How can bisphosphonate drugs help prevent some women’s breast cancer spreading?

Bisphosphonates are drugs which protect your bones. They slow down the process that breaks down bone.

There are three groups of people for whom doctors often prescribe bisphosphonates as part of their standard practice:

For about 20 years, people with different types of cancer (not just breast cancer) whose cancer has already spread to the bone have been prescribed bisphosphonates. Its purpose for these secondary cancer patients is to reduce bone damage caused by their cancer and to prevent fractures. Pamidronate, ibandronic acid, sodium clodronate and zoledronic acid are all currently used to help prevent this damage.

Who else might benefit from bisphosphonates?

In July 2015 a study was published which looked at the risks and benefits of giving women with early (or primary) breast cancer bisphosphonates after their main treatment (usually surgery) as well as standard chemotherapy and hormone treatments. It analysed the results of a large number of previous studies which looked at the role of bisphosphonates in reducing the spread of breast cancer to the bones.

This new study found that, for some women, bisphosphonates can lower the risk of their breast cancer spreading to the bone.

They can be effective for women who:

  • have been diagnosed with early breast cancer of any type within the last six months, and
  • have already gone through the menopause or have had treatment to stop their ovaries from functioning

For women who met these criteria, bisphosphonates reduced the risk of:

  • breast cancer spreading to the bone within 10 years of diagnosis by 28% (from 8.8% to 6.6%)
  • dying from breast cancer within 10 years of diagnosis by 18% (from 18% to 14.7%)

Do bisphosphonates help lower the risk of spread for women who have finished treatment?

We don’t know yet whether women who have already finished surgery, radiotherapy and chemotherapy treatment would benefit from starting bisphosphonates too. All the women taking bisphosphonates whose results were studied started the treatment within six months of their breast cancer diagnosis, so there is no clear evidence of benefit from these drugs for other women.

Are bisphosphonates routinely available?

Bisphosphonates to prevent the spread of breast cancer are available for postmenopausal women at high risk of their breast cancer recurring in Scotland and Wales.

In England, NHS England’s Breast Cancer Clinical Expert Group has recommended the use of bisphosphonates to prevent the spread of breast cancer in postmenopausal women. NICE has also recommended they be considered for postmenopausal women at high risk of recurrence. But we know that bisphosphonates are not yet routinely available in every area.

Breast Cancer Now thinks that all newly-diagnosed post-menopausal women who might benefit from bisphosphonates should be offered them to lower the risk of their disease spreading.

Who can you talk to about bisphosphonates?

Your oncologist may not mention bisphosphonates, but you can still ask them about the potential benefits and risks of bisphosphonates for you.

If you are already taking bisphosphonates because you have osteoporosis or another bone disease, you can still talk to your oncologist about whether your prescription needs to change.

How do you take bisphosphonates?

The three bisphosphonates that can lower the risk of breast cancer spreading are zoledronic acid, ibandronate and clodronate.

You can take bisphosphonates two ways:

  • through a drip into your vein one day every six months (zoledronic acid)
  • one tablet a day (ibandronate or clodronate)

In some areas not all of these options may be available. Your oncologist can advise on which drug may be suitable for you.

Women taking bisphosphonates to lower the risk of breast cancer spread to their bones usually take them for three years.

Do bisphosphonates have side effects?

Bisphosphonates generally have few side effects and, because they are not new drugs, health professionals know how to manage any side effects if they do appear. Serious side effects are rare.

Possible side effects include:

Ibandronate tablets:

  • Inflammation and ulceration of the oesophagus (food pipe)
  • Nausea
  • Stomach pains
  • Inflammation of your tongue
  • Joint pain

Zoledronic acid drip:

  • Flu like symptoms such as fever, aching muscles or headache
  • Irregular heartbeats (very rare – fewer than 1 in 10,000 people affected)
  • Inflammation in the eye (very rare)

Rare side effects that may be linked to both these drugs include:

  • Osteonecrosis of the jaw (ONJ) - a condition where some cells in your jawbone die. To lower your risk of ONJ if you are taking bisphosphonates, you should have regular dental check-ups and talk to your oncologist if you need dental treatment. However, ONJ is more likely in people taking high doses of bisphosphonates and high doses aren’t prescribed as part of this treatment.
  • Osteocronosis of the auditory canal in your ear (very rare – fewer than 1 in 10,000 people affected)

Different bisphosphonates each carry the risk of different side effects. If your oncologist recommends bisphosphonates for you, you can discuss how they may affect you. They will also advise which possible side effects need urgent advice from your oncologist or GP.

Information last reviewed: July 2018

Next review due: October 2019