What Are the Stages of Breast Cancer?
The stages of breast cancer are determined based on the size and location of the tumor, whether it has spread to nearby tissues or lymph nodes, and whether it has metastasized to other parts of the body.
The American Joint Committee on Cancer (AJCC) staging system is commonly used to classify breast cancer stages. Here's an overview of the stages:
Stage 0: Carcinoma In Situ (CIS) or Non-Invasive Breast Cancer
- Stage 0 refers to non-invasive breast cancer, also known as carcinoma in situ (CIS). In this stage, abnormal cells are confined to the milk ducts (ductal carcinoma in situ, DCIS) or lobules (lobular carcinoma in situ, LCIS) and have not invaded the surrounding breast tissue.
Stage I: Localized Invasive Breast Cancer
- Stage I indicates that the cancer is small and has not spread beyond the breast. The tumor is typically less than 2 centimeters in diameter and has not affected the lymph nodes or other organs.
Stage II: Locally Advanced Breast Cancer
- Stage II breast cancer is more extensive than Stage I but remains confined to the breast and nearby tissues. The tumor may be larger, between 2 and 5 centimeters in diameter, and may have spread to a small number of lymph nodes in the armpit (axillary lymph nodes).
Stage III: Regionally Advanced Breast Cancer
- Stage III breast cancer indicates that the cancer has grown larger or has spread to more lymph nodes in the armpit or near the breastbone (internal mammary lymph nodes). The tumor may also invade the chest wall or the skin of the breast.
Stage IV: Metastatic Breast Cancer
- Stage IV, also known as advanced or metastatic breast cancer, means the cancer has spread beyond the breast and nearby lymph nodes to other parts of the body, including the bones, lungs, liver, brain, or distant lymph nodes.
It's important to note that breast cancer staging is complex and involves various factors, including the size and type of tumor, hormone receptor status, and the presence of certain molecular markers. Your healthcare team will determine the specific stage of your breast cancer based on these factors and recommend the appropriate treatment accordingly.