Which type of breast cancer has the poorest prognosis?

Metastatic breast cancer (also called stage IV, stage 4, secondary breast cancer, or advanced breast cancer) has the poorest prognosis. This is when cancer has spread beyond the breast and nearby lymph nodes to create tumors in other parts of the body, such as the bones, lungs, liver, or brain.

Metastatic breast cancer cannot be cured but it can be treated for as long as someone responds to treatment. The five-year survival rate for stage 4 breast cancer is 22% to 27%, with a median survival of three years, but new treatments and therapies mean there is a lot more hope for many years of good quality life than two decades ago.

What are the stages of breast cancer?

The stages of breast cancer are:

• Stage 0: Noninvasive: Cancer is limited to the inside of the milk duct or lobules and is non-invasive, for example, Ductal Carcinoma In Situ or Lobular Carcinoma In Situ
• Stage I: Breast cancer is small and only in the breast tissue, or in lymph nodes closest to the breast
• Stage II: Breast cancer is either in the breast or in the nearby lymph nodes or both
• Stage III: Cancer has spread from the breast to lymph nodes close to the breast or to the skin of the breast or to the chest wall
• Stage IV: Breast cancer that has spread to other parts of the body.

Non-invasive (stage 0) and early-stage invasive breast cancers (stages I and II) have a better prognosis than later-stage cancers (stages III and IV).