There are four main stages : Stage 0, Stage I, Stage II, and Stage III.
Stage 0: This is the earliest stage of breast cancer. The cancer is still confined to the milk ducts or lobules and has not spread outside of them.
Stage I: The cancer has begun to spread outside of the milk ducts.
Stage II: The cancer has spread to the lymph nodes under the arm.
Stage III: The cancer has spread to lymph nodes in the chest.