About two–thirds of breast cancers are oestrogen and/or progesterone hormone receptor positive, also known as hormone sensitive. This means these hormones can direct breast cancer cells to grow, multiply and repair treatment damage. Hormonal therapy is a treatment that interferes with this process by reducing oestrogen in the body, lowering the chances the breast cancer will come back.

For post-menopausal women a drug called an aromatase inhibitor is usually prescribed – Letrozole (Femara), Anastrozole (Arimidex) or Exemestane (Aromasin).  A good overview of hormonal therapy can be found at lbbc.org (Living beyond breast cancer)

So far so good-but for reasons not fully understood, many women will have side effects from these drugs, while others will have minimal or no side effects.

What are the side effects and what might help?

Common side effects-

Joint (arthralgia) & Muscle (Myalgia) Pain and Joint Stiffness  – these can affect all joints – most common are hands, wrists, feet, knees, hips lower back and shoulders – often worse in the morning.

  • Gentle exercise such as walking, biking, swimming or any water based exercise, do as able, doesn’t need to all be done in one session. Do from mid-morning on when joints have “warmed up”.
  • Yoga, Tai Chi and stretching exercises can alleviate joint stiffness.
  • If your feet are affected have slippers by your bed to slip into when you first get up.
  • Talk to your doctor about paracetamol, anti-inflammatory medications (if able to take), or other pain medications may help with the pain. Your doctor can also check these symptoms are related to your hormone therapy medication and not other conditions, such as osteo- or rheumatoid arthritis.
  • Get your Vitamin D levels checked by your doctor – having optimal levels of Vit D has been shown to lessen joint pain & stiffness – exercise outside where possible (be SunSmart when outdoors)
  • The good news is that AI induced joint and muscle pain do not cause permanent joint or muscle damage
  • Loss of bone mineral density – can cause osteopenia/osteoporosis or bone fractures.
  • Prior to starting treatment a bone density scan (DEXA) will show baseline bone strength so your doctor can monitor your bones during treatment – if you have existing osteopenia/osteoporosis, or there is a decline in bone strength during treatment you may be offered a bisphosphonate bone strengthening medication. You may also be offered calcium and Vitamin D supplements
  • Eat a healthy calcium rich diet. Spend time in the sun (Be SunSmart) Exercise as above.
  • If you smoke try to give up – talk to your practice nurse or community public health clinic.


  • Insomnia & Fatigue

As a result of night sweats/hot flashes, joint and muscle pain, sleep is often disturbed resulting in fatigue.

  • Talk to your doctor-see last point above.
  • Regular exercise helps- however don’t exercise too close to usual bedtime. Instead relax – read a book, meditate – whatever helps you relax. Avoid daytime naps if possible.
  • Avoid computer/tablets/ipad use in hour prior to going to bed. Try to stick to regular bedtime when possible.
  • Avoid caffeine late afternoon & evening. Drinking alcohol later in evening can disturb sleep rhythms. Also check  posted  blog on  August 18th
  • Loss of libido (sexual desire)

Due to reduced hormone levels many women feel a change in sexual desire – it is important to give yourself the courage to talk about this with both your partner and health team

  • Talking to other women on the same treatment-best tips and understanding of anyone!
  • Other medications such as some anti -depressants may also affect libido – check with your doctor if there are other anti-depressants which might help with mood but not reduce sexual desire.
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  • Vaginal dryness or itching

Reduction of oestrogen can also cause vaginal dryness which can make intercourse uncomfortable, cause   irritation/itching, discharge, thrush and urinary infections.

  • Use a vaginal moisturiser such as Replens, regularly to avoid urinary tract infections -available at your chemist
  • Use a lubricant such as Astroglide or Sylk during sexual activity – don’t use warming lubricants as these can be drying.
  • Your doctor may also discuss the risks and benefits with you, re using a regular low dose, localised oestrogen only, vaginal cream, a couple of times a week.
  • Hot flushes & night sweats See Julie’s blog October 4th
  • Exercise (as above) helps with hot flushes.
  • Yoga, relaxation, meditation and breathing techniques may help. Acupuncture and hypnosis are also options to try.
  • Identify triggers-e.g. alcohol, spicy food, hot baths/showers, hot drinks, overheating.
  • Wear loose cool clothing-cotton, silk or drytec clothing materials.
  • Have cotton sheets and layered bedding that’s easy to remove-put a cold pack under your pillow and turn pillow as needed. Keep your bedroom cool.
  • If you are having problems functioning during the day, and interrupted sleep your doctor may prescribe a low dose anti- depressant medication to can help with this-always tell your doctor if taking herbal remedies as these can interact with prescribed medication.


Many of the side effects above are temporary, very few woman get them all and many resolve post treatment – some mimic ageing effects and may return more slowly as you age.

If symptoms limit your day to day  life your doctor will often give you a short AI-free holiday before trying you on another type of AI which will work in a similar way but may not give you the same side effects. If none suit you may go on the drug used by premenopausal women called Tamoxifen. Before stopping your medication always discuss with your doctor so you can look at your individual risks and benefits and make an informed decision.

A good overview of hormonal therapy can befound at lbbc.org(living beyond breast cancer) and the Cancer Society has many resources – email us at  info@cancersoc.org.nz or phone the nurses on 0800 CANCER (226 237).

Margot Wilson

Supportive Care Nurse

Cancer Society Marlborough

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