Bone health

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

Bone mineral density, or bone density, refers to the thickness and strength of bone. Because the hormone 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. 

This condition in which bones lose their strength and density is called osteoporosis. This can lead to bones 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.

The treatments that affect bone density

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.

Some people may 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.

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 refer you for a bone mineral density scan. Under some circumstances, you can get a Medicare rebate for a bone mineral density scan, 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.

Keeping your bones healthy

These are some of the ways you can 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 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 – for most people, adequate vitamin D levels are reached through regular incidental exposure to the sun.
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

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.

Alcohol

Alcohol consumption has been shown to lower bone density, and regularly drinking alcohol increases the risk of developing breast cancer.

The National Health and Medical Research Council (NHMRC) recommends that healthy Australian adults drink no more than four standard drinks on any one day and no more than 10 standards drinks per week.

The less you drink, the lower your risk of harm from alcohol. Even drinking small amounts of alcohol increases your cancer risk. Cancer Council Australia recommends people limit drinking alcohol, or if you choose to drink follow the NHMRC recommendation.

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.

Quitline 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 may be 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 Government Department of Health and Aged Care recommends a total of two-and-a-half hours of exercise every week. Read their guidelines for physical activity according to your age.

Medication

If your breast cancer treatment is known to reduce bone density, your doctor may prescribe medication that helps to strengthen bones and reduce your risk of bone fracture.

Common medications used to treat low bone density include:

Bisphosphonates help strengthen your bones and reduce your risk of fractures. They may also be given to protect your bones if you are taking an aromatase inhibitor. This can be given as a tablet, e.g. Fosamax (alendronate) or an injection into the vein, e.g. Zometa (zoledronic acid).
Prolia (denosumab) is an injection given below the skin (subcutaneously), usually every six months. It can be given by your GP or general practice nurse.

In postmenopausal women the bone-strengthening medications can also help reduce the risk of your breast cancer returning. Your breast cancer specialist may discuss this with you.

If you have osteopenia and are taking an aromatase inhibitor, the doctor may discuss treatment to help reduce your risk of fracture.

Things you can do now

Visit Healthybones Australia for information on maintaining and improving bone health.
Download the Healthybones Australia fact sheet on Breast Cancer and Bone Health.
Visit the Cancer Council website for information about alcohol and the risk of developing cancer and how much sun is needed for healthy bones.
Visit My Journey BCNA's online tool for information tailored to your diagnosis.

Back to Information and Resources Hub

Menu

Information

Support

News & Events

Get involved

Donate

About BCNA

Our Impact

Bone health

Jump to section

Jump to section

Topics in this article

1800 500 258

The treatments that affect bone density

Checking your bone density