Hormonal therapy is one of the main treatments for breast cancer in men. Most men with breast cancer have oestrogen-receptor (ER) positive cancers.
Hormones help control how cells grow and what they do in the body. The hormone oestrogen encourages some breast cancers to grow.
Hormonal therapy reduces the levels of oestrogen in the body or stop it attaching to the cancer cells.
The most commonly used hormonal therapy is tamoxifen, but other therapies are sometimes used. You may take hormonal therapy for at least 5 years to reduce the risk of breast cancer coming back. Some men may be advised to take it for longer.
Tamoxifen is an anti-oestrogen drug that stops oestrogen attaching to breast cancer cells and making them grow. You take it daily as a tablet, usually for 5 years. Some men may continue taking it for longer than 5 years if the side effects are not causing problems.
A rare side effect of tamoxifen is a blood clot. Your cancer doctor can give you more information about this.
Aromatase inhibitors (AIs) also reduce oestrogen levels. These drugs reduce oestrogen levels in men by stopping male hormones (androgens) being made into oestrogen. Your cancer doctor may prescribe an aromatase inhibitor such as:
You take them daily as a tablet.
You usually have an AI if:
- you cannot take tamoxifen
- the cancer has come back or spread and tamoxifen is no longer helping.
Some of the oestrogen in a man’s body is produced directly by the testicles, not by androgens. Because of this, your cancer doctor may give you another drug called goserelin (Zoladex®) along with your AI.
The testicles are stimulated to make the hormones oestrogen and testosterone by signals from the pituitary gland in the brain.
Goserelin blocks these messages and stops the testicles making oestrogen and testosterone. Goserelin is given as a slow release implant that is injected just under the skin once every 1 to 3 months.
Below is a sample of the sources used in our breast cancer in men information. If you would like more information about the sources we use, please contact us at firstname.lastname@example.org
European Society for Medical Oncology. Primary breast cancer: ESMO clinical practice guidelines for diagnosis, treatment and follow-up. Annals of oncology 26 (supplement 5): v8–v30. 2015.
Gradishar WJ, et al. Breast cancer in men. UpToDate online. June 2018.
Morrow M, et al. Chapter 79: malignant tumors of the breast. DeVita, Hellman and Rosenberg’s cancer: principals and practice of oncology (10th edition). Lippincott Williams and Wilkins. 2014.
National Institute for Health and Care Excellence (NICE). Early and locally advanced breast cancer: diagnosis and management. July 2018.
National Institute for Health and Care Excellence (NICE). Advanced breast cancer: diagnosis and treatment. Clinical Guideline 81. February 2009, updated August 2017.
Scottish Intercollegiate Guidelines Network. SIGN 134. Treatment of primary breast cancer: a national clinical guideline. September 2013.
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editors, Dr Rebecca Roylance, Consultant Medical Oncologist; and Dr Mark Verrill, Consultant Medical Oncologist.
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