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Bone health

Did you know that some breast cancer treatments can reduce your bone mineral density? 

Bone mineral density, or bone density, is a term that refers to the thickness and strength of bone. As oestrogen helps to protect bones, treatments that reduce oestrogen, or stop it from working, can reduce bone density and increase your risk of bone fractures.  

Osteoporosis is a condition in which bones lose their strength and density. This can lead to bone becoming brittle, fragile and more likely to break. Your risk of osteoporosis also increases with age and other factors, such as your family or medical history.Not all breast cancer treatments reduce bone density. The treatments that are known to affect bone density include: 

  • Hormone-blocking therapies, including the aromatase inhibitors (anastrozole, letrozole and exemestane), that reduce the amount of oestrogen in your body,potentially resulting in reduced bone density. Tamoxifen blocks the effect of oestrogen on cancer cells. It may slightly increase the risk of osteoporosis for premenopausal women. In postmenopausal women, taking tamoxifen slows down bone loss and reduces the risk of osteoporosis 
  • Chemotherapy – some chemotherapy medicines and anti-nausea medicines (steroids) given with chemotherapy can have a direct effect on your bone health. Chemotherapy can also contribute to bone loss if it causes an early onset of menopause. 
  • Ovarian suppression – ovarian suppression is the term when the ovaries are temporarily (e.g. medication such as Zoladex) or permanently stopped from working to reduce the amount of oestrogen in the body. This means that there is less oestrogen in the body for the cancer to grow. Having less oestrogen in the body can reduce bone density. 

Checking your bone density

If you are currently taking, or about to begin taking, one of the above treatments, it is a good idea to speak with your doctor about your bone health. It’s important to discuss your bone health early on, as most people with lowered bone density do not experience any symptoms. In fact, most people don’t realise their bone density is low until they fracture a bone. 

To check your bone density, your doctor may refer you for a bone mineral density test, which is sometimes called a DXA or DEXA test. This test is painless. It measures bone density at the hip and spine using low-dosage X-rays. It is quite different from the bone scans that you may have as part of your breast cancer diagnosis or follow-up. 

Your breast cancer specialist, GP or nurse can give you information about what you can do to reduce your risk of developing osteoporosis and can tell you whether  a bone mineral density scan is recommended for you. Under some circumstances, you can get a Medicare rebate for a bone mineral density test, but there will often be an out-of-pocket cost. To find out if you are eligible for a Medicare rebate, and what your out-of-pocket costs may be, ask the imaging clinic before you make the appointment. 

Some people’s results from the DEXA scan may show they have decreased bone density, but not enough to be classed as osteoporosis. This is called osteopenia. If you have osteopenia, you may have a higher risk of fractures and may go on to develop osteoporosis. If you have osteopenia and are taking an aromatase inhibitor, the doctor may discuss with you treatment to help reduce your risk of fracture.  

Keeping your bones healthy

There are things you can do to help keep your bones healthy:

Diet and nutrition

A balanced diet supports good bone health. 

Calcium

  • Calcium is essential for building and maintaining healthy bones.  
  • A healthy diet that includes foods high in calcium (e.g. dairy products, oily fish such as sardines or salmon and dark green leafy vegetables). 

Vitamin D 

Vitamin D is important because it helps your body absorb calcium, which in turn promotes bone health. You can easily increase your Vitamin D levels by: 

  • spending time in the sun – expose your arms/legs for around 5–10 minutes a day in the warmer months and around 15–20 minutes in the cooler months 
  • including foods such as oily fish (sardines, herring and mackerel), liver, and egg yolks in your diet. Some margarine, milks and cereals also have small amounts of Vitamin D added. 
  • Taking vitamin D supplements. 

Magnesium

  • Helps your body regulate calcium and vitamin D and is found in green vegetables, nuts, seeds, legumes, whole grain and avocados. 

Supplements

Your GP may recommend a calcium and vitamin D supplement. 

If you are concerned about your calcium or vitamin D levels, have a chat with your doctor. 

Vitamin D

Vitamin D is important because it helps your body absorb calcium, which in turn promotes bone health. You can easily increase your Vitamin D levels by:

  • spending time in the sun – expose your arms/legs for around 5–10 minutes a day in the warmer months and around 15–20 minutes in the cooler months
  • including foods such as oily fish (sardines, herring and mackerel), liver, and egg yolks in your diet. Some margarine, milks and cereals also have small amounts of Vitamin D added.
  • taking Vitamin D supplements

If you are concerned about your Vitamin D levels, have a chat with your doctor.

Smoking

Smoking is known to lower bone density. Giving up smoking will improve your bone health, as well as your general health. If you would like to quit smoking, your GP can help you work out a plan that can improve your chances of quitting successfully. The Quitline (13 78 48) offers free phone advice, support and information resources to help you quit.

Exercise

Getting regular exercise is a very effective way of increasing bone density and reducing your risk of bone fracture. The types of exercises that are helpful include:

  • Weight-bearing exercises – in which your body has to bear its own weight, such as walking, jogging, netball, tennis and dancing.
  • Resistance training exercises – including free weights and weight machines found in gyms.

The Australian Department of Health and Ageing recommends a total of two-and-a-half hours of exercise every week. BCNA’s Exercise and breast cancer booklet has information on the benefits of exercise, as well as practical strategies to stay motivated. It also includes an exercise diary for you to keep track of your achievements.

Medication

If your breast cancer treatment is known to reduce bone density, your doctor may prescribe a type of drug that helps to strengthen bones and reduce your risk of bone fracture. Common drugs used to treat low bone density include:

  • Fosamax (alendronate): tablets that are usually taken once a day or once a week depending on the dose
  • Actonel EC (risedronate): tablets that are usually taken once a day or once a week depending on the dose
  • Prolia (denosumab): an injection given below the skin (subcutaneously), usually every six months. It can be given by your GP or general practice nurse.

More information

For more information on bone health during breast cancer, you might like to consider the following resources: