Why it's done

Hormone therapy for breast cancer is only used to treat cancers that are hormone sensitive.

Some breast cancers are fueled by the natural hormones estrogen and progesterone. Doctors refer to these cancers as estrogen receptor positive (ER positive) or progesterone receptor positive (PR positive).

Your doctor determines if your cancer is ER positive or PR positive by analyzing a sample of your cancer cells.

Hormone therapy for breast cancer can help to:

  • Prevent cancer from coming back
  • Decrease the risk of cancer developing in other breast tissue
  • Slow or stop the growth of cancer that has spread
  • Reduce the size of a tumor prior to surgery