Breast cancer is a complex disease. All breast cancer cases are not the same. Once breast cancer has been found, more tests will be done to find out the specific pattern of breast cancer. This important step is called staging. Knowing the exact breast cancer stage will help your doctor plan your treatment. Your doctor will want to know:
The size of the tumor and exactly where it is in your breast
If the cancer has spread within your breast
If cancer is present in your lymph nodes under your arm