Hormone-blocking treatment for men with HR+ metastatic breast cancer

About 90% of male breast cancers are oestrogen receptor positive (ER+). This is a type of hormone receptor positive (HR+) breast cancer.

Most people with HR+ metastatic breast cancer start treatment with hormone-blocking therapy.

Chemotherapy may also be part of your treatment at different times.

The aims of hormone-blocking therapies are to:

• lower the amount of oestrogen in the body
• block the action of oestrogen on breast cancer cells.

To understand the treatment types and how they work, go to About hormone-blocking therapy.

Which hormone-blocking treatment is right for you?

The treatment depends on what hormone-blocking therapies you had before for breast cancer, if any.

Your medical oncologist can explain why they recommend particular treatments for you.

First line treatment

The first hormone-blocking therapy you take is called ‘first line’ treatment.

First line therapy usually involves tamoxifen or an aromatase inhibitor. You take this in combination with an injection (such as goserelin). This stops the testicles from making oestrogen and testosterone.

Doctors can add targeted treatments, such as CDK4/6 inhibitors, to hormone-blocking therapies. This can control the cancer for longer. Read about Targeted therapies for hormone receptor-positive metastatic breast cancer.

You continue to take your first line treatment until:

• it is no longer working, or
• side effects mean you can’t continue.

Usually, you then move to ‘second line’ therapy.

Second line treatment

Your medical oncologist may discuss changing to a different hormone-blocking therapy as a second line treatment.

They may also offer chemotherapy as a second, or later, line of therapy.

Your oncologist will try to continue hormone-blocking therapies for as long as possible. Third and even fourth line treatments may be possible once treatments stop being effective.

Over time – often several years – you will probably be treated with many different therapies.

Managing side effects

Different hormone-blocking therapies can cause different side effects. Find out about Side effects for men of hormone-blocking therapies and how to reduce them.