ranging from 1 to 3. Cell growth that follows a slower, more orderly pattern is considered Grade 1. If cells are multiplying in a faster, more disorganized way, the cell growth grade is labeled Grade 3.
Generally speaking, the lower the histological grade of the breast cancer, the more favorable the outcome. However, tumors that are higher grade tend to be more responsive to aggressive treatments like radiation and chemotherapy than are low-grade cancers.