What is hormonal therapy?

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.

Hormonal therapy is also used if breast cancer comes back in the same area or spreads to another part of the body (secondary breast cancer). Doctors usually prescribe a different hormonal therapy to tamoxifen.

Types of hormonal therapy

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

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.

Goserelin (Zoladex®)

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.

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