The diagnosis of breast cancer is based on four characteristics – the size of cancer, whether cancer is in the lymph nodes, whether the cancer is invasive or non-invasive, and whether the cancer metastasis to other parts of the body beyond the breasts. The tests and procedure to diagnose breast cancer include a breast exam, breast ultrasound, mammogram, breast magnetic resonance imaging (MRI), and removing a sample of breast cells for testing also known as a biopsy. The stages of breast cancer will help you and your doctor to understand the possible outcomes of your condition. It will help your doctor to understand which treatments are needed.

• Stage 1
  The stage 1 of breast cancer is divided into two subcategories – stage 1A and stage 2A. The difference between these two subcategories are the lymph nodes that have the evidence of cancer and size of the tumor. In the stage 1A of breast cancer, the tumor is smaller than the approximate size of a peanut. It is around two centimeters or smaller. Cancer has not spread to the lymph nodes. The stage 1B of breast cancer is when even the lymph nodes have evidence of cancer with small clusters of cells. The approximate width of the cluster is around 2mm. Also, there is no tumor found in the breasts and if there is, then it is as small as 2cms.
• Stage 2
  Even the stage 2 of breast cancer has two subcategories. They are stage 2A and 2B. In stage 2A no tumor can be found in your breast. In stage 2A, there are three possibilities. The cancerous cells have no actual tumor and less than four axillary lymph nodes have cancer cells present in them being the first possibility. The second one is that the tumor is less than 2cms. The third possibility is that the tumor has not spread to the lymph nodes yet and the tumor that is not present in the lymph nodes is between 2 to 5cms. The stage 2B is where the tumor is larger than 5cms. However, it has not spread to any axillary lymph nodes.
• Stage 3
  There are three subcategories of stage 3. They are stage 3A. stage 3B, and stage 3C. The difference between these categories is the size of the tumor and whether cancer has spread to the lymph nodes or not. There are three possibilities in stage 3A. They being that the tumor is less than 2cms and cancer has spread to 4-9 lymph nodes, or the tumor is larger than 5cms and near the breastbone or underarm, cancer has spread to the lymph nodes, or there are cancer clusters found in the lymph nodes. The stage 3B consists of a tumor which can be of any size, cancer has spread to the lymph nodes, and it has also spread to the breast wall or chest skin. In stage 3C, there can be a tumor of any size and cancer has spread to more than ten lymph nodes or cancer has spread to lymph nodes near collar bone or cancer has spread to the lymph nodes near the breastbone and underarm.
• Stage 4
  The stage 4 of breast cancer has spread to other parts of the body like brain, bones, lungs, and liver. The stage 4 of breast cancer is considered as incurable but with certain treatments, it can extend several years of your life.