What Is Hormonal Therapy?

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Hormonal therapy, also called endocrine therapy or anti-hormone treatment, is used to treat hormone-receptor-positive breast cancers — those that rely on the female hormones oestrogen and/or progesterone for growth. These cancers are known as ER-positive and/or PR-positive, and they make up about 70 % of all breast cancers.

 

Hormonal therapy can be given after surgery, chemotherapy, or radiotherapy to reduce the risk of recurrence, or before surgery to shrink the tumour. By blocking or reducing oestrogen, hormonal therapy effectively “starves” cancer cells of the hormones that help them grow.

 

It may also be used for ductal carcinoma in situ (DCIS) or in women at high genetic or family risk to lower the chance of developing breast cancer.

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How Does Hormonal Therapy Work?

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Breast-cancer cells that are hormone-receptor-positive have receptors — like locks — on their surface. Oestrogen acts as the key that fits the lock and switches the cell “on,” stimulating growth. Hormonal therapy works by blocking the receptor or reducing hormone production, preventing the cancer cell from receiving that growth signal.

 

Hormone-receptor testing is part of standard pathology after biopsy or surgery, and treatment is recommended only if the cancer is receptor-positive.

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Types of Hormonal Therapy

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1. Tamoxifen

 

Tamoxifen blocks oestrogen receptors on breast-cancer cells, stopping oestrogen from triggering cell growth.

 

• Usually taken as a tablet once daily for five to ten years.

• Can be used before or after menopause.

• May be given for a few years before switching to an aromatase inhibitor.

• Proven to reduce the risk of breast-cancer recurrence and new breast cancers.

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Additional benefits: helps maintain bone density, may reduce cholesterol, and can lower heart-disease risk.

 

Common side effects: hot flushes, sweats, vaginal dryness or discharge, fluid retention, mild weight gain.

Uncommon side effects: tiredness, mood change, rash, dizziness.

Rare side effects: blood clots (risk similar to the oral contraceptive pill), uterine-lining cancer (< 1 % after 10 years), vision change.

 

Fertility: do not become pregnant or breast-feed while on tamoxifen and for up to two months after stopping. Use non-hormonal contraception such as condoms or a copper IUD.

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2. Aromatase Inhibitors

 

Aromatase inhibitors (AIs) are used after menopause, when most oestrogen is made outside the ovaries by an enzyme called aromatase. AIs block this enzyme, dramatically reducing oestrogen levels.

 

• Taken as a daily tablet for about five years, sometimes after two to three years of tamoxifen.

• Slightly more effective than tamoxifen in preventing recurrence.

• Commonly prescribed drugs:

   

  • Anastrozole (Arimidex®)

  • Letrozole (Femara®)

  • Exemestane (Aromasin®)

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Common side effects: joint or muscle aches, hot flushes, vaginal dryness.

Uncommon side effects: fatigue, insomnia, low libido, bone thinning.

 

Because AIs can reduce bone density, your doctor may recommend:

 

• Bone-density testing before and during therapy.

• Weight-bearing exercise, adequate calcium and vitamin D.

• Bone-strengthening medication if osteopenia or osteoporosis is present.

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3. Turning Off or Removing the Ovaries

 

For premenopausal women, oestrogen is mainly produced by the ovaries. Temporarily turning off or surgically removing the ovaries reduces oestrogen levels and helps stop cancer growth.

 

a. Medical ovarian suppression

 

• Monthly injections (e.g. Goserelin /Zoladex®) temporarily stop ovarian hormone production.

• Causes temporary menopause — symptoms include hot flushes, mood swings, and sleep changes.

• If injections stop, ovarian function usually returns.

 

 

b. Surgical removal (Oophorectomy)

 

• A permanent option, performed laparoscopically or through a small lower-abdominal incision.

• Induces immediate menopause and may also lower the risk of ovarian cancer.

• Can be combined with tamoxifen or an aromatase inhibitor.

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Managing Menopausal Symptoms

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All hormonal therapies reduce oestrogen and can trigger menopausal symptoms such as hot flushes, mood changes, vaginal dryness, and altered libido.

Symptoms vary in intensity and often settle over time as the body adjusts.

 

Tips for relief:

 

• Light, layered clothing and good hydration for hot flushes.

• Regular exercise and stress-reduction techniques.

• Vaginal moisturisers or lubricants for dryness.

• Avoid hormone-replacement therapy unless specifically advised by your specialist.

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If side effects become difficult, do not stop medication on your own — speak with your oncologist. Often a dose adjustment or alternative drug can help.

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Duration and Follow-Up

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Hormonal therapy is typically prescribed for five to ten years, depending on the cancer’s features and response to treatment.

Regular follow-up appointments monitor side effects, bone health, and recurrence risk.

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Key Points

 

• Works only for hormone-receptor-positive breast cancers.

• Given after or before surgery, chemotherapy, or radiotherapy.

• Tamoxifen suits pre- or post-menopausal women; Aromatase inhibitors are for post-menopause.

• Ovarian suppression or removal reduces oestrogen in younger women.

• Side effects are manageable, and most women tolerate therapy well.

 

 

 

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