Hormonal treatment

Hormonal treatment for breast cancer is the use of drugs that either reduce the production or block the effect of natural hormones that can affect cancer cell growth. There are many different types of hormonal breast cancer treatment. In this section, learn how hormonal treatment works, and explore the following topics:

• The role of menopause in hormonal treatment
• Types of hormonal treatment
• Possible side effects of hormonal treatment
• Staying on your hormonal treatment plan

How hormonal treatment works

Hormones such as estrogen and progesterone are naturally produced by your body. Certain breast cancer tumors need hormones to grow. These tumors are said to have receptors for the hormones estrogen and/or progesterone.

Breast cancer tumors that have these receptors are specifically called estrogen receptor positive and/or progesterone receptor positive, or generally called hormone receptor positive. About two-thirds of women with breast cancer have tumors that contain estrogen receptors.

Lab tests of your cancer biopsy tell your medical team whether your breast cancer is hormone receptor positive.

• Hormonal treatment (estrogen-reducing/blocking) works best when the tumor cells are hormone receptor positive
• For those cancers that are not hormone receptor positive, hormonal treatment usually has little effect and is generally not used
• Hormonal treatment for breast cancer is not the same as hormone replacement therapy (also called HRT), which supplies estrogen to women to help ease the symptoms of menopause. HRT should not be used if you have been diagnosed with breast cancer

Hormonal treatment is commonly used as adjuvant therapy, which means it is used immediately after surgery and/or radiation therapy.

• Hormonal treatment does not take the place of surgery and/or radiation for early breast cancer
• Rather, it is used before or after these initial treatments

Some hormonal treatments can also be used as neoadjuvant therapy, which means they are used before surgery and/or radiation.

• Neoadjuvant therapy may reduce the size of the tumor so it is easier to remove during surgery or easier to treat with radiation
• In some cases, neoadjuvant therapy may reduce the tumor size so it's small enough to allow for breast-conserving surgery rather than a mastectomy