Hormonal Therapy

What is Hormonal Therapy?

Hormonal therapy is another form of systemic treatment for cancer. It is considered for use when a breast cancer is found to be positive for estrogen or progesterone receptors.[1] Hormonal therapy entails the use of drugs that specifically bind these estrogen or progesterone receptors in place of the body’s own estrogen or progesterone, and inhibits the function that these hormones have in cell division, or cancer growth. It is not typically used alone for the treatment of breast cancer but in combination with chemo, radiation, and/or surgery. An exception to this is late-stage metastatic cancer that is unresectable, in an effort to slow growth and further metastasis when nothing else can be done.

What are the Types of Hormonal Therapy Medication?

There are three types of drugs used in hormonal therapy for breast cancer. These are:

  • Aromatase inhibitors
  • Estrogen-Receptor Downregulators (ERDs)
  • Selective Estrogen-Receptor Modulators (SERMs)

How does it Work?

The purpose of hormonal therapy drugs is to block or alter the way estrogen and progesterone from binding their receptors on breast cancer cells. Estrogen and progesterone are a type of hormone called a steroid hormone. When they bind to their receptor on the cell surface, a series of reactions occurs that ultimately affects the growth and division of that cell. They may also decrease the overall amount of receptors present on the cell surface.[2]

Hormonal therapy is not useful when breast cancer is hormone-receptor negative. Since hormone therapy does have side effects and risks, it should not be used in these types of cancer.

What are the Side Effects and Risks?

Below are the side effects and risks associated with hormonal therapy. Most patients do not experience all of these and many of these side effects have an extremely low risk of occurrence. However, some are more severe than others and it is important that you understand all of the potential side effects prior to considering hormonal therapy.

Potential Side Effects

Aromatase Inhibitors



Back pain Yes Yes
Blood clots Rare but possible Yes
Bone/joint pain Yes
Bone thinning Yes
Bone tumor pain increased Yes
Cholesterol – higher levels Yes
Constipation Yes Yes
Depression Yes
Diarrhea Yes
Dizziness Yes Yes
Drowsiness Yes
Dry skin Yes
Endometrial cancer Yes
Fatigue Yes Yes
Flu-like  symptoms
Hair thinning/loss Yes Yes
Headache Yes Yes Yes
Hot flashes Yes Yes Yes
Infertility Yes
Injection site pain Yes
Insomnia Yes Yes
Leg cramps Yes
Loss of libido Yes
Mood swings Yes
Nausea Yes Yes Yes
Osteoporosis Yes
Rash Yes
Sore throat Yes
Stomach pain Yes
Stroke Yes
Sweating, increased Yes
Swelling, increased
Uterine cancer Yes
Vision problems Yes
Water retention Yes
Weakness Yes
Weight gain Yes

What are the Benefits?

Hormonal therapy reduces the risk of breast cancer recurrence and slows growth of breast cancer that has already metastasized, both of which can increase survival. It is also a very well-tolerated form of treatment that can be used in combination with other forms of treatment or alone, when patients cannot endure chemotherapy, radiation or surgery.


Hormonal therapy is not indicated for all breast cancer patients, only those who are found to have hormone receptor-positive breast cancer. It is a wonderful treatment option for all stages of breast cancer.


1 Hirshaut, Y; and Pressman, PI (2008). Breast Cancer. The Complete Guide. 5th edition. New York: Bantam Books.

2 Sarg, M. S. and Gross, A. D. (2007). The Cancer Dictionary Third Edition. New York: Checkmark Books.

This article was originally published on July 27,2012 and last revision and update of it was 9/2/2015.