Are hormonal therapies for breast cancer the same as HRT?

No:

• Hormonal breast cancer therapies act to stop the production of hormones or block your body’s natural hormones from reaching cancer cells.
• Hormone replacement therapy (HRT) is given to healthy women to reduce menopausal symptoms by increasing the amount of oestrogen in the body. It is not a breast cancer treatment.

Does HRT increase the risk of breast cancer?
For some people, long-term exposure to oestrogen medications such as Hormone Replacement Therapy (HRT) or the Pill (oral contraceptive) will lead to a small increase in breast cancer risk.

For every 10,000 women taking HRT it has been estimated that an extra 8 will develop breast cancer. For one particular person it is very difficult to work out whether or not increased exposure to oestrogens will increase breast cancer risk.

In general, professionals think that the possible small increase in risk should not affect the decision of an otherwise healthy woman to use hormone treatments such as the contraceptive pill or HRT.

You should talk to your doctor to weigh up the small increased risk against the benefits of hormone medications.

What are endocrine therapies?
You may hear hormonal therapy referred to as “endocrine therapy”.

“Endocrine” is a word used to describe the natural hormones (such as oestrogen) that are made by glands in the body. These hormones affect the behaviour of other cells in the body.

Do I still have oestrogen in my body if I am post-menopausal?
Before the menopause the ovaries secrete most of the oestrogen in your body, but this stops when you reach the menopause and your ovaries become inactive.

However, your body is able to make oestrogen in another way, which becomes the main source of the hormone after the menopause. Your adrenal glands, which are above your kidneys, make other hormones called androgens and an enzyme called aromatase, which is found in your muscle, fatty tissue, liver and also breast tumours, changes these androgens into oestrogen.

This is the way in which your body ‘manufactures’ low levels of oestrogen after the menopause when your periods have stopped.

How do hormonal therapies differ from chemotherapy?
Chemotherapy involves giving drugs that disrupt the way in which the breast cancer cells divide. This means that the cancer cells stop growing and are killed.

However, since most chemotherapy drugs act on all dividing cells, they affect the normal, healthy cells of the body as well as the cancer cells. This is why people who are receiving chemotherapy often experience unpleasant side effects such as hair loss, nausea and vomiting, tiredness or reduced numbers of red or white blood cells.

Hormonal therapies act differently. They do not kill the cancer cells directly. Instead, they block the hormone receptor-positive cancer cells from receiving the supply of oestrogen, which they need in order to grow.

This means that hormonal therapies spare the normal cells of the body and can produce fewer side effects.

Side-effects of hormonal therapy
How will I know if my breast cancer is suitable for treatment with a hormonal therapy?

Your doctor can perform tests on the biopsy sample of your breast tumour to find out if your cancer is hormone receptor-positive.

If the tumour is hormone receptor-positive then your doctor is likely to prescribe a hormonal therapy. If your tumour is hormone receptor-negative then it is unlikely to respond to hormonal therapies, and in this case your doctor may recommend treatment with a course of chemotherapy.

What is adjuvant therapy?
Adjuvant means “in addition to”.

In breast cancer, this refers to treatment given after surgery.

After surgery, microscopic deposits of the disease, undetectable by current methods, may sometimes remain behind. These deposits may, after several years or even decades, develop into a clinically detectable tumour

Adjuvant therapy helps to prevent or delay these cells from multiplying, and it may decrease the chance that your breast cancer will come back (recur).

The three most common forms of adjuvant treatment are

• radiation (radiotherapy),
• chemotherapy and
• hormonal therapy.

Most patients will receive a course of radiotherapy immediately following surgery and then go on to receive additional drug treatment in the form of chemotherapy or hormonal therapy – or sometimes a combination of the two. Hormonal therapy is the most well tolerated of these.

What hormonal therapies are commonly available?
There are a number of different types of hormonal therapy. Your doctor will recommend the one most suitable for you, and this will depend upon a number of factors including your age and the stage of your breast cancer.