How is breast cancer staged?

How is breast cancer staged?

The stage describes the extent of the cancer in the body. It is based on whether the cancer
is invasive or non-invasive, the size of the tumor, how many lymph nodes are involved,
and if it has spread to other parts of the body. The stage of a cancer is one of the most
important factors in determining prognosis and treatment options.
Staging is the process of finding out how widespread a cancer is when it is diagnosed.
Depending on the results of your physical exam and biopsy, your doctor may want you to
have certain imaging tests such as a chest x-ray, mammograms of both breasts, bone
scans, computed tomography (CT) scans, magnetic resonance imaging (MRI), and/or
positron emission tomography (PET) scans. Blood tests may also be done to evaluate
your overall health and sometimes can indicate if the cancer has spread to certain organs.


The American Joint Committee on Cancer (AJCC) TNM
system
A staging system is a standardized way for the cancer care team to summarize
information about how far a cancer has spread. The most common system used to
describe the stages of breast cancer is the American Joint Committee on Cancer (AJCC)
TNM system.
The stage of a breast cancer can be based either on the results of physical exam, biopsy,
and imaging tests (called the clinical stage), or on the results of these tests plus the results
of surgery (called the pathologic stage). The staging described here is the pathologic
stage, which includes the findings after surgery, when the pathologist has looked at the
breast mass and nearby lymph nodes. Pathologic staging is likely to be more accurate
than clinical staging, as it allows the doctor to get a firsthand impression of the extent of
the cancer.
The TNM staging system classifies cancers based on their T, N, and M stages:
· The letter T followed by a number from 0 to 4 describes the tumor's size and spread
to the skin or to the chest wall under the breast. Higher T numbers mean a larger
tumor and/or wider spread to tissues near the breast.
· The letter N followed by a number from 0 to 3 indicates whether the cancer has
spread to lymph nodes near the breast and, if so, how many lymph nodes are affected.
· The letter M followed by a 0 or 1 indicates whether the cancer has spread to distant
organs -- for example, the lungs or bones.