When breast cancer is diagnosed, it is classified by stages. The variance is from stage I to stage IV, with the latter being the most severe. In order to complete the staging, the pathologist grades the tumor from which the cancer originated. The tumor-grading system goes from T0 (no tumor) to T1 (low grade) to T2 (intermediate grade) and T3 (high grade), with a T1 breast cancer tumor as the smallest with the least amount of growth.
System
The most widely used system in grading breast cancer from T0 to T3 is Scarff-Bloom-Richardson (SBR). Through the years pathologists have modified it a bit. Though it is sometimes referred to as the Nottingham, Elston-Ellis or Black grade system, the basic principles of tumor grading are the same.
Size
The SBR grading system is used to indicate the size of the primary tumor that is causing the breast cancer. T0 indicates that there is no tumor. A tumor that has been graded as T1 is less than 2 centimeters in size across its widest point. (Two centimeters is less than one-third of an inch.)
Clinical
A T1 breast cancer tumor has tubule formation in the majority of the tumor. It will also contain a mitotic count of less than 10 mitoses per hpf (high-power field). The nuclear pleomorphism consists of cells that are small, regular and uniform.
Additional Grades
In addition to the T (tumor) grade system there is also the N (lymph nodes) and M (metastasis) grading for breast cancer. The N grading goes from N0 (has not spread at all) to N3 (cancer has spread through the lymph nodes). The M system is defined as M0 if the cancer has not spread or M1 if it has. It is possible to have T1 breast cancer with any combination of lymph node and metastasis involvement.
Considerations
While a T1 breast cancer is the earliest for the grade, the staging and other grades are also important to indicate how far the cancer has spread and available treatment options. The tumor grade is the most accurate in those patients with cancer that hasn't spread into the lymph nodes. In addition, the T1-3 grading system isn't accurate for ductual carcinoma in situ (DCIS) since it is more of a disease of the cells than a tumor.
Tags: breast cancer, cancer spread, less than, lymph nodes, tumor grade
